Management of hypertension, angina pectoris, and/or vasospastic (Prinzmetal’s) angina.
Management of supraventricular arrhythmias and rapid ventricular rates in atrial flutter or fibrillation.
Prevention of migraine headache.
Management of cardiomyopathy.
PO (Adults): 80–120 mg 3 times daily, increased as needed. Patients with poor ventricular
function, hepatic impairment, or geriatric patients — 40 mg 3 times daily initially.
Extended-release preparations — 120–240 mg/day as a single dose; may be increased as needed (range 240–480 mg/day).
PO (Children up to 15 yr): 4–8 mg/kg/day in divided doses.
IV (Adults): 5 –10 mg (75– 150 mcg/kg); may repeat with 10 mg (150 mcg/kg) after 15–30 min.
IV (Children 1–15 yr): 2–5 mg (100–300 mcg/kg); may repeat after 30 min (initial dose not to exceed 5 mg; repeat dose not to exceed 10 mg).
IV (Children <1 yr): 0.75–2 mg (100–200 mcg/kg); may repeat after 30 min.
Inhibits the transport of calcium into myocardial and vascular smooth muscle cells, resulting in inhibition of excitation- contraction coupling and subsequent contraction. ↓ SA and AV conduction and prolongs AV node refractory period in conduction tissue.
Therapeutic Effects: Systemic vasodilation resulting in ↓ blood pressure.
Coronary vasodilation resulting in ↓ frequency and severity of attacks of angina.
Suppression of ventricular tachyarrhythmias.
Hypersensitivity to verapamil; sick sinus syndrome or second- or third-degree AV block except with functioning pacemaker; patients with atrial flutter or fibrillation and accessory bypass tract; cardiogenic shock.
Hypotension (less than 90 mm Hg systolic); severe left ventricular dysfunction.
Severe hypotension; severe CHF, unless secondary to supraventricular tachycardia amenable to verapamil; concomitant use (within few hours) of IV beta-adrenergic blocking agents; ventricular tachycardia.
Hypotension (3%); first-degree AV block (2%); abnormal ECG, angina pectoris, AV dissociation, chest pain, CHF/pulmonary edema, claudication, hypertension, MI, palpitation, purpura, syncope (2% or less); AV block, bradycardia (1%).
Symptomatic hypotension (2%); bradycardia, severe tachycardia (1%).
Headache (12%); dizziness, fatigue (5%); lethargy (3%); asthenia, cerebrovascular accident, confusion, equilibrium disorders, extrapyramidal symptoms, insomnia, paresthesia, psychotic symptoms, shakiness, somnolence (2% or less); sleep disturbance (1%).
Dizziness, headache (1%).
Erythema multiforme, exanthema, hair loss, hyperkeratosis, macules, rash, sweating, Stevens-Johnson syndrome, urticaria (2% or less).
Pharyngitis, rhinitis (3%); blurred vision, tinnitus (2% or less).
Constipation (12%); dyspepsia, nausea (3%); diarrhea, dry mouth, GI distress, gingival hyperplasia (2% or less).
Gynecomastia, impotence, increased urination, spotty menstruation (2% or less).
Ecchymosis or bruising (2% or less).
Elevated liver enzymes (2% or less).
Galactorrhea/hyperprolactinemia (2% or less).
Arthralgia, muscle cramps (2% or less); myalgia (1%).
Upper respiratory tract infection (5%); sinusitis (3%); dyspnea (2% or less).
Infection (12%); flu-syndrome, peripheral edema (4%); aggravated allergy, edema, pain (2% or less).
Alcohol blood levels may be elevated, prolonging the intoxicating effects. Patients should limit their alcohol consumption while taking verapamil.
Antihypertensive agents (eg, ACE inhibitors [eg, captopril], diuretics [eg, chlorothiazide], vasodilators [eg, hydralazine])
Verapamil has additive effects on lowering blood pressure. Monitor blood pressure and adjust treatment as needed.
Antineoplastic regimens (cyclophosphamide, oncovin, prednisone, and procarbazine, or vindesine, adriamycin, and cisplatin)
These regimens can reduce verapamil absorption. Closely monitor the clinical response of the patient and adjust the verapamil dose as needed.
Risk of bleeding may be increased compared with aspirin alone. Monitor bleeding times.
Barbiturates (eg, phenobarbital)
Verapamil Cl may be increased, reducing plasma concentrations and the pharmacologic effect. Monitor the clinical response of the patient and adjust the verapamil dose as needed.
