There are three possibilities: firstly, hypertensive drugs cause allergy and angioneurotic oedema. The second is that irregular use of hypertensive medication has caused renal damage, resulting in nephrogenic oedema. The third, the most common, is the administration of anti-hypertensive drugs of the calcium channel blocker class such as nifedipine and verapamil, which results in vasodilatation, accumulation of body fluid and exudation, and the development of edema of the ankle and back of the foot.