Amlodipine is a drug mainly used to treat high blood pressure. It is more effective than other similar medications and has low rates of side effects, making it a good choice for patients. It has also been used to treat a number of other ailments, including chest pain and migraines, as well as several other conditions that are just beginning to be explored by health researchers. Read on to learn more about the uses and risks of amlodipine.
Disclaimer: By writing this post, we are not recommending this drug. Some of our readers who were already taking the drug requested that we commission a post on it, and we are simply providing information that is available in the scientific and clinical literature. Please discuss your medications with your doctor.
What Is Amlodipine?
Amlodipine is a widely-used drug commonly prescribed for treating high blood pressure and chest pain (angina).
Amlodipine’s main action is to block calcium channels. Calcium channels control how blood vessels throughout the body tighten or relax (more calcium = more contraction). Amlodipine prevents blood vessels from contracting by blocking these channels from taking in more calcium, which leads to lower blood pressure and freer blood flow [R].
Amlodipine is different than other calcium channel blockers as it also releases nitric oxide from blood vessels. Nitric oxide is one of the body’s natural mechanisms for regulating blood flow (it dilates blood vessels), and this extra effect may explain why amlodipine is more effective at improving blood pressure [R].
It also increases blood flow to the kidneys, which helps them filter the blood better [R].
Amlodipine is available as 2.5 mg, 5 mg, and 10 mg tablets [R].
How Does Amlodipine Compare to Other Blood Pressure Medications?
Amlodipine is one of many medications that can be prescribed to control blood pressure. By knowing how it compares with other medications, you can assure that you are getting the best drug for your symptoms.
Many commonly-prescribed drugs for high blood pressure are beta and alpha blockers. Beta blockers decrease blood pressure by slowing the heart rate down, and alpha blockers increase blood flow by relaxing the blood vessels. Amlodipine was found to be as effective as both of these types of drugs in reducing blood pressure [R].
Uses of Amlodipine
1) Lowers Blood Pressure
A clinical review of 18 different studies (including data from 1,896 patients in total) concluded that taking amlodipine leads to clinically significant reductions in blood pressure [R].
A study with 50 patients found that high blood pressure returned to normal levels in 80% of patients who took amlodipine, compared to only 50% of the patients who took a diuretic (hydrochlorothiazide) [R].
If you happen to be forgetful, amlodipine may be your drug of choice, as it was shown to both lower and maintain blood pressure better than losartan after 2 missed doses in a study with 211 elderly patients with high blood pressure [R].
Although blood pressure problems are relatively rare among young people, amlodipine may also be used to lower blood pressure in children. In a study with 268 children, amlodipine lowered systolic blood pressure with very low rates of side effects [R].
2) Improves Angina (Chest Pain)
A study in 52 angina patients found that amlodipine greatly reduced the number of angina episodes after just 4 weeks of daily treatment. It was also relatively safe, with swelling in the limbs (peripheral edema) as the only reported side effect [R].
Similarly, in a large-scale study of 825 patients with coronary heart disease (which can lead to angina). amlodipine reduced the number of sudden (“unstable”) angina episodes over a 3-year period [R].
Amlodipine reduced the number of angina episodes in another study of 29 angina patients. Amlodipine also increased the amount of time that patients could exercise (“exercise tolerance”), suggesting that amlodipine might have a beneficial effect on circulation in general [R].
3) May Correct Some Heart Abnormalities
The left ventricle is a large part of the human heart that is the last “stop” for your blood before it passes to the rest of your body (through the aortic valve). However, the size of the left ventricle (ventricular mass) can sometimes grow abnormally large, which can be an indication of a larger problem. For example, a study with 774 young adults found that an increased left ventricular mass was associated with an increased risk of high blood pressure (hypertension) [R].
However, a study found that amlodipine and lisinopril (another popular blood pressure medication) were equally effective in returning the left ventricle to a more normal size, suggesting that these drugs may also help treat other underlying factors that may be contributing to elevated blood pressure [R].
