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Pharmacologic class: Calcium channel blocker
Therapeutic class: Antianginal, antihypertensive
Pregnancy risk category C
Inhibits calcium transport into myocardial and vascular smooth muscle cells, causing cardiac output and myocardial contractions to decrease
Capsules: 20 mg, 30 mg
Capsules (sustained-release): 30 mg, 45 mg, 60 mg
Injection: 2.5 mg/ml in 10-ml ampules
Indications and dosages
➣ Chronic stable angina, given alone or with beta-adrenergic blockers
Adults: Titrate dosage individually, starting with 20 to 40 mg P.O. (immediate-release) t.i.d. Wait at least 3 days before increasing dosage.
➣ Hypertension, given alone or with other antihypertensives
Adults: Titrate dosage individually, starting with 20 mg P.O. (immediate release) t.i.d. Wait at least 3 days before increasing dosage. Dosage range is 20 to 40 mg P.O. t.i.d. Patient may be switched to sustained-release capsules at nearest equivalent daily dosage of immediate-release capsules, starting with 30 mg P.O. b.i.d. Effective range is 30 to 60 mg/day.
➣ Short-term treatment of hypertension when oral therapy isn't feasible or desirable
Adults: Continuous I.V. infusion of 0.5 mg/hour (equal to 20 mg P.O. q 8 hours), or 1.2 mg/hour (equal to 30 mg P.O. q 8 hours), or 2.2 mg/hour (equal to 40 mg P.O. q 8 hours)
• Raynaud's disease
• Heart failure
• Hypersensitivity to drug
• Advanced aortic stenosis
Use cautiously in:
• hepatic or mild renal impairment
• hypotension, heart failure, significant left ventricular dysfunction
• pregnant or breastfeeding patients (safety not established)
• children younger than age 18 (safety not established).
• Give immediate-release capsules without regard to meals; if GI upset occurs, give with meals. Don't give with grapefruit or grapefruit juice.
• Don't open, crush, break, or let patient chew sustained-release capsules. Give with meals, but not with high-fat meals, grapefruit, or grapefruit juice.
• For I.V. use, dilute each 25-mg ampule with 240 ml of compatible I.V. fluid (such as dextrose 5% in water, normal saline solution, dextrose 5% with normal saline solution, or half-normal saline solution) to a concentration of 0.1 mg/ml.
Don't dilute with sodium bicarbonate 5% or lactated Ringer's injection (incompatible).
• Don't mix with furosemide, heparin, or thiopental.
Give by slow I.V. infusion. Titrate dosage to blood pressure response.
CNS: dizziness, headache, asthenia, drowsiness, paresthesia
CV: hypotension, peripheral edema, chest pain, increased angina, palpitations, tachycardia
GI: nausea, dyspepsia, dry mouth
Drug-drug. Cimetidine: increased nifedipine blood level
Cyclosporine: increased cyclosporine blood level
Fentanyl anesthesia: increased hypotension
Drug-food. Grapefruit, grapefruit juice: increased drug blood level and effects
High-fat meal (sustained-release form): decreased drug blood level
Drug-herbs. Ephedra (ma huang), yohimbine: antagonism of drug's anti-hypertensive effect
St. John's wort: decreased nifedipine blood level
Drug-behaviors. Alcohol use: additive hypotension, increased drowsiness or dizziness
• Assess vital signs and cardiovascular status.
• Monitor fluid intake and output. Assess for signs and symptoms of heart failure.
• Tell patient he may take immediate-release capsules without regard to meals. If GI upset occurs, advise him to take them with food, but not with grapefruit or grapefruit juice.
• Tell patient not to open, crush, break, or chew sustained-release capsules. Instruct him to take them with meals, but not with high-fat meals, grapefruit, or grapefruit juice.
• Tell patient to monitor blood pressure and report abnormal findings.
Advise patient to immediately report chest pain or blood pressure drop.
• Instruct patient to consult prescriber before drinking alcohol or taking herbs or over-the-counter drugs (especially cold remedies).
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, foods, herbs, and behaviors mentioned above.