Verapamil – Effect, Application & Risks
Verapamil
Verapamil is a vasodilating drug that belongs to the group of calcium antagonists or calcium channel blockers. According to the Vaughan/Williams classification, verapamil is one of the antiarrhythmics .
What is Verapamil?
Verapamil is an active ingredient that is widely used to treat cardiac arrhythmia . The drug has been on the Essential Medicines List since 1983. This list is maintained by the World Health Organization (WHO).
Verapamil is available in mono or combination form. Commercially available preparations contain the drug in the form of a racemate . It is a 1:1 mixture of enantiomers. The absorption of verapamil increases with long-term administration from 20% to 40%. A high first-pass effect can be observed. The half-life of the drug is 3-7 hours. Excretion takes place via the bile acids and the kidneys .
Pharmacological action
Verapamil is a calcium channel blocker. Calcium antagonists reduce the influx of calcium ions into the interior of muscle cells. As a result, the smooth muscles contract less. As a result, the blood vessels dilate . The influx of calcium into the heart ‘s voltage-gated calcium channels is also blocked. Inhibiting the influx of calcium reduces the heart muscle ‘s ability to beat. This is also referred to as a negative inotropic effect. The heart rate is also reduced. This reduces the heart’s need for oxygen, blood pressure drops, the vessels dilate and the load on the heart is relieved. through theVascular dilation also provides the heart muscle with more oxygen-rich blood.
However, verapamil not only has a vasodilating effect, but also delays conduction in the AV node of the heart.
Medical Application & Use
Verapamil is commonly used in patients with coronary artery disease (CAD). Chronically stable angina pectoris , unstable angina pectoris and spastic angina pectoris are also indications for the drug. Angina pectoris is an attack -like pain in the chest. It is caused by a temporary disruption in blood flow to the heart. Angina pectoris is usually caused by coronary artery disease. This in turn is caused by one or more narrowed coronary arteries .
The drug is also used in patients who have had a heart attack . However, it is only used if there is no heart failure and if beta blockers cannot be used.
Verapamil is one of the most important antiarrhythmic drugs. These are used to treat cardiac arrhythmias. Since the pulse rate is lowered, the drug can also be prescribed for atrial fibrillation or atrial flutter. In addition, verapamil is used to prevent cluster headaches . A very high dosage is necessary to suppress the attacks. Since this can also affect the heart, regular ECG examinations must be carried out when taking it.
In rare cases, verapamil is used to lower blood pressure in arterial hypertension . In other countries, verapamil is also administered for induratio penis plastica ( curvature of the penis ). Men with this condition experience severe pain when they get an erection , which is caused by an unnaturally sharp bending of the penis. Verapamil is not approved for the treatment of this disease in Germany.
Risks & side effects
Undesirable side effects include a reduced heart rate, AV blockage (up to and including third-degree AV block), low blood pressure, constipation , headaches and dizziness . The drug must not be used in shock , acute myocardial infarction and pronounced bradycardia . Sinus node syndrome , manifest heart failure and atrial fibrillation in patients with Wolff-Parkinson-White syndrome (WPW syndrome) are also possible contraindications .
Verapamil should also not be taken in the case of known hypersensitivity and in the first six months of pregnancy . Beta blockers should also not be administered together with the drug. Otherwise, an AV block with a life-threatening drop in blood pressure can occur. In the case of first-degree AV block, low blood pressure and a low heart rate, as well as impaired liver function , Lambert-Eaton syndrome , myasthenia gravis and advanced muscular dystrophy , verapamil may only be administered under careful monitoring. Since verapamil also passes into breast milk , it should be taken while breastfeedingonly be used in exceptional cases.
It should be noted that grapefruit can lead to improved absorption of verapamil when taken at the same time. Thus, a stronger effect can occur. Diuretic drugs can also increase the antihypertensive effect. The concomitant use of verapamil and cholesterol-lowering drugs in higher doses increases the risk of developing rhabdomyolysis . The dose of the cholesterol-lowering drug should be adjusted accordingly.
If loperamide and verapamil are taken at the same time, respiratory disorders can be triggered. Loperamide is used to treat diarrhea . If verapamil is taken, another preparation should be used if possible.
Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.