What it's for (Indications)
- Treatment of essential hypertension (raised blood pressure) in adults and pediatric patients.
- Also indicated for diabetic nephropathy (kidney disease caused by diabetes) in type II diabetes mellitus.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | Losartan potassium should be administered orally, usually once daily, with or without food. It is recommended to take the medication at the same time each day to maintain consistent drug levels. Dosing must be individualized. The usual starting dose for adult hypertensive patients is 50 mg once daily. For patients with possible depletion of intravascular volume (e.g., those treated with diuretics) or a history of hepatic impairment, a lower starting dose of 25 mg once daily is recommended. Total daily doses can range from 25 mg to 100 mg, administered once or twice daily. If blood pressure is not adequately controlled with Losartan potassium alone, a low dose of a diuretic (such as hydrochlorothiazide) may be added for an additive effect. No initial dosage adjustment is necessary for elderly patients or for patients with renal impairment, including those on dialysis. |
Safety & Warnings
Common Side Effects
- Common side effects include dizziness, lightheadedness, diarrhea, stomach pain, cold, back pain, chest pain, and stuffy nose.
- Patients may also experience liver function abnormalities, myalgia (muscle pain), migraine, urticaria (red itchy bumps on skin), pruritus rash, hyperkalemia (high potassium levels), hypoglycemia, and renal failure.
- Rare but severe adverse reactions reported include anaphylactic reactions (life-threatening allergic reaction), angioedema (severe swelling under the skin surface, especially of lips, face, larynx, glottis, throat, and tongue), hepatitis (inflammation of the liver), cough, anemia (lack of red blood cells), hypotension (low blood pressure), renal impairment, and increased blood urea, creatinine, and potassium levels.
- In cases of overdose, symptoms may include increased heart rate, hypotension, or slow heart rate.
- In general, treatment with Losartan potassium has been well-tolerated, with overall incidence of adverse experiences similar to placebo in controlled clinical trials.
Serious Warnings
- Black Box Warning: WARNING: FETAL TOXICITY. When pregnancy is detected, discontinue Losartan potassium as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus.
- Use with caution in patients with renal impairment, hepatic impairment, intravascular volume depletion (e.
- g.
- , those on diuretics), renal artery stenosis (narrowing), kidney transplantation, primary aldosteronism (hormonal disorder leading to high blood pressure), severe heart failure, aortic stenosis (narrowing), arrhythmias (abnormal heart rhythm), cardiomyopathy (heart muscle weakness), and those with a history of angioedema.
- Monitor serum potassium levels, especially in elderly patients and those with renal impairment.
- Avoid consuming alcohol, as it can further lower blood pressure.
- Patients should inform their doctor about any other medical conditions or medications they are taking.
- Avoid unnecessary exposure to sunlight; use sunscreen and eyeshades as this medicine can increase sun sensitivity.
- Store at room temperature, away from direct heat and sunlight, out of reach of children and pets.
- Caution should be exercised when driving or operating machinery due to potential dizziness.
How it Works (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. Angiotensin II, formed from angiotensin I by ACE, is a potent vasoconstrictor and the primary vasoactive hormone of the renin-angiotensin system. Losartan does not exhibit partial agonist activity at the AT1 receptor and has a much greater affinity (approximately 1000-fold) for the AT1 receptor than for the AT2 receptor.