Beta-blockers (eg, metoprolol)
May result in increased hypotension and adverse reactions because of additive depressant effects on myocardial contractility or AV conduction. Avoid verapamil in patients with any degree of ventricular dysfunction if they are receiving beta-blockers.
Pharmacologic and adverse reactions may be increased by verapamil. Closely monitor the clinical response of the patient and adjust buspirone dose as needed.
Clinical effects and toxicities of verapamil may be reversed. Unless calcium salts are being used as an antagonist in treating verapamil overdose, use calcium salts with caution in patients taking verapamil.
Increased carbamazepine serum levels. Monitor serum levels and adjust dose as needed.
The interaction between cimetidine and chronically administered verapamil has not been studied. Variable results on Cl have been obtained in acute studies of healthy volunteers; Cl of verapamil was either reduced or unchanged. If an interaction is suspected, adjust the verapamil dose as needed.
Synergistic effects resulting in sinus bradycardia have been reported in association with coadministration of clonidine and verapamil. Monitor heart rate during concurrent use of verapamil and clonidine.
Colchicine plasma concentrations may be elevated by verapamil, increasing the risk of toxicity. Colchicine dosing adjustment may be needed for patients also receiving verapamil. Use with caution and closely monitor for colchicine toxicity. The recommended colchicine dose for the treatment of a gout flare in patients receiving verapamil is 1.2 mg for one dose. A 3-day lapse should occur before subsequent colchicine administration. The recommended max colchicine dose for treatment of familial Mediterranean fever in patients receiving verapamil is 1.2 mg daily.
Increased cyclosporine levels may result, increasing the pharmacologic effect and risk of toxicity. However, verapamil may be nephroprotective when given before cyclosporine. Monitor cyclosporine levels and adjust dose as needed.
CYP3A4 inducers (eg, rifampin)
Verapamil plasma levels may be reduced, decreasing the pharmacologic effect. Closely monitor CV status and adjust dose as needed.
CYP3A4 inhibitors (eg, erythromycin, ritonavir)
Verapamil plasma levels may be elevated, increasing the pharmacologic effects and adverse reactions. Closely monitor cardiac function and adjust the dose as needed.
Hyperkalemia and myocardial depression has been reported in a patient following coadministration of oral verapamil and IV dantrolene. Monitor serum potassium and cardiac function.
Increased serum digoxin or digitoxin levels may occur. Monitor digoxin levels and adjust dose as needed. Because both drugs slow AV conduction, also monitor for AV block or excessive bradycardia. If possible, control patients with mild ventricular dysfunction with optimum doses of digitalis and/or diuretics before starting verapamil treatment.
Do not use 48 h before or 24 h after verapamil.
Risk of life-threatening ventricular arrhythmias, including torsades de pointes, may be increased. Coadministration with verapamil is contraindicated.
Doxorubicin serum concentrations may be elevated. Monitor the clinical response of the patient and adjust treatment as needed.
Dronedarone plasma concentrations and pharmacologic effects may be increased. Verapamil may enhance the electrophysiologic effects of dronedarone. Also, verapamil plasma concentrations and pharmacologic effects may be increased. Initiate verapamil at low doses in patients receiving dronedarone. Monitor the ECG. Increase the verapamil dosage if the ECG demonstrates tolerability.
Eletriptan plasma concentrations may be elevated, increasing the pharmacologic effects and risk of adverse reactions. Closely monitor for signs of eletriptan adverse reactions.
Verapamil may elevate eplerenone plasma concentrations, increasing the pharmacologic effects and risk of toxicity. Closely monitor the clinical response of the patient and adjust the eplerenone dose as needed.
Verapamil may elevate everolimus plasma concentrations, increasing the pharmacologic effects and risk of adverse reactions. If coadministration cannot be avoided, closely monitor everolimus blood concentrations when verapamil is started or stopped. Adjust the everolimus dose as needed.
Verapamil may elevate fentanyl plasma concentrations, increasing the pharmacologic effects and risk of toxicity. When fentanyl and verapamil are coadministered, the manufacturer recommends closely monitoring patients for an extended period of time. Dosage increases should be done conservatively.
May prolong AV conduction. Concurrent therapy with flecainide and verapamil may result in additive negative inotropic effect and prolongation of atrioventricular conduction. Carefully monitor cardiac function and adjust treatment as needed.
Verapamil plasma concentrations may be elevated. This increase is not expected to have any clinical consequences.
