Dosing and uses of Norvasc (amlodipine)
Adult dosage forms and strengths
tablet
- 2.5mg
- 5mg
- 10mg
Hypertension
5 mg/day PO initially; may be increased by 2.5 mg/day every 7-14 days; not to exceed 10 mg/day PO; maintenance: 5-10 mg/day PO
Coronary Artery Disease
Treatment of chronic stable angina and vasospastic angina (Prinzmetal or variant angina) and angiographically documented coronary artery disease (CAD) in patients without heart failure or ejection fraction (EF) <40%
5-10 mg/day PO initially; maintenance: 10 mg/day PO
Angina
5-10 mg/day PO; maintenance: 10 mg/day PO
Dosage modifications
Hepatic insufficiency: Consider starting with 2.5 mg/day PO
Severe hepatic impairment: Titrate slowly
Dosing Considerations
Also given in combination with benazepril (Lotrel), atorvastatin (Caduet), olmesartan (Azor), telmisartan (Twynsta), and valsartan (Exforge)
Pediatric dosage forms and strengths
tablet
- 2.5mg
- 5mg
- 10mg
Hypertension
<6 years: Safety and efficacy not established
≥6 years: 2.5-5 mg/day PO
Geriatric dosage forms and strengths
Start dosing at low end of dosing range; elderly patients have greater frequency of decreased renal, hepatic or cardiac function
Hypertension
2.5-5 mg/day PO initially; may be increased by 2.5 mg/day every 7-14 days; not to exceed 10 mg/day PO; maintenance: 5-10 mg/day PO
Coronary Artery Disease
Treatment of chronic stable angina and vasospastic angina (Prinzmetal or variant angina) and angiographically documented CAD in patients without heart failure or EF <40%
2.5-10 mg/day PO initially; maintenance: 10 mg/day PO
Angina
2.5-10 mg/day PO; maintenance: 10 mg/day
Norvasc (amlodipine) adverse (side) effects
>10%
Edema (1.8-10.8%)
Pulmonary edema (7-15%)
1-10%
Headache (7.3%)
Fatigue (4.5%)
Palpitations (0.7-4.5%)
Dizziness (1.1-3.4%)
Nausea (2.9%)
Flushing (0.7-2.6%)
Abdominal pain (1.6%)
Somnolence (1.4%)
Male sexual disorder (1-2%)
Drowsiness (1%)
Pruritus (1-2%)
Skin rash (1-2%)
Muscle cramps (1-2%)
Muscle weakness (1-2%)
Postmarketing Reports
Extrapyramidal disorder
Warnings
Contraindications
Hypersensitivity
Cautions
Congestive heart failure (CHF)
Persistent progressive dermatologic reactions
Symptomatic hypotension with or without syncope possible, particularly with severe aortic stenosis; because of gradual onset of action, acute hypotension unlikely
Worsening of angina and acute myocardial infarction (MI) can develop after dose is started or increased, particularly with severe obstructive CAd
Peripheral edema may develop within 2-3 weeks of starting therapy
Use with caution in patients with hypertrophic cardiomyopathy; reduction in afterload may worsen symptoms associated with this condition
May reduce coronary perfusion and result in ischemia in patients with severe aortic stenosis; use caution
Extensively metabolized by liver; titrate dose slowly with severe hepatic impairment
Initiate at lower dose in the elderly
Titrate dose every 7-14 days on a given dose; peak antihypertensive effect is delayed
Co-administration with CYP3A inhibitors (moderate and strong) results in increased systemic exposure to amlodipine and may require dose reduction; monitor for symptoms of hypotension and edema when amlodipine is co-administered with CYP3A inhibitors to determine the need for dose adjustment
Amlodipine may increase systemic exposure of cyclosporine or tacrolimus when co-administered; frequent monitoring of trough blood levels of cyclosporine and tacrolimus recommended; adjust dose when appropriate
Pregnancy and lactation
Pregnancy category: C
Lactation: Unknown whether drug is excreted in milk; use not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Norvasc (amlodipine)
Mechanism of action
Inhibits transmembrane influx of extracellular calcium ions across membranes of myocardial cells and vascular smooth muscle cells without changing serum calcium concentrations; this inhibits cardiac and vascular smooth muscle contraction, thereby dilating main coronary and systemic arteries
Increases myocardial oxygen delivery in patients with vasospastic angina
Absorption
Bioavailability: 64-90%
Onset: 24-96 hr
Duration: 24 hr (antihypertensive effect)
Peak plasma time: 6-12 hr
Distribution
Protein bound: 93-98%
Vd: 21 L/kg
Metabolism
Extensively metabolized in liver by CYP3A4
Metabolites: Pyridine analogue (inactive)
Elimination
Half-life: 30-50 hr
Excretion: Urine (70%)
