Diclofenac Potassium

— THERAPEUTIC CATEGORIES —
  • Arthritis/rheumatic disorders
  • Dysmenorrhea
  • Nonnarcotic analgesics

Diclofenac Potassium Generic Name & Formulations

General Description

Diclofenac potassium 50mg; tabs.

Pharmacological Class

NSAID (benzeneacetic acid deriv.).

How Supplied

Contact supplier.

Storage

Store at room temperature 20°C to 25°C (68°F to 77°F). Protect from moisture.

Diclofenac Potassium Indications

Indications

Osteoarthritis. Rheumatoid arthritis.

Diclofenac Potassium Dosage and Administration

Adult

Use lowest effective dose for shortest duration. Osteoarthritis: 50mg 2–3 times daily. Rheumatoid arthritis: 50mg 3–4 times daily.

Children

Not established.

Diclofenac Potassium Contraindications

Contraindications

Aspirin allergy. Coronary artery bypass graft surgery.

Diclofenac Potassium Boxed Warnings

Boxed Warning

Risk of serious cardiovascular and gastrointestinal events.

Diclofenac Potassium Warnings/Precautions

Warnings/Precautions

Not interchangeable with other forms of diclofenac. Increased risk of serious cardiovascular events (including MI, stroke). Avoid in recent MI, severe heart failure; if necessary, monitor. Increased risk of serious GI adverse events (including inflammation, bleeding, ulceration, perforation). History of ulcer disease and/or GI bleeding. Hypertension; monitor BP closely. Hepatic or renal impairment. Discontinue if signs/symptoms of liver disease develop, or if abnormal LFTs persist or worsen. Dehydration. Hypovolemia. Advanced renal disease: not recommended. Hyperkalemia. Coagulation disorders. Monitor CBCs, blood chemistry, hepatic, and renal function in long-term therapy. Pre-existing asthma. May mask signs of infection or fever. Discontinue at 1st sign of rash or any other hypersensitivity. Elderly. Debilitated. Labor & delivery. Pregnancy (≥30 weeks gestation; avoid). Nursing mothers.

Warnings/Precautions

Cardiovascular Thrombotic Events

Clinical trials of several COX-2 selective and nonselective NSAIDs of up to 3 years duration have shown an increased risk of serious cardiovascular thrombotic events, including myocardial infarction (MI) and stroke.

  • Incidence of serious cardiovascular thrombotic events greater in patients with known cardiovascular disease or risk factors.
  • Increased risk has been observed as early as the first weeks of treatment (based on observational studies).
  • Higher doses have been linked to increased cardiovascular thrombotic risk.
  • To minimize risk, use the lowest effective dose for the shortest time possible.
  • Evidence regarding use of aspirin to mitigate risk has not been consistent; aspirin coadministered with diclofenac may increase the risk of serious GI adverse events.

NSAIDs are contraindicated in the setting of coronary artery bypass graft (CABG) surgery. Based on findings from 2 large studies evaluating a COX-2 selective NSAID, use in the first 10–14 days after CABG resulted in an increased incidence of MI and stroke.

Post-MI Patients

Among patients treated with NSAIDs in the post-MI period, there was an increase in the risk of reinfarction, cardiovascular-related death, and all-cause mortality beginning in the first week of treatment, according to observational studies.

  • Incidence of death in the first year in the NSAID cohort: 20 per 100 person years
  • Incidence of death in the first year in the non-NSAID cohort: 12 per 100 person years
  • The relative risk of death in NSAID users persisted over at least the next 4 years of follow up.

Avoid the use of diclofenac potassium in patients with recent MI unless the benefits are expected to outweigh the risk of recurrent cardiovascular thrombotic events. Monitor for signs of cardiac ischemia if used in patients with recent MI.

Hypertension

  • NSAIDs can lead to new onset hypertension or worsening of pre-existing hypertension.
  • Impaired responses to thiazides and loop diuretics possible when taken with NSAIDs.
  • Use with caution in patients with hypertension; monitor BP.

Heart Failure and Edema

  • Meta-analysis of randomized controlled trials showed ~2-fold increase in hospitalizations for heart failure in patients treated with COX-2 selective and nonselective NSAIDs compared with placebo.
  • NSAID use was also associated with increased risk of MI, hospitalization for heart failure and death in a Danish National Registry study of patients with heart failure.
  • Fluid retention and edema have been observed in some patients treated with NSAIDs.
  • Diclofenac may blunt the cardiovascular effects of diuretics, ACE inhibitors, ARBs.
  • Avoid use in patients with severe heart failure unless benefits outweigh risk of worsening heart failure.
  • Monitor for signs of worsening heart failure if diclofenac potassium is used in patients with severe heart failure.

Gastrointestinal (GI) Effects

  • NSAIDs can cause serious GI adverse events including inflammation, bleeding, ulceration, and perforation of the esophagus, stomach, small intestine, or large intestine.
  • These can occur at any time, with or without warning symptoms (only 1 in 5 patients who develop a serious upper GI adverse event on NSAIDs is symptomatic).
  • Incidence of upper GI ulcers, gross bleeding, or perforation with NSAIDs: ~1% of patients treated for 3-6 months and 2-4% of patients treated for 1 year.
  • Prior history of ulcer disease or GI bleeding: prescribe with caution; these patients have a >10-fold increased risk for developing GI bleed vs those without these risk factors.
  • Other factors that increase risk of GI bleed in patients treated with NSAIDs: concomitant oral corticosteroids, anticoagulants; longer duration of NSAID use; smoking; alcohol; older age; and poor general health status.
  • Use the lowest effective dose for the shortest possible duration to minimize the potential for GI adverse events.
  • If a serious GI adverse event occurs, discontinue NSAID therapy.
    Alternative therapies should be explored for patients considered at high risk for GI effects.