4) May Prevent Side Effects from Arthritis Treatment
Several of the drugs commonly prescribed to arthritis patients to treat their symptoms have the side effect of raising blood pressure. A study in arthritis patients who were taking the common arthritis medication indomethacin found that amlodipine was more effective than enalapril (an ACE inhibitor) at preventing these side effects [R].
5) May Reduce the Risk of Dementia in the Elderly
High blood pressure (hypertension) has been linked to an increased risk for developing dementia, although most drugs that treat high blood pressure have not been shown to decrease the long-term risk of dementia. However, amlodipine was associated with significantly reduced risk of dementia in patients who were >60 years old in a large-scale study with 15,664 patients taking various blood pressure-reducing medications [R].
6) May Help Prevent or Treat Opioid Addiction
People who take opioid painkillers for extended periods of time gradually develop tolerance, eventually requiring higher and higher doses of opioids to achieve the same effects. They also experience an increased sensitivity to pain (hyperalgesia) after they stop taking opioids, which can make it even harder to successfully quit using these drugs.
However, several mouse studies have found that amlodipine may be able to prevent both of these side effects of opioid use. Amlodipine shows potential for preventing or treating opioid addiction in humans, although more studies need to confirm this [R, R, R].
7) May Help Reduce Migraines
Calcium channel blockers (like amlodipine) have been used in the past to prevent migraines. A series of case studies in migraine patients found that amlodipine reduced the number of migraines, or even stopped them altogether. Although it has not yet been studied enough to get official FDA approval for this use, these early reports indicate that amlodipine may be useful for controlling migraines when prescribed “off-label” [R].
Combining Amlodipine with Other Drugs
Many different systems in the body are involved in controlling blood pressure. Since each blood pressure medication only affects one of these systems at a time, by using multiple drugs together it is possible to target several of these systems at once [R, R].
Combining amlodipine with the following drugs can increase its effectiveness:
- Aliskiren: A study with 1,247 patients found that a combination of amlodipine with aliskiren was more effective in reducing blood pressure than amlodipine alone [R].
- Telmisartan: A study with 300 patients found that a steady dose of amlodipine became more effective as telmisartan doses were increased [R].
- Olmesartan: A variety of studies have found that adding olmesartan to amlodipine treatment is not only more effective at lowering blood pressure, but also reduces the side effects of amlodipine [R].
- Valsartan: A study with 443 patients who were originally on only one medication (monotherapy) found that a combination drug containing both amlodipine and valsartan (also called Exforge) controlled blood pressure better [R].
In a double-blind study with 3 different drugs (olmesartan, amlodipine, and hydrochlorothiazide), the combination of all 3 lowered blood pressure more than just the combination of amlodipine and olmesartan, or any single drug on its own [R].
The combinations used in all of these studies were found to be safe, with minimal side effects.
Amlodipine has generally low rates of side effects. According to a large-scale study involving 12,831 patients, only 3% of all patients decided to stop taking amlodipine due to side effects [R].
A study with 97 patients found that amlodipine had a significantly lower rate of side effects compared to nifedipine, a similar blood pressure medication [R].
A large-scale analysis of data from over 11,000 patients found that the side effects of amlodipine were relatively rare, and included a headache (in 7% of patients), abdominal pain (2%), fatigue (5%), and nausea (3%) [R, R].
- Swelling or inflammation (edema)
- Muscle cramps
- Heart palpitations
- Increased heart rate
- Nosebleeds (epistaxis)
- Swollen eyes or “pink eye” (conjunctivitis)
- Increased frequency of urination, or sleep interruptions from having to urinate (nocturia)
- Itchiness throughout the body (generalized pruritus)
Contraindications and Cautions
Contraindications include [R]:
- Past hypersensitivity to amlodipine or any of its components.
Cautions include [R]:
- Amlodipine should be used with caution in patients with unstable angina, severe hypotension, heart failure, cardiogenic shock, severe aortic stenosis, and hepatic impairment.
