Irbesartan/Hydrochlorothiazid Heumann (Hydrochlorothiazide, Irbesartan)

• Irbesartan/Hydrochlorothiazide is used to treat conditions within the hypertension disease family.
• Hypertension: reduces systolic and diastolic blood pressure in patients with elevated readings.
• Left ventricular hypertrophy: helps prevent progression of pressure‑induced cardiac remodeling.
• Proteinuria associated with hypertension: decreases urinary protein excretion and protects renal function.

• Irbesartan selectively blocks AT1 receptors, preventing angiotensin II‑mediated vasoconstriction and aldosterone release, which lowers systemic vascular resistance. Hydrochlorothiazide inhibits sodium‑chloride reabsorption in the distal convoluted tubule, promoting diuresis, reducing extracellular fluid volume, and further decreasing blood pressure.

Common Side Effects

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

Serious or Rare Side Effects

• Severe dehydration or electrolyte imbalance
• Acute kidney injury or worsening renal function
• Hyperkalemia or severe hypokalemia
• Allergic reactions such as rash, angioedema, or anaphylaxis
• Blood dyscrasias (e.g., agranulocytosis, thrombocytopenia)
• Hepatic dysfunction or jaundice

• Before initiating therapy, consider the following precautions.
• Monitor blood pressure regularly: ensure therapeutic response and avoid hypotension.
• Assess renal function: check serum creatinine and eGFR at baseline and periodically.
• Check electrolytes: especially potassium and sodium levels.
• Avoid use in severe hepatic impairment: dose adjustments may be required.
• Use caution in elderly patients: increased sensitivity to blood pressure changes.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Irbesartan/Hydrochlorothiazide may interact with several medicines.

Major Interactions (Avoid)

• Aliskiren: combined use can increase risk of renal impairment.
• Potassium‑sparing diuretics or supplements: may cause dangerous hyperkalemia.
• Lithium: can raise lithium levels, leading to toxicity.
• ACE inhibitors or other ARBs: additive effects on potassium and renal function.
• NSAIDs: may reduce antihypertensive efficacy and impair renal function.

Moderate Interactions (Monitor Closely)

• Other thiazide or loop diuretics: monitor electrolytes and volume status.
• Antihypertensive agents (beta‑blockers, calcium channel blockers): may enhance blood pressure lowering.
• CYP2C9 inhibitors (e.g., fluconazole): can increase irbesartan plasma concentrations.
• Antidiabetic drugs: diuretic‑induced changes in glucose control may require dose adjustment.
• Anticoagulants: diuretic‑induced dehydration may affect INR stability.