Hepatic Effects

  • In clinical trials of diclofenac-containing products, meaningful elevations (eg, >3xULN of aspartate aminotransferase (AST) were observed in about 2% of approximately 5,700 patients at some time during diclofenac treatment.
  • Measure transaminases at baseline and periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms.
  • Transaminases should be monitored within 4 to 8 weeks after initiating treatment with diclofenac.
  • For patients with symptoms/signs suggesting liver dysfunction, or in whom abnormal liver test has occurred: evaluate for more severe hepatic reaction.
  • Discontinue diclofenac potassium if abnormal liver tests persist or worsen, if clinical signs/symptoms of liver disease develop, or if systemic manifestations (eg, eosinophilia, rash) occur. 

Renal Effects

  • Long-term NSAID use has been associated with renal papillary necrosis and other renal injury.
  • Renal toxicity has also been seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion; in these patients administration of NSAIDs may cause a dose-dependent reduction in prostaglandin formation and, secondarily in renal blood flow, which may result in overt renal decompensation.
  • Patients with impaired renal function, heart failure, liver dysfunction, on diuretics or ACE inhibitors, those who are volume-depleted and the elderly are at greatest risk of this reaction.
  • Discontinuing NSAID therapy usually leads to recovery.
  • Correct volume status in dehydrated or hypovolemic patients prior to initiating diclofenac potassium. 
  • Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia during use of diclofenac potassium. 
  • Avoid the use of diclofenac potassium in patients with advanced renal disease unless the benefits are expected to outweigh the risk of worsening renal function. 

Hyperkalemia

  • Increases in serum potassium concentration, including hyperkalemia, have been reported with use of NSAIDs, even in some patients without renal impairment. In patients with normal renal function, these effects have been attributed to a hyporeninemic-hypoaldosteronism state. 

Anaphylactic Reactions

  • Diclofenac has been associated with anaphylactic reactions in patients with and without known hypersensitivity to diclofenac and in patients with aspirin-sensitive asthma.
  • A subpopulation of patients with asthma may have aspirin-sensitive asthma which may include chronic rhinosinusitis complicated by nasal polyps; severe, potentially fatal bronchospasm; and/or intolerance to aspirin and other NSAIDs. 
  • Because cross-reactivity between aspirin and other NSAIDs has been reported in such aspirin-sensitive patients, diclofenac potassium is contraindicated in patients with this form of aspirin sensitivity. 
  • When diclofenac potassium is used in patients with preexisting asthma (without known aspirin sensitivity), monitor patients for changes in the signs and symptoms of asthma.

Serious Skin Reactions

  • NSAIDs can cause serious skin adverse events including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis.
  • Discontinue treatment at the first appearance of skin rash or any other sign of hypersensitivity.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) has been reported in patients taking NSAIDs, such as diclofenac potassium. 
  • Some of these events have been fatal or life-threatening. 
  • DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling. Other clinical manifestations may include hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis. 
  • Sometimes symptoms of DRESS may resemble an acute viral infection. Eosinophilia is often present. 
  • Because this disorder is variable in its presentation, other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident. Discontinue diclofenac potassium if such signs or symptoms are present; evaluate the patient immediately. 

Hematological Effects

  • Anemia is sometimes seen in patients receiving NSAIDs.
  • Check hemoglobin/hematocrit if patients exhibit signs/symptoms of anemia during long-term treatment.
  • Patients who may be adversely affected by alterations in platelet function (eg, those with coagulation disorders or receiving anticoagulants) should be carefully monitored.

Pregnancy Considerations

Use of NSAIDs, including diclofenac potassium can cause premature closure of the fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment. Because of these risks, limit dose and duration of diclofenac potassium use between about 20 and 30 weeks of gestation, and avoid diclofenac potassium use at about 30 weeks of gestation and later in pregnancy.

There are no adequate and well-controlled studies in pregnant women. There are no studies on the effects of diclofenac potassium during labor or delivery. In animal studies, NSAIDS, including diclofenac, inhibit prostaglandin synthesis, cause delayed parturition, and increase the incidence of stillbirth.

Nursing Mother Considerations

Based on available data, diclofenac potassium may be present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for diclofenac potassium tablets and any potential adverse effects on the breastfed infant from the diclofenac potassium tablets or from the underlying maternal condition.

Pediatric Considerations

Safety and effectiveness in pediatric patients have not been established.

Geriatric Considerations

Elderly patients are at greater risk for NSAID-associated serious cardiovascular, gastrointestinal, and/or renal adverse reactions, as compared to younger patients,. If the anticipated benefit for the elderly patient outweighs these potential risks, start dosing at the low end of the dosing range, and monitor patients for adverse effects.

Diclofenac is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Renal Impairment Considerations

Monitor patients with impaired renal function closely.

