Irbesartán/Hidroclorotiazida Tecnigen (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazide is used to treat hypertension, acting on the renin‑angiotensin system and fluid balance.

• Essential hypertension: lowers systolic and diastolic blood pressure to reduce cardiovascular risk.
• Hypertension requiring diuretic therapy: adds diuretic effect to improve blood‑pressure control in volume‑dependent cases.
• Hypertension with concomitant cardiovascular risk: helps achieve target pressures in patients with additional risk factors such as dyslipidaemia or smoking.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors, preventing vasoconstriction and aldosterone‑mediated sodium retention. Hydrochlorothiazide acts on the distal convoluted tubule to inhibit NaCl reabsorption, increasing urinary excretion of sodium and water, which reduces plasma volume. This dual action also attenuates sympathetic activation and improves endothelial function, contributing further to antihypertensive efficacy.

Irbesartan/Hydrochlorothiazide may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Dizziness: sensation of light‑headedness, especially after the first doses.
• Headache: mild to moderate intensity, often transient.
• Increased urination: due to the diuretic component.
• Electrolyte imbalance (low potassium): mild hypokalaemia may occur.
• Fatigue: general feeling of tiredness.
• Mild gastrointestinal upset: nausea or abdominal discomfort.

Serious or Rare Side Effects

• Severe dehydration: marked fluid loss requiring medical attention.
• Hyperkalemia: elevated potassium levels that can affect heart rhythm.
• Acute kidney injury: sudden decline in renal function.
• Angioedema: swelling of face, lips, tongue or airway.
• Severe hypotension: dangerous drop in blood pressure.
• Allergic reactions: rash, itching, or anaphylaxis.

Before initiating therapy with Irbesartan/Hydrochlorothiazide, several precautions should be considered.

• Monitor blood pressure: ensure adequate control and avoid excessive hypotension.
• Check electrolytes: especially potassium and sodium levels during treatment.
• Assess renal function: periodic serum creatinine and eGFR measurements are recommended.
• Use caution in severe hepatic impairment: dose adjustments may be required.
• Consider elderly patients: increased sensitivity to blood‑pressure changes and electrolyte disturbances.
• Store at room temperature: keep in the original packaging, protect from moisture and direct sunlight.

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

Major Interactions (Avoid)

• Aliskiren: combined renin‑angiotensin blockade may increase risk of renal impairment and hyperkalaemia.
• Potassium‑sparing diuretics (e.g., spironolactone): can cause dangerous hyperkalaemia.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs): may blunt antihypertensive effect and worsen renal function.

Moderate Interactions (Monitor Closely)

• ACE inhibitors or other ARBs: additive blood‑pressure lowering and potassium rise.
• Lithium: thiazide component may increase lithium levels, risking toxicity.
• Antidiabetic agents: diuretic effect can affect glucose control.
• CYP2C9 inhibitors (e.g., fluconazole): may raise irbesartan concentrations.
• High‑dose corticosteroids: can counteract antihypertensive action.