Guideline for Switching from Losartan to Telmisartan

Direct Switching Protocol

• The American College of Cardiology states that a direct switch from losartan to telmisartan can be performed without any wash‑out period because both agents are angiotensin II receptor blockers with similar mechanisms of action. 1

Initial Dosing and Therapeutic Range

• Begin telmisartan at 40 mg once daily when converting a patient previously on losartan 50 mg. 1
• Telmisartan’s approved therapeutic range is 20–80 mg daily, and most patients achieve adequate blood‑pressure control with doses of 40–80 mg. 1
• Losartan 50 mg represents a mid‑range dose (usual 50–100 mg); therefore, telmisartan 40 mg is a clinically reasonable starting point for equivalence. 1

Uptitration Strategy

• If seated blood pressure remains ≥140/90 mm Hg after 2–4 weeks on telmisartan 40 mg, increase the dose to 80 mg once daily. 1
• 80 mg is the maximum recommended dose of telmisartan for hypertension. 1

Monitoring Requirements (within 1–2 weeks of the switch)

• Renal function (serum creatinine) should be re‑checked, especially in patients with pre‑existing kidney disease, diabetes, or diuretic use. 4
• Serum potassium must be monitored because all ARBs carry a risk of hyperkalaemia, heightened in chronic‑kidney‑disease or potassium‑supplement users. 1
• Blood pressure should be assessed both in the office and, when possible, via home measurements to confirm adequate control. 2
• Continue periodic monitoring of these parameters after any dose adjustment. 4

Special Populations

Pregnancy

• Both losartan and telmisartan are contra‑indicated in pregnancy; pregnancy status should be verified in women of child‑bearing potential before initiating therapy. 1

History of Angioedema

• Patients who have experienced angioedema with a prior ARB should not be switched to any other ARB. 1
• For patients with ACE‑inhibitor‑related angioedema, wait at least 6 weeks after discontinuation before starting an ARB, and proceed with extreme caution. 2

Hepatic Impairment

• In mild‑to‑moderate hepatic impairment, start telmisartan at 40 mg (the standard initial dose). 1

Heart Failure

• In heart‑failure trials, losartan 150 mg daily demonstrated superiority over 50 mg, whereas telmisartan has been less extensively studied in this population. 5

Practical Implementation & Outpatient Safety

• The switch can be safely performed in an outpatient setting for most patients. 1
• If blood pressure remains uncontrolled on telmisartan 80 mg, consider adding hydrochlorothiazide 12.5–25 mg before introducing additional antihypertensive classes. 1