Treatment with diclofenac potassium is not recommended in patients with advanced renal disease; if needed, close monitoring of the patient’s renal function is advisable.

Hepatic Impairment Considerations

Hepatic metabolism accounts for almost 100% of diclofenac potassium tablets elimination, so patients with hepatic disease may require reduced doses of diclofenac potassium tablets compared to patients with normal hepatic function.

Diclofenac Potassium Pharmacokinetics

Absorption

Diclofenac is 100% absorbed after oral administration compared to intravenous (IV) administration as measured by urine recovery. However, due to first-pass metabolism, only about 50% of the absorbed dose is systemically available.

Distribution

The apparent volume of distribution (V/F) of diclofenac potassium is 1.3 L/kg.

Diclofenac is more than 99% bound to human serum proteins, primarily to albumin. Serum protein binding is constant over the concentration range (0.15 to 105 mcg/mL) achieved with recommended doses.

Metabolism

Five diclofenac metabolites have been identified in human plasma and urine. The metabolites include 4'hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy-diclofenac. The formation of 4’-hydroxy-diclofenac is primarily mediated by CYP2C9. Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CYP2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy- and 3’-hydroxy-diclofenac.

Elimination

Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Approximately 65% of the dose is excreted in the urine and approximately 35% in the bile as conjugates of unchanged diclofenac plus metabolites. The terminal half-life of unchanged diclofenac is approximately 2 hours.

Diclofenac Potassium Interactions

Interactions

Avoid concomitant aspirin, salicylates (eg, diflunisal, salsalate) or other NSAIDs. Increased risk of GI bleed with anticoagulants, antiplatelets, oral corticosteroids, SSRIs, SNRIs, smoking, alcohol, or prolonged NSAID therapy; monitor. May antagonize, or increase risk of renal failure with diuretics (eg, loop or thiazides), ACE inhibitors, ARBs, or β-blockers; monitor closely. Potentiates digoxin; monitor levels. May potentiate lithium, methotrexate, cyclosporine; monitor for toxicity. Concomitant with pemetrexed may increase risk of pemetrexed-associated myelosuppression, renal, and GI toxicity. Potentiated by CYP2C9 inhibitors (eg, voriconazole) and antagonized by CYP2C9 inducers (eg, rifampin); may need dose adjustments. Caution with other hepatotoxic drugs (eg, acetaminophen, certain antibiotics, antiepileptics).

Diclofenac Potassium Adverse Reactions

Adverse Reactions

GI disturbances, anemia, dizziness, edema, headaches, pruritus, rash (may be serious), tinnitus; cardiovascular thrombotic events, GI ulcer/bleed, hepatotoxicity, renal toxicity, hypersensitivity reactions.

Diclofenac Potassium Clinical Trials

See Literature

Diclofenac Potassium Note

Notes

Formerly known under the brand name Cataflam.

Diclofenac Potassium Patient Counseling

Patient Counseling

Be alert to the symptoms of cardiovascular thrombotic events, as the use of NSAIDs may increase the risk of these events. 

Be alert to the signs/symptoms of GI tract ulcerations and bleeding (eg, epigastric pain, dyspepsia, melena, and hematemesis); follow-up is important if GI effects occur. 

Be alert to the signs/symptoms of serious skin reactions (eg, SJS, TEN, exfoliative dermatitis); use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.

Be alert to the symptoms of CHF (eg, shortness of breath, unexplained weight gain, or edema).

Hepatotoxicity is possible; discontinue therapy if symptoms such as nausea, fatigue, lethargy, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms occur.

Seek immediate emergency help if anaphylactic reaction (eg, difficulty breathing, swelling of the face or throat) occurs.

Pregnant patients: avoid diclofenac potassium during late pregnancy due to possible premature closure of the ductus arteriosus.

Diclofenac Potassium Generic Name & Formulations

General Description

Diclofenac potassium 50mg; tabs.

Pharmacological Class

NSAID (benzeneacetic acid deriv.).

How Supplied

Contact supplier.

Storage

Store at room temperature 20°C to 25°C (68°F to 77°F). Protect from moisture.

Diclofenac Potassium Indications

Indications

Dysmenorrhea.

Diclofenac Potassium Dosage and Administration

Adult

Use lowest effective dose for shortest duration. 50mg 3 times daily; may give 100mg initially.

Children

Not established.

Diclofenac Potassium Contraindications

Contraindications

Aspirin allergy. Coronary artery bypass graft surgery.

Diclofenac Potassium Boxed Warnings

Boxed Warning

Risk of serious cardiovascular and gastrointestinal events.

Diclofenac Potassium Warnings/Precautions

Warnings/Precautions

Not interchangeable with other forms of diclofenac. Increased risk of serious cardiovascular events (including MI, stroke). Avoid in recent MI, severe heart failure; if necessary, monitor. Increased risk of serious GI adverse events (including inflammation, bleeding, ulceration, perforation). History of ulcer disease and/or GI bleeding. Hypertension; monitor BP closely. Hepatic or renal impairment. Discontinue if signs/symptoms of liver disease develop, or if abnormal LFTs persist or worsen. Dehydration. Hypovolemia. Advanced renal disease: not recommended. Hyperkalemia. Coagulation disorders. Monitor CBCs, blood chemistry, hepatic, and renal function in long-term therapy. Pre-existing asthma. May mask signs of infection or fever. Discontinue at 1st sign of rash or any other hypersensitivity. Elderly. Debilitated. Labor & delivery. Pregnancy (≥30 weeks gestation; avoid). Nursing mothers.

