These tablets are used to control high blood pressure. They are also used for problems where there is too much water in your body. The medical name for this is ‘oedema’.

Why have I been prescribed Centyl K?

  • These tablets are used to control high blood pressure. They are also used for problems where there is too much water in your body. The medical name for this is ‘oedema’.

How does it work?

  • The tablets contain an active ingredient called bendroflumethiazide. This is one of a group of medicines known as diuretics (“water tablets”). Bendroflumethiazide reduces the amount of water in your body, getting rid of any excess water via the kidneys, by increasing the amount of urine you produce. This also reduces the amount of salts in your body and together these actions can lower blood pressure. The tablets also contain potassium chloride which adds to the potassium you get from your diet.
The remains of the tablet are white and will leave your body when you go to the toilet (empty your bowels).

When and how do I take it?

  • Take the tablet(s) whole with at least 100 ml (a small cupful) of water.
  • Do not chew or crush the tablet(s). This is important because each tablet releases the potassium slowly. If you chewed the tablet and let the potassium out of it too quickly, this could cause some stomach problems.
  • Stick to the dose your doctor tells you. Take your tablet(s) at the same time each day. This makes it easier to remember it. Most people take their tablet(s) in the morning.

What’s the dose?

High Blood Pressure:

  • The usual dose is 1 or 2 tablets daily as a single dose.


  • The dose will depend on your particular condition. Your doctor may give you between 1 and 4 tablets at the start of your treatment. Your dose will usually be reduced to 1 or 2 tablets daily, depending on your response. The tablets are usually taken as a single dose.

Could it interact with other tablets?

Tell your doctor if you are taking any medicines for:

  • blood pressure
  • heart problems
  • diabetes
  • inflammation or pain (e.g. non-steroidal anti-inflammatory medicines)
  • the removal of uric acid (the substance that causes gout) from the body
  • high cholesterol
  • irregular heartbeat
  • depression (as you should not take Centyl® K tablets if you are taking lithium)
  • You should not take Centyl® K tablets if you are taking medicines that make you sensitive to light.
  • Always tell your doctor and pharmacist about all other medicines you are taking, including ones that you have bought yourself and herbal medicines.

What are the possible risks or side-effects?

  • Like all medicines, Centyl® K tablets can cause side effects.
  • These are usually not serious but contact your doctor immediately if you develop any of the following more serious side effects; severe abdominal pain, vomiting and back pain or severe pain in the head, chest, or pelvic area and skin sores.
  • Contact your doctor as soon as possible if you have any of the following less serious problems; headache, dizziness, faintness (especially if standing up quickly), tiredness, problems passing urine, unusual thirst and dry mouth, stomach upset, a general malaise, any bleeding problems, excessive bruising, increase in infections (particularly sore throats) or gout.
  • Other possible side effects are muscle cramps, skin rashes, skin reactions to strong light, prickling sensations, worsening of any short-sightedness or difficulty for a man in achieving an erection.
  • Some side effects are not noticed e.g. changes in the levels of some substances in the blood such as certain salts or blood cells, or an increase in blood sugar or sugar in the urine. Your doctor may stop giving you your treatment if you have problems with your blood chemistry. If you are worried about any problems with your treatment see your doctor.
  • It is normal to pass urine more often after taking the tablets. This is the usual way to get rid of the excess water in your body.

Can I drink alcohol while taking it?

  • You are more likely to have a drop in blood pressure on standing or sitting up if you drink alcohol while you are being treated with Centyl K.

What if I’m pregnant/breastfeeding?

  • Tell your doctor BEFORE you are given Centyl® K tablets if you are pregnant, might be pregnant or you are breastfeeding.

If you have any more questions please ask your Pharmacist.

Remember to keep all medicines out of reach of children
Please Note:
We have made every effort to ensure that the content of this information sheet is correct at time of publish, but remember that information about drugs may change. This sheet does not list all the uses and side-effects associated with this drug. For full details please see the drug information leaflet which comes with your medicine. Your doctor will assess your medical circumstances and draw your attention to any information or side-effects which may be relevant in your particular case.



1. website- Centyl-K SPC  +Tablets/

2. Centyl-K PIL  +Tablets/ 

Health Reference: Hypertension