Verapamil instructions for use
Verapamil refers to calcium channel blockers. It is used in the therapy of cardiovascular diseases. It shows anti-anginal, antiarrhythmic and antihypertensive properties.
Form of issue and composition
Verapamil is available in the form of film-coated tablets in doses of 40 mg and 80 mg. Tablets with instructions are placed in cardboard packaging (10 and 50 tablets per pack). Another dosage form is a solution for intravenous administration.
The main active ingredient is verapamil hydrochloride.
Auxiliary components: calcium phosphate disubstituted, starch, magnesium stearate, hydroxypropylmethylcellulose, butylhydroxyanisole, purified talc, gelatin, titanium dioxide, methylparaben, indigocarmine.
Pharmacodynamics. Verapamil - a blocker of calcium channels with antiarrhythmic, antianginal and antihypertensive properties.
Verapamil reduces the need for oxygen in the myocardium by reducing contractility and heart rate. As a result of the drug, the coronary vessels of the heart expand, the coronary blood flow increases. The tone of peripheral arteries and the general peripheral vascular resistance decrease.
The drug has a therapeutic effect with supraventricular arrhythmia due to oppression of the automatism of the sinus node.
Verapamil is the drug of choice in the therapy of vasospastic angina. The pronounced therapeutic effect of verapamil is noted in the treatment of other forms of angina pectoris.
Pharmacokinetics. When taking the tablets, more than 90% of the accepted dose of the active substance is absorbed. In the liver, verapamil is metabolized. The hypotensive activity of the main metabolite - norverapamil is less pronounced than in unchanged verapamil. 90% of verapamil is bound to plasma proteins. With a single tablet administration, the elimination half-life is 2.8-7.4 hours, with repeated administration, the elimination half-life can range from 4.5 hours to 12 hours.
Indications for use
Verapamil is used for:
- Therapy and prevention of angina pectoris (otherwise - chronic stable angina), resting angina (unstable angina), vasospastic angina pectoris;
- Therapy and prevention of cardiac rhythm disturbances - paroxysmal supraventricular tachycardia, supraventricular extrasystole, flicker and atrial flutter;
- Therapy of arterial hypertension.
Contraindications to the appointment of Verapamil are:
- Acute heart failure;
- Chronic heart failure (at stage IIB, III);
- Severe bradycardia;
- Atrioventricular block (II and III degree);
- Synotrial blockade;
- Syndromes: Morgagni-Adams-Stokes, Wolff-Parkinson-White, weakness of the sinus node;
- Cardiogenic shock;
- Simultaneous intravenous injection of β-blockers;
- Age to 18 years;
- Hypersensitivity to the main or auxiliary components.
Dosing and Administration
Verapamil is taken during or after a meal, washed down with a small amount of liquid. Doses are set individually based on the form, severity of the pathology, individual patient characteristics and the effectiveness of the treatment.
Adults for the prevention of attacks of arrhythmia, angina pectoris and hypertension are prescribed 40-80 mg verapamil 3-4 times a day. It is possible to increase the single dose to 120-160 mg. The maximum daily dosage of verapamil is 480 mg.
Patients with severe functional impairment of the liver verapamil is prescribed in minimal therapeutic doses, and the maximum allowable daily dose is 120 mg.
When using verapamil, unwanted side effects can develop:
- Cardiovascular system - atrioventricular block, bradycardia, reddening of face, arterial hypotension, signs of heart failure (especially in predisposed patients with high doses of verapamil);
- From the side of the nervous system - headache, dizziness, inhibition, nervous excitability, fatigue;
- On the part of the digestive system - vomiting, nausea, constipation, increased activity of liver enzymes;
- Allergic reactions - skin itching and rash;
- Other reactions - peripheral edema.
When an overdose of verapamil (intake of up to 6 g of a drug) develops hypertension, sinus bradycardia, atrioventricular blockade or asystole. Deep loss of consciousness is possible.
To treat the drug poisoning intravenously, calcium gluconate, dopamine, noradrenaline or isoproterenol is administered. Depending on the clinical signs of poisoning, prescriptions are prescribed for symptomatic therapy. Hemodialysis in this case is not effective.
During the application of Verapamil required mandatory monitoring of the functions of the heart, blood vessels, respiratory system.
In some pathologies, verapamil is administered with caution. It:
- Pronounced functional disorders of the liver (the maximum dose for such violations is 120 mg);
- Arterial hypotension;
- Initial stages of chronic heart failure;
- Atrioventricular blockade of the 1st degree;
- Combination with β-adrenoblockers, antiarrhythmics, inhalation anesthetics causes an increase in cardiotoxic effect, manifested by atrioventricular blockade, a sharp decrease in blood pressure and heart rate, heart failure;
- Combination with carbamazepine and lithium preparations causes an increase in neurotoxic effects;
- Combination with acetylsalicylic acid increases the risk of bleeding;
- Combination with muscle relaxants enhances their effect;
- Simultaneous administration with diuretics and antihypertensive drugs causes an increase in the hypotensive effect of verapamil;
- In combination with digoxin, its plasma concentration increases and kidney excretion worsens (digoxin level in plasma should be constantly monitored);
- In combination with quinidine, its plasma concentration increases, and accordingly the probability of severe hypotension increases;
- In combination with prazosin, theophylline, cyclosporin their plasma concentration increases;
- Cimetidine and ranitidine increase the plasma concentration of verapamil;
- Phenobarbital and rifampicin lower the plasma concentration and therapeutic effect of verapamil.
Pregnancy and lactemia
Pregnant women Verapamil is prescribed only in situations where the intended benefit to the mother exceeds the potential threat to the fetus.
Verapamil is excreted in breast milk, so for the period of treatment, breastfeeding is canceled.
The structural analogues of Verapamil include preparations of Finoptin, Isoptin, Isoptin CP 240, Verogalide EP 240.
Terms and conditions of storage
Verapamil is stored out of reach of children, protected from moisture and sunlight, at a temperature of up to 25 ° C. Shelf life is 3 years. Do not take the pill after the expiration date indicated on the package.
Verapamil tablets 40 mg, 50 tablets - 35-45 rubles.
Verapamil tablets 80 mg, 50 tablets - 55-75 rubles.