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What is amlodipine?

Amlodipine is a prescription drug that falls under the category of calcium-channel blockers.¹

This medication is primarily used to treat high blood pressure (hypertension). It’s sometimes taken along with other medications as part of combination therapy.

Amlodipine relaxes the blood vessels, lowering blood pressure and allowing blood to flow more easily through the system. When blood vessels constrict (narrow), the pressure of blood in the vessels increases, forcing the heart to work harder to pump blood through the body.

This is a cause of chronic high blood pressure and blood vessel damage, which can lead to cardiovascular disease. Damage can occur to vessels anywhere in the body, but when the arteries in the heart are involved (coronary artery disease), it results in blockages and chest pain from a lack of oxygen to the heart muscle (angina).

What is amlodipine used to treat?

Amlodipine is approved by the US Food and Drug Administration (FDA) for treating the following conditions:²

  • High blood pressure

  • Coronary artery disease (CAD)

  • Chronic stable angina

  • Vasospastic angina

  • CAD documented by angiography

Doctors occasionally prescribe amlodipine for off-label uses, meaning they are not approved by the FDA. Some of these include Raynaud phenomenon, silent ischemia, left ventricular hypertrophy, diabetic kidney disease, and some cases of pulmonary hypertension.³

Children under six years of age with high blood pressure are also treated off-label, as amlodipine is not approved for use in this age group.

Dosage forms and strengths

Amlodipine is available as an oral tablet in varying strengths (generic, Norvasc):

  • 2.5mg

  • 5mg

  • 10mg

The drug is also available as a solution (Katerzia, Norliqva):

  • 1mg/mL

Amlodipine has a longer half-life than other calcium-channel blockers, so it can be taken once daily.⁴

The dosage you are prescribed will depend on the condition being treated, your age, any other health conditions you have, and any other medicines you are currently taking.

Amlodipine dosing recommendations for hypertension

  • Adults: 5mg once-daily initial dose with a possible increase every 1–2 weeks to the maximum dosage of 10mg per day

  • Children aged six years or over: 2.5–5mg per day with a maximum of 10mg daily

  • Adults aged over 65 years: 2.5mg per day for the initial dose, increasing to a maximum dose of 10mg per day in 1–2 weeks

Amlodipine dosing recommendations for angina and coronary artery disease (CAD):

  • Adults: 5–10mg per day

  • Adults over the age of 65 years: initial dose of 5mg per day

How do you take amlodipine?

Amlodipine is typically prescribed to be taken once a day, irrespective of dosage strength. While it’s generally safe to take amlodipine at any time of the day, it is important to take your dose around the same time of the day. This allows your body to use the medication fully before the next dose.

You can take amlodipine with water, with or without food. If you have difficulty swallowing tablets, you can try taking the solution form or dissolve a tablet in water and drink it immediately.

Seeing results

Amlodipine’s action is delayed due to its relatively long half-life. Given the once-a-day standard dosing for amlodipine, it can take 4–10 days to accumulate in the body and reach a steady state. This is because the drug takes a long time to be absorbed in the body.⁵

Who should not take amlodipine?

Amlodipine may not be safe for you if you have any of the following conditions:⁶

  • Liver disease

  • Severe heart failure

  • Severe aortic stenosis

  • Recent heart attack

  • Unstable angina, severe coronary artery disease

  • An allergy to amlodipine

  • Severe hypotension

Children younger than six years of age should not take amlodipine.

Potential side effects of amlodipine

The side effects of amlodipine range from mild to severe. Most milder side effects will improve after a few days, but call your doctor if the symptoms persist or worsen.⁷

Common side effects of amlodipine include the following:

  • Headache

  • Dizziness

  • Rash, itching

  • Fatigue, drowsiness

  • Stomach pains

  • Swelling of the hands, feet, or ankles

  • Muscle cramps

  • Nausea, vomiting

  • Flushing

  • Male sexual dysfunction

  • Nosebleed

Severe side effects of amlodipine include the following signs of amlodipine allergy:

  • Rash, hives

  • Difficulty breathing, wheezing

  • Swelling of the face, tongue, or throat

  • Trouble swallowing

  • Vomiting

  • Loss of consciousness

It’s also possible to develop the following signs of liver issues:

  • Excessive fatigue and weakness

  • Yellowing of the skin or the sclera (the white part of the eyes)

  • Upper right-sided abdominal pain

  • Flu-like symptoms

  • Elevated liver enzymes

Other severe side effects of amlodipine include the following:

Serious adverse effects of amlodipine may indicate an allergic reaction, liver problems, or heart disease. If you experience one or more of the side effects above after taking amlodipine, seek immediate medical attention.

Overdose

Amlodipine is prescribed for long-term use and can have serious risks when misused or not taken as prescribed.

Taking too much amlodipine can cause serious side effects such as:⁸

  • Difficulty breathing

  • Rapid heart rate

  • Low blood pressure

  • Dizziness

  • Fainting, loss of consciousness

  • Shock

Call 911 immediately if you experience any adverse side effects from overdosing on amlodipine.

Amlodipine and pregnancy

Amlodipine has been designated a category C medication in pregnancy by the FDA. This indicates that it has not been proven safe for use during pregnancy. More human testing is needed to establish the drug’s effect on the pregnancy or fetus.

