Irbesartan + Hidroclorotiazida Farmoz (Hydrochlorothiazide, Irbesartan)

Irbesartan/Hydrochlorothiazide acts on the renin‑angiotensin‑aldosterone system to control elevated blood pressure.

• Hypertension: reduces systolic and diastolic blood pressure in patients with primary hypertension.
• Hypertension with fluid retention: provides additional diuretic effect to manage volume overload.
• Hypertension uncontrolled by monotherapy: offers combined ARB and thiazide action for patients needing two agents.

• Irbesartan selectively blocks AT1 receptors, preventing angiotensin II‑mediated vasoconstriction and aldosterone release. Hydrochlorothiazide inhibits sodium‑chloride reabsorption in the distal convoluted tubule, increasing urinary excretion of water and electrolytes, which together lower peripheral resistance and plasma volume, resulting in reduced arterial pressure.

Common side effects are generally mild and may resolve with continued therapy.

Common Side Effects

• Dizziness: sensation of light‑headedness, especially after standing.
• Headache: mild to moderate pain in the head region.
• Increased urination: more frequent need to void due to diuretic action.
• Electrolyte imbalance: low potassium or sodium levels.
• Fatigue: feeling unusually tired or weak.
• 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.
• Angioedema: swelling of face, lips, tongue, or throat.
• Severe hypotension: marked drop in blood pressure causing fainting.
• Allergic reactions: rash, itching, or anaphylaxis.

Before initiating therapy, consider the following safety measures.

• Blood pressure monitoring: ensure target levels are achieved without excessive drop.
• Renal function assessment: check serum creatinine and eGFR periodically.
• Electrolyte surveillance: monitor potassium and sodium levels, especially in patients on other diuretics.
• Hepatic impairment: use with caution in patients with liver disease.
• Pregnancy and lactation: safety not established; avoid unless benefits outweigh risks.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Irbesartan/Hydrochlorothiazide may interact with several drug classes.

Major Interactions (Avoid)

• ACE inhibitors: combined use can increase risk of hyperkalemia and renal dysfunction.
• Lithium: diuretic component may raise lithium concentrations, leading to toxicity.
• Potassium‑sparing diuretics: additive effect on serum potassium, risking hyperkalemia.
• Rifampin: enzyme induction may reduce irbesartan plasma levels.
• NSAIDs: may blunt antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Other antihypertensives: additive blood‑pressure lowering may require dose adjustment.
• CYP2C9 inhibitors (e.g., fluconazole): may increase irbesartan exposure.
• Antidiabetic agents: diuretic‑induced changes in glucose may affect glycemic control.
• High‑dose corticosteroids: can counteract antihypertensive effect.
• Alcohol: may enhance dizziness and hypotensive effects.