What is amlodipine?
Amlodipine is a calcium channel blocker, a class of drugs that also includes diltiazem, felodipine, and isradipine, among others.
Amlodipine is primarily used to treat high blood pressure in adults and children six years old and above, either alone or in combination with another medication. It has several other uses, most of which are related to conditions connected to coronary artery disease. You can read more about the range of conditions amlodipine is used to treat in the following question: What is amlodipine used for?
Amlodipine is available in the form of tablets, capsules, liquid solutions, or suspensions, and usually comes in strengths ranging from 2.5 mg to 10 mg. Amlodipine is commonly sold under brand names, including Norvasc (tablets & capsules) and Katerzia (liquid solution), and is also available as a generic medication.
Amlodipine may also be prescribed in combination with another blood pressure-lowering medication, such as an ACE inhibitor, a diuretic, or an ARB. Combination products containing amlodipine and other medications are available, which can be more convenient, safer, and more cost-effective than taking multiple products.
Amlodipine also comes as a combination product containing medications used to treat other conditions that are common in people diagnosed with high blood pressure. Amlodipine and atorvastatin (sold under the brand name Caduet), for example, may be prescribed to people living with high blood pressure and high cholesterol.
The contents of this article refer only to amlodipine as a standalone product, unless otherwise stated.
What is amlodipine used for?
Amlodipine is primarily used to treat high blood pressure (hypertension), coronary artery disease, and angina (chest pain caused by reduced blood flow to your heart).
Treatment for adults usually starts at 5 mg per day; small, fragile, or elderly patients or patients with liver problems may start at 2.5 mg per day along with another blood pressure-lowering medication. The maximum dosage for adults (as recommended by both the FDA in the US and NHS in the UK) is 10 mg per day.
Dosage for children between 6-17 years old usually ranges from 2.5 mg to 5 mg per day.
Amlodipine may also be used ‘off-label’ (in a manner not approved by the FDA or your country’s equivalent regulatory body) to treat conditions including Raynaud’s disease and congestive heart failure.
What is amlodipine besylate?
As with many drugs, amlodipine is produced in its salt form to improve solubility in water, which helps absorption into your bloodstream and makes the drug more effective. Besylate refers to the specific salt form for amlodipine. Other salts can also be used, including maleate and mesylate.
There is no evidence that the salt form used affects the therapeutic effects of amlodipine. To avoid confusion, therefore, it is usually simply referred to as ‘amlodipine’ regardless of the salt form.
How does amlodipine work?
Amlodipine, like other calcium channel blockers, selectively prevents the release of calcium from entering the muscle cells of your heart and artery walls. It effectively shuts the door (ion channel) through which calcium enters these cells. Because calcium plays a key role in contracting the muscles that line your heart and artery walls, clocking its entry helps relax the muscles.
This, subsequently, widens your blood vessels and improves blood flow, which is how your blood pressure is reduced.
Amlodipine is also believed to reduce the workload of your heart and the energy and oxygen it needs, while simultaneously increasing oxygen supply by widening your coronary arteries and arterioles (the small branches of an artery). This increased oxygen supply is believed to be key in reducing chest pain (angina) related to coronary artery disease.
Amlodipine belongs to a subcategory of calcium channel blockers called dihydropyridines. The other class of calcium channel blockers, called non-dihydropyridines (including diltiazem and verapamil), have the additional effect of slowing your heart rate down. Unlike amlodipine, non-dihydropyridines can be used to treat heart rhythm disorders, such as atrial fibrillation and supraventricular tachycardia.
How long does it take for amlodipine to lower blood pressure?
Amlodipine starts working within hours of your first dose. However, it can take a few weeks for it to have its full effect. If you are taking amlodipine for high blood pressure, you might not feel any different, especially if you were not experiencing any symptoms (as is common with high blood pressure). Even if you do not feel any different, that does not mean the medicine is not working. You should continue taking it as prescribed. If you have any concerns about how well amlodipine is working, you should speak to your doctor.
If you are taking amlodipine for angina or other conditions, it may take a few weeks for your symptoms to improve.
What are the side effects of amlodipine?
In rare cases, when you start taking amlodipine or increase your dosage, it can cause a heart attack or make angina symptoms worse. If this happens, contact your doctor immediately or visit a hospital emergency room.
