amlodipine besylate
(am loe' di peen)
Norvasc

Pregnancy Category C

Drug classes
Calcium channel-blocker
Antianginal drug
Antihypertensive

Therapeutic actions
Inhibits the movement of calcium ions across the membranes of cardiac and arterial muscle cells; inhibits transmembrane calcium flow, which results in the depression of impulse formation in specialized cardiac pacemaker cells, slowing of the velocity of conduction of the cardiac impulse, depression of myocardial contractility, and dilation of coronary arteries and arterioles and peripheral arterioles; these effects lead to decreased cardiac work, decreased cardiac oxygen consumption, and in patients with vasospastic (Prinzmetal's) angina, increased delivery of oxygen to cardiac cells.

Indications
· Angina pectoris due to coronary artery spasm (Prinzmetal's variant angina)
· Chronic stable angina, alone or in combination with other agents
· Essential hypertension, alone or in combination with other antihypertensives

Contraindications and cautions
· Contraindicated with allergy to amlodipine, impaired hepatic or renal function, sick sinus syndrome, heart block (second or third degree), lactation.
· Use cautiously with CHF.

Available forms
Tablets--2.5, 5, 10 mg

Dosages
ADULTS
Initially 5 mg PO daily; dosage may be gradually increased over 10–14 days to a maximum dose of 10 mg PO daily.
PEDIATRIC PATIENTS
Safety and efficacy not established.
GERIATRIC PATIENTS OR PATIENTS WITH HEPATIC IMPAIRMENT
Initially, 2.5 mg PO daily; dosage may be gradually adjusted over 7–14 days based on clinical assessment.

Pharmacokinetics
Route
Onset
Peak
Oral
Unknown
6–12 hr


Metabolism: Hepatic; T1/2: 30–50 hr
Distribution: Crosses placenta; may pass into breast milk
Excretion: Urine

Adverse effects
· CNS: Dizziness, light-headedness, headache, asthenia, fatigue, lethargy
· CV: Peripheral edema, arrhythmias
· Dermatologic: Flushing, rash
· GI: Nausea, abdominal discomfort

Interactions
Drug-drug
· Possible increased serum levels and toxicity of cyclosporine if taken concurrently

Nursing considerations
Assessment
· History: Allergy to amlodipine, impaired hepatic or renal function, sick sinus syndrome, heart block, lactation, CHF
· Physical: Skin lesions, color, edema; P, BP, baseline ECG, peripheral perfusion, auscultation; R, adventitious sounds; liver evaluation, GI normal output; liver and renal function tests, urinalysis

Interventions
· Monitor patient carefully (BP, cardiac rhythm, and output) while adjusting drug to therapeutic dose; use special caution if patient has CHF.
· Monitor BP very carefully if patient is also on nitrates.
· Monitor cardiac rhythm regularly during stabilization of dosage and periodically during long-term therapy.
· Administer drug without regard to meals.

Teaching points</SPAN>
· Take with meals if upset stomach occurs.
· These side effects may occur: nausea, vomiting (small, frequent meals may help); headache (adjust lighting, noise, and temperature; medication may be ordered).
· Report irregular heartbeat, shortness of breath, swelling of the hands or feet, pronounced dizziness, constipation.

Adverse effects in Italic are most common; those in Bold are life-threatening.