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diltiazem hydrochloride
Adizem-60§, Adizem-SR§, Adizem-XL Plus§, Angitil SR§, Apo-Diltiaz†, Calcicard CR§, Cardizem, Cardizem CD, Cardizem SR, Dilacor XR, Dilzem SR§, Dilzem XL§, Slozem§, Tiazac, Tildiem§, Tildiem LA§, Tildiem Retard§, Viazem XL§, Zemtard 300XL§

Pregnancy Risk Category C

How supplied
Tablets:
30 mg, 60 mg, 90 mg, 120 mg
Capsules (extended-release; Cardizem CD, Dilacor XR, Tiazac):
120 mg, 180 mg, 240 mg, 300 mg, 360 mg (Tiazac)
Capsules (sustained-release
; Cardizem SR): 60 mg, 90 mg, 120 mg, 180 mg, 240 mg
Injection:
5 mg/ml

Action
A calcium channel blocker that inhibits calcium ion influx across cardiac and smooth-muscle cells, decreasing myocardial contractility and oxygen demand. Also dilates coronary arteries and arterioles.

Indications & dosage
Vasospastic angina (Prinzmetal's or variant angina), classic chronic stable angina pectoris--

Adults:
30 mg P.O. t.i.d. or q.i.d. before meals and h.s., increased gradually to maximum of 360 mg daily in divided doses. Or, 120 or 180 mg (extended-release). Adjusted as needed and tolerated to maximum of 480 mg daily.
Hypertension
--
Adults:
60 to 120 mg P.O. b.i.d.
(sustained-release). Adjusted to effect. Maximum dose is 360 mg daily. Or, initially 180 to 240 mg daily (extended-release). Dosage adjusted, p.r.n.
Atrial fibrillation or flutter, paroxysmal supraventricular tachycardia
--
Adults:
0.25 mg/kg as an I.V. bolus injection over 2 minutes. If response is inadequate, 0.35 mg/kg I.V. after 15 minutes followed by a continuous infusion of 10 mg/hour. Some patients respond well to a rate of 5 mg/hour; maximum dose is 15 mg/hour.

Adverse reactions
CNS:
headache, dizziness, asthenia, somnolence.
CV:
edema, arrhythmias, flushing, bradycardia, hypotension, conduction abnormalities, heart failure, AV block, abnormal ECG.
GI:
nausea, constipation, abdominal discomfort.
Hepatic:
acute hepatic injury.
Skin:
rash.

Interactions
Drug-drug.
Anesthetics: effects may be potentiated. Monitor patient.
Carbamazepine:
increased levels of carbamazepine. Monitor carbamazepine levels and watch for signs and symptoms of toxicity.
Cimetidine:
may inhibit diltiazem metabolism. Monitor for toxicity, additive AV node conduction slowing.
Cyclosporine:
diltiazem may increase serum cyclosporine levels, possibly by decreasing its metabolism, leading to increased risk of cyclosporine toxicity. If used concurrently, monitor cyclosporine levels.
Digoxin:
diltiazem may increase serum levels of digoxin. Monitor for toxicity.
Furosemide:
forms a precipitate when mixed with diltiazem injection. Administer through separate I.V. lines.
Propranolol, other beta blockers:
may precipitate heart failure or prolong conduction time. Use together cautiously.

Effects on diagnostic tests
None reported.

Contraindications
Contraindicated in patients with hypersensitivity to drug, sick sinus syndrome or second- or third-degree AV block in the absence of an artificial pacemaker, systolic blood pressure below 90 mm Hg, acute MI, or pulmonary congestion (documented by X-ray).

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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