HMG-CoA reductase inhibitors (eg, atorvastatin, lovastatin, simvastatin)
Plasma concentrations of certain HMG-CoA reductase inhibitors may be elevated. In addition, verapamil concentrations may be elevated, increasing the pharmacologic effects and risk of toxicity. If coadministration cannot be avoided, administer a conservative dose of the HMG-CoA reductase inhibitor. Advise patients to report any unexplained muscle pain, tenderness, or weakness. Monitor the clinical response and for adverse reactions to verapamil. Adjust the dose as needed.
Hydantoins (eg, phenytoin)
The pharmacologic effects of verapamil may be decreased. Monitor CV status closely. Adjust dose as needed.
Coadministration increases imipramine serum concentrations and the risk of adverse reactions (eg, anticholinergic effects, sedation). Monitor imipramine serum concentrations and the clinical response of the patient. Adjust the imipramine dose as needed.
Inhalational anesthetics (eg, enflurane)
Coadministration may potentiate cardiac effects and vascular dilation. Titrate doses carefully to avoid excessive CV depression.
Coadminister with verapamil with caution because of variable effects.
Macrolide antibiotics (eg, clarithromycin, erythromycin, telithromycin)
Increased risk of cardiotoxicity. Closely monitor cardiac function.
Midazolam plasma concentrations may be elevated, increasing and prolonging CNS depression. The dosage of midazolam may need to be decreased when given with verapamil. Monitor the patient for possible prolonged sedation.
Nondepolarizing muscle relaxants (eg, pancuronium)
Enhanced muscle relaxant effects and prolonged respiratory depression may occur. If coadministration cannot be avoided, closely monitor the patient and adjust doses as needed.
Cl of these agents may be reduced by verapamil, increasing plasma levels. Close clinical monitoring and adjustments in the dose of these agents as needed is appropriate.
Increased prazosin serum levels may result, increasing sensitivity to prazosin-induced postural hypotension. Advise patients to take precautions regarding postural hypotension. If an excessive fall in BP occurs, consider decreasing the prazosin dose during verapamil coadministration.
Coadministration may increase the therapeutic and adverse reactions of quinidine. Use quinidine with verapamil only when no alternatives exist. Closely monitor quinidine serum levels and cardiac effects. Verapamil may counteract the effects of quinidine on AV conductions. In patients with hypertrophic cardiomyopathy, coadministration of verapamil and quinidine may cause clinically important hypotension. Avoid concurrent use of verapamil and quinidine in patients with hypertrophic cardiomyopathy.
Ranolazine plasma concentrations may be elevated, increasing the pharmacologic effects and risk of toxicity. Limit the dosage of ranolazine to 500 mg twice daily. During verapamil coadministration, closely monitor for signs of ranolazine toxicity, including QT interval prolongation.
Loss of effectiveness of oral verapamil may occur. Closely monitor CV status and adjust the verapamil dose as needed.
Risperidone plasma concentrations may be elevated, increasing the pharmacologic effects and risk of adverse reactions. In patients receiving risperidone, closely monitor the clinical response of the patient after starting, stopping, or changing the verapamil dose. Adjust the risperidone dose as needed.
St. John’s wort
Verapamil plasma concentrations may be reduced, decreasing the efficacy. If St. John’s wort cannot be avoided, assess the clinical response of the patient to verapamil when St. John’s wort is started or stopped. Adjust the verapamil dose as needed.
Coadministration may decrease the therapeutic effects of oral verapamil. Monitor CV status closely. Adjust the verapamil dose as needed.
Tolvaptan concentrations may be elevated, increasing the pharmacologic effects and risk of adverse reactions. Avoid coadministration.
Therapeutic Classification: antianginals, antiarrhythmics (class IV), antihypertensives,
vascular headache suppressants
Pharmacologic Classification: calcium channel blockers
Absorption: 90% absorbed after oral administration, but much is rapidly metabolized,
resulting in bioavailability of 20–25%.
Distribution: Small amounts enter breast milk.
Protein Binding: 90%.
Metabolism/Excretion: Mostly metabolized by the liver.
Half-life: 4.5–12 hr.
|PO||30-90 min †||3-7 hr|
|PO ER||5-7 hr||24 hr|
|IV||3-5 min||2 hr|
Single dose; effects from multiple doses may not be evident for 24–48 hr ‡ Antiarrhythmic effects;
hemodynamic effects begin 3–5 min after injection and persist for 10–20