Introduction

Nifedipine appears as odorless yellow crystals or powder with the chemical name dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydro-3,5-pyridinedicarboxylate. It is the first generation of calcium channel blocker used to treat chronic stable hypertension and angina. The structure is shown in fig. 1.

Fig. 1 Structure of nifedipine

Application as a calcium channel blocker

Nifedipine is a calcium channel blocker that belongs to the dihydropyridine subclass. It was patented in 1967 and approved for use in the United States in 1981. FDA-approved indications include chronic stable hypertension and angina.

• Chronic stable hypertension

Chronic stable hypertension is caused by the narrowing or constriction of blood vessels, which is related to calcium ions entering the cells lining blood vessels through calcium channels. Chronic stable hypertension may lead to stroke, coronary artery disease, heart failure, dementia and atrial fibrillation. As a calcium channel blocker, nifedipine blocks the calcium channels in the blood vessels and slows the entry of calcium ions into the cells lining blood vessels, which promotes dilation of blood vessels and reduces blood pressure.

• Angina

Angina, also known as angina pectoris, is chest pain or pressure that is usually caused by insufficient blood supply to the heart muscle. The discomfort of angina is usually described as a pressure, heaviness, tightness, squeezing, burning, or choking sensation. Similar to the control of nifedipine for chronic stable hypertension, nifedipine can slow the entry of calcium ions into myocardial cells and promote dilatation of coronary arteries, leading to an increase in myocardial oxygen delivery. Nifedipine thus has antianginal properties.