Irbesartan/Hydrochlorothiazide Brown & Burk (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazide is indicated for the management of hypertension, acting on the renin‑angiotensin‑aldosterone system and renal sodium handling.

• Essential hypertension: reduces systolic and diastolic blood pressure to target levels.
• Secondary hypertension: assists in controlling blood pressure when caused by another underlying condition.
• General hypertension: provides long‑term blood pressure control in adult patients.

• Irbesartan selectively blocks AT1 receptors, preventing angiotensin II‑mediated vasoconstriction and aldosterone release, which promotes vasodilation. Hydrochlorothiazide inhibits Na⁺/Cl⁻ reabsorption in the distal convoluted tubule, increasing urinary sodium and water excretion, thereby decreasing plasma volume. The combined actions lower systemic vascular resistance and cardiac preload, resulting in reduced arterial 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 hyponatremia
• Angio‑edema or severe allergic reaction
• Liver function abnormalities
• Significant drops in blood pressure (hypotension).

Before initiating therapy, consider the following precautions:

• Monitor blood pressure regularly: ensure therapeutic response and avoid hypotension.
• Assess renal function: adjust therapy if creatinine clearance is reduced.
• Check electrolytes: especially potassium and sodium levels.
• Use caution in elderly patients: increased sensitivity to blood pressure changes.
• Avoid in patients with severe hepatic impairment: limited data on safety.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Irbesartan/Hydrochlorothiazide may interact with several medicines. Review patient medication lists carefully.

Major Interactions (Avoid)

• Aliskiren: combined use can increase risk of renal dysfunction and hyperkalemia.
• 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 blood pressure and potassium.
• NSAIDs (high dose): may blunt antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Other antihypertensives: may require dose adjustment to prevent hypotension.
• Digoxin: monitor serum levels as diuretic‑induced electrolyte changes can affect toxicity.
• Antidiabetic agents: diuretic‑induced changes in glucose may require dose modification.
• Corticosteroids: may increase sodium retention, counteracting diuretic effect.
• Antimicrobials (e.g., trimethoprim): can raise potassium levels.