- Hypertension (extended-release only),
- Angina pectoris,
- Vasospastic (Prinzmetal's) angina.
- Prevention of migraine headache.
- Management of HF or cardiomyopathy.
Inhibits calcium transport into myocardial and vascular smooth muscle cells, resulting in inhibition of excitation-contraction coupling and subsequent contraction.
- Systemic vasodilation, resulting in decreased BP.
- Coronary vasodilation, resulting in decreased frequency and severity of attacks of angina.
Absorption: Well absorbed after oral administration, but large amounts are rapidly metabolized (primarily by CYP3A4 enzyme system), resulting in ↓ bioavailability (45–70%); bioavailability is ↑ (80%) with extended-release forms.
Protein Binding: 92–98%.
Metabolism and Excretion: Mostly metabolized by the liver.
Half-life: 2–5 hr.
|PO||20 min||unknown||6–8 hr|
|PO–ER||unknown||6 hr||24 hr|
- Sick sinus syndrome;
- 2nd- or 3rd-degree AV block (unless an artificial pacemaker is in place);
- Systolic BP <90 mm Hg;
- Coadministration with grapefruit juice, rifampin, rifabutin, phenobarbital, phenytoin, carbamazepine, or St. John's wort.
Use Cautiously in:
- Severe hepatic impairment (↓ dose recommended);
- History of porphyria;
- Severe renal impairment (↓ dose may be necessary);
- History of serious ventricular arrhythmias or HF;
- Pedi: Safety and effectiveness not established in children
- Geri: Short-acting forms appear on Beers list due to ↑ risk of hypotension and constipation in older adults (↓ dose recommended); also associated with ↑ incidence of falls.
Adverse Reactions/Side Effects
CV: ARRHYTHMIAS, HF, peripheral edema, bradycardia, chest pain, hypotension, palpitations, syncope, tachycardia
Derm: STEVENS-JOHNSON SYNDROME, flushing, dermatitis, erythema multiforme, ↑ sweating, photosensitivity, pruritus/urticaria, rash
EENT: blurred vision, disturbed equilibrium, epistaxis, tinnitus
Endo: gynecomastia, hyperglycemia
Neuro: headache, abnormal dreams, anxiety, confusion, dizziness, drowsiness, dysgeusia, jitteriness, nervousness, psychiatric disturbances, weakness.
GI: ↑ liver enzymes, anorexia, constipation, diarrhea, dry mouth, dyspepsia, GI obstruction, nausea, ulcer, vomiting
GU: dysuria, nocturia, polyuria, sexual dysfunction, urinary frequency
Hemat: anemia, leukopenia, thrombocytopenia
Metabolic: weight gain
MS: joint stiffness, muscle cramps
Neuro: paresthesia, tremor
Resp: cough, dyspnea, shortness of breath
Misc: gingival hyperplasia
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
- Rifampin, rifabutin, phenobarbital, phenytoin, or carbamazepine may significantly ↓ levels and effects; concurrent use is contraindicated.
- Ketoconazole, fluconazole, itraconazole, clarithromycin, erythromycin, nefazodone, saquinavir, indinavir, nelfinavir, or ritonavir may ↑ levels and effects; consider initiating nifedipine at lowest dose.
- Additive hypotension may occur when used concurrently with fentanyl, other antihypertensives, nitrates, acute ingestion of alcohol, or quinidine.
- Antihypertensive effects may be ↓ by concurrent use of NSAIDs.
- May ↑ serum levels and risk of toxicity from digoxin.
- Concurrent use with beta blockers, digoxin, or disopyramide may result in bradycardia, conduction defects, or HF.
- Cimetidine and propranolol may ↓ metabolism and ↑ risk of toxicity.
- May ↓ metabolism of and ↑ risk of toxicity from cyclosporine, tacrolimus, prazosin, quinidine, or carbamazepine.
- ↑ risk of GI obstruction when used concurrently with H2 blockers, opioids, NSAIDs, laxatives, anticholinergic drugs, levothyroxine, or neuromuscular blockers.
- Strong CYP3A4 inducers, including carbamazepine, phenobarbital, phenytoin, and rifampin may ↓ levels and effects; avoid concurrent use
St. John's wort may significantly ↓ levels and effects; concurrent use is contraindicated.
Grapefruit and grapefruit juice ↑ serum levels and effect; avoid concurrent use.
PO (Adults): Immediate-release– 10–30 mg 3 times daily (not to exceed 180 mg/day); Extended-release– 30–90 mg once daily (not to exceed 90–120 mg/day).
Availability (generic available)
Capsules: 5 mg , 10 mg, 20 mg
Extended-release tablets: 30 mg, 60 mg, 90 mg
Lab Test Considerations:
Total serum calcium concentrations are not affected by calcium channel blockers.
- Monitor serum potassium periodically. Hypokalemia increases risk of arrhythmias; should be corrected.
- Monitor renal and hepatic functions periodically during long-term therapy. Several days of therapy may cause ↑ hepatic enzymes, which return to normal upon discontinuation of therapy.
- Nifedipine may cause positive ANA and direct Coombs' test results.
Advise patient to take medication as directed, even if feeling well. Take missed doses as soon as possible unless almost time for next dose; do not double doses. May need to be discontinued gradually.
- Instruct patient on technique for monitoring pulse. Instruct patient to contact health care professional if heart rate is <50 bpm.
- Advise patient to avoid grapefruit or grapefruit juice during therapy.
- Caution patient to change positions slowly to minimize orthostatic hypotension.
- May cause drowsiness or dizziness. Advise patient to avoid driving or other activities requiring alertness until response to the medication is known.
- Geri: Teach patients and family about risk for falls and how to reduce risk in the home.
- Instruct patient on importance of maintaining good dental hygiene and seeing dentist frequently for teeth cleaning to prevent tenderness, bleeding, and gingival hyperplasia (gum enlargement).
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to avoid concurrent use of alcohol or OTC medications and herbal products, especially cold preparations, without consulting health care professional.
- Advise patient to notify health care professional if rash, irregular heartbeat, dyspnea, swelling of hands and feet, pronounced dizziness, nausea, constipation, or hypotension occurs or if headache is severe or persistent.
- Caution patient to wear protective clothing and use sunscreen to prevent photosensitivity reactions.
- Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
Instruct patient on concurrent nitrate or beta-blocker therapy to continue taking both medications as directed and use SL nitroglycerin as needed for anginal attacks.
- Inform patient that anginal attacks may occur 30 min after administration because of reflex tachycardia. This is usually temporary and is not an indication for discontinuation.
- Advise patient to contact health care professional if chest pain does not improve, worsens after therapy, or occurs with diaphoresis; if shortness of breath occurs; or if persistent headache occurs.
- Caution patient to discuss exercise restrictions with health care professional before exertion.
Encourage patient to comply with other interventions for hypertension (weight reduction, low-sodium diet, smoking cessation, moderation of alcohol consumption, regular exercise, and stress management). Medication controls but does not cure hypertension.
- Instruct patient and family in proper technique for monitoring BP. Advise patient to take BP weekly and to report significant changes to health care professional.
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