Olmesartán/Hidroclorotiazida Normon (Olmesartan Medoxomil, Hydrochlorothiazide)

Olmesartan/hydrochlorothiazide is used in cardiovascular therapy to lower blood pressure through combined angiotensin II blockade and diuresis.

• Hypertension: helps achieve target blood pressure when monotherapy is insufficient.
• Heart failure with reduced ejection fraction: used as part of a regimen to reduce fluid overload and improve outcomes.
• Diabetic nephropathy: assists in slowing progression by controlling hypertension and reducing intraglomerular pressure.

• Olmesartan medoxil selectively blocks the AT1 subtype of angiotensin II receptors, preventing vasoconstriction and aldosterone release. Hydrochlorothiazide inhibits sodium‑chloride reabsorption in the distal convoluted tubule, promoting natriuresis and diuresis. The combined actions lower systemic vascular resistance and plasma volume, resulting in reduced arterial pressure.

Adverse reactions may range from mild to severe and should be monitored during therapy.

Common Side Effects

• Dizziness or light‑headedness
• Headache
• Fatigue
• Increased urination
• Electrolyte disturbances (e.g., low potassium)
• Mild renal function changes

Serious or Rare Side Effects

• Angio‑edema
• Severe hypotension
• Acute kidney injury
• Hyperkalemia
• Severe electrolyte imbalance
• Hepatic dysfunction

When prescribing olmesartan/hydrochlorothiazide, clinicians should consider several safety aspects.

• Renal impairment: adjust dose or monitor function regularly.
• Electrolyte balance: check serum potassium and sodium periodically.
• Hepatic disease: use with caution in patients with liver dysfunction.
• Pregnancy: contraindicated in the second and third trimesters.
• Elderly patients: start at lower dose and monitor for orthostatic hypotension.
• Store at ambient temperature: keep in original packaging, protect from moisture and light.

Olmesartan/hydrochlorothiazide may interact with several drug classes, requiring vigilance.

Major Interactions (Avoid)

• Potassium‑rich supplements or salts: risk of hyper‑kalaemia.
• Aliskiren combined with ACE inhibitors or ARBs in diabetic patients: increased renal risk.
• NSAIDs (high‑dose): may blunt antihypertensive effect and worsen renal function.

Moderate Interactions (Monitor Closely)

• Lithium: may increase serum lithium levels.
• Other antihypertensives: additive blood‑pressure lowering effect.
• Antidiabetic drugs: may enhance hypoglycaemic effect.
• Loop diuretics: combined diuretic effect may cause electrolyte loss.
• CYP3A4 inhibitors: may modestly increase olmesartan exposure.