Other common side effects include:
- Pounding heartbeat
- Swollen feet or ankles
These side effects are often mild and will often go away as your body gets used to amlodipine. However, if they are more severe, don’t go away, or get worse, you should contact your doctor at once.
More serious symptoms include:
- Severe stomach pain, sometimes with bloody diarrhea and/or nausea and vomiting
- Yellowing of your skin or the white of your eyes
- New or worsening chest pain (as mentioned above)
If you experience any of these symptoms, you should contact your doctor immediately.
Allergic reactions to amlodipine are rare but can occur. Signs of a serious allergic reaction should be treated as a medical emergency. They include:
- Skin rash – for example itchy, red, or swollen skin
- Tightness in the chest or throat
- Trouble breathing or talking
- Swollen mouth, face, lips, tongue, or throat
This is not an extensive list of possible side effects of amlodipine. For more information about side effects, please read the information leaflet that comes with the medication or speak to your doctor or pharmacist.
Does amlodipine interact with other drugs?
Amlodipine can interact with many different other drugs. Some of the potentially severe interactions include:
- Several cancer treatments, including apalutamide, ceritinib, enzalutamide, mitotane
- Several epilepsy treatments, including carbamazepine, fosphenytoin, phenytoin
- Rifabutin, rifampin, and rifapentine (antibiotics used to treat tuberculosis)
- Siponimod (used to treat multiple sclerosis)
This is far from an extensive list of the drugs that can interact with amlodipine. You should inform your doctor about every medication you take (prescription and over the counter). If the risk of a serious interaction outweighs the benefits of amlodipine, your doctor may consider a different medication.
Similarly, you should inform your doctor of any supplements or herbal remedies you take, including multivitamins and St. John’s wort, as they can also interact with amlodipine.
Should I take amlodipine in the morning or at night?
It does not matter whether you take amlodipine in the morning or evening (or any other time during the day), nor does it matter whether you take it with or without food.
However, it is highly recommended that you take it at the same time every day. You can coincide taking your medication with another consistent activity, such as brushing your teeth, or use a medication reminder app.
What should I do if I miss a dose of amlodipine?
If you realize you have missed your dose of amlodipine within 12 hours of the time you usually take it, take it as soon as possible and continue with your next dose at the regular time.
If you realize you have missed your dose of amlodipine after 12 hours or longer, skip the dose and take your next dose at the regular time. Do not double your dosage to make up for the one you missed.
What should I do if I overdose on amlodipine?
If you take too much amlodipine, you should contact your doctor or a poison control center immediately or go straight to a hospital emergency room. Do not drive yourself.
Can I drive while taking amlodipine?
Some of the side effects of amlodipine, such as dizziness or headaches, can impair your ability to drive. When you first start taking amlodipine, it is therefore recommended that you see how your body reacts before driving or operating machinery.
If you do not experience side effects, or they subside over time, it is generally considered safe to drive while taking amlodipine.
Can I drink alcohol while taking amlodipine?
Alcohol does not directly interact with amlodipine, so it is usually safe to drink in moderation.
However, a possible short-term effect of alcohol – even in small amounts – is lowering your blood pressure. Combined with the therapeutic blood pressure-lowering effects of amlodipine, the risk of side effects such as dizziness or sleepiness may increase.
If this happens, it is recommended that you avoid drinking alcohol while taking amlodipine.
Can I take amlodipine when pregnant or breastfeeding?
Studies have shown that amlodipine has adverse effects on pregnant rats when given at a dose equivalent to 10 mg per day for humans. However, no reliable human studies have investigated the effects of amlodipine on pregnant women or nursing mothers.
Due to the lack of evidence, most doctors will prescribe an alternative treatment with a more defined safety profile. Amlodipine is normally used only if the benefits of the treatment outweigh the risk of harm to the mother and/or baby, and if no preferable alternative is available.
If you are taking amlodipine and are pregnant or you are planning on having a baby, you should speak to your doctor about the safest option.
Can my child take amlodipine?
Amlodipine has been approved for use in children aged six years old and above. Doctors will usually prescribe a lower starting dosage for children than adults, often 2.5 mg per day. The maximum recommended dosage for children is 5 mg per day.
The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.