What is the starting dose of olmesartan (angiotensin II receptor antagonist) for adults with hypertension?

Olmesartan Starting Dose for Adult Hypertension

The starting dose of olmesartan for adults with hypertension is 20 mg once daily, which can be increased to 40 mg once daily after 2 weeks if additional blood pressure reduction is needed. 1

Standard Dosing Protocol

• Initial dose: 20 mg once daily when used as monotherapy in patients who are not volume-contracted 1
• Titration schedule: After 2 weeks of therapy, if further blood pressure reduction is required, increase to 40 mg once daily 1
• Maximum effective dose: 40 mg once daily—doses above this do not appear to provide greater antihypertensive effect 1
• Dosing frequency: Once-daily dosing is recommended; twice-daily dosing offers no advantage over the same total dose given once daily 1

Special Considerations for Volume Depletion

For patients with possible intravascular volume depletion (e.g., those on diuretics or with impaired renal function), consider a lower starting dose and initiate under close medical supervision. 1

• This precaution is critical to avoid symptomatic hypotension in volume-depleted states 1

Comparative Efficacy Evidence

The 20 mg starting dose of olmesartan demonstrates superior antihypertensive efficacy compared to standard starting doses of other ARBs:

• Olmesartan 20 mg once daily is more effective than:

  • Losartan 50 mg once daily 2, 3
  • Valsartan 80 mg once daily 2
  • Irbesartan 150 mg once daily 2

• Faster onset of action: Olmesartan achieves significant blood pressure reductions more rapidly than other ARBs, with greater reductions in both diastolic and systolic blood pressure evident at 4 weeks 3

• 24-hour blood pressure control: The once-daily dosing provides sustained antihypertensive efficacy throughout the entire 24-hour dosing interval, with trough-to-peak ratios above 50% 2, 4

Clinical Response Rates

At the 20 mg starting dose after 8 weeks of treatment:

• Response rate: 76% of patients (defined as diastolic BP <90 mmHg or improvement >10 mmHg from baseline) 5
• Control rate: 70% of patients achieve target blood pressure 5
• Mean blood pressure reduction: Approximately 11.8 mmHg reduction in diastolic BP and 17.1 mmHg reduction in systolic BP 5

Tolerability Profile

• Olmesartan is well tolerated at the 20 mg starting dose, with only 30.9% of patients experiencing adverse events, most of which are mild 5
• Common adverse effects are minimal and include dizziness, headache, and cough (though cough is less frequent than with ACE inhibitors) 3

Important Clinical Caveat

Do not adjust the starting dose based solely on age or mild-to-moderate renal or hepatic impairment. While pharmacokinetic studies show increased plasma concentrations in elderly patients and those with renal or hepatic dysfunction, these increases are several-fold lower than the well-tolerated concentrations observed with 80 mg daily dosing 6. However, in patients with severe renal impairment, consider a lower starting dose with a maximum daily dose not exceeding 20 mg 6.