Product Overview
[Drug Name]
Generic Name: Verapamil Hydrochloride Tablets
Trade Name: Xinyi
English Name: Verpamil Hydrochloride Tablets
Chinese Pinyin: Yansuan Weiapami Pian
[Ingredients]
The main ingredient of this product is verapamil hydrochloride. Its chemical name is: α-[3-[[2-(3,4-dimethoxyphenyl)ethyl]methylamino]propyl]-3,4-dimethoxy-α-isopropylphenylacetonitrile hydrochloride. Molecular formula: C27H38N2O4·HCl. Molecular weight: 491.07
[Properties]
This product is a sugar-coated tablet. After removing the sugar, it appears white.
[Indications]
1. Angina pectoris: variant angina; unstable angina; chronic stable angina.
2. Arrhythmias: Used in combination with digoxin to control the ventricular rate in chronic atrial fibrillation and/or atrial flutter; to prevent recurrent episodes of paroxysmal supraventricular tachycardia.
3. Essential hypertension.
[Dosage and Administration]
Treatment is individualized through dose adjustment. The safe and effective dose is no more than 480 mg (12 tablets) per day.
1. Angina: The general dose is 80-120 mg (2-3 tablets) of verapamil orally three times a day. A safe dose for patients with hepatic impairment and the elderly is 40 mg (1 tablet) orally three times a day. The dose may be increased approximately 8 hours after administration based on efficacy and safety assessments.
2. Arrhythmias: For patients with chronic atrial fibrillation taking digitalis, the total daily dose is 240-320 mg (6-8 tablets) orally three or four times a day. For the prevention of paroxysmal supraventricular tachycardia (in patients not taking digitalis), the total daily dose for adults is 240-480 mg (6-12 tablets) orally three or four times daily. Ages 1-5 years: Daily dose 4-8 mg/kg divided orally three times daily; or 40-80 mg (1-2 tablets) orally every 8 hours. Ages >5 years: 80 mg (2 tablets) orally every 6-8 hours.
3. Essential hypertension: The general starting dose is 80 mg (2 tablets) orally three times daily. The daily dose can be as high as 360-480 mg (9-12 tablets). For elderly or thin individuals who respond to lower doses, a starting dose of 40 mg (1 tablet) orally three times daily should be considered.
[Adverse Reactions]
Serious adverse reactions are rare when starting with the recommended single dose and total daily dose and titrating upward. Adverse reactions with an incidence of 1-10% include: constipation (7.3%); dizziness, mild headache (3.5%); nausea (2.7%); hypotension (2.5%); headache (2.2%); peripheral edema (2.1%); congestive heart failure (1.8%); sinus bradycardia, first-, fifth-, or third-degree atrioventricular block; rash (1.2%); fatigue; palpitations; elevated transaminases, with or without elevated alkaline phosphatase and bilirubin; these elevations are sometimes transient and may disappear even with continued verapamil treatment. Adverse reactions with an incidence of <1% include: hypotension; tachycardia; flushing; galactorrhea; gingival hyperplasia; and non-obstructive paralytic ileus.
Contraindications:
1. Severe left ventricular dysfunction. 2. Hypotension (systolic blood pressure less than 90 mmHg) or cardiogenic shock. 3. Sick sinus syndrome (except in patients with a functional pacemaker). 4. Second or third degree atrioventricular block (except in patients with a functional pacemaker). 5. Patients with atrial flutter or atrial fibrillation and concurrent atrioventricular accessory pathways. 6. Patients with a known hypersensitivity to verapamil hydrochloride.
