Is starting a low‑dose losartan appropriate for an adult with uncomplicated essential hypertension who has been non‑adherent to prior therapy and has no contraindications such as pregnancy, bilateral renal‑artery stenosis, severe renal impairment, or hyper‑kalemia?

Starting Losartan in a Previously Non-Adherent Hypertensive Patient

Yes, starting losartan at 50 mg once daily is appropriate for an adult with uncomplicated essential hypertension who has been non-adherent to prior therapy, with a plan to titrate to 100 mg once daily within 2–4 weeks to achieve maximum cardiovascular benefit. 1, 2

Initial Dosing Strategy

• Start with losartan 50 mg once daily as the FDA-approved initial dose for hypertension in adults without volume depletion 1
• Plan to increase to 100 mg once daily within 2–4 weeks based on blood pressure response, as this is the target dose that provides proven cardiovascular and renal benefits 2, 1
• The 50 mg dose is appropriate for initiation, but do not leave patients on 50 mg long-term—clinical trials demonstrating cardiovascular protection used 100 mg daily 2, 3

Blood Pressure Targets and Monitoring

• Target blood pressure is <130/80 mmHg for most adults with hypertension to reduce cardiovascular risk 4
• Measure blood pressure at 2–4 week intervals until target is achieved, ideally within 3 months of starting therapy 4
• Home blood pressure monitoring is recommended; a home reading ≥135/85 mmHg corresponds to office hypertension ≥140/90 mmHg 4

Mandatory Laboratory Monitoring

• Check serum creatinine and potassium within 1–2 weeks of starting losartan or increasing the dose, especially in patients with diabetes or chronic kidney disease 5, 2
• Accept up to 30% increase in serum creatinine within the first 4 weeks—this is expected and reflects beneficial hemodynamic changes, not drug toxicity 5
• Monitor potassium closely as ARBs increase hyperkalemia risk, particularly with concomitant NSAIDs, potassium supplements, or renal impairment 5, 2

Escalation Strategy for Inadequate Response

• If blood pressure remains ≥140/90 mmHg on losartan 100 mg daily after 4–8 weeks, add hydrochlorothiazide 12.5–25 mg once daily as combination therapy provides additive blood pressure reduction 4, 1
• For blood pressure ≥160/100 mmHg at presentation, consider starting with two antihypertensive medications from the outset (losartan plus a thiazide diuretic or calcium channel blocker) 4
• If triple therapy is needed, add a dihydropyridine calcium channel blocker (e.g., amlodipine) to the ARB-diuretic combination 4

Addressing Non-Adherence

• Before escalating therapy, directly assess medication adherence through specific questioning about cost, access barriers, side effects, or misunderstanding of the treatment plan 2
• Simplify the regimen with once-daily dosing and consider single-pill combinations when multiple agents are needed to improve adherence 4
• Do not assume prior non-adherence was due to side effects—patients often stop medications for non-medical reasons that can be addressed 2

Critical Safety Considerations

• Never combine losartan with an ACE inhibitor or direct renin inhibitor (aliskiren)—this dual RAAS blockade increases risks of hyperkalemia, syncope, and acute kidney injury without providing additional benefit 4, 5, 2
• Avoid NSAIDs when possible as the combination with losartan significantly increases acute kidney injury risk, hyperkalemia, and can blunt the antihypertensive effect by 5 mmHg 5
• Discontinue losartan immediately if pregnancy is detected due to serious fetal toxicity risk 2

Common Pitfalls to Avoid

• Do not underdose losartan—the proven cardiovascular and renal benefits were achieved with 100 mg daily, not 50 mg 2, 3
• Do not delay treatment in grade 2 hypertension (≥160/100 mmHg)—start drug therapy immediately along with lifestyle interventions 4
• Do not stop losartan for modest creatinine increases (<30%)—this is an expected hemodynamic effect that indicates appropriate RAAS blockade 5
• Do not forget to reassess the need for antihypertensive therapy if the patient was previously non-adherent for extended periods, as blood pressure may have changed 4

Special Populations

• For patients with hepatic impairment, start with losartan 25 mg once daily due to 5-fold increase in plasma concentrations 1, 2
• For elderly or frail patients, the standard 50 mg starting dose is appropriate, but titration may be more gradual over 2–4 weeks with close monitoring for postural hypotension 2
• For patients with volume depletion (e.g., on diuretic therapy), consider starting with 25 mg once daily to reduce first-dose hypotension risk 1