Warnings/Precautions

Cardiovascular Thrombotic Events

Clinical trials of several COX-2 selective and nonselective NSAIDs of up to 3 years duration have shown an increased risk of serious cardiovascular thrombotic events, including myocardial infarction (MI) and stroke.

  • Incidence of serious cardiovascular thrombotic events greater in patients with known cardiovascular disease or risk factors.
  • Increased risk has been observed as early as the first weeks of treatment (based on observational studies).
  • Higher doses have been linked to increased cardiovascular thrombotic risk.
  • To minimize risk, use the lowest effective dose for the shortest time possible.
  • Evidence regarding use of aspirin to mitigate risk has not been consistent; aspirin coadministered with diclofenac may increase the risk of serious GI adverse events.

NSAIDs are contraindicated in the setting of coronary artery bypass graft (CABG) surgery. Based on findings from 2 large studies evaluating a COX-2 selective NSAID, use in the first 10–14 days after CABG resulted in an increased incidence of MI and stroke.

Post-MI Patients

Among patients treated with NSAIDs in the post-MI period, there was an increase in the risk of reinfarction, cardiovascular-related death, and all-cause mortality beginning in the first week of treatment, according to observational studies.

  • Incidence of death in the first year in the NSAID cohort: 20 per 100 person years
  • Incidence of death in the first year in the non-NSAID cohort: 12 per 100 person years
  • The relative risk of death in NSAID users persisted over at least the next 4 years of follow up.

Avoid the use of diclofenac potassium in patients with recent MI unless the benefits are expected to outweigh the risk of recurrent cardiovascular thrombotic events. Monitor for signs of cardiac ischemia if used in patients with recent MI.

Hypertension

  • NSAIDs can lead to new onset hypertension or worsening of pre-existing hypertension.
  • Impaired responses to thiazides and loop diuretics possible when taken with NSAIDs.
  • Use with caution in patients with hypertension; monitor BP.

Heart Failure and Edema

  • Meta-analysis of randomized controlled trials showed ~2-fold increase in hospitalizations for heart failure in patients treated with COX-2 selective and nonselective NSAIDs compared with placebo.
  • NSAID use was also associated with increased risk of MI, hospitalization for heart failure and death in a Danish National Registry study of patients with heart failure.
  • Fluid retention and edema have been observed in some patients treated with NSAIDs.
  • Diclofenac may blunt the cardiovascular effects of diuretics, ACE inhibitors, ARBs.
  • Avoid use in patients with severe heart failure unless benefits outweigh risk of worsening heart failure.
  • Monitor for signs of worsening heart failure if diclofenac potassium is used in patients with severe heart failure.

Gastrointestinal (GI) Effects

  • NSAIDs can cause serious GI adverse events including inflammation, bleeding, ulceration, and perforation of the esophagus, stomach, small intestine, or large intestine.
  • These can occur at any time, with or without warning symptoms (only 1 in 5 patients who develop a serious upper GI adverse event on NSAIDs is symptomatic).
  • Incidence of upper GI ulcers, gross bleeding, or perforation with NSAIDs: ~1% of patients treated for 3-6 months and 2-4% of patients treated for 1 year.
  • Prior history of ulcer disease or GI bleeding: prescribe with caution; these patients have a >10-fold increased risk for developing GI bleed vs those without these risk factors.
  • Other factors that increase risk of GI bleed in patients treated with NSAIDs: concomitant oral corticosteroids, anticoagulants; longer duration of NSAID use; smoking; alcohol; older age; and poor general health status.
  • Use the lowest effective dose for the shortest possible duration to minimize the potential for GI adverse events.
  • If a serious GI adverse event occurs, discontinue NSAID therapy.
    Alternative therapies should be explored for patients considered at high risk for GI effects.

Hepatic Effects

  • In clinical trials of diclofenac-containing products, meaningful elevations (eg, >3xULN of aspartate aminotransferase (AST) were observed in about 2% of approximately 5,700 patients at some time during diclofenac treatment.
  • Measure transaminases at baseline and periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms.
  • Transaminases should be monitored within 4 to 8 weeks after initiating treatment with diclofenac.
  • For patients with symptoms/signs suggesting liver dysfunction, or in whom abnormal liver test has occurred: evaluate for more severe hepatic reaction.
  • Discontinue diclofenac potassium if abnormal liver tests persist or worsen, if clinical signs/symptoms of liver disease develop, or if systemic manifestations (eg, eosinophilia, rash) occur. 

Renal Effects

  • Long-term NSAID use has been associated with renal papillary necrosis and other renal injury.
  • Renal toxicity has also been seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion; in these patients administration of NSAIDs may cause a dose-dependent reduction in prostaglandin formation and, secondarily in renal blood flow, which may result in overt renal decompensation.
  • Patients with impaired renal function, heart failure, liver dysfunction, on diuretics or ACE inhibitors, those who are volume-depleted and the elderly are at greatest risk of this reaction.
  • Discontinuing NSAID therapy usually leads to recovery.
  • Correct volume status in dehydrated or hypovolemic patients prior to initiating diclofenac potassium. 
  • Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia during use of diclofenac potassium. 
  • Avoid the use of diclofenac potassium in patients with advanced renal disease unless the benefits are expected to outweigh the risk of worsening renal function. 

