Drug Detail:Amlodipine (Amlodipine [ am-loe-di-peen ])
Drug Class: Calcium channel blocking agents
1. How it works
- Amlodipine may be used to treat heart conditions such as angina and high blood pressure.
- Amlodipine inhibits the influx of calcium ions across cardiac (heart) and smooth muscle causing relaxation of these muscles and dilation (widening). The exact way amlodipine works in angina is not known; however, experts believe it helps prevent spasm of the coronary artery and reduces how hard the heart has to work to pump blood around the body, lowering its oxygen requirements. Amlodipine does not change the levels of calcium in the blood.
- Amlodipine belongs to a class of medicines called calcium channel blockers (sometimes called calcium channel antagonists).
2. Upsides
- May be used for the treatment of high blood pressure (hypertension), alone or in combination with other agents for high blood pressure.
- May be used as an ongoing treatment to relieve symptoms such as chest pain in people with chronic stable angina, or angina due to coronary artery spasm. Will not relieve acute episodes of angina (other medications such as sublingual nitroglycerin are used for this purpose).
- In African Americans, calcium channel blockers such as amlodipine may be recommended over other types of heart medications (for example ACE inhibitors, ARBs) for the treatment of hypertension.
- Appears to have little or no interaction with grapefruit or grapefruit products or antacids.
- Can improve a person's tolerance to exercise and keep their blood pressure at acceptable levels during exercise. Heart rate at maximal exercise does not change or is slightly reduced.
- Has a long duration of action.
- May be taken with or without food.
- Generic amlodipine is available.
3. Downsides
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Edema (swelling around the ankles) is the main side effect. Shortness of breath, dizziness, fast or irregular heart beat, flushing, and wheezing have also been reported.
- Lower doses may be needed in patients with liver disease. When starting treatment in those already on antihypertensive treatment, use a lower starting dose of 2.5 mg/day.
- Rarely, excessively low blood pressure may be experienced by some people. The risk is higher for people with severe aortic stenosis. Blood pressure should be monitored regularly.
- Rarely, some patients may experience an increase in the frequency or severity of angina or acute myocardial infarction (heart attack) when starting amlodipine. The risk is greater in those with severe obstructive coronary artery disease.
- May interact with a number of other drugs including those that inhibit hepatic enzymes CYP3A and other drugs that also lower blood pressure. See prescribing information for a full list of drug interactions.
Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects
4. Tips
- May be taken with or without food.
- The manufacturer states that there is no concern about taking amlodipine with grapefruit juice.
- Be careful when going from sitting to standing as blood pressure may drop.
- Report to your doctor any signs of dizziness, tiredness, flushing, nausea, indigestion, shortness of breath, excessive weight gain, muscle rigidity or tremors, or edema.
- Dial 911 or report to an emergency department if wheezing, facial swelling, chest tightness, cough, or seizures occur suddenly.
- Do not stop taking amlodipine suddenly. Although no "rebound" effect has been reported, it is better to slowly decrease the dosage over a period of time.
- Your doctor may advise you to take sublingual nitroglycerin for any break-through angina pain.
5. Response and effectiveness
- Peak concentrations of amlodipine occur between 6 and 12 hours of an oral dose. The effect of amlodipine lasts for approximately 24 hours.
6. Interactions
Medicines that interact with amlodipine may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with amlodipine. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.
Common medications that may interact with amlodipine include:
- anticonvulsants, such as carbamazepine or fosphenytoin
- antifungal agents, such as itraconazole or ketoconazole
- alfentanil
- amiodarone
- beta-blockers, such as atenolol, labetalol, or metoprolol
- buspirone
- benzodiazepines such as midazolam or triazolam
- carbamazepine
- cimetidine
- cyclosporine
- rifampin
- lovastatin or simvastatin
- quinidine
- NSAIDs, such as diclofenac, ibuprofen, and indomethacin, may decrease the blood pressure-lowering capabilities of amlodipine
- sildenafil
- other medications that inhibit or induce CYP 3A4.
Note that this list is not all-inclusive and includes only common medications that may interact with amlodipine. You should refer to the prescribing information for amlodipine for a complete list of interactions.