Olmesartan Medoxomil/Hydrochlorothiazide Actavis (Olmesartan Medoxomil, Hydrochlorothiazide)

Olmesartan Medoxomil/Hydrochlorothiazide acts on the renin‑angiotensin‑aldosterone system and renal sodium handling to lower blood pressure.

• Hypertension: reduces systolic and diastolic blood pressure in patients with primary (essential) hypertension.
• High blood pressure associated with fluid overload: improves control when combined volume reduction is needed.
• Resistant hypertension: provides additional blood‑pressure lowering when monotherapy is insufficient.

• Olmesartan medoxil selectively blocks AT1 receptors, preventing angiotensin II‑mediated vasoconstriction and aldosterone release. Hydrochlorothiazide inhibits NaCl reabsorption in the distal convoluted tubule, increasing urinary sodium and water excretion, which lowers plasma volume. The combined actions produce additive reductions in systemic vascular resistance and circulating fluid volume, resulting in sustained blood‑pressure control.

Common Side Effects

• Dizziness: feeling light‑headed, especially after the first doses.
• Headache: mild to moderate intensity.
• Fatigue: general tiredness or lack of energy.
• Increased urination: due to the diuretic component.
• Electrolyte imbalance: mild changes in potassium or sodium levels.
• Cough: occasional dry throat irritation.

Serious or Rare Side Effects

• Severe hypotension: marked drop in blood pressure causing fainting.
• Acute kidney injury: sudden loss of renal function.
• Hyperkalemia: dangerously high potassium levels.
• Allergic reactions: rash, itching, or swelling.
• Pancreatitis: abdominal pain with elevated enzymes.
• Liver dysfunction: abnormal liver function tests.

Before initiating therapy, clinicians should assess cardiovascular status, renal function, and electrolyte balance.

• Blood pressure monitoring: check regularly to avoid excessive hypotension.
• Renal function: evaluate serum creatinine and eGFR before and during treatment.
• Electrolyte assessment: monitor potassium and sodium levels, especially in patients on other diuretics.
• Caution in diabetes: watch for changes in blood‑glucose control.
• Avoid in severe hepatic impairment: dose adjustment may be required.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Olmesartan Medoxomil/Hydrochlorothiazide may interact with several drug classes.

Major Interactions (Avoid)

• Aliskiren: combined use can cause severe hypotension and renal dysfunction.
• Potassium‑sparing diuretics or supplements: risk of hyperkalemia.
• Lithium: increased lithium levels leading to toxicity.
• ACE inhibitors or other ARBs: additive effects on blood pressure and renal function.
• NSAIDs: may blunt antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Antidiabetic agents: diuretic‑induced changes in glucose may require dose adjustment.
• Other antihypertensives: may enhance blood‑pressure lowering, requiring titration.
• CYP450 inhibitors: potential alteration of olmesartan metabolism.
• Thiazide‑type diuretics: additive electrolyte disturbances.
• Antacids containing aluminum or magnesium: may reduce absorption of olmesartan.