Hyperkalemia

  • Increases in serum potassium concentration, including hyperkalemia, have been reported with use of NSAIDs, even in some patients without renal impairment. In patients with normal renal function, these effects have been attributed to a hyporeninemic-hypoaldosteronism state. 

Anaphylactic Reactions

  • Diclofenac has been associated with anaphylactic reactions in patients with and without known hypersensitivity to diclofenac and in patients with aspirin-sensitive asthma.
  • A subpopulation of patients with asthma may have aspirin-sensitive asthma which may include chronic rhinosinusitis complicated by nasal polyps; severe, potentially fatal bronchospasm; and/or intolerance to aspirin and other NSAIDs. 
  • Because cross-reactivity between aspirin and other NSAIDs has been reported in such aspirin-sensitive patients, diclofenac potassium is contraindicated in patients with this form of aspirin sensitivity. 
  • When diclofenac potassium is used in patients with preexisting asthma (without known aspirin sensitivity), monitor patients for changes in the signs and symptoms of asthma.

Serious Skin Reactions

  • NSAIDs can cause serious skin adverse events including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis.
  • Discontinue treatment at the first appearance of skin rash or any other sign of hypersensitivity.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) has been reported in patients taking NSAIDs, such as diclofenac potassium. 
  • Some of these events have been fatal or life-threatening. 
  • DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling. Other clinical manifestations may include hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis. 
  • Sometimes symptoms of DRESS may resemble an acute viral infection. Eosinophilia is often present. 
  • Because this disorder is variable in its presentation, other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident. Discontinue diclofenac potassium if such signs or symptoms are present; evaluate the patient immediately. 

Hematological Effects

  • Anemia is sometimes seen in patients receiving NSAIDs.
  • Check hemoglobin/hematocrit if patients exhibit signs/symptoms of anemia during long-term treatment.
  • Patients who may be adversely affected by alterations in platelet function (eg, those with coagulation disorders or receiving anticoagulants) should be carefully monitored.

Pregnancy Considerations

Use of NSAIDs, including diclofenac potassium can cause premature closure of the fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment. Because of these risks, limit dose and duration of diclofenac potassium use between about 20 and 30 weeks of gestation, and avoid diclofenac potassium use at about 30 weeks of gestation and later in pregnancy.

There are no adequate and well-controlled studies in pregnant women. There are no studies on the effects of diclofenac potassium during labor or delivery. In animal studies, NSAIDS, including diclofenac, inhibit prostaglandin synthesis, cause delayed parturition, and increase the incidence of stillbirth.

Nursing Mother Considerations

Based on available data, diclofenac potassium may be present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for diclofenac potassium tablets and any potential adverse effects on the breastfed infant from the diclofenac potassium tablets or from the underlying maternal condition.

Pediatric Considerations

Safety and effectiveness in pediatric patients have not been established.

Geriatric Considerations

Elderly patients are at greater risk for NSAID-associated serious cardiovascular, gastrointestinal, and/or renal adverse reactions, as compared to younger patients,. If the anticipated benefit for the elderly patient outweighs these potential risks, start dosing at the low end of the dosing range, and monitor patients for adverse effects.

Diclofenac is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Renal Impairment Considerations

Monitor patients with impaired renal function closely.

Treatment with diclofenac potassium is not recommended in patients with advanced renal disease; if needed, close monitoring of the patient’s renal function is advisable.

Hepatic Impairment Considerations

Hepatic metabolism accounts for almost 100% of diclofenac potassium tablets elimination, so patients with hepatic disease may require reduced doses of diclofenac potassium tablets compared to patients with normal hepatic function.

Diclofenac Potassium Pharmacokinetics

Absorption

Diclofenac is 100% absorbed after oral administration compared to intravenous (IV) administration as measured by urine recovery. However, due to first-pass metabolism, only about 50% of the absorbed dose is systemically available.

Distribution

The apparent volume of distribution (V/F) of diclofenac potassium is 1.3 L/kg.

Diclofenac is more than 99% bound to human serum proteins, primarily to albumin. Serum protein binding is constant over the concentration range (0.15 to 105 mcg/mL) achieved with recommended doses.

Metabolism

Five diclofenac metabolites have been identified in human plasma and urine. The metabolites include 4'hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy-diclofenac. The formation of 4’-hydroxy-diclofenac is primarily mediated by CYP2C9. Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CYP2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy- and 3’-hydroxy-diclofenac.

Elimination

Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Approximately 65% of the dose is excreted in the urine and approximately 35% in the bile as conjugates of unchanged diclofenac plus metabolites. The terminal half-life of unchanged diclofenac is approximately 2 hours.

Diclofenac Potassium Interactions

Interactions

Avoid concomitant aspirin, salicylates (eg, diflunisal, salsalate) or other NSAIDs. Increased risk of GI bleed with anticoagulants, antiplatelets, oral corticosteroids, SSRIs, SNRIs, smoking, alcohol, or prolonged NSAID therapy; monitor. May antagonize, or increase risk of renal failure with diuretics (eg, loop or thiazides), ACE inhibitors, ARBs, or β-blockers; monitor closely. Potentiates digoxin; monitor levels. May potentiate lithium, methotrexate, cyclosporine; monitor for toxicity. Concomitant with pemetrexed may increase risk of pemetrexed-associated myelosuppression, renal, and GI toxicity. Potentiated by CYP2C9 inhibitors (eg, voriconazole) and antagonized by CYP2C9 inducers (eg, rifampin); may need dose adjustments. Caution with other hepatotoxic drugs (eg, acetaminophen, certain antibiotics, antiepileptics).

