Interpril (Zofenopril Calcium, Hydrochlorothiazide)

Interpril is an antihypertensive combination that addresses conditions within the cardiovascular system.

• Hypertension: lowers elevated blood pressure by reducing vascular resistance.
• Edema associated with heart failure: promotes fluid excretion to decrease swelling.
• Heart failure adjunct therapy: supports overall cardiac function by managing fluid overload and blood pressure.

• Zofenopril calcium blocks the angiotensin‑converting enzyme, preventing formation of angiotensin II and reducing vasoconstriction, while hydrochlorothiazide inhibits Na⁺/Cl⁻ reabsorption in the distal convoluted tubule, increasing urinary sodium and water loss. The combined actions decrease circulating blood volume and peripheral resistance, resulting in lowered arterial pressure.

Common side effects are generally mild and transient.

Common Side Effects

• Cough: dry, persistent throat irritation.
• Dizziness or light‑headedness, especially after standing.
• Headache.
• Fatigue or general weakness.
• Increased urination due to the diuretic component.
• Electrolyte changes such as low potassium.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue, or airway.
• Severe hypotension: markedly low blood pressure causing fainting.
• Acute kidney injury or worsening renal function.
• Significant electrolyte disturbances (e.g., hyponatremia, hyperkalemia).
• Pancreatitis.
• Severe skin reactions such as Stevens‑Johnson syndrome.

Before initiating therapy, consider the following safety measures.

• Blood pressure monitoring: ensure target levels are achieved without excessive drops.
• Renal function assessment: evaluate serum creatinine and eGFR periodically.
• Electrolyte surveillance: check potassium and sodium levels, especially with diuretic use.
• Pregnancy avoidance: drug is contraindicated in pregnancy (Category D).
• Elderly caution: start at lower doses and monitor for orthostatic symptoms.
• Store at room temperature: keep tablets in the original container, protect from moisture and direct sunlight.

Interpril may interact with several medicines; categorize the risk level.

Major Interactions (Avoid)

• Concomitant use with aliskiren in diabetic patients.
• Combined therapy with other ACE inhibitors or ARBs.

Moderate Interactions (Monitor Closely)

• NSAIDs: may blunt antihypertensive effect and affect renal function.
• Potassium‑sparing diuretics or supplements: increase risk of hyperkalemia.
• Lithium: can raise lithium serum concentrations, risking toxicity.