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verapamil
Apo-Verap†, Calan, Isoptin, Novo-Veramil†, Nu-Verap†

verapamil hydrochloride
Anpec‡, Calan, Calan SR, Cordilox‡, Cordilox SR‡, Half-Securon SR§, Isoptin, Isoptin SR, Novo-Veramil†, Securon§, Securon SR§, Univer§, Veracaps SR‡, Verapress MR§, Verelan

Pregnancy Risk Category C

How supplied
verapamil

Tablets:
40 mg, 80 mg, 120 mg
verapamil hydrochloride

Tablets:
40 mg, 80 mg, 120 mg, 160 mg‡
Tablets (extended-release):
120 mg, 180 mg, 240 mg, 360 mg
Capsules (extended-release):
120 mg, 160 mg‡, 180 mg, 240 mg, 360 mg
Injection:
2.5 mg/ml

Action
Not clearly defined. A calcium channel blocker that inhibits calcium ion influx across cardiac and smooth-muscle cells, thus decreasing myocardial contractility and oxygen demand; it also dilates coronary arteries and arterioles.

Indications & dosage
Vasospastic angina (Prinzmetal's or variant angina); classic chronic, stable angina pectoris; chronic atrial fibrillation
--
Adults:
starting dose is 80 to 120 mg P.O. t.i.d. Dosage increased at weekly intervals, p.r.n. Some patients may require up to 480 mg daily.
Supraventricular arrhythmias
--
Adults:
0.075 to 0.15 mg/kg (5 to 10 mg) by I.V. push over 2 minutes with ECG and blood pressure monitoring. Repeat dose in 30 minutes if no response occurs.
Children under age 1:
0.1 to 0.2 mg/kg as I.V. bolus over 2 minutes with continuous ECG monitoring. Repeat dose in 30 minutes if no response occurs.
Children ages 1 to 15:
0.1 to 0.3 mg/kg as I.V. bolus over 2 minutes; not to exceed 5 mg.
Hypertension
--
Adults:
240 mg extended-release tablet P.O. once daily in the morning. If response isn't adequate, give an additional 120 mg in the evening or 240 mg q 12 hours or an 80-mg immediate-release tablet t.i.d.

Adverse reactions
CNS:
dizziness, headache, asthenia.
CV:
transient hypotension, heart failure, pulmonary edema, bradycardia, AV block, ventricular asystole, ventricular fibrillation, peripheral edema.
GI:
constipation, nausea.
Hepatic:
elevated liver enzymes.
Skin:
rash.

Interactions
Drug-drug.
Antihypertensives, quinidine: may result in hypotension. Monitor blood pressure.
Carbamazepine, cardiac glycosides:
may increase serum levels of these drugs. Monitor for toxicity.
Cyclosporine:
may increase cyclosporine serum levels. Monitor cyclosporine levels.
Disopyramide, flecainide, propranolol, other beta blockers (including ophthalmic timolol):
may cause heart failure. Use together cautiously.
Lithium:
may decrease or increase serum lithium levels. Monitor closely.
Rifampin:
may decrease oral bioavailability of verapamil. Monitor patient for lack of effect.
Drug-herb.
Black catechu: additive effects. Avoid concomitant use.
Yerba maté:
may decrease clearance of yerba maté methylxanthines and cause toxicity. Use together cautiously.
Drug-food.
Any food: increased absorption. Take drug with food.
Drug-lifestyle.
Alcohol use: verapamil may enhance the effects of alcohol. Avoid use.

Effects on diagnostic tests
None reported.

Contraindications
Contraindicated in patients with hypersensitivity to drug, severe left ventricular dysfunction, cardiogenic shock, second- or third-degree AV block or sick sinus syndrome except in presence of functioning pacemaker, atrial flutter or fibrillation and accessory bypass tract syndrome, severe heart failure (unless secondary to verapamil therapy), and severe hypotension. I.V. verapamil is contraindicated in patients receiving I.V. beta blockers and in those with ventricular tachycardia.

Nursing considerations

I.V. administration

Patient teaching

*Liquid contains alcohol. **May contain tartrazine.  †Canada  ‡Australia  §U.K.  OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING

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