Amlodipine besylate is a blood pressure medication that works by relaxing your blood vessels so blood flows through them more easily. It belongs to a class of drugs called calcium channel blockers and is one of four first-line treatments recommended for high blood pressure in the 2025 guidelines from the American Heart Association and American College of Cardiology. Doctors also prescribe it for chest pain caused by reduced blood flow to the heart.
How Amlodipine Lowers Blood Pressure
Your blood vessels have a layer of smooth muscle that contracts and relaxes to regulate blood flow. That contraction depends on calcium entering the muscle cells through tiny gates called L-type calcium channels. Amlodipine binds to those channels and blocks calcium from getting in. Without that calcium signal, the muscle can’t tighten, so the vessel stays relaxed and widens. The result is lower resistance to blood flow and a measurable drop in blood pressure.
This effect is concentrated in the peripheral blood vessels rather than the heart itself, which is why amlodipine is classified as a dihydropyridine calcium channel blocker. It’s a distinction worth knowing because other calcium channel blockers act more on the heart’s rhythm and pumping strength, while amlodipine primarily acts as a vasodilator.
What It Treats
Amlodipine is approved for three main conditions: high blood pressure (hypertension), chronic stable angina, and vasospastic angina (sometimes called Prinzmetal’s angina).
For high blood pressure, it’s taken once daily and can be used alone or alongside other medications. Clinical trials show systolic blood pressure reductions in the range of 7 to 14 mmHg at the standard 5 mg dose, depending on the patient. In the landmark ALLHAT trial, which followed over 33,000 people for nearly five years, amlodipine performed identically to other first-line blood pressure drugs in preventing fatal heart disease and nonfatal heart attacks, with a 6-year event rate of 11.3%.
For angina, amlodipine reduces how often chest pain episodes occur by keeping coronary arteries relaxed and open. In studies of vasospastic angina, where arteries temporarily spasm and restrict blood flow, amlodipine decreased the average number of weekly chest pain episodes by about 18%, and roughly a third of patients were completely free of chest pain after six weeks. Patients also needed less nitroglycerin to manage breakthrough episodes.
How It’s Taken
The typical starting dose for adults is 5 mg once a day, with a maximum of 10 mg. Older adults or people with liver problems usually start at 2.5 mg. For children ages 6 to 17, the effective dose ranges from 2.5 to 5 mg daily.
One of amlodipine’s practical advantages is its unusually long duration in the body. After you take a dose, it reaches its peak concentration in your blood between 6 and 12 hours later. Its elimination half-life is 30 to 50 hours, meaning the drug is still actively working well into the next day. This long action makes it forgiving if you’re a few hours late taking your pill, and it means once-daily dosing provides steady blood pressure control around the clock. It also means the drug takes several days to reach its full effect when you first start it.
Common Side Effects
The most well-known side effect is swelling in the ankles and feet, called peripheral edema. This happens in roughly 1 in 6 people who take amlodipine. It occurs because the drug dilates arteries but not veins to the same degree, so more fluid gets pushed into the tissues of the lower legs. The swelling is not a sign of heart failure or kidney damage. It’s a direct mechanical consequence of how the drug opens blood vessels, and it tends to be more noticeable at higher doses.
Other side effects include dizziness, flushing, and fatigue, all of which relate to the blood pressure drop. Most people tolerate amlodipine well, and its overall side effect profile is one reason guidelines list it as a preferred first-line option.
Important Drug Interactions
Amlodipine interferes with how your liver breaks down certain cholesterol medications. If you take simvastatin or lovastatin, the dose of those drugs should not exceed 20 mg per day while you’re on amlodipine. Without that limit, amlodipine raises the blood levels of those statins high enough to increase the risk of muscle damage.
If you take sildenafil (commonly used for erectile dysfunction) alongside amlodipine, expect a more pronounced blood pressure drop. Studies in people with high blood pressure found an additional reduction of about 8 mmHg systolic and 7 mmHg diastolic when the two drugs were combined. That’s not necessarily dangerous, but it can cause lightheadedness or fainting, especially when standing up quickly.
Why It’s Widely Prescribed
Amlodipine has been on the market since the early 1990s and remains one of the most commonly prescribed blood pressure medications worldwide. Several features explain its staying power: it works across a broad range of patients regardless of age or ethnicity, it requires only one pill a day, it has a long track record of safety in large clinical trials, and it’s available as a low-cost generic. It can be combined with most other blood pressure drugs when a single medication isn’t enough, and it pulls double duty for people who have both hypertension and angina. For many people, it becomes a medication they take for years or decades as part of long-term cardiovascular risk management.