Sounds like 'ah-KAR-bose'

Acarbose is used to treat type 2 diabetes. Find out how to take it safely and possible side effects. Acarbose is also called Glucobay or Accarb.

Type of medicine Also called
  • Medication for type 2 diabetes
  • Glucobay®
  • Accarb®

What is acarbose?

Acarbose is used to treat type 2 diabetes, together with exercise, good nutrition, weight loss and other lifestyle measures. It may be used alone or with other medicines for diabetes. Acarbose works by slowing the digestion and absorption of carbohydrates (sugars) and in this way lowers high blood glucose after each meal. To work properly acarbose must be taken at the start of a meal (with the first bites). In New Zealand acarbose is available as tablets (50 mg and 100 mg).

Read more about type 2 diabetes and medicines for type 2 diabetes.  


  • The starting dose of acarbose is 50 milligrams 3 times a day.
  • Depending on your blood glucose level, your doctor may increase your dose to 100 milligrams 3 times a day. Some people may need a higher dose.    
  • Always take your acarbose exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much acarbose to take, how often to take it and any special instructions.

How to take acarbose

  • Timing: Chew your acarbose tablet with the first mouthfuls of food at each meal, or swallow the tablet whole with a little water just before your meal.
  • Limit or avoid drinking alcohol while you are taking acarbose. It may affect your blood glucose control.
  • Missed dose: If you forget your dose with your meal, wait to take the next dose with your next meal. Do not take double the dose and do not take the tablets between meals. 
  • Keep taking acarbose regularly. To control your diabetes, you must keep taking acarbose every day. 
  • Unwell from vomiting or diarrhoea (runny poos): If you are unwell and dehydrated from vomiting or diarrhoea, ask your healthcare provider for advice. They may recommend that you stop taking acarbose until you are better. Read more about diabetes sick day plan

Precautions – before taking acarbose

  • Do you have problems with your kidney or liver?
  • Are you pregnant or breastfeeding?
  • Do you have problems with your stomach (tummy) such as inflammatory bowel disease, ulcerative colitis or Crohn's disease, or have you had bowel surgery (stomach operation)?

If so, it’s important that you tell your doctor or pharmacist before you start acarbose. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Side effects

Like all medicines, acarbose can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Low blood glucose

Sometimes acarbose, when used with other diabetes medicines, may lower your blood glucose too much. This is called hypoglycaemia or a 'hypo'. Hypos are most likely to occur when acarbose is used together with glipizide, gliclazide, or insulin to control your diabetes, or if you delay or miss a meal or snack, drink alcohol, exercise more than usual or can't eat because of nausea or vomiting.

  • Hypoglycaemia may cause you to feel weak, faint, dizzy or irritable. You may get a headache, tremor (shakes) or blurred vision.
  • If this happens, drink something sweet such as a small glass of sweetened soft drink or fruit juice, or have a glucose tablet. It is best to use glucose rather than sucrose (sugar and cane sugar) because sucrose takes longer to break down if taken with acarbose and can cause diarrhoea. Follow this up with a snack such as a sandwich.
  • Tell your doctor or nurse if this happens.
  • Read more about hypoglycaemia and diabetes sick day plan.

Other side effects

Side effects* What should I do?**
  • Bloating or gas in the tummy
  • Diarrhoea (loose, watery stools)
  • These are very common when you first start taking acarbose (they affect more than 1 in 10 people).   
  • Eating foods containing sucrose (sugar) with acarbose is likely to make these symptoms worse.
  • These effects usually go away with time. Tell your doctor if troublesome.
  • Nausea (feeling sick)
  • Vomiting (being sick)
  • Indigestion
  • Loss of appetite 
  • These are less common side effects (they affect fewer than 1 in 10 people).   
  • Tell your doctor if troublesome.
  • Signs of an allergic reaction such as skin rash, itching, swelling of your lips, face and mouth, or difficulty breathing. 
  • Tell your doctor immediately or phone Healthline free on 0800 611 116.
  • Signs of problems with your liver such as yellowing of your skin or eyes, dark urine or pain in your abdomen. 
  • Tell your doctor immediately or phone Healthline free on 0800 611 116. 
* For more information on side effects, see the Medsafe consumer information leaflets Glucobay and Accarb.
** Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


Acarbose may interact with a few medications and herbal supplements, so check with your doctor or pharmacist before starting acarbose or before starting any new medicines.

Learn more

The following links have more information on acarbose.

Acarbose (Māori) New Zealand Formulary Patient Information
Glucobay Medsafe Consumer Information Sheet


  1. Acarbose New Zealand Formulary [accessed April 2017]
  2. Managing patients with type 2 diabetes: from lifestyle to insulin BPAC, NZ, 2015
  3. Glucobay Medsafe Datasheet
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 05 May 2019