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Alpha-glucosidase Inhibitor

Acarbose

Brand names: Glucobay

Acarbose is an alpha-glucosidase inhibitor used in type-2 diabetes to lower post-meal blood glucose; prominent gastrointestinal effects limit its use and it is generally reserved for when other treatments are unsuitable.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION There is no fixed dosage regimen for the management of diabetes mellitus with acarbose tablets or any other pharmacologic agent. Dosage of acarbose tablets must be individualized on the basis of both effectiveness and tolerance while not exceeding the maximum recommended dose of 100 mg t.i.d. Acarbose tablets should be taken three times daily at the start (with the first bite) of each main meal. Acarbose tablets should be started at a low dose, with gradual dose escalation as described below, both to reduce gastrointestinal side effects and to permit identification of the minimum dose required for adequate glycemic control of the patient.If the prescribed diet is …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-08-12. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It inhibits intestinal alpha-glucosidase enzymes, slowing the breakdown of complex carbohydrates and sucrose and thereby blunting the rise in blood glucose after meals.

Prescribing in practice

  • If hypoglycaemia occurs when acarbose is combined with insulin or a sulfonylurea, treat with glucose rather than sucrose, because acarbose blocks the breakdown of sucrose.
  • Flatulence, abdominal discomfort and diarrhoea are common, especially early in treatment, and reduce with continued use.
  • Avoid in inflammatory bowel disease, intestinal obstruction or conditions worsened by increased intestinal gas formation.

Monitoring

Monitor glycaemic control including post-meal glucose and HbA1c; liver enzymes may be checked during treatment as transient rises can occur.

Counselling the patient

  • Take each dose with the first mouthful of food.
  • Wind, bloating and loose stools are common at first and usually ease over time.
  • If you also take insulin or a sulfonylurea and have a hypo, use glucose tablets or gel rather than ordinary sugar.

Evidence & guidelines

An option for type-2 diabetes when other oral glucose-lowering drugs are not tolerated or suitable (NICE NG28).

Reference: NICE NG28 (Type 2 DM); STOP-NIDDM Trial; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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