A calcium-channel blocker (dihydropyridine)
Felodipine
A once-daily calcium-channel blocker for high blood pressure that relaxes blood vessels — with grapefruit best avoided.
What is Felodipine?
Felodipine is a calcium-channel blocker of the dihydropyridine type, used mainly to lower high blood pressure. Like amlodipine, it works by relaxing and widening the blood vessels so the heart does not have to pump against as much resistance.
Education and reference only. This is a plain-language guide to Felodipine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Felodipine is a calcium-channel blocker of the dihydropyridine type, used mainly to lower high blood pressure. Like amlodipine, it works mostly by relaxing and widening blood vessels rather than slowing the heart, so it is a common choice for blood-pressure control, including in older people and those of African or Caribbean family background. It is taken as a long-term, once-daily modified-release tablet. Common brands include Plendil and Cabren.
How it works
Felodipine blocks the channels that let calcium into the muscle cells in the walls of arteries. Calcium is what makes those muscles tighten, so blocking it allows the artery walls to relax and widen. Wider, more relaxed arteries offer less resistance to blood flow, which lowers blood pressure. Because it acts mainly on blood vessels rather than the heart's conducting system, it does not slow the heart rate the way some other calcium-channel blockers (such as diltiazem and verapamil) do.
Company & origin
Originated / developed by: Astra AB (Hässle).
Felodipine was discovered by Hässle, the cardiovascular research division of Sweden's Astra AB (patent filed 1979), and was launched around 1988; it gained US FDA approval (marketed with Merck) in 1991.
What it treats
Conditions Felodipine is used for
Practical use
How to take Felodipine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Swallow felodipine tablets whole with water and do not crush or chew them, as they are designed to release slowly.
- Avoid grapefruit and grapefruit juice, which can raise the amount of medicine in your blood and increase side effects.
- Take it at around the same time each day to keep the effect steady.
- Be aware that swollen ankles, flushing and headache can occur, especially in the first weeks.
- Do not stop the medicine on your own; speak to your prescriber if side effects are troublesome.
Weighing it up
Advantages & disadvantages of Felodipine
Advantages
- Effective at lowering blood pressure, often as a once-daily tablet.
- Works well alongside other blood-pressure medicines such as ACE inhibitors or ARBs.
- Does not slow the heart rate the way some other heart medicines do.
- Useful option for people who cannot take certain other blood-pressure drugs.
Disadvantages
- Commonly causes ankle swelling, flushing and headaches.
- Interacts with grapefruit, which can increase side effects.
- Must be swallowed whole, which may not suit everyone.
- Can cause palpitations or dizziness in some people.
Practical use
Good to know
Felodipine is a once-daily modified-release tablet that should be swallowed whole — not crushed or chewed — so the medicine is released slowly over the day. Its typical side effects come from relaxing blood vessels: ankle swelling, flushing and headache, which often ease over the first weeks. An important practical point is grapefruit: grapefruit and grapefruit juice raise felodipine levels in the body and can increase side effects, so they are best avoided. It is taken long-term, and blood pressure is reviewed to confirm it is working.
Who should not take it / use with caution
- People with certain unstable heart conditions, such as recent heart attack, unstable angina or significant uncontrolled heart failure.
- People with a very tight narrowing of the heart's outflow (severe aortic stenosis) or very low blood pressure.
- Used with caution in significant liver disease, and avoided in pregnancy unless specifically advised.
Monitoring
- Blood pressure to confirm response
- For ankle swelling, flushing or headache
- Tolerability over the first weeks
Side effects
- Ankle or lower-leg swelling, flushing, and headache — common early on and often easing with time.
- Palpitations (an awareness of the heartbeat) or dizziness in some people.
- Less commonly, overgrowth of the gums, tiredness, or a fast heart rate; very rarely, a worsening of angina when first starting.
Key interactions
- Grapefruit and grapefruit juice raise its levels and the risk of side effects — best avoided.
- Certain antibiotics, antifungals and other medicines that affect the same liver enzymes can raise or lower its levels.
- Care alongside other blood-pressure-lowering medicines, which can add to its effect.
Available as: Modified-release tablets (several strengths), designed to be swallowed whole.
Answers
Felodipine: frequently asked questions
Why must I avoid grapefruit with felodipine?
Grapefruit and grapefruit juice block a liver enzyme that breaks felodipine down, so its levels in the body rise and side effects such as flushing, headache and ankle swelling become more likely. It is best to avoid grapefruit and grapefruit juice while taking it.
Why are my ankles swelling?
Ankle and lower-leg swelling is a recognised effect of dihydropyridine calcium-channel blockers like felodipine, because they relax blood vessels. It is usually harmless and often eases with time, but tell your prescriber if it is troublesome — sometimes the medicine or approach is adjusted.
Can I crush or split the tablet?
No — felodipine is a modified-release tablet designed to let the medicine out slowly over the day, so it should be swallowed whole and not crushed, chewed or split. If you have trouble swallowing it, ask your pharmacist about alternatives.
Does felodipine slow my heart rate?
No — unlike some other calcium-channel blockers (diltiazem and verapamil), felodipine works mainly on the blood vessels rather than the heart's rhythm, so it does not slow the heart rate. It may, if anything, cause a mild awareness of the heartbeat in some people.
What is the difference between felodipine and Plendil or Cabren?
They are the same medicine — felodipine is the generic (active-ingredient) name, and Plendil and Cabren are brand names. Generic felodipine contains the identical active ingredient.
The wider class
About Calcium-channel blockers
Felodipine belongs to the calcium-channel blockers class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF: Felodipine.
- electronic Medicines Compendium (SmPC): Felodipine (Plendil).
- NICE NG136: Hypertension in adults.
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