Verapamil Hydrochloride Sustained Release Tablets

Pharmacological action Verapamil hydrochloride is a calcium ion antagonist. It exerts its pharmacological action by regulating the influx of calcium ions on the cell membranes of myocardial conduction cells, myocardial contractile cells, and arterial smooth muscle cells, but does not change the serum calcium concentration. Verapamil hydrochloride dilates the main coronary arteries and arterioles in normal and ischemic parts of the heart, antagonizes spontaneous or ergonovine-induced coronary artery spasm, increases the delivery of myocardial oxygen to patients with coronary artery spasm, relieves and prevents coronary artery spasm; Verapamil reduces total peripheral resistance and reduces myocardial oxygen consumption. It can be used to treat variant angina and unstable angina. Verapamil reduces calcium ion influx, prolongs the effective refractory period of the atrioventricular node, slows conduction, and can reduce the ventricular rate of patients with chronic atrial fibrillation and atrial flutter; it reduces the frequency of paroxysmal supraventricular tachycardia. Verapamil usually has little effect on normal sinus heart rate, but can cause sinus arrest or sinoatrial block in patients with sick sinus syndrome; Verapamil does not change the action potential or intraventricular conduction time of normal atria, but it reduces the amplitude, speed and conduction speed of the depolarization of the inhibited atrial fibers, which may shorten the forward effective refractory period of the additional bypass channel, accelerate the ventricular rate of patients with atrioventricular bypass combined with atrial flutter or atrial fibrillation, and even induce ventricular fibrillation. Verapamil produces a blood pressure-lowering effect by reducing the vascular resistance of the systemic circulation, and generally does not cause postural hypotension or reflex tachycardia. Verapamil reduces afterload, inhibits myocardial contraction, and can improve left ventricular diastolic function. In isometric or dynamic myocardial exercise, verapamil does not change the cardiac contractile function of patients with normal ventricular function. In patients with organic heart disease, the negative inotropic effect of verapamil can be offset by the effect of reducing afterload, and the cardiac index does not decrease. However, patients with severe left ventricular dysfunction (e.g., pulmonary wedge pressure greater than 20 mmHg or ejection fraction less than 30%), or patients taking beta-blockers or other myocardial depressant drugs, may experience worsening of cardiac function. Animal experiments suggest that the local anesthetic effect of verapamil is 1.6 times that of procaine equimolar. The effect and dosage in humans are still unclear. Carcinogenicity, mutagenicity and reproductive toxicity Verapamil is not carcinogenic. The Ames test confirmed that verapamil is not mutagenic. Long-term use of verapamil ge;30mg/Kg/d by Beagle dogs resulted in lens-shaped and/or suture-shaped changes, and ge;62.5mg/Kg/d caused cataracts with obvious symptoms. There have been no reports of cataract formation in humans due to verapamil. No impairment of fertility was observed in female mice. The effect on human fertility is still unclear.

Verapamil Hydrochloride

This product is off-white tablets.

Essential hypertension.

1 The starting dose is 180 mg, taken orally once in the morning. For patients with an increased response to verapamil (i.e., the elderly or those with a thin body), 120 mg taken orally once a day may be safe as a starting dose. The dose may be increased based on weekly assessments of efficacy and safety, and 24 hours after the last dose. 2 If a satisfactory therapeutic effect is not achieved with 180 mg of Verapamil extended-release tablets taken orally once a day, the dose may be increased in the following ways: (1) 240 mg taken orally in the morning. (2) 180 mg taken orally once in the morning and evening; or 240 mg taken orally once in the morning and 120 mg taken orally once in the evening. (3) 240 mg taken orally every 12 hours. 3. When switching from regular tablets to Verapamil extended-release tablets, the total dose may remain unchanged.

1. Take the recommended single dose and daily total as the starting dose and gradually adjust the dose upward. Serious adverse reactions are rare. 2. Adverse reactions with an incidence of 1-10%: 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 (1.4%), I, II or III degree atrioventricular block (1.2%); rash (1.2%); fatigue; palpitations; elevated transaminases, with or without elevated alkaline phosphatase and bilirubin, which are sometimes transient and may disappear even with continued use of verapamil. 3. Adverse reactions with an incidence of 1%: hypotension; tachycardia; flushing; galactorrhea; gingival hyperplasia; non-obstructive paralytic ileus, etc.

1 Severe left ventricular dysfunction. 2 Hypotension (systolic blood pressure less than 90 mmHg) or cardiogenic shock. 3 Sick sinus syndrome (except for patients with functional pacemakers). 4 II or III degree atrioventricular block (except for patients with functional pacemakers). 5 Patients with atrial flutter or atrial fibrillation and atrioventricular bypass pathway. 6 Patients known to be allergic to verapamil hydrochloride.

Precautions for children: Safety and efficacy in children under 18 years of age have not been established. Precautions for pregnancy and lactation: Verapamil can cross the placenta. The pros and cons of using it in pregnant women should be weighed. Verapamil can be secreted into breast milk, and breastfeeding should be interrupted during the use of verapamil. Precautions for the elderly: The elimination half-life may be prolonged in elderly patients, and it must be considered that liver or kidney dysfunction is more common in the elderly. Generally, a lower starting dose should be used in the elderly.

1 Cytotoxic drugs such as cyclophosphamide, vincristine, procarbazine, prednisone, vinblastine, doxorubicin, and cisplatin reduce the absorption of verapamil. 2 Phenobarbital increases the clearance of verapamil. 3 Ramifen significantly reduces the bioavailability of oral verapamil. 4 Cimetidine may increase the bioavailability of verapamil. 5 Verapamil inhibits the elimination of ethanol, leading to increased ethanol concentration in the blood, which may prolong the toxic effects of alcohol. 6 Combined with beta-receptor blockers, it may enhance the inhibitory effect on atrioventricular conduction, heart rate, and/or cardiac contraction. 7 Long-term use of verapamil increases the blood concentration of digoxin by 50-75%. Verapamil significantly affects the pharmacokinetics of digoxin in patients with cirrhosis, reducing the total clearance and extrarenal clearance of digoxin by 27% and 29%, respectively. Therefore, when taking verapamil, the doses of digoxin and digitalis must be reduced. 8 When used in combination with antihypertensive drugs such as vasodilators, angiotensin-converting enzyme inhibitors, and diuretics, the antihypertensive effects are additive, and patients receiving combined antihypertensive therapy should be appropriately monitored. 9 Combination with amiodarone may increase cardiac toxicity. 10 When verapamil is used in combination with flecainide, negative inotropic effects can be additive and atrioventricular conduction can be prolonged. 11 Verapamil can increase the blood concentrations of carbamazepine, cyclosporine, and theophylline. 12 There are reports that verapamil increases patients' sensitivity to lithium (neurotoxicity). 13 Animal experiments suggest that when inhaled anesthetics are used simultaneously with verapamil, the doses of both drugs need to be carefully adjusted to avoid excessive cardiac suppression. 14 Do not take disopyramide within 48 hours before or 24 hours after taking verapamil.

Keep away from light, tightly closed and in a dry place.

120mg

24 months

North China Pharmaceutical Company.Ltd

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