[Precautions]
1. Heart Failure: Verapamil's negative inotropic effects can be compensated by reduced afterload (lowering vascular resistance), with the net effect not impairing ventricular function. However, verapamil should be avoided in patients with severe left ventricular dysfunction (pulmonary wedge pressure greater than 20 mmHg or ejection fraction less than 30%), moderate to severe heart failure, or any degree of ventricular dysfunction already receiving beta-blocker therapy. Patients with mild heart failure who must use verapamil should have their clinical symptoms controlled with digitalis or diuretics before treatment. 2. Preexcitation Syndrome: Verapamil can accelerate antegrade conduction along the atrioventricular accessory pathway. Intravenous verapamil therapy in patients with an AV accessory pathway and atrial flutter or atrial fibrillation can accelerate ventricular rate and even induce ventricular fibrillation by accelerating anterograde conduction along the AV accessory pathway. Although this has not been reported with oral verapamil, oral verapamil may be hazardous in such patients and is therefore contraindicated. 3. Conduction block: Verapamil may cause atrioventricular and sinus node block, associated with increased plasma concentrations, particularly during the early, incremental phase of treatment. This can result in first-degree AV block, transient sinus bradycardia, and sometimes nodal escape beats. High-degree AV block is uncommon (0.8%). When significant first-degree AV block develops or develops into full- or deep-degree AV block, dose reduction or discontinuation is indicated. 4. Hepatic impairment: Verapamil is extensively metabolized in the liver and should be used with caution in patients with impaired liver function. In severe hepatic impairment, the elimination half-life of verapamil is prolonged to 14-16 hours, requiring only 30% of the normal dose. 5. Renal Impairment: Verapamil should be used with caution in patients with renal impairment. Verapamil cannot be eliminated by hemodialysis. 6. Impaired Neuromuscular Transmission: Verapamil has been reported to impair neuromuscular transmission in patients with muscular dystrophy; dose reduction may be necessary in such patients. 7. Serum Calcium: Verapamil does not alter serum calcium concentrations, but there have been reports that elevated serum calcium levels may affect verapamil's efficacy. 8. Because verapamil can cause elevated transaminases, liver function should be monitored regularly in patients receiving verapamil therapy as a precaution.
[Use in Special Populations]
Precautions for Pediatric Use:
Safety and efficacy in children under 18 years of age have not been established.
Precautions for Pregnancy and Lactation: Verapamil crosses the placenta. Use only in pregnant women with a clear need for treatment and when the benefits outweigh the risks to the fetus. Verapamil is excreted into breast milk. Breastfeeding should be discontinued while taking verapamil.
Precautions for Elderly Patients:
The elimination half-life may be prolonged in elderly patients, and the greater prevalence of hepatic or renal impairment in the elderly must be considered. Generally, a lower initial dose is used in the elderly.
[Drug Interactions]
1. Cytotoxic drugs such as cyclophosphamide, vincristine, procarbazine, prednisone, vinblastine, doxorubicin, and cisplatin reduce verapamil absorption. 2. Phenobarbital, hydantoins, vitamin D, sulfamethoxazole, and ramifluan reduce verapamil plasma concentrations by increasing hepatic metabolism. 3. Cimetidine may increase verapamil bioavailability. 4. Verapamil inhibits the elimination of ethanol, leading to increased blood ethanol concentrations and potentially prolonging the toxic effects of alcohol. 5. A few case reports have reported that the combined use of verapamil and aspirin prolongs bleeding time compared to aspirin alone.
[Pharmacological Actions]
1. Verapamil hydrochloride is a calcium antagonist. Its pharmacological effects are achieved by regulating calcium ion influx across the membranes of myocardial conduction cells, contractile cells, and arterial smooth muscle cells, without altering serum calcium concentrations. Verapamil hydrochloride dilates the main coronary arteries and arterioles in both normal and ischemic areas of the heart, antagonizing spontaneous or ergonovine-induced coronary artery spasm. It increases myocardial oxygen delivery in patients with coronary artery spasm, thereby relieving and preventing coronary artery spasm. Verapamil also reduces total peripheral resistance and myocardial oxygen consumption. It can be used to treat variant angina and unstable angina.
Storage: Store in sealed containers.
Strength: 40 mg
Packaging: 40 mg x 30 seconds per vial.
Expiry Life: 24 months
Approval Number: National Medicine Standard H31021538
Manufacturer: Shanghai Xinyi Pharmaceutical Co., Ltd.
