Irbesartan/Hydroklortiazid Actavis (Hydrochlorothiazide, Irbesartan)

• Irbesartan/Hydrochlorothiazide is an antihypertensive combination that acts on the renin‑angiotensin system and renal sodium handling to lower blood pressure.
• Essential hypertension: reduces systolic and diastolic blood pressure in patients with primary hypertension.
• Hypertension requiring combined ARB and diuretic therapy: provides dual mechanism for improved control when monotherapy is insufficient.
• Resistant hypertension: used as part of a multi‑drug regimen for patients whose blood pressure remains elevated despite other treatments.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors, preventing vasoconstriction and aldosterone‑mediated sodium retention. Hydrochlorothiazide inhibits Na+/Cl‑ reabsorption in the distal convoluted tubule, increasing urinary sodium and water excretion, thereby reducing plasma volume. The combined actions produce additive reductions in systemic vascular resistance and circulating fluid volume, resulting in lower arterial pressure.

Common Side Effects

• Dizziness or light‑headedness, especially after the first dose.
• Headache.
• Increased frequency of urination.
• Fatigue or mild weakness.
• Electrolyte disturbances such as low potassium.
• Mild gastrointestinal discomfort.

Serious or Rare Side Effects

• Severe dehydration or electrolyte imbalance.
• Acute kidney injury or worsening renal function.
• Hyperkalemia, especially when used with potassium‑sparing agents.
• Angioedema or severe allergic reaction.
• Significant drops in blood pressure (hypotension).
• Blood dyscrasias such as agranulocytosis or thrombocytopenia.

• Before initiating therapy, clinicians should assess baseline blood pressure, renal function, and electrolyte status.
• Monitor blood pressure regularly: adjust therapy based on response.
• Check renal function: evaluate serum creatinine and eGFR before and during treatment.
• Assess electrolytes: especially potassium and sodium levels.
• Avoid use in severe renal impairment: contraindicated when creatinine clearance is markedly reduced.
• Use caution in elderly patients: increased sensitivity to hypotension and electrolyte shifts.
• Store below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Irbesartan/Hydrochlorothiazide may interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• ACE inhibitors or aliskiren in pregnancy: risk of angioedema and renal dysfunction.
• Potassium‑sparing diuretics or supplements: can cause dangerous hyperkalemia.
• Lithium: increased lithium levels and toxicity.
• NSAIDs: may blunt antihypertensive effect and impair renal function.
• Cyclosporine or tacrolimus: heightened risk of nephrotoxicity.

Moderate Interactions (Monitor Closely)

• Other antihypertensives (beta‑blockers, calcium channel blockers): may enhance hypotensive effect.
• Additional thiazide or loop diuretics: increase risk of electrolyte disturbances.
• Antidiabetic agents: diuretic‑induced changes in glucose may require dose adjustment.
• CYP2C9 inhibitors (e.g., fluconazole): may raise irbesartan plasma levels.
• Antacids containing aluminum or magnesium: may affect absorption of hydrochlorothiazide.