Pregnancy and Breastfeeding Considerations
In general, there are no definitive studies that have shown amlodipine to be a risk to the fetus. However, caution is always advised if you are going to take the medication while pregnant, and the benefits of taking the medication should be weighed versus any potential risk to the fetus. A small pilot study found that amlodipine had no adverse effects on the fetus [R]. Please speak to your doctor or a qualified healthcare professional [R].
It is also not known if it is safe to use while breastfeeding, therefore caution is always advised if you are breastfeeding while taking the medication. Please speak to your doctor or a qualified healthcare professional.
There are some drugs that have some major interactions with amlodipine that are important to be aware of:
- Aspirin and amlodipine both bind to the same protein in the blood (albumin), which helps to control how much of each is active in the bloodstream. Taking both drugs together means that they will each compete for binding to this protein, which can lead to dangerously high levels of the active drugs circulating throughout the body [R].
- Ibuprofen and piroxicam may decrease the effects of amlodipine, reducing its ability to lower blood pressure [R].
- Cyclosporine: Amlodipine can increase the amount of cyclosporine that is absorbed into the bloodstream by as much as 40%, leading to much higher doses of cyclosporine than intended [R].
- Simvastatin (FloLipid, Zocor, Juvisync): Amlodipine can increase the amount of simvastatin that gets absorbed into the bloodstream, although this does not appear to strengthen its cholesterol-reducing effects [R]
However, there are also many more potential drug interactions. Therefore, it is important to give your doctor a complete list of any vitamins, supplements, or other drugs you are taking when getting a prescription for a blood pressure medication.
A typical dose of amlodipine is generally between 5 to 10mg / day, although this may vary between individuals and can only be determined by your prescribing doctor. Also note that your doctor may start you off on a small dose, and increase it gradually as needed.
More than 90% of the drug is directly absorbed by your body, and it stays in your bloodstream for up to 2 days or more [R].
Fortunately, amlodipine doesn’t need to be taken at the exact same time every day in order to be effective. It will reach a steady level in your body after about 7 to 8 days of taking it and will stay at a relatively constant level afterward as long as you don’t miss too many of your daily doses [R, R].
Blood pressure medications can be taken either in a single large daily dose or split into 2 smaller doses taken twice per day. However, a study on drug compliance found that people are generally less likely to miss a dose when taking a once-per-day dosage—so if you tend to be forgetful, it might be best to ask your doctor to prescribe you a single larger dose [R].
Because amlodipine is used to lower high blood pressure, taking too much of it at once could cause severely low blood pressure (hypotension), which could be fatal.
Although the amount that it would take to cause death in a human is unknown, data from overdose studies in animals suggest that the equivalent human dose would be extremely large, amounting to many times more than even the largest typical daily dose [R].
For example, there is a case study of a young teenage girl who attempted suicide by taking 150 mg of amlodipine (equivalent to about 15 to 30 pills at once). She was taken to the hospital approximately 4 hours after and survived with a full recovery [R].
In one other case, a 51-year-old male successfully committed suicide by taking 50 pills of amlodipine [R].
Since the typical dose of amlodipine is only 5 to 10mg, the risk of accidentally overdosing on amlodipine is quite small so long as it is being taken as directed.
Nonetheless, since this drug is fairly common in the household, it is very important to keep it stored safely and out of the reach of children. There was a reported case of a 19-month-old child accidentally ingesting 30 mg, although it was non-fatal and the child eventually made a full recovery [R].
Limitations and Caveats
While many studies have found amlodipine to be safer and more effective than most other blood pressure drugs, there have been a few exceptions.
One study compared amlodipine to fosinopril (Monopril), an enzyme inhibitor that relaxes the blood vessels, leading to improved blood flow. Although both medications were equally effective at reducing blood pressure, fosinopril had the additional benefit of reducing the risk of major vascular events (such as heart attacks and strokes) over a 3-year period [R].
In one other study in 421 elderly patients, amlodipine was as effective as valsartan at lowering blood pressure, but that valsartan had fewer side effects than amlodipine [R].