Irbesartan/Hydrochloorthiazide 1a Pharma (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazide acts on the renin‑angiotensin‑aldosterone system and renal sodium handling to lower blood pressure.

• Essential hypertension: reduces systolic and diastolic pressure and lowers cardiovascular risk.
• Hypertension requiring diuretic therapy: provides combined antihypertensive and diuretic effects for better control.
• Resistant hypertension: adds an additional mechanism when monotherapy is insufficient.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors, preventing vasoconstriction and aldosterone release, while hydrochlorothiazide inhibits NaCl reabsorption in the distal convoluted tubule, increasing urinary sodium and water excretion. The combined actions decrease peripheral vascular resistance and plasma volume, resulting in lowered arterial blood pressure.

Common Side Effects

• Dizziness: feeling light‑headed, especially after the first doses.
• Headache: mild to moderate intensity.
• Fatigue: general tiredness or lack of energy.
• Increased urination: due to the diuretic component.
• Electrolyte imbalance: low potassium or sodium levels.
• Mild gastrointestinal upset: nausea or abdominal discomfort.

Serious or Rare Side Effects

• Severe dehydration: excessive fluid loss leading to low blood pressure.
• Acute kidney injury: sudden decline in renal function.
• Hyperkalemia: dangerously high potassium levels.
• Anaphylaxis: severe allergic reaction with rash, swelling, or breathing difficulty.
• Blood disorders: such as agranulocytosis or leukopenia.
• Liver injury: elevated liver enzymes or hepatitis.

Before initiating therapy, consider the following precautions:

• Monitor blood pressure: check regularly to assess efficacy.
• Assess renal function: evaluate serum creatinine and eGFR before and during treatment.
• Check electrolytes: especially potassium and sodium levels.
• Avoid in severe hepatic impairment: use with caution or consider alternatives.
• Consider pregnancy status: category unknown; avoid unless benefits outweigh risks.
• Store at ambient temperature: keep below 25°C, protect from moisture and light in the original container.

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

Major Interactions (Avoid)

• Potassium‑sparing diuretics or supplements: risk of hyperkalemia.
• ACE inhibitors or other ARBs: additive effect on potassium and renal function.
• Lithium: increased lithium levels and toxicity.
• NSAIDs: may reduce antihypertensive effect and impair renal function.
• Cyclosporine: increased risk of renal dysfunction.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may enhance antihypertensive effect.
• Other diuretics: additive diuretic effect.
• Antidiabetic agents: may increase hypoglycemic effect.
• Antihistamines: may increase dizziness.
• Alcohol: may potentiate hypotension.