Irbesartán/Hidroclorotiazida Pharma Combix (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazide is used in the management of hypertension, targeting elevated blood pressure and related cardiovascular stress.

• Essential hypertension: lowers systolic and diastolic blood pressure to target levels.
• Controlled hypertension: assists patients who require additional blood pressure reduction beyond monotherapy.
• Hypertension with fluid retention: combines diuretic action to reduce plasma volume and improve blood pressure control.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors, preventing vasoconstriction, aldosterone secretion and sodium retention. Hydrochlorothiazide acts on the distal convoluted tubule, inhibiting NaCl reabsorption, which promotes natriuresis and diuresis, decreasing plasma volume and peripheral vascular resistance. The complementary actions result in additive blood‑pressure‑lowering effects. The blockade of AT1 receptors also improves endothelial function, while the diuretic effect reduces preload, together enhancing overall cardiovascular hemodynamics.

The combination may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

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

Serious or Rare Side Effects

• Severe hypotension.
• Acute kidney injury.
• Hyperkalemia.
• Angioedema.
• Pancreatitis.
• Severe allergic reactions (e.g., Stevens‑Johnson syndrome).

When prescribing Irbesartan/Hydrochlorothiazide, several precautions should be observed to ensure safe use.

• Blood pressure monitoring: check BP regularly to avoid excessive lowering.
• Renal function assessment: evaluate serum creatinine and eGFR before and during therapy.
• Electrolyte surveillance: monitor potassium and sodium levels, especially in patients on other diuretics.
• Use with caution in diabetes: may affect glucose control.
• Avoid in severe hepatic impairment: limited data on safety.
• Store at below 25°C: keep in the original pack, protect from moisture.

Irbesartan/Hydrochlorothiazide can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Aliskiren in diabetic patients: increased risk of renal impairment and hyperkalemia.
• Potassium‑sparing diuretics or supplements: may cause dangerous hyperkalemia.
• ACE inhibitors or other ARBs: additive effects on potassium and renal function.
• Lithium: increased lithium levels leading to toxicity.
• NSAIDs (high dose): may reduce antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Other antihypertensives (beta‑blockers, calcium channel blockers): may enhance blood pressure lowering.
• CYP2C9 inhibitors (e.g., fluconazole, amiodarone): can increase irbesartan plasma concentrations.
• Antidiabetic drugs: diuretic may affect glucose control.
• Anticoagulants (warfarin): thiazide may increase INR.
• High‑protein diets or supplements affecting electrolyte balance.