Irbesartan/Hydrochlorothiazid Micro Labs (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazid is indicated for hypertension management, acting on the renin‑angiotensin‑aldosterone system to lower blood pressure.

• Hypertension: helps achieve target blood pressure when lifestyle measures are insufficient.
• Heart failure with reduced ejection fraction: used as part of combination therapy to reduce morbidity.
• Diabetic nephropathy: slows progression of kidney damage in patients with type 2 diabetes.
• Post‑myocardial infarction: assists in blood‑pressure control to lower risk of recurrent events.
• Chronic kidney disease: aids in blood‑pressure control to protect renal function.

• Irbesartan blocks the binding of angiotensin II to the AT1 receptor, preventing vasoconstriction and aldosterone release. Hydrochlorothiazide inhibits sodium‑chloride reabsorption in the distal convoluted tubule, promoting diuresis. The combined actions reduce intravascular volume and peripheral resistance, resulting in lower systemic blood pressure.

Common Side Effects

• Dizziness: may occur especially after the first doses.
• Headache: mild to moderate intensity.
• Fatigue: general feeling of tiredness.
• Increased urination: due to the diuretic component.
• Electrolyte imbalance: mild changes in potassium or sodium levels.
• Cough: occasional dry throat irritation.

Serious or Rare Side Effects

• Severe hypotension: marked drop in blood pressure causing fainting.
• Acute kidney injury: sudden decline in renal function.
• Hyperkalemia: dangerously high potassium levels.
• Angio‑edema: swelling of face, lips, or airway.
• Liver injury: elevated transaminases or jaundice.
• Blood dyscrasias: rare blood cell abnormalities.

When prescribing Irbesartan/Hydrochlorothiazid, clinicians should consider patient‑specific factors and monitor relevant parameters.

• Renal function: assess baseline creatinine and eGFR before initiation.
• Electrolytes: monitor potassium and sodium levels regularly.
• Blood pressure: check for excessive hypotension after dose changes.
• Pregnancy: avoid use in the second and third trimesters due to fetal risk.
• Drug interactions: review concomitant medications for additive hypotensive effects.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Irbesartan/Hydrochlorothiazid may interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Potassium‑sparing diuretics or supplements: risk of hyper‑kalemia.
• ACE inhibitors or other ARBs: additive renal impairment and hypotension.
• NSAIDs: may blunt antihypertensive effect and affect renal function.

Moderate Interactions (Monitor Closely)

• Lithium: increased lithium levels and toxicity risk.
• Antidiabetic agents: enhanced hypoglycaemic effect.
• Beta‑blockers: may potentiate blood‑pressure lowering.
• Cyclosporine or tacrolimus: increased risk of nephrotoxicity.
• Digoxin: altered serum concentrations.