Drug information of Verapamil
Mechanism of effect
Verapamil hydrochloride is a calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) that exerts its pharmacologic effects by modulating the influx of ionic calcium across the cell membrane of the arterial smooth muscle as well as in conductile and contractile myocardial cells.
Verapamil is an L-type calcium channel blocker that also has antiarrythmic activity.
More than 90% of the orally administered dose of Verapamil hydrochloride is absorbed. Because of rapid biotransformation of Verapamil during its first pass through the portal circulation, bioavailability ranges from 20% to 35%. Peak plasma concentrations are reached between 1 and 2 hours after oral administration. In healthy men, orally administered Verapamil undergoes extensive metabolism in the liver. Approximately 70% of an administered dose is excreted as metabolites in the urine and 16% or more in the feces within 5 days.
Drug indicationsAngina Pectoris , (hypertension (high blood pressure , Arrhythmias , Migraine Prophylaxis , Cluster Headache , Bipolar Disorder , Supraventricular Tachycardia , Idiopathic Hypertrophic Subaortic Stenosis
Usual Adult Dose for Hypertension Immediate release tablets (Calan (R)): Initial dose: 80 mg orally 3 times a day; alternatively, 40 mg orally 3 times a day may be considered in patients who might respond to lower doses (e.g., small stature) Maintenance dose: Upward titration should be based on therapeutic efficacy, assessed at the end of the dosing interval. Daily dosages of 360 and 480 mg have been used but there is no evidence that dosages beyond 360 mg provided added effect. Extended release tablets (Covera HS (R)): Initial dose: 180 mg orally once a day at bedtime Maintenance dose: If adequate response is not obtained with the initial dose, it may be titrated upward. Usual Adult Dose for Supraventricular Tachycardia IV: Initial dose: 5 to 10 mg (0.075 to 0.15 mg/kg) given as an IV bolus over at least 2 minutes Repeat dose: 10 mg (0.15 mg/kg) 30 minutes after the first dose if the initial response is not adequate An optimal interval for subsequent doses has not been determined and must be individualized for each patient. Usual Pediatric Dose for Supraventricular Tachycardia IV: Less than 1 year: Generally not recommended due to potential risk of severe apnea, bradycardia, hypotensive reactions, and cardiac arrest; IV calcium should be available at bedside Initial dose: 0.1 to 0.2 mg/kg/dose (usual single dose range: 0.75 to 2 mg/dose) should be administered as an IV bolus over at least 2 minutes under continuous ECG monitoring Repeat dose: 0.1 to 0.2 mg/kg/dose (usual single dose range: 0.75 to 2 mg/dose) 30 minutes after the first dose if the initial response is not adequate (under continuous ECG monitoring) An optimal interval for subsequent doses has not been determined and must be individualized for each patient. 1 to 15 years: Initial dose: 0.1 to 0.3 mg/kg/dose (usual single dose range: 2 to 5 mg/dose) should be administered as an IV bolus over at least 2 minutes; doses of 5 mg should not be exceeded Repeat dose: 0.1 to 0.3 mg/kg/dose (usual single dose range: 2 to 5 mg/dose) 30 minutes after the first dose if the initial response is not adequate; doses of 10 mg should not be exceeded An optimal interval for subsequent doses has not been determined and must be individualized for each patient.
Drug contraindicationshypersensitivity to drug or its components. , Second- or third-degree AV block , Sick sinus syndrome , hypotension (less than 90 mm Hg systolic) , atrial flutter , atrial fibrillation , Wolff-Parkinson-White syndrome , Lown-Ganong-Levine syndrome , Severe left ventricular dysfunction
Side effectsnausea , Headache , constipation , dizziness , fatigue , rash , flushing , Bradycardia , Dyspnea , hypotension , edema , Increased ALT , Increased AST , pulmonary edema , AV block
InteractionsErgotamine-C , Everolimus , Ipratropium bromide , isosorbide dinitrate , Ifosfamide , Imatinib , Budesonide , Propranolol , Tamsulosin , Trazodone , Triptorelin , Topotecan , Tolterodine , Daunorubicin , Deflazacort , Rituximab , Simvastatin , Fluticasone propinate , Lovastatin , Metoprolol , Methyldopa , Nitroglycerin , Hydralazine , Atracurium , Atenolol , Erythromycin , Cimetidine , Cyclosporine , Phenobarbital , Lithium carbonate , Carbamazepine , Clonidine , Quinidine , Carvedilol , Colchicine , Yohimbine , Flecainide , Phentolamine Mesylate , Disulfiram , Bisoprolol , Rosuvastatin , fentanyl , Cyclobenzaprine , Rifabutin , Atazanavir , Ranolazine , Levobunolol , Dabigatran , Doxazosin , propoxyphene , Axitinib , Ivabradine , Dolasetron , Afatinib , Dofetilide , Alosetron , Halofantrine , Carteolol , Nebivolol , Amisulpride , Pazopanib , Betrixaban , Flibanserin , Avanafil , Edoxaban , Treprostinil , Entrectinib , Lorlatinib , Eliglustat , Suvorexant , riociguat , Gefitinib , neratinib , Cannabidiol , lasmiditan , talazoparib , cyclopenthiazide , Fidaxomicin , Florbetapir F18
1-Since Verapamil is highly metabolized by the liver, it should be administered cautiously to patients with impaired hepatic function 2-Verapamil should be administered cautiously to patients with impaired renal function.
Points of recommendation
1-Verapamil may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. 2-Drinking alcohol can further lower your blood pressure and may increase certain side effects of verapamil. 3-Grapefruit and grapefruit juice may interact with verapamil and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor. 4-Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose 5-Your blood pressure will need to be checked often. Your kidney or liver function may also need to be checked.
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