Recent studies have indicated there is no increased risk of congenital anomalies in the fetus with the use of amlodipine in the first trimester. In fact, the findings of a meta-analysis established that amlodipine can be used safely for the treatment of high blood pressure during pregnancy.⁹ ¹⁰

Amlodipine and breastfeeding

Research shows that although amlodipine has been found to pass through breast milk in trace amounts, it has shown no effects on the infant. Amlodipine can be prescribed to breastfeeding mothers without risking the infant’s health.¹¹

Generally, your doctor will determine whether it’s safe for you to take amlodipine during pregnancy or breastfeeding, depending on your individual circumstances.

Missed doses

If you miss a dose of amlodipine, take it as soon as you remember. However, if it has been over 12 hours since the time of your missed dose, skip it and take the next dose at your regularly scheduled time.

Note that skipping multiple doses of amlodipine may worsen your blood pressure and lead to other complications, such as a heart attack or stroke.

Drug interactions

Certain drugs are known to cause interactions when taken along with amlodipine. These drugs include the following:¹²

Transplant medications

Most transplant medications work as immunosuppressants to prevent organ rejection. Taking medications such as cyclosporine (Gengraf, Neoral), sirolimus (Rapamune), and tacrolimus (Prograf, Protopic) along with amlodipine can increase their blood levels, causing a greater risk of liver and kidney problems.

Erectile dysfunction drugs

Sildenafil (Viagra), avanafil (Stendra), and tadalafil (Cialis) are medications used to treat erectile dysfunction and work by relaxing blood vessels to increase blood flow to the penis. Since amlodipine also relaxes blood vessels, taking it with these medications may cause severely low blood pressure.

Lipid-lowering drugs

Simvastatin (Zocor) and lovastatin (Mevacor) are used to treat high cholesterol and prevent heart attacks in people who are at risk. Taking this type of medication along with amlodipine can increase your blood levels of these drugs, increasing the risk of muscle damage.

HIV medications

Ritonavir (Norvir), atazanavir (Reyataz), darunavir (Prezista), and fosamprenavir (Lexiva) are antiviral drugs often used in the treatment of HIV infection. Taking these drugs can increase amlodipine levels in the blood and worsen its side effects, particularly low blood pressure.

Long-term treatment with these antivirals may require a dose adjustment for amlodipine.

Antibiotics

Rifampin, clarithromycin (Biaxin), and erythromycin may affect amlodipine levels.

Certain antifungal medications

Antifungal medications such as voriconazole (Vfend), itraconazole (Sporanox), and ketoconazole (Nizoral) block certain processes in the liver, affecting its ability to break down amlodipine. Taking these antifungal medications can increase the levels of amlodipine in the blood along with the risk of severe side effects.

Antipsychotics and antidepressants

Clozapine (Clozaril), olanzapine (Zyprexa), clomipramine (Anafranil), haloperidol (Haldol), thioridazine (Mellaril), risperidone (Risperdal), mirtazapine (Remeron), and quetiapine (Seroquel) can cause an increased risk of arrhythmias and/or low blood pressure (hypotension).

Anti-seizure medications

Drugs like phenobarbital (Luminal), topiramate (Topamax), and phenytoin (Dilantin) can affect blood levels of amlodipine and may increase your risk of low blood pressure.

Nitroglycerin

Taking amlodipine with nitroglycerin increases your risk of low blood pressure. 

Warfarin

Taking warfarin (Coumadin) alongside amlodipine can increase your risk of bleeding.

Pain medications and sedatives

Pain-relieving drugs, such as tramadol (Ultram), oxymorphone (Opana), hydrocodone (Vicodin), meperidine (Demerol), and morphine, and sedatives, like oxazepam (Serax) and midazolam (Versed), should be taken with caution due to their potential interactions with amlodipine. This could lead to low blood pressure, cardiac arrhythmias, and respiratory depression.

Herbs and natural supplements

Echinacea, ginkgo, garlic, licorice, St. John’s wort, niacin, flaxseed, coenzyme Q-10, caffeine, and ginseng all have potential interactions with amlodipine.

Can I drink alcohol while taking amlodipine?

Drinking alcohol while taking amlodipine is not recommended due to an increased risk of low blood pressure.

If you drink alcohol, you may experience the following symptoms:

  • Headache

  • Dizziness

  • Low blood pressure

If symptoms persist or become severe, call your doctor and avoid alcohol use while you are taking amlodipine.

What to discuss with your doctor before starting amlodipine

Before your doctor prescribes amlodipine, they need to be informed of the following:

  • Any medications or supplements you are currently taking or take occasionally

  • All medical conditions, including liver or heart disease

  • Any previous allergic reaction to amlodipine or a similar drug

  • Current pregnancy or if you plan on becoming pregnant

Stopping amlodipine

It’s not safe to stop taking amlodipine suddenly, as it may worsen your blood pressure and potentially lead to withdrawal syndrome.¹³

If you wish to discontinue the medication, speak to your doctor who will advise you on how to gradually reduce your dosage until you can stop it safely.

Drug approval history

Amlodipine was first approved by the FDA in 1987.¹⁴

Tips for taking amlodipine

  1. Always take amlodipine as prescribed, and try to take it at the same time each day.

  2. Call your doctor or 911 if you experience any adverse side effects.

  3. Limit alcohol use when taking amlodipine.

  4. Store your medicine at room temperature in a dry, dark place.

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Disclaimer

Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.