Amlodipine
Pronouncation: (am-LOW-dih-PEEN)
Class: Calcium channel blocking agent
Trade Names:
Norvasc
- Tablets 2.5 mg
- Tablets 5 mg
- Tablets 10 mg
Mechanism of Action
Pharmacology
Inhibits movement of calcium ions across cell membrane in systemic and coronary vascular smooth muscle.
Pharmacokinetics
Absorption
T max is 6 to 12 h.
Distribution
Bioavailability is 64% to 90%. About 93% is protein bound.
Metabolism
About 90% is converted to inactive metabolites in the liver.
Elimination
10% of the parent compound and 60% of the metabolites are excreted in the urine. Elimination is biphasic. T ½ is about 30 to 50 h.
Duration
24 h.
Special Populations
Hepatic Function Impairment
Clearance is decreased and AUC may increase about 40% to 60%. May require lower initial dose.
Elderly
Clearance is decreased and AUC may increase about 40% to 60%. May require lower initial dose.
Moderate to severe heart failure
Clearance is decreased and AUC may increase about 40% to 60%. May require lower initial dose.
Indications and Usage
Hypertension; chronic stable angina; vasospastic (Prinzmetal or variant) angina.
Contraindications
Sick sinus syndrome; second- or third-degree atrioventricular (AV) block, except with a functioning pacemaker.
Dosage and Administration
Adults
PO 5 to 10 mg every day.
Elderly
PO Initially 2.5 mg every day.
Hepatic Impairment
PO Initially 2.5 mg every day.
Storage/Stability
Store in tightly closed container in cool location at 59° to 86°F.
Drug Interactions
Beta-blockers
May cause increased adverse cardiac reactions as a result of myocardial depression.
Fentanyl
Severe hypotension or increased fluid volume requirements have occurred with similar drug.
Laboratory Test Interactions
None well documented.
Adverse Reactions
Cardiovascular
Palpitations; peripheral edema; syncope; tachycardia; bradycardia; arrhythmias; ventricular asystoles.
CNS
Headache; dizziness; lightheadedness; fatigue; lethargy; somnolence.
Dermatologic
Dermatitis; rash; pruritus; urticaria.
GI
Nausea; abdominal discomfort; cramps; dyspepsia.
Respiratory
Shortness of breath; dyspnea; wheezing.
Miscellaneous
Flushing; sexual difficulties; muscle cramps, pain or inflammation.
Precautions
Pregnancy
Category C .
Lactation
Undetermined.
Children
Safety and efficacy not established.
Hepatic Function
Cautious use is required.
CHF
Cautious use is required with this condition.
Overdosage
Symptoms
Nausea, weakness, dizziness, drowsiness, confusion, slurred speech, hypotension, bradycardia, second- or third-degree AV block.
Patient Information
- Teach patient how to monitor pulse before taking medication. Tell patient not to take medication if pulse if less than 50 bpm and to call health care provider.
- Explain to patient how to monitor BP daily.
- Instruct patient not to stop taking this medication suddenly because doing so can cause chest pain and MI.
- Teach patient importance of good oral hygiene and frequent visits to dentist while taking medication.
- Inform patient that frequent follow-up appointments with health care provider are important to adjust medication dosage.
- Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
- Instruct patient to avoid intake of alcoholic beverages or other CNS depressants.
- Advise patient that drug may cause drowsiness, and to use caution while driving or performing other tasks requiring mental alertness.
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