What Is Verapamil Hydrochloride and How Does It Work?
Verapamil hydrochloride is an L-type calcium channel blocker that works by selectively inhibiting the influx of calcium ions to conductile and contractile myocardial cells and vascular smooth muscle cells. The drug has antiarrhythmic properties due to its effect in slowing atrioventricular conduction, thereby reducing the ventricular rate and quickening the ventricular response. Verapamil hydrochloride also has a vasodilation response, which increases blood flow and oxygen supply to the heart.1 This drug can be used to treat angina and arrhythmia, hypertension, and certain types of headaches.
Angina: Verapamil hydrochloride is used to treat angina by relaxing and preventing coronary artery spasms, and by reducing energy consumption (and thus oxygen usage) by the heart.2
Arrhythmia: Verapamil hydrochloride is used for rapid conversion of paroxysmal supraventricular tachycardia to a normal sinus rhythm and for temporary control of a rapid ventricular rate in atrial flutter or atrial fibrillation.
Hypertension: Verapamil hydrochloride’s vasodilation properties make the drug suitable for treating hypertension.
Headaches: Verapamil hydrochloride is sometimes used off-label to treat migraines and cluster headaches.
Side Effects and Drug Interactions
Common side effects in patients taking verapamil hydrochloride include3:
Itchy skin or skin rash
Fatigue or weakness
Feeling of warmth
Redness or tingly feeling under the skin
Patients who suffer from severity of these common side effects should contact their pharmacist or physician right away. Patients who experience a severe allergic reaction (hives, difficulty breathing, swelling of the face, lips, tongue, or throat) should call for emergency help right away. Patients who experience fast or slow heartbeats, fainting, fever, sore throat, headache with
severe blistering, peeling, or skin rash, restless muscle movements in eyes, tongue, jaw, or neck, shortness of breath, swelling, rapid weight gain, loss of appetite, jaundice, or dark urine or clay-colored stools should inform their physician immediately.
Patients who are allergic to verapamil hydrochloride should not take this drug. Patients who have or have had heart failure, blood pressure conditions, elevated liver enzymes, an accessory bypass tract, an atrioventricular block, or hypertrophic cardiomyopathy should inform their physician before starting this medication. This drug is contraindicated for patients who suffer from severe left ventricular dysfunction, hypotension, cardiogenic shock, sick sinus syndrome (except in patients who have a ventricular pacemaker), second- or third-degree atrioventricular block (again, unless patient has a ventricular pacemaker), and atrial flutter or atrial fibrillation accompanied by an accessory bypass tract.
Latest News and Research
The many uses of verapamil hydrochloride are still being studied. In a current clinical trial, the safety and efficacy of oral verapamil hydrochloride is under investigation in patients with recent onset of Type I diabetes.4 The goals are to assess beta cell survival, insulin production and glucose control, with an eye toward treating type I diabetes. If successful, as initial results indicate, this drug would be able to reverse destruction of beta cells, essentially reversing the effects of the disease.
The use of verapamil hydrochloride is under study for treating, or rather preventing, filoviruses such as Ebola virus from entering cells.5 An in vitro study of verapamil hydrochloride, as well as other ion channel blocking drugs already on the market, show that this may be a promising way to halt Ebola and other filoviruses from taking hold in the human body.
Verapamil hydrochloride is also being studied for treatment of tuberculosis.6 In a mouse model, the drug was shown to reduce tolerance by bacteria and showed increased efficacy of the primary medication. Further studies are needed but the drug shows promise for reducing treatment time in patients.