What are the side effects of Captopril?

Under normal circumstances, captopril is commonly available in tablet and injectable formulations. Its potential side effects may include cough, hypotension, hyperkalemia, renal impairment, and angioedema. A detailed analysis is as follows:

1. Cough

Captopril inhibits angiotensin-converting enzyme, thereby decreasing the degradation of bradykinin, which accumulates in the body and stimulates receptors in the respiratory tract, leading to dry cough. This cough is typically persistent with little or no sputum production and may appear weeks or even months after starting the medication. Some patients may need to discontinue the drug due to severe coughing.

2. Hypotension

The main effect of captopril is to lower blood pressure. During the initial phase of treatment or during dosage adjustments, excessive lowering of blood pressure may occur, leading to hypotension. Patients may experience symptoms such as dizziness, fatigue, visual darkening, or even syncope, particularly when standing up suddenly or changing positions.

3. Hyperkalemia

Captopril reduces aldosterone secretion, resulting in decreased excretion of potassium ions and consequently elevated serum potassium levels. Hyperkalemia may affect normal cardiac function, causing arrhythmias, and in severe cases, cardiac arrest. Patients may experience palpitations, chest tightness, numbness in limbs, especially those with renal insufficiency or those concurrently using potassium-sparing diuretics.

4. Renal Impairment

Captopril may have adverse effects on renal function, especially in patients with bilateral or unilateral renal artery stenosis. Administration of captopril may reduce renal perfusion pressure, leading to a decrease in glomerular filtration rate and increased serum creatinine and blood urea nitrogen levels. In severe cases, it may lead to renal failure.

5. Angioedema

Captopril may induce allergic reactions in the body, increasing vascular permeability and causing edema in the skin and submucosal tissues. Commonly affected areas include the face, lips, tongue, and throat. Severe angioedema may lead to airway obstruction.

Although captopril is an effective antihypertensive drug, it may also cause various side effects. Therefore, when using captopril, patients should follow medical instructions, monitor their physical responses carefully, and seek timely medical attention for any adverse effects.