Diltiazem is the name given to a certain calcium antagonist. The drug is used to treat cardiovascular disease.
What is diltiazem?
Diltiazem is the name given to a certain calcium antagonist. The drug is used to treat cardiovascular disease. Diltiazem is an antiarrhythmic drug that belongs to the calcium antagonists or calcium channel blockers. The active ingredient has vasodilatory properties and causes a delay in performance within the AV node of the heart. Furthermore, diltiazem belongs to the benzothiazepines. Diltiazem was approved in Europe in the early 1980s. The drug is primarily used to treat cardiovascular diseases and is marketed by the pharmaceutical company Pfizer in Germany under the name Dilzem. In addition, several other suppliers market the drug as a generic.
Pharmacologic action
Diltiazem is a calcium channel blocker. The active ingredient is able to combine all three active properties of calcium channel blockers. First, it reduces the heart‘s need for oxygen and increases blood flow to the heart muscle. This has the advantage that angina pectoris attacks can be reduced or even completely prevented. At the same time, diltiazem exerts its effect on the blood vessels by dilating them. This results in the lowering of elevated blood pressure. Diltiazem also has a positive effect on the heart muscle, making the drug suitable for the treatment of cardiac arrhythmias. If the drug is administered in medically suitable doses, it causes the heart’s beating rate to slow down. This delays the transmission of excitation between the ventricles and the atrium, which in turn significantly reduces the workload on the heart. As a calcium channel blocker, diltiazem blocks special channels within the muscle cell walls that allow calcium to flow into the cells. The calcium inside the cells causes the muscle cells to tense, resulting in constriction of the blood vessels. However, the effect of diltiazem allows the muscle cells to relax and dilate the vessels (vasodilatation). The bioavailability of the calcium channel blocker is around 40 percent. The drug is metabolized by the liver. The average plasma half-life is reported to be four hours. Removal of diltiazem from the body occurs through urine and stool.
Medicinal use and application
Diltiazem is administered for hypertension in which there are no organic causes. Heart disease associated with a problematic oxygen supply to the heart muscle and circulatory disorders in the coronary arteries represent another important indication. This is the case with coronary artery disease (CAD). Thus, diltiazem is used for the treatment of stable, unstable and vasospastic angina pectoris. As an antiarrhythmic agent, diltiazem can also be used to treat cardiac arrhythmias. The drug is suitable for the prevention of paroxysmal supraventricular tachycardia. In atrial flutter and atrial fibrillation, the drug can slow the pulse rate. Occasionally, diltiazem is used following kidney transplantation to counteract rejection of the transplanted organ. Furthermore, it can reduce the toxicity of ciclosporin A during immunosuppressive treatment. Diltiazem can also be administered topically. The active ingredient is used in the form of a cream or ointment for the treatment of anal fissures. The drug is also suitable for the treatment of diffuse esophageal spasms in order to relax the esophageal muscles. Diltiazem is usually taken as a sustained-release tablet that releases the active ingredient continuously. For the treatment of hypertension and coronary artery disease, one tablet is administered twice a day. If necessary, the dose can also be increased to four sustained-release tablets daily. Since taking diltiazem is a long-term therapy, the active ingredient is usually taken permanently.
Risks and side effects
Taking diltiazem may cause side effects in some patients. These are mostly fatigue, headache, dizziness, muscle pain, general weakness, edema of the ankles or legs, joint pain, and allergic reactions such as exanthema and itching.Rarely, swelling of the lymph nodes, autoimmune diseases such as lupus erythematosus, growths on the gums, and an increase in white blood cells are seen. If the dosage is too high, there is a risk of conduction disorders, a sharp drop in blood pressure, bradycardia, palpitations, cardiac muscle weakness, erectile dysfunction in men, and fainting if the heart is already damaged. If hypersensitivity to diltiazem is present, affected individuals must refrain from taking the calcium channel blocker. The same applies in the case of cardiac muscle weakness, sinus node syndrome (impaired conduction of impulses to the heart), acute myocardial infarction, shock, and certain cardiac arrhythmias in which there is a high heart rate. Only cautious dosing of diltiazem is allowed in case of ventricular tachycardia or limitations of liver function. During pregnancy and lactation, administration of the calcium channel blocker should be avoided. Women of childbearing potential must rule out pregnancy before starting therapy with diltiazem. The drug must also not be used in children, as there is insufficient knowledge about the effects of the drug on them. In addition, interactions with the simultaneous use of other drugs must be taken into account. For example, cardiac arrest due to AV blockade and an increased blood pressure-lowering effect is sometimes possible with the administration of inhalation anesthetics. An increase in the effect of diltiazem can occur through a combination with antiarrhythmic drugs such as quinidine or beta blockers. The effect of the drug is reduced by the simultaneous administration of enzyme inducers. These include phenytoin, phenobarbital, and rifampicin. Diltiazem, in turn, may reduce the effect of lithium. Alkaline infusion and injection solutions are considered incompatible with diltiazem, so that no mixing with the calcium channel blocker may take place in these. Otherwise, there is a risk of flocculation with diltiazem within the solution.
