Acarbose (Precose) for Postprandial Glucose Control — Weight & Metabolism
Alpha-glucosidase inhibitor that slows carbohydrate absorption to reduce postprandial glucose spikes, with cardiovascular benefits demonstrated in the STOP-NIDDM trial.
Overview
Acarbose is an alpha-glucosidase inhibitor that competitively blocks enzymes (maltase, sucrase, isomaltase) in the small intestinal brush border, slowing complex carbohydrate digestion and glucose absorption. This specifically targets postprandial hyperglycemia, reducing post-meal glucose excursions by 30-70 mg/dL. HbA1c reduction is modest at 0.7-1.0%. The STOP-NIDDM trial (n=1,429) showed 25% reduction in progression from impaired glucose tolerance to diabetes and a 49% reduction in cardiovascular events. The ACