Acarbose

Key facts

• Acarbose is an alpha-glucosidase inhibitor that slows the digestion of starches and sugars in the gut, blunting the blood sugar rise after meals in type 2 diabetes.
• You take it with the first bite of each main meal; taken at any other time it has little effect.
• Acarbose alone does not cause low blood sugar, but combined with insulin or a sulfonylurea it can. If hypoglycemia happens, treat it with glucose tablets or gel, not ordinary table sugar, because acarbose blocks the breakdown of sucrose.
• Gas, bloating, and diarrhoea are common as your gut adjusts; severe abdominal pain needs urgent review.

What acarbose treats

Acarbose treats type 2 diabetes, used alongside diet and exercise, either alone or together with other diabetes medicines such as metformin, a sulfonylurea, or insulin. It specifically targets the blood sugar spike that follows meals rather than fasting blood sugar.

How acarbose works

Starches and complex sugars must be broken into simple sugars before the gut can absorb them. Acarbose blocks alpha-glucosidase, the enzyme in the small intestine that does this breaking down. Carbohydrates are then digested and absorbed more slowly and further along the gut, so glucose enters the blood gradually instead of in a rapid post-meal surge.

Before you take it

• Do not take acarbose if you have inflammatory bowel disease, a bowel obstruction, or a large hernia, since trapped gas can worsen these conditions.
• Tell your doctor about cirrhosis or significant liver disease; acarbose is not recommended in these cases.
• Tell your prescriber about all other diabetes medicines, since combining acarbose with insulin or a sulfonylurea raises the risk of hypoglycemia.
• Digestive enzyme supplements and some other gut medicines can reduce how well acarbose works.

Side effects

Common effects are gas, bloating, flatulence, loose stools, and mild stomach cramps, which usually ease as your gut adjusts over the first weeks.

Stop and seek urgent medical care for any of these:

• Severe or worsening abdominal pain, or a distended, tender abdomen.
• Signs of low blood sugar, such as shaking, sweating, or confusion, if you also take insulin or a sulfonylurea.
• A rash, facial swelling, or difficulty breathing.

Safety essentials

• If hypoglycemia occurs while you take acarbose with insulin or a sulfonylurea, treat it with pure glucose (tablets or gel), not table sugar or regular sweets, since acarbose stops sucrose being broken down and absorbed quickly.
• Carry glucose tablets and make sure people close to you know how to recognise and treat a low if you take acarbose alongside insulin or a sulfonylurea.
• Report severe abdominal pain or bloating promptly, since acarbose is avoided in bowel disease and can worsen it.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.