What is the recommended dosing of olmesartan (angiotensin II receptor antagonist) for a typical adult patient with hypertension, considering factors such as renal function and potential hyperkalemia?

Olmesartan Dosing for Hypertension

For adult hypertension, start olmesartan at 20 mg once daily and increase to 40 mg once daily after 2 weeks if blood pressure remains uncontrolled; doses above 40 mg provide no additional benefit. 1

Standard Adult Dosing

• Initial dose: 20 mg once daily for patients who are not volume-depleted 1, 2
• Titration: Increase to 40 mg once daily after 2 weeks if further blood pressure reduction is needed 1, 2
• Maximum dose: 40 mg once daily – higher doses do not provide greater antihypertensive effect 1, 3
• Frequency: Once daily dosing only – twice-daily dosing offers no advantage over the same total dose given once daily 1

Special Populations and Dose Adjustments

Volume-Depleted Patients

• Start with close medical supervision and consider a lower starting dose in patients with possible intravascular volume depletion (e.g., those on diuretics, particularly with impaired renal function) 1

Renal Impairment

• Severe renal insufficiency (CrCl <20 mL/min): Maximum 20 mg daily 4
• Monitor serum creatinine and potassium within 2-4 weeks of initiation or dose increase 5
• Accept up to 30% increase in serum creatinine within 4 weeks as expected hemodynamic effect 5
• Continue olmesartan even when eGFR falls below 30 mL/min/1.73 m² unless symptomatic hypotension or uncontrolled hyperkalemia develops 5

Hepatic Impairment

• Moderate hepatic insufficiency (Child-Pugh score 7-9): Maximum 20 mg daily 4

Monitoring Parameters

Critical monitoring includes:

• Blood pressure response within 2 weeks of initiation or dose change 1, 6
• Serum creatinine and potassium within 2-4 weeks of starting or adjusting dose 5
• Assess for symptomatic hypotension at each visit 5
• Monitor for hyperkalemia, especially in patients with CKD or those on potassium supplements or potassium-sparing drugs 2

Combination Therapy Considerations

When monotherapy is insufficient:

• Add hydrochlorothiazide 12.5-25 mg daily as preferred combination strategy 2, 6
• Combination therapy (olmesartan 20 mg + HCTZ 12.5 mg) is more effective than dose titration alone for non-responders 6
• Do NOT combine with ACE inhibitors, other ARBs, or direct renin inhibitors – this increases risk of hyperkalemia, hypotension, and acute renal failure 2

Common Pitfalls to Avoid

Critical errors to prevent:

• Don't stop olmesartan for mild creatinine increases (<30%) – this is an expected hemodynamic effect, not kidney injury 5
• Don't underdose – the 40 mg dose provides significantly better blood pressure control than 20 mg in non-responders 6
• Don't discontinue prematurely for hyperkalemia – manage potassium medically (dietary restriction, potassium binders) before reducing or stopping olmesartan 5
• Don't use in pregnancy – ARBs cause fetal harm and are contraindicated 2
• Don't combine with other renin-angiotensin system blockers – this triples the risk of hyperkalemia and acute kidney injury 2

Clinical Context

Blood pressure targets:

• Target <130/80 mmHg for most patients with hypertension 2
• Evaluate response at 2 weeks – 76% of patients respond to olmesartan 20 mg, but only 47% achieve normalization (<90 mmHg DBP) 6
• For non-responders at 2 weeks, either increase to 40 mg or add hydrochlorothiazide 6