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, pregnancy.

 

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 enter 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

        Possible increased serum levels and toxicity of cyclosporine if taken concurrently

 

Nursing considerations

CLINICAL ALERT!

Name confusion has been reported between Norvasc (amlodipine) and Navane (thiothixene); use caution.

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

        WARNING: 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

        Take with meals if upset stomach occurs.

        You may experience these side effects: Nausea, vomiting (eat frequent small meals); 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.