Norvasc (amlodipine besylate) is used to treat hypertension, chronic stable angina in coronary artery disease, or angina caused by coronary artery spasm (Prinzmetal's angina). Norvasc is classed as a calcium channel blocker.
Mechanism of Action
At the cellular level, norvasc interferes with the transfer of calcium ions across cell membranes. Primarily the cell membranes of vascular smooth muscle and cardiac muscle are affected. By interfering with the transfer of calcium across these cell membranes, two main events occur. First, arteries and veins begin to vasodilate (relax and open up) which decreases cardiac work load. This reduces blood pressure. The second effect takes place in the cardiac cells. The speed of cardiac conduction is delayed. This means the heart rate is slowed.
Available Forms and Dosage
Tablets are available in 2.5mg, 5mg, and 10mg doses. Daily dose ranges from 2.5mg to 10mg per day. Follow prescriber dosing instructions.
Side Effects
Low blood pressure, dizziness, and fatigue are common during initiation of therapy. Peripheral swelling may occur as well as rash and flushing of the face. Report any severe or persistent symptoms to the prescribing physician.
Considerations
Norvasc can cause significant hypotension, so blood pressure should be monitored during initial phases of treatment. Rise slowly from laying or sitting positions and allow time for blood pressure to adjust after position changes.
Warning
Norvasc is contraindicated for patients with sick sinus syndrome and first or second degree heart block. Use cautiously in patients with congestive heart failure.
References
- National Institutes of Health
- Karch, A. M. (2008). 2008 Lippincott's Nursing Drug Guide. New York: Lippincott Williams & Wilkins
