Which of the following are chemical classifications of calcium channel blockers?

Calcium channel blockers are classified primarily based on their chemical structure, which influences their pharmacological properties. The correct classification includes benzothiazepines and dihydropyridines. Benzothiazepines, such as diltiazem, act on both calcium channels and have effects on cardiac tissues, leading to a reduction in heart rate and myocardial contractility. Dihydropyridines, like amlodipine and nifedipine, primarily affect peripheral vascular resistance, making them potent vasodilators with minimal direct effects on the heart.

The other options do not represent classifications related to calcium channel blockers. Amines and amino acids pertain to different classes of compounds and do not encompass the calcium channel blocker category. Steroids and NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) are unrelated pharmacological classes primarily focused on inflammatory processes and hormonal effects. Similarly, beta-blockers and angiotensin II receptor antagonists belong to different pharmacological classes that target the cardiovascular system but do not function as calcium channel blockers. Thus, the correct answer highlights the specific chemical classifications that are relevant to the function and action of calcium channel blockers.