Irbesartan And Hydrochlorothiazide Milpharm (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazide is used to manage hypertension and related cardiovascular conditions.

• Hypertension: reduces systolic and diastolic blood pressure in patients with primary hypertension.
• Hypertensive nephropathy: slows progression of kidney damage associated with high blood pressure.
• Heart failure with reduced ejection fraction: assists in controlling fluid overload and blood pressure when combined with diuretics.

• Irbesartan selectively blocks the angiotensin II type 1 (AT1) receptor, preventing angiotensin II‑mediated vasoconstriction, aldosterone release and sympathetic activation. Hydrochlorothiazide acts on the distal convoluted tubule, inhibiting NaCl reabsorption, which promotes natriuresis and diuresis, decreasing plasma volume. The combined effect results in lowered peripheral resistance and reduced cardiac preload, producing an overall antihypertensive response. This dual mechanism enhances blood pressure control compared with monotherapy.

The most frequently reported adverse reactions with Irbesartan/Hydrochlorothiazide involve electrolyte changes and mild gastrointestinal symptoms.

Common Side Effects

• Dizziness: light‑headed sensation, especially after standing.
• Headache: mild to moderate intensity.
• Increased urination: due to diuretic action.
• Electrolyte imbalance: low potassium or sodium levels.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue, potentially airway obstruction.
• Severe hypotension: marked drop in blood pressure causing faintness.
• Acute kidney injury: sudden decline in renal function, indicated by rising creatinine.

When prescribing Irbesartan/Hydrochlorothiazide, clinicians should consider several precautionary measures to ensure patient safety.

• Renal function: assess baseline kidney function and monitor creatinine.
• Electrolytes: check serum potassium and sodium before initiation and during therapy.
• Volume depletion: avoid use in patients with dehydration or excessive diuretic use.
• Pregnancy: contraindicated in the second and third trimesters; avoid unless benefits outweigh risks.
• Concomitant drugs: review for interactions with potassium‑sparing agents or NSAIDs.
• Store at ambient temperature: keep below 25°C in the original container, protect from moisture and light.

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

Major Interactions (Avoid)

• Potassium‑sparing diuretics or supplements: risk of hyperkalaemia.
• ACE inhibitors or other ARBs: additive effect on blood pressure and renal function.
• NSAIDs: may reduce antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Lithium: increased lithium levels, monitor serum concentration.
• Cyclosporine or tacrolimus: may increase serum creatinine.
• Antidiabetic drugs: diuretic may affect glucose control, monitor blood sugar.