1) Non dihydropyridines
Is a calcium channel blocker. It has been used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, and most recently, headaches. Verapamil has also been used as a vasodilator during cryopreservation of blood vessels. It is a class 4 antiarrhythmic, more effective than digoxin in controlling ventricular rate.
Mechanism and uses:
Verapamil's mechanism in all cases is to block voltage-dependent Calcium channels. In cardiac pharmacology, Calcium channel blockers are considered class IV antiarrhythmic agents. Since Calcium channels are especially concentrated in the sinoatrial and atrio-ventricular nodes, these agents can be used to decrease impulse conduction through the AV node, thus protecting the ventricles from atrial tachyarrhythmias.
Calcium channels are also present in the smooth muscle that lines blood vessels. By relaxing the tone of this smooth muscle, calcium-channel blockers dilate the blood vessels. This has led to their use in treating hypertension and angina pectoris. The pain of angina is caused by a deficit in oxygen supply to the heart.
Calcium channel blockers like Verapamil will dilate blood vessels, which increases the supply of blood and oxygen to the heart. This controls chest pain, but only when used regularly. It does not stop chest pain once it starts. A more powerful vasodilator such as nitroglycerin may be needed to control pain once it starts.
- Heart block
- Heart Failure
- Facial flushing
- Increased urination
2) Dihydropyridines (DHP)
Is a dihydropyridine calcium channel blocker. Its main uses are in angina pectoris (especially Prinzmetal's angina) and hypertension, although a large number of other uses have recently been found for this agent, such as Raynaud's phenomenon, premature labor, and painful spasms of the esophagus in cancer and tetanus patients. It is also commonly used for the small subset of pulmonary hypertension patients whose symptoms respond to calcium channel blockers.
Long-term treatment of hypertension (high blood pressure) and angina pectoris. In hypertension, recent clinical guidelines generally favour diuretics and ACE inhibitors, although calcium channel antagonists are still favoured as primary treatment for older black patients. Sublingual nifedipine has previously been used in hypertensive emergencies. This was found to be dangerous, and has been abandoned.
- Reflex tachycardia
- Ankle Edema