Losartan Potassium

Pharmacokinetic Profile: Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.

Renal Considerations: Renal: No initial dose reduction required unless volume-depleted, but requires close monitoring of creatinine and K+ as eGFR declines; suspend during acute dehydrating illness ('Sick Day Rule'). Hepatic: Plasma concentrations doubled in cirrhosis—initiate at 25 mg once daily.

Hepatic Considerations: Renal: No initial dose reduction required unless volume-depleted, but requires close monitoring of creatinine and K+ as eGFR declines; suspend during acute dehydrating illness ('Sick Day Rule'). Hepatic: Plasma concentrations doubled in cirrhosis—initiate at 25 mg once daily.

• Dizziness, nasal congestion, fatigue, mild hyperkalaemia, transient musculoskeletal ache.
• Severe hyperkalaemia, acute renal failure in renal artery stenosis, rare angioedema, hepatotoxicity.

• Potassium-sparing diuretics (Spironolactone, Eplerenone), K+ supplements, or salt substitutes (LoSalt) -> severe hyperkalaemia
• NSAIDs -> blunted antihypertensive effect and acute kidney injury ('Triple Whammy' with diuretic)
• Lithium -> reversible lithium toxicity
• CYP2C9 inducers (Rifampicin) reduce active E-3174 metabolite and lower BP efficacy; Fluconazole inhibits conversion to E-3174 (clinical significance: monitor BP response over 1–2 weeks)

Pregnancy, Lactation, Paediatric & Geriatric Use: Evaluate maternal-foetal benefit-risk ratio and age-appropriate organ function before prescribing.

Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.

• Patient Counselling Checklist: Highlight that losartan uniquely lowers serum uric acid mildly by inhibiting renal URAT1 reabsorption, making it particularly advantageous in hypertensive patients prone to gout. Maintain adequate hydration during initial weeks.
• Meal & Clock Timing Instruction: With or without food (typically after breakfast). (Once daily in the morning, or divided twice daily (morning and evening) if 50 mg BD is prescribed for smoother 24-hour BP control.)
• Missed Dose Protocol: Take as soon as remembered unless within 6–8 hours of the next scheduled dose. Do not double the dose.
• Geriatric Dispensing Pearl: Shorter half-life than telmisartan (parent drug ~2 h, active metabolite ~6–9 h); some elderly patients experience evening BP breakthrough on once-daily dosing and may be prescribed 25–50 mg BD. Initiate at 25 mg in patients >75 years or on diuretics.

Storage & Dispensing Governance: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: Oral Film-Coated Tablets: 25 mg, 50 mg, 100 mg