Cyclobenzaprine Hcl Tablets

— THERAPEUTIC CATEGORIES —
  • Muscle spasms

Cyclobenzaprine Hcl Tablets Generic Name & Formulations

General Description

Cyclobenzaprine HCl 5mg, 7.5mg, 10mg; tabs.

Pharmacological Class

Muscle relaxant (central).

How Supplied

Contact supplier.

Mechanism of Action

Cyclobenzaprine HCl relieves skeletal muscle spasm of local origin without interfering with muscle function. It is ineffective in muscle spasm due to central nervous system disease.

Cyclobenzaprine Hcl Tablets Indications

Indications

Relief of acute muscle spasm, as adjunct to rest and physical therapy.

Cyclobenzaprine Hcl Tablets Dosage and Administration

Adult

≥15yrs: initially 5mg 3 times daily, may increase to 10mg 3 times daily; max 2–3 weeks. Elderly or mild hepatic impairment: initially 5mg and then titrate slowly upward.

Children

<15yrs: not established.

Cyclobenzaprine Hcl Tablets Contraindications

Contraindications

Acute post-MI. Arrhythmias, heart block, other conduction disturbances. CHF. Hyperthyroidism. During or within 14 days of MAOIs.

Cyclobenzaprine Hcl Tablets Boxed Warnings

Not Applicable

Cyclobenzaprine Hcl Tablets Warnings/Precautions

Warnings/Precautions

Moderate-to-severe hepatic impairment: not recommended. Urinary retention. Glaucoma. Increased intraocular pressure. Elderly. Pregnancy (Cat.B). Nursing mothers.

Warnings/Precautions

Serotonin Syndrome

  • Increased risk of serotonin syndrome with other serotonergic drugs (eg, SSRIs, SNRIs, tricyclic antidepressants, tramadol, bupropion, meperidine, verapamil, or MAOIs); monitor closely.

  • Serotonin syndrome symptoms may include mental status changes (e.g., confusion, agitation, hallucinations), autonomic instability (e.g., diaphoresis, tachycardia, labile blood pressure, hyperthermia), neuromuscular abnormalities (e.g., tremor, ataxia, hyperreflexia, clonus, muscle rigidity), and /or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).

  • Discontinue treatment and any concomitant serotonergic agents immediately if serotonin syndrome occurs and initiate supportive symptomatic treatment. If concomitant use with other serotonergic drugs is clinically warranted, monitor closely especially during treatment initiation or dose increase.

General

  • Use caution in patients with a history of urinary retention, angle-closure glaucoma, increased intraocular pressure, and in patients taking anticholinergic medication.

Impaired Hepatic Function

  • Hepatic impairment increased plasma concentrations of cyclobenzaprine.

  • Use with caution in patients with mild hepatic impairment: start with cyclobenzaprine 5mg and titrate slowly upward.

  • Do not use cyclobenzaprine in patients with moderate to severe hepatic impairment.

Pregnancy Considerations

Pregnancy Category B

  • There are no adequate and well-controlled studies in pregnant women. Only use cyclobenzaprine during pregnancy if clearly needed.

Nursing Mother Considerations

It is not known whether cyclobenzaprine is excreted in human milk. Exercise caution when using cyclobenzaprine in nursing women.

Pediatric Considerations

Safety and efficacy of cyclobenzaprine HCl in pediatric patients below 15 years of age have not been established.

Geriatric Considerations

Increased risk for CNS adverse events (eg, hallucinations and confusion, cardiac events resulting in falls or other sequelae, drug-drug and drug-disease interactions) in elderly. Only use cyclobenzaprine in elderly if clearly needed. In elderly patients, initiate cyclobenzaprine 5mg and titrate slowly upward.

Hepatic Impairment Considerations

  • Hepatic impairment increased plasma concentrations of cyclobenzaprine.

  • Use with caution in patients with mild hepatic impairment: start with cyclobenzaprine 5mg and titrate slowly upward.

Cyclobenzaprine Hcl Tablets Pharmacokinetics

Absorption

Mean oral bioavailability: 33% to 55%.

Distribution

Highly bound to plasma protein.

Metabolism

Extensively metabolized by CYP3A4, 1A2, and to a lesser extent, 2D6.

 

Elimination

Renal. Half-life: 18 hours (range: 8–37 hours). Plasma clearance: 0.7 L/min.

Cyclobenzaprine Hcl Tablets Interactions

Interactions

See Contraindications. Hypertensive crisis with MAOIs. Increased risk of serotonin syndrome with other serotonergic drugs (eg, SSRIs, SNRIs, tricyclic antidepressants, tramadol, bupropion, meperidine, verapamil, or MAOIs); monitor closely. Potentiates anticholinergics, alcohol, other CNS depressants. May antagonize guanethidine, clonidine. Tramadol increases seizure risk.

Cyclobenzaprine Hcl Tablets Adverse Reactions

Adverse Reactions

Drowsiness, dry mouth, dizziness, fatigue, headache, GI upset, asthenia, irritability, nervousness, blurred vision, confusion, arrhythmias, tachycardia, hypotension.

Cyclobenzaprine Hcl Tablets Clinical Trials

Clinical Trials

The approval was based on 8 double-blind controlled clinical studies which included 642 patients comparing cyclobenzaprine HCl 10mg, diazepam, and placebo. The studies evaluated muscle spasm, local pain, and tenderness, limitation of motion, and restriction in activities of daily living. 

  • In 3 of the studies, cyclobenzaprine achieved a significantly greater improvement vs diazepam, while in other studies the improvement was comparable between both treatment arms.

  • Cyclobenzaprine and diazepam demonstrated to have comparable adverse reactions. Dry mouth was observed more frequently in patients treated with cyclobenzaprine, and dizziness was more frequent in patients treated with diazepam.

The efficacy of cyclobenzaprine 5mg was based on 2 seven-day, double-blind, controlled clinical trials which included 1405 patients. 

  • In 1 study, cyclobenzaprine 5mg and 10mg three times daily was compared to placebo; in the other study, cyclobenzaprine 5mg and 2.5mg three times daily was compared to placebo. The primary endpoints were global impression of change, medication helpfulness, and relief from starting backache.

  • Results showed that cyclobenzaprine 5mg achieved statistically significant superiority for all 3 primary endpoints at day 8 and, in the study comparing 5 and 10mg at day 3 or 4 as well. Cyclobenzaprine 10mg also had a similar effect for all endpoints.

Cyclobenzaprine Hcl Tablets Note

Notes

Formerly known under the brand names Flexeril, Fexmid.

Cyclobenzaprine Hcl Tablets Patient Counseling

Patient Counseling

  • Advise patients that using cyclobenzaprine with alcohol or other CNS depressants may impair mental and/or physical abilities required for performance of hazardous tasks (eg, operating machinery or driving a motor vehicle).

  • For elderly patients, initiate cyclobenzaprine 5mg and titrate slowly upward.

  • Because of the risk for serotonin syndrome, exercise caution with the concomitant use of cyclobenzaprine HCl and other drugs (eg, SSRIs, SNRIs, TCAs, tramadol, bupropion, meperidine, verapamil, or MAO inhibitors. Seek medical care immediately if signs and symptoms of serotonin syndrome occur.