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Hyzaar Generic Name & Formulations
Legal Class
Rx
General Description
Losartan potassium, hydrochlorothiazide; 50/12.5mg, 100/12.5mg, 100/25mg; tabs.
Pharmacological Class
Angiotensin II receptor blocker (ARB) + thiazide diuretic.
How Supplied
Tabs 50/12.5mg, 100/12.5mg—30, 90, 1000; 100/25mg—30, 90
Manufacturer
Generic Availability
YES
Mechanism of Action
Losartan and its principal active metabolite block the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor found in many tissues, (e.g., vascular smooth muscle, adrenal gland). Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly increasing excretion of sodium and chloride in approximately equivalent amounts. Indirectly, the diuretic action of hydrochlorothiazide reduces plasma volume, with consequent increases in plasma renin activity, increases in aldosterone secretion, increases in urinary potassium loss, and decreases in serum potassium.
Hyzaar Indications
Indications
Hypertension (not for initial therapy unless HTN is severe). To reduce stroke in hypertensive patients with left ventricular hypertrophy (LVH); this benefit may not apply to black patients.
Hyzaar Dosage and Administration
Adult
Initially 50/12.5mg once daily (100/12.5mg if BP not controlled on losartan 100mg alone); may increase after 3 weeks as needed to max 100/25mg daily. HTN with LVH (BP not controlled on losartan alone): initially 50/12.5mg once daily; increase as needed to 100/12.5mg, then to max 100/25mg daily.
Children
Not established.
Nursing Considerations
Patients should be asked to report pregnancies to their physicians as soon as possible.
Hyzaar Contraindications
Contraindications
Anuria. Sulfonamide allergy. Concomitant aliskiren in patients with diabetes.
Hyzaar Boxed Warnings
Boxed Warning
Fetal toxicity.
Hyzaar Warnings/Precautions
Warnings/Precautions
Fetal toxicity may develop; discontinue if pregnancy is detected. Correct salt/volume depletion before starting therapy, or reduce initial dose. Hepatic impairment: initial therapy not recommended. Severe renal impairment (CrCl<30mL/min): not established. Severe CHF. Renal artery stenosis. Asthma. SLE. Gout. Diabetes. Postsympathectomy. Acute myopia. Secondary angle-closure glaucoma. Monitor serum electrolytes, calcium, BP, renal function periodically. Pregnancy: avoid. Nursing mothers: not recommended.
Hyzaar Pharmacokinetics
Absorption
Losartan Potassium
-
Systemic bioavailability: ~33%.
-
Mean peak concentrations are reached in 1 hour.
- Food slows absorption of losartan, but has only minor effects on area under the curve.
Distribution
Losartan Potassium
-
Volume of distribution: ~34 L.
-
Highly bound to plasma protein, primarily albumin, with a plasma free fraction of 1.3%.
Elimination
Losartan Potassium
-
Fecal (60%), renal (35%).
-
Total plasma clearance: ~600 mL/min with renal clearance of ~75 mL/min.
-
Half-life: ~2 hours.
Hydrochlorothiazide
-
Renal.
-
Half-life: 5.6–14.8 hours.
Hyzaar Interactions
Interactions
See Contraindications. Hyperkalemia with concomitant other drugs that may increase serum potassium (eg, K+ supplements, K+ sparing diuretics, K+ containing salt substitutes). Dual inhibition of the renin-angiotensin system with ARBs, ACEIs, or aliskiren may increase risk of hypotension, hyperkalemia, renal function changes; monitor closely. Avoid concomitant aliskiren in renal impairment (CrCl <60mL/min). May be antagonized by, and renal toxicity potentiated by NSAIDs, including selective COX-2 inhibitors (monitor renal function periodically in elderly and/or volume-depleted). May increase lithium toxicity (monitor). Orthostatic hypotension with alcohol, other CNS depressants. Adjust antihyperglycemics. Hypokalemia with corticosteroids, ACTH. Potentiates other antihypertensives, skeletal muscle relaxants. Concomitant cholestyramine, colestipol; administer at least 4hrs before or 4–6hrs after resin administration.
Hyzaar Adverse Reactions
Adverse Reactions
Dizziness, upper respiratory infection, cough, back pain; hypersensitivity reactions, renal impairment, electrolyte abnormalities; HCTZ: increased risk for non-melanoma skin cancer.
Hyzaar Clinical Trials
See Literature
Hyzaar Note
Not Applicable
Hyzaar Patient Counseling
See Literature
