Diamicron MR (Gliclazide)

How does it work?

Diamicron MR tablets contain the active ingredient gliclazide, which is a type of medicine called a sulphonylurea. (NB. Gliclazide is also available without a brand name, ie as the generic medicine.) Gliclazide is used to help control blood sugar levels in people with type 2 diabetes.

People with type 2 diabetes (non-insulin dependent diabetes) have a deficiency of a hormone called insulin. Insulin is produced by the pancreas and is the main hormone responsible for controlling sugar levels in the blood. It normally makes the cells of the body remove excess sugar from the blood. In type 2 diabetes insulin is produced inefficiently in response to surges of blood sugar, such as following a meal. The cells of the body also become resistant to the action of insulin that is produced, which means that blood sugar levels can become too high.

Gliclazide works mainly by stimulating the cells in the pancreas that produce insulin. These cells are called beta cells. Gliclazide causes the beta cells to produce more insulin. This helps to decrease the amount of sugar in the blood of people with type 2 diabetes.

Gliclazide improves insulin production immediately after eating. This is called early or first phase insulin secretion. The enhanced insulin production results in a blood sugar lowering effect in response to meals or glucose, as occurs naturally in people without diabetes.

Gliclazide is used when dietary measures, weight loss and physical exercise are not enough to control blood sugar levels in people with type 2 diabetes.

Gliclazide also has effects in the blood vessels. It has been shown to prevent blood cells called platelets from clumping together in the blood. It also increases the breakdown of blood clots that form within the blood vessels. This may help prevent the long-term complications of diabetes, which may be partly due to changes in the blood vessels caused by these mechanisms.

Diamicron MR tablets are known as modified release tablets. They are designed to release the gliclazide gradually over a few hours, so that there is an effective level of gliclazide in the blood for 24 hours. This helps control blood sugar for 24 hours. The tablets are taken as a single dose once a day, at breakfast time. They should be swallowed whole and not broken, chewed or crushed, as this would damage the modified release action.

What is it used for?

  • Type 2 (non-insulin dependent) diabetes, when diet, exercise and weight loss have failed to fully control blood sugar.


  • Your doctor may want you to check your blood sugar level from time to time while you are taking this medicine. Make sure you discuss how to do this and how often with your GP, pharmacist or diabetes specialist.
  • On rare occasions, low blood sugar (hypoglycaemia) can occur as a side effect of this medicine. This is more likely to happen if you suddenly do more exercise than normal, have your meals at irregular times, eat less than usual, or miss meals altogether. For this reason, it is important that you follow any dietary or exercise advice given to you by your doctor. You should also make sure you are aware of the symptoms of hypoglycaemia (these may include cold sweats, cool pale skin, tremor, anxious feeling, unusual tiredness or weakness, confusion, difficulty in concentration, excessive hunger, temporary vision changes, headache or nausea) and what to do if you experience these symptoms. Discuss this with your GP, pharmacist or diabetes specialist.
  • People who are taking antidiabetic tablets should only drink alcohol in moderation and accompanied by food. This is because alcohol can make your warning signs of low blood sugar less clear, and can cause delayed low blood sugar, even several hours after drinking.
  • If you get an infection or illness, or have an accident while taking this medicine you should let your doctor know, because when the body is put under stress this medicine may become less effective at controlling your blood sugar. In these cases your doctor may need to temporarily replace your treatment with insulin. You should also consult your doctor about your diabetes treatment if you are due to have surgery under a general anaesthetic, or if you get pregnant. In these situations blood sugar is normally controlled by insulin.
  • This type of medicine can cause liver problems on rare occasions. For this reason, you should let your doctor know if you develop any of the following symptoms while taking this medicine, as they may indicate a problem with your liver: unexplained nausea, vomiting, abdominal pain, fatigue, loss of appetite, darkened urine or yellowing of the skin or whites of the eyes (jaundice).

Use with caution in

  • Elderly people.
  • Decreased kidney function.
  • Decreased liver function.
  • Underactive thyroid gland (hypothyroidism).
  • Insufficient production of hormones by the pituitary gland (pituitary insufficiency).
  • Insufficient production of natural steroid hormones by the adrenal glands (adrenal insufficiency).
  • Malnutrition.
  • Severe vascular disease, eg severe coronary heart disease.

Not to be used in

  • Children.
  • Allergy to medicines from the sulphonamide group, eg the antibiotic sulfamethoxazole.
  • Allergy to other sulphonylureas, eg glibenclamide, tolbutamide.
  • Type 1 (insulin dependent) diabetes.
  • Diabetic ketoacidosis.
  • Coma due to ketoacidosis in severe and inadequately treated diabetes (diabetic coma or pre-coma).
  • Severely decreased kidney function.
  • Severely decreased liver function.
  • Hereditary blood disorders called porphyrias.
  • Pregnancy.
  • Breastfeeding.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine should not be used during pregnancy. Diabetes is usually controlled using insulin during pregnancy, because this provides a more stable control of blood sugar. If you get pregnant while taking this medicine, or are planning a pregnancy, you should seek medical advice from your doctor.
  • It is not known if this medicine passes into breast milk. It should not be used by breastfeeding women, because it could potentially cause low blood sugar in a nursing infant. Seek medical advice from your doctor.

Label warnings

  • This medicine should be swallowed whole, not chewed.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.

  • Disturbances of the gut such as diarrhoea, constipation, indigestion, nausea, vomiting or abdominal pain.
  • Temporary visual disturbances at start of treatment.
  • Low blood glucose level (hypoglycaemia).
  • Skin reactions such as rash and itch.
  • Disturbances in the normal levels of blood cells in the blood.
  • Yellowing of the skin and eyes (jaundice).
  • Disturbance in liver function.
  • Inflammation of the liver (hepatitis).

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

Many medicines can affect blood sugar levels. It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

The following medicines may enhance the blood sugar lowering effect of this medicine and therefore increase the chance of low blood sugar (hypoglycaemia). If you start treatment with any of these your dose of this medicine may therefore need decreasing:

  • anticoagulants, eg warfarin (anticoagulant effect may also be altered - if you are taking an anticoagulant with this medicine your doctor may want to perform extra monitoring of your blood clotting time or blood sugar)
  • ACE inhibitors, eg captopril, enalapril (these can cause unpredictable drops in blood sugar)
  • cimetidine
  • disopyramide
  • fibrates, eg clofibrate
  • fluconazole
  • insulin
  • MAOI antidepressants, eg phenelzine
  • miconazole (should not be taken with gliclazide)
  • other antidiabetic tablets
  • phenylbutazone
  • large doses of salicylates, eg aspirin (small pain relieving doses do not normally have this effect)
  • sulphonamide antibiotics, eg sulfamethoxazole, co-trimoxazole.

Beta-blockers, eg propranolol (including eye drops containing beta-blockers) can mask some of the signs of low blood sugar, such as increased heart rate and tremor. They also prolong episodes of low blood sugar and impair recovery back to normal glucose levels.

The following medicines may increase blood glucose levels. If you start treatment with any of these your dose of this medicine may therefore need increasing:

  • some antipsychotic medicines, eg chlorpromazine, olanzapine
  • corticosteroids, eg hydrocortisone, prednisolone
  • danazol
  • diuretics, especially thiazide diuretics, eg bendroflumethiazide
  • oestrogens and progesterones, such as those contained in oral contraceptives.

Other medicines containing the same active ingredient

Diamicron Vivazide

Gliclazide tablets are also available without a brand name, ie as the generic medicine.