Diclofenac Potassium Adverse Reactions

Adverse Reactions

GI disturbances, anemia, dizziness, edema, headaches, pruritus, rash (may be serious), tinnitus; cardiovascular thrombotic events, GI ulcer/bleed, hepatotoxicity, renal toxicity, hypersensitivity reactions.

Diclofenac Potassium Clinical Trials

See Literature

Diclofenac Potassium Note

Notes

Formerly known under the brand name Cataflam.

Diclofenac Potassium Patient Counseling

Patient Counseling

Be alert to the symptoms of cardiovascular thrombotic events, as the use of NSAIDs may increase the risk of these events. 

Be alert to the signs/symptoms of GI tract ulcerations and bleeding (eg, epigastric pain, dyspepsia, melena, and hematemesis); follow-up is important if GI effects occur. 

Be alert to the signs/symptoms of serious skin reactions (eg, SJS, TEN, exfoliative dermatitis); use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.

Be alert to the symptoms of CHF (eg, shortness of breath, unexplained weight gain, or edema).

Hepatotoxicity is possible; discontinue therapy if symptoms such as nausea, fatigue, lethargy, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms occur.

Seek immediate emergency help if anaphylactic reaction (eg, difficulty breathing, swelling of the face or throat) occurs.

Pregnant patients: avoid diclofenac potassium during late pregnancy due to possible premature closure of the ductus arteriosus.

Diclofenac Potassium Generic Name & Formulations

General Description

Diclofenac potassium 50mg; tabs.

Pharmacological Class

NSAID (benzeneacetic acid deriv.).

How Supplied

Contact supplier.

Storage

Store at room temperature 20°C to 25°C (68°F to 77°F). Protect from moisture.

Diclofenac Potassium Indications

Indications

Mild to moderate pain.

Diclofenac Potassium Dosage and Administration

Adult

Use lowest effective dose for shortest duration. 50mg 3 times daily; may give 100mg initially.

Children

Not established.

Diclofenac Potassium Contraindications

Contraindications

Aspirin allergy. Coronary artery bypass graft surgery.

Diclofenac Potassium Boxed Warnings

Boxed Warning

Risk of serious cardiovascular and gastrointestinal events.

Diclofenac Potassium Warnings/Precautions

Warnings/Precautions

Not interchangeable with other forms of diclofenac. Increased risk of serious cardiovascular events (including MI, stroke). Avoid in recent MI, severe heart failure; if necessary, monitor. Increased risk of serious GI adverse events (including inflammation, bleeding, ulceration, perforation). History of ulcer disease and/or GI bleeding. Hypertension; monitor BP closely. Hepatic or renal impairment. Discontinue if signs/symptoms of liver disease develop, or if abnormal LFTs persist or worsen. Dehydration. Hypovolemia. Advanced renal disease: not recommended. Hyperkalemia. Coagulation disorders. Monitor CBCs, blood chemistry, hepatic, and renal function in long-term therapy. Pre-existing asthma. May mask signs of infection or fever. Discontinue at 1st sign of rash or any other hypersensitivity. Elderly. Debilitated. Labor & delivery. Pregnancy (≥30 weeks gestation; avoid). Nursing mothers.

Warnings/Precautions

Cardiovascular Thrombotic Events

Clinical trials of several COX-2 selective and nonselective NSAIDs of up to 3 years duration have shown an increased risk of serious cardiovascular thrombotic events, including myocardial infarction (MI) and stroke.

  • Incidence of serious cardiovascular thrombotic events greater in patients with known cardiovascular disease or risk factors.
  • Increased risk has been observed as early as the first weeks of treatment (based on observational studies).
  • Higher doses have been linked to increased cardiovascular thrombotic risk.
  • To minimize risk, use the lowest effective dose for the shortest time possible.
  • Evidence regarding use of aspirin to mitigate risk has not been consistent; aspirin coadministered with diclofenac may increase the risk of serious GI adverse events.

NSAIDs are contraindicated in the setting of coronary artery bypass graft (CABG) surgery. Based on findings from 2 large studies evaluating a COX-2 selective NSAID, use in the first 10–14 days after CABG resulted in an increased incidence of MI and stroke.

Post-MI Patients

Among patients treated with NSAIDs in the post-MI period, there was an increase in the risk of reinfarction, cardiovascular-related death, and all-cause mortality beginning in the first week of treatment, according to observational studies.

  • Incidence of death in the first year in the NSAID cohort: 20 per 100 person years
  • Incidence of death in the first year in the non-NSAID cohort: 12 per 100 person years
  • The relative risk of death in NSAID users persisted over at least the next 4 years of follow up.

Avoid the use of diclofenac potassium in patients with recent MI unless the benefits are expected to outweigh the risk of recurrent cardiovascular thrombotic events. Monitor for signs of cardiac ischemia if used in patients with recent MI.

