Losartan

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Losartan (brand name Cozaar) — Antihypertensive; Angiotensin II receptor blocker (ARB).

Identification

• Therapeutic class: Antihypertensive.
• Pharmacologic class: Angiotensin II receptor blocker (ARB).

Pharmacology

• Mechanism of action: Blocks angiotensin II at the AT1 receptor, causing vasodilation and reduced aldosterone without the bradykinin buildup that causes ACE inhibitor cough.
• Onset / peak / duration: Onset within hours; peak blood pressure effect 3 to 6 weeks of therapy; duration about 24 hours.
• Half-life / therapeutic level: Half-life 2 hours (active metabolite 6 to 9 hours); no routine level.

Clinical use

• Indications: Hypertension, diabetic nephropathy, stroke risk reduction in left ventricular hypertrophy.
• Usual dose, route, frequency: 25 to 100 mg PO daily in 1 to 2 doses.
• Maximum dose / adjustments: Max 100 mg/day; lower starting dose with volume depletion or hepatic impairment.

Safety

• Contraindications: Pregnancy, concurrent aliskiren in diabetes, angioedema history with ARBs.
• Black box warning: Fetal toxicity; discontinue when pregnancy detected.
• Interactions: Potassium-sparing agents and potassium supplements (hyperkalemia), NSAIDs (renal risk), lithium, potassium salt substitutes (food).
• Pregnancy / lactation: Contraindicated.
• High-alert: No.

Adverse effects

• Common side effects: Dizziness, fatigue, hyperkalemia; cough much less common than with ACE inhibitors.
• Serious effects to report: Angioedema (rare), hyperkalemia, renal impairment.
• Antidote / reversal: None specific; supportive care.

Nursing process

• Assessment before administration: Blood pressure, potassium, renal function, pregnancy status.
• Interventions during therapy: Monitor for hypotension and potassium changes.
• Monitor: Blood pressure, potassium, BUN and creatinine.
• Evaluation / expected outcome: Blood pressure control without cough.

Patient teaching

• Patient teaching: A good option for patients who developed cough on ACE inhibitors.
• Notify provider if: Swelling, severe dizziness, signs of high potassium, pregnancy.
• Administration tips: With or without food; consistent timing.