Losartan

• Hypertension in adults and children aged 6 years and older.
• Stroke-risk reduction in hypertension with left ventricular hypertrophy; the label states evidence of this benefit does not apply to Black patients.
• Diabetic nephropathy in type 2 diabetes with a history of hypertension, elevated creatinine and urine albumin-to-creatinine ratio ≥300 mg/g; reduces progression to doubling of creatinine or end-stage renal disease.

Heart failure and other off-label uses are outside this focused label-based dosing reference; they are not represented as Cozaar-approved indications.

Start 0.7 mg/kg once daily, up to 50 mg, as tablet or suspension; adjust to BP response. Doses above 1.4 mg/kg or 100 mg daily have not been studied. Not recommended below age 6 or with eGFR <30 mL/min/1.73 m².

Mild-to-moderate hepatic impairment: start 25 mg once daily; severe impairment has not been studied. Adult renal impairment alone requires no adjustment unless also volume depleted, but renal function must be monitored in susceptible patients.

Take with or without food. The label provides a pharmacist preparation for 200 mL of 2.5 mg/mL suspension using ten 50 mg tablets, purified water, Ora-Plus and Ora-Sweet SF. Follow the complete label method; shake before dosing. Do not assume another compounded or commercial liquid has the same concentration or shelf life.

Hypersensitivity to any component; concomitant aliskiren in patients with diabetes.

Cozaar carries a boxed warning for fetal toxicity. Drugs acting directly on the renin-angiotensin system can injure or kill a developing fetus. Discontinue losartan as soon as pregnancy is detected.

Adult hypertension trials reported dizziness, upper respiratory infection, nasal congestion and back pain more often than placebo. Kidney-disease trials also reported hypotension and hyperkalemia. Angioedema and anaphylaxis have been reported after marketing; stop and seek emergency help for face, tongue or throat swelling.

Contact a clinician or Poison Control promptly after excess dosing. Hypotension and tachycardia are the most likely overdose effects; bradycardia may also occur. Treatment is supportive, and neither losartan nor its active metabolite can be removed by hemodialysis.

• Potassium supplements, potassium salt substitutes and other potassium-raising drugs: monitor serum potassium.
• Lithium: levels and toxicity may increase; monitor concentrations.
• NSAIDs, including COX-2 inhibitors: may reduce BP effect and impair renal function, especially with older age, volume depletion or renal disease; monitor renal function.
• ACE inhibitors, other ARBs or aliskiren: dual blockade increases hypotension, hyperkalemia and acute kidney injury. Avoid in general; aliskiren is contraindicated with diabetes and should be avoided when GFR <60 mL/min.
• Rifampin reduces losartan/metabolite exposure; fluconazole reduces active-metabolite exposure. Clinical consequences of CYP2C9 inhibition have not been established; review response rather than assume a validated adjustment.

Avoid use and plan an alternative before pregnancy. Second/third trimester exposure can cause oligohydramnios, fetal renal failure, lung/skull abnormalities and death. After exposure, specialist evaluation may include ultrasound and neonatal monitoring for hypotension, oliguria and hyperkalemia.

Human milk excretion is unknown; losartan and its active metabolite occur in rat milk. The label advises choosing between discontinuing breastfeeding and discontinuing treatment, taking maternal need into account.

Pediatric hypertension evidence covers ages 6–16; safety/effectiveness below 6 or with pediatric GFR <30 mL/min/1.73 m² are not established. No overall age-related safety/efficacy difference was observed, but greater sensitivity in older patients is possible.

The LIFE subgroup did not establish Cozaar’s cardiovascular-event benefit in Black patients with hypertension and LVH. The label qualifies the stroke indication; treatment choices should account for the individual indication and response.

Losartan and its active carboxylic-acid metabolite block angiotensin II binding to AT₁ receptors, reducing vasoconstrictor and aldosterone effects. Neither inhibits ACE or bradykinin degradation.

Absorption

Approximately 33% oral bioavailability; parent peak about 1 hour, metabolite 3–4 hours.

Metabolism

First-pass CYP metabolism; CYP2C9 and CYP3A4 contribute in vitro.

Half-life

Parent approximately 2 hours; active metabolite 6–9 hours.

Elimination

Urinary and biliary/fecal pathways; neither parent nor metabolite is removed by hemodialysis.

• Assess BP response and symptoms of hypotension after initiation and titration.
• Check renal function and serum potassium periodically, particularly with kidney disease, volume depletion or interacting drugs.
• Monitor lithium if co-prescribed; review NSAID use and potassium products.

• Take consistently as prescribed. If a dose is missed, take it when remembered unless the next dose is near; do not double.
• Discuss pregnancy plans and report pregnancy immediately.
• Report vomiting, diarrhea or dehydration; dizziness or fainting needs clinical review.
• Avoid unreviewed potassium supplements or salt substitutes. Seek emergency help for airway/facial swelling.

Strengths / appearance

25 mg white oval, 951; 50 mg white oval, 952 and reverse score; 100 mg white teardrop, 960.

Label packager

Organon LLC

Example NDC

78206-122-02 · 50 mg, 90 tablets.

U.S. status

Prescription medicine; New Drug Application labeling.

Cozaar tablets

25 mg, 50 mg and 100 mg oral tablets.

Label-prepared suspension

2.5 mg/mL; pharmacist preparation under the complete label instructions.

Tablets: 25°C; excursions permitted to 15–30°C. Keep container tightly closed and protect from light. The exact label-prepared 2.5 mg/mL suspension is refrigerated at 2–8°C for up to four weeks; shake and return promptly to refrigeration. Keep medicines away from children.