Hypertension

  • NSAIDs can lead to new onset hypertension or worsening of pre-existing hypertension.
  • Impaired responses to thiazides and loop diuretics possible when taken with NSAIDs.
  • Use with caution in patients with hypertension; monitor BP.

Heart Failure and Edema

  • Meta-analysis of randomized controlled trials showed ~2-fold increase in hospitalizations for heart failure in patients treated with COX-2 selective and nonselective NSAIDs compared with placebo.
  • NSAID use was also associated with increased risk of MI, hospitalization for heart failure and death in a Danish National Registry study of patients with heart failure.
  • Fluid retention and edema have been observed in some patients treated with NSAIDs.
  • Diclofenac may blunt the cardiovascular effects of diuretics, ACE inhibitors, ARBs.
  • Avoid use in patients with severe heart failure unless benefits outweigh risk of worsening heart failure.
  • Monitor for signs of worsening heart failure if diclofenac potassium is used in patients with severe heart failure.

Gastrointestinal (GI) Effects

  • NSAIDs can cause serious GI adverse events including inflammation, bleeding, ulceration, and perforation of the esophagus, stomach, small intestine, or large intestine.
  • These can occur at any time, with or without warning symptoms (only 1 in 5 patients who develop a serious upper GI adverse event on NSAIDs is symptomatic).
  • Incidence of upper GI ulcers, gross bleeding, or perforation with NSAIDs: ~1% of patients treated for 3-6 months and 2-4% of patients treated for 1 year.
  • Prior history of ulcer disease or GI bleeding: prescribe with caution; these patients have a >10-fold increased risk for developing GI bleed vs those without these risk factors.
  • Other factors that increase risk of GI bleed in patients treated with NSAIDs: concomitant oral corticosteroids, anticoagulants; longer duration of NSAID use; smoking; alcohol; older age; and poor general health status.
  • Use the lowest effective dose for the shortest possible duration to minimize the potential for GI adverse events.
  • If a serious GI adverse event occurs, discontinue NSAID therapy.
    Alternative therapies should be explored for patients considered at high risk for GI effects.

Hepatic Effects

  • In clinical trials of diclofenac-containing products, meaningful elevations (eg, >3xULN of aspartate aminotransferase (AST) were observed in about 2% of approximately 5,700 patients at some time during diclofenac treatment.
  • Measure transaminases at baseline and periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms.
  • Transaminases should be monitored within 4 to 8 weeks after initiating treatment with diclofenac.
  • For patients with symptoms/signs suggesting liver dysfunction, or in whom abnormal liver test has occurred: evaluate for more severe hepatic reaction.
  • Discontinue diclofenac potassium if abnormal liver tests persist or worsen, if clinical signs/symptoms of liver disease develop, or if systemic manifestations (eg, eosinophilia, rash) occur. 

Renal Effects

  • Long-term NSAID use has been associated with renal papillary necrosis and other renal injury.
  • Renal toxicity has also been seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion; in these patients administration of NSAIDs may cause a dose-dependent reduction in prostaglandin formation and, secondarily in renal blood flow, which may result in overt renal decompensation.
  • Patients with impaired renal function, heart failure, liver dysfunction, on diuretics or ACE inhibitors, those who are volume-depleted and the elderly are at greatest risk of this reaction.
  • Discontinuing NSAID therapy usually leads to recovery.
  • Correct volume status in dehydrated or hypovolemic patients prior to initiating diclofenac potassium. 
  • Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia during use of diclofenac potassium. 
  • Avoid the use of diclofenac potassium in patients with advanced renal disease unless the benefits are expected to outweigh the risk of worsening renal function. 

Hyperkalemia

  • Increases in serum potassium concentration, including hyperkalemia, have been reported with use of NSAIDs, even in some patients without renal impairment. In patients with normal renal function, these effects have been attributed to a hyporeninemic-hypoaldosteronism state. 

Anaphylactic Reactions

  • Diclofenac has been associated with anaphylactic reactions in patients with and without known hypersensitivity to diclofenac and in patients with aspirin-sensitive asthma.
  • A subpopulation of patients with asthma may have aspirin-sensitive asthma which may include chronic rhinosinusitis complicated by nasal polyps; severe, potentially fatal bronchospasm; and/or intolerance to aspirin and other NSAIDs. 
  • Because cross-reactivity between aspirin and other NSAIDs has been reported in such aspirin-sensitive patients, diclofenac potassium is contraindicated in patients with this form of aspirin sensitivity. 
  • When diclofenac potassium is used in patients with preexisting asthma (without known aspirin sensitivity), monitor patients for changes in the signs and symptoms of asthma.

Serious Skin Reactions

  • NSAIDs can cause serious skin adverse events including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis.
  • Discontinue treatment at the first appearance of skin rash or any other sign of hypersensitivity.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) has been reported in patients taking NSAIDs, such as diclofenac potassium. 
  • Some of these events have been fatal or life-threatening. 
  • DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling. Other clinical manifestations may include hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis. 
  • Sometimes symptoms of DRESS may resemble an acute viral infection. Eosinophilia is often present. 
  • Because this disorder is variable in its presentation, other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident. Discontinue diclofenac potassium if such signs or symptoms are present; evaluate the patient immediately. 

