Lavestra (Losartan Potassium)

Losartan potassium works by blocking the angiotensin II pathway, helping to lower blood pressure and protect the heart and kidneys.

• Hypertension: reduces systolic and diastolic pressure to achieve target blood pressure levels.
• Heart failure: improves cardiac output and reduces hospitalizations.
• Diabetic nephropathy: slows progression of kidney damage by lowering intraglomerular pressure.

• Losartan potassium selectively antagonizes angiotensin II type 1 (AT1) receptors, preventing angiotensin II from inducing vasoconstriction, aldosterone release, and sodium‑water retention. This leads to vasodilation, reduced blood volume, and decreased peripheral resistance, thereby lowering arterial pressure and alleviating strain on the cardiovascular system.

Losartan is generally well tolerated, but patients may experience a range of adverse reactions.

Common Side Effects

• Dizziness: mild to moderate light‑headedness, especially after standing.
• Headache: tension‑type headache occurring early in therapy.
• Fatigue: feeling of tiredness without obvious cause.
• Nasal congestion: mild blockage of nasal passages.
• Back pain: occasional musculoskeletal discomfort.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue, or throat requiring immediate medical attention.
• Hyperkalemia: elevated potassium levels that can affect heart rhythm.
• Acute kidney injury: sudden decline in renal function, especially in patients with pre‑existing kidney disease.
• Severe hypotension: marked drop in blood pressure causing fainting.
• Liver injury: abnormal liver enzymes indicating hepatic stress.

Before initiating therapy, clinicians should evaluate patient‑specific factors and monitor for potential risks.

• Monitor blood pressure: adjust dose to maintain target levels.
• Assess renal function: check serum creatinine and eGFR periodically.
• Check electrolytes: especially potassium, to avoid hyperkalemia.
• Use caution in hepatic impairment: dose may need adjustment.
• Avoid in patients with known hypersensitivity to losartan or other ARBs.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Losartan may interact with several drug classes, influencing efficacy or safety.

Major Interactions (Avoid)

• ACE inhibitors: combined use can increase risk of angioedema and renal impairment.
• Potassium‑sparing diuretics or supplements: may cause dangerous hyperkalemia.
• Aliskiren (in pregnancy): heightened risk of fetal toxicity.
• Lithium: losartan can raise lithium concentrations, leading to toxicity.
• NSAIDs: may diminish antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Thiazide diuretics: may enhance initial blood‑pressure‑lowering effect.
• Rifampin: can reduce losartan plasma levels, decreasing efficacy.
• CYP2C9 or CYP3A4 inhibitors (e.g., fluconazole): may increase losartan exposure.
• Anticoagulants (e.g., warfarin): monitor INR as losartan may affect anticoagulation control.