Losartan potassium
Losartan potassium (Cozaar)
Losartan potassium
(loh- SAR-tan)
Pregnancy Category: C (first trimester), D (second and third trimesters) Cozaar (Rx)

Classification: Antihypertensive, angiotensin II receptor antagonist

See Also: See also Angtiotensin II Receptor Antagonists and Antihypertensive Agents.

Action/Kinetics: Undergoes significant first-pass metabolism in the liver, where it is converted to an active carboxylic acid metabolite that is responsible for most of the angiotensin receptor blockade. Rapidly absorbed after PO administration, although food slows absorption. Peak plasma levels of losartan and metabolite: 1 hr and 3-4 hr, respectively. When used alone, decease in BP in blacks was less than in non-blacks. t 1/2, losartan: 2 hr; t 1/2, metabolite: 6-9 hr. The drug and metabolite are highly bound to plasma proteins. Maximum effects: 1 week (3 to 6 weeks in some clients). Drug and metabolites are excreted through both the urine (35%) and feces (60%).

Uses: Antihypertensive

Special Concerns: In severe CHF there is a risk of oliguria and/or progressive azotemia with acute renal failure and/or death (which are rare). In those with unilateral or bilateral renal artery stenosis, there is a risk of increased serum creatinine or BUN. Lower doses are recommended in those with hepatic insufficiency.

Side Effects: GI: Diarrhea, dyspepsia, anorexia, constipation, dental pain, dry mouth, flatulence, gastritis, vomiting, taste perversion. CV: Angina pectoris, second-degree AV block, CVA, MI, ventricular tachycardia, ventricular fibrillation hypotension, palpitation, sinus bradycardia, tachycardia, orthostatic effects. CNS: Dizziness, insomnia, anxiety, anxiety disorder, ataxia, confusion, depression, abnormal dreams, hypesthesia, decreased libido, impaired memory, migraine, nervousness, paresthesia, peripheral neuropathy, panic disorder, sleep disorder, somnolence, tremor, vertigo. Respiratory: URI, cough, nasal congestion, sinus disorder, sinusitis, dyspnea, bronchitis, pharyngeal discomfort, epistaxis, rhinitis, respiratory congestion. Musculoskeletal: Muscle cramps, myalgia, joint swelling, musculoskeletal pain, stiffness, arthralgia, arthritis, fibromyalgia, muscle weakness; pain in the back, legs, arms, hips, knees, shoulders. Dermatologic: Alopecia, dermatitis, dry skin, ecchymosis, erythema, flushing, photosensitivity, pruritus, rash, sweating, urticaria. GU: Impotence, nocturia, urinary frequency, UTI. Ophthalmologic: Blurred vision, burning/stinging in the eye, conjunctivitis, decrease in visual acuity. Miscellaneous: Gout, anemia, tinnitus, facial edema, fever, syncope.

Laboratory Test Alterations: Minor BUN, serum creatinine. Occasional liver enzymes and/or serum bilirubin. Small H&H.;

Overdose Management: Symptoms: Hypotension, tachycardia, bradycardia (due to vagal stimulation). Treatment: Supportive treatment. Hemodialysis is not indicated.

Drug Interactions: Losartan plus phenobarbital plasma losartan level (20%).

How Supplied: Tablet: 25 mg, 50 mg

Dosage
?Tablets Hypertension.
Adults: 50 mg once daily with or without food. Total daily doses range from 25 to 100 mg. In those with possible depletion of intravascular volume (e.g., clients treated with a diuretic), use 25 mg once daily. If the antihypertensive effect (measured at trough) is inadequate, a twice-a-day regimen, using the same dose, may be tried; or an increase in dose may give a more satisfactory result. If BP is not controlled by losartan alone, a diuretic (e.g., hydrochlorothiazide) may be added.