Hematological Effects

  • Anemia is sometimes seen in patients receiving NSAIDs.
  • Check hemoglobin/hematocrit if patients exhibit signs/symptoms of anemia during long-term treatment.
  • Patients who may be adversely affected by alterations in platelet function (eg, those with coagulation disorders or receiving anticoagulants) should be carefully monitored.

Pregnancy Considerations

Use of NSAIDs, including diclofenac potassium can cause premature closure of the fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment. Because of these risks, limit dose and duration of diclofenac potassium use between about 20 and 30 weeks of gestation, and avoid diclofenac potassium use at about 30 weeks of gestation and later in pregnancy.

There are no adequate and well-controlled studies in pregnant women. There are no studies on the effects of diclofenac potassium during labor or delivery. In animal studies, NSAIDS, including diclofenac, inhibit prostaglandin synthesis, cause delayed parturition, and increase the incidence of stillbirth.

Nursing Mother Considerations

Based on available data, diclofenac potassium may be present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for diclofenac potassium tablets and any potential adverse effects on the breastfed infant from the diclofenac potassium tablets or from the underlying maternal condition.

Pediatric Considerations

Safety and effectiveness in pediatric patients have not been established.

Geriatric Considerations

Elderly patients are at greater risk for NSAID-associated serious cardiovascular, gastrointestinal, and/or renal adverse reactions, as compared to younger patients,. If the anticipated benefit for the elderly patient outweighs these potential risks, start dosing at the low end of the dosing range, and monitor patients for adverse effects.

Diclofenac is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Renal Impairment Considerations

Monitor patients with impaired renal function closely.

Treatment with diclofenac potassium is not recommended in patients with advanced renal disease; if needed, close monitoring of the patient’s renal function is advisable.

Hepatic Impairment Considerations

Hepatic metabolism accounts for almost 100% of diclofenac potassium tablets elimination, so patients with hepatic disease may require reduced doses of diclofenac potassium tablets compared to patients with normal hepatic function.

Diclofenac Potassium Pharmacokinetics

Absorption

Diclofenac is 100% absorbed after oral administration compared to intravenous (IV) administration as measured by urine recovery. However, due to first-pass metabolism, only about 50% of the absorbed dose is systemically available.

Distribution

The apparent volume of distribution (V/F) of diclofenac potassium is 1.3 L/kg.

Diclofenac is more than 99% bound to human serum proteins, primarily to albumin. Serum protein binding is constant over the concentration range (0.15 to 105 mcg/mL) achieved with recommended doses.

Metabolism

Five diclofenac metabolites have been identified in human plasma and urine. The metabolites include 4'hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy-diclofenac. The formation of 4’-hydroxy-diclofenac is primarily mediated by CYP2C9. Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CYP2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy- and 3’-hydroxy-diclofenac.

Elimination

Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Approximately 65% of the dose is excreted in the urine and approximately 35% in the bile as conjugates of unchanged diclofenac plus metabolites. The terminal half-life of unchanged diclofenac is approximately 2 hours.

Diclofenac Potassium Interactions

Interactions

Avoid concomitant aspirin, salicylates (eg, diflunisal, salsalate) or other NSAIDs. Increased risk of GI bleed with anticoagulants, antiplatelets, oral corticosteroids, SSRIs, SNRIs, smoking, alcohol, or prolonged NSAID therapy; monitor. May antagonize, or increase risk of renal failure with diuretics (eg, loop or thiazides), ACE inhibitors, ARBs, or β-blockers; monitor closely. Potentiates digoxin; monitor levels. May potentiate lithium, methotrexate, cyclosporine; monitor for toxicity. Concomitant with pemetrexed may increase risk of pemetrexed-associated myelosuppression, renal, and GI toxicity. Potentiated by CYP2C9 inhibitors (eg, voriconazole) and antagonized by CYP2C9 inducers (eg, rifampin); may need dose adjustments. Caution with other hepatotoxic drugs (eg, acetaminophen, certain antibiotics, antiepileptics).

Diclofenac Potassium Adverse Reactions

Adverse Reactions

GI disturbances, anemia, dizziness, edema, headaches, pruritus, rash (may be serious), tinnitus; cardiovascular thrombotic events, GI ulcer/bleed, hepatotoxicity, renal toxicity, hypersensitivity reactions.

Diclofenac Potassium Clinical Trials

See Literature

Diclofenac Potassium Note

Notes

Formerly known under the brand name Cataflam.

Diclofenac Potassium Patient Counseling

Patient Counseling

Be alert to the symptoms of cardiovascular thrombotic events, as the use of NSAIDs may increase the risk of these events. 

Be alert to the signs/symptoms of GI tract ulcerations and bleeding (eg, epigastric pain, dyspepsia, melena, and hematemesis); follow-up is important if GI effects occur. 

Be alert to the signs/symptoms of serious skin reactions (eg, SJS, TEN, exfoliative dermatitis); use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.

Be alert to the symptoms of CHF (eg, shortness of breath, unexplained weight gain, or edema).

Hepatotoxicity is possible; discontinue therapy if symptoms such as nausea, fatigue, lethargy, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms occur.

Seek immediate emergency help if anaphylactic reaction (eg, difficulty breathing, swelling of the face or throat) occurs.

Pregnant patients: avoid diclofenac potassium during late pregnancy due to possible premature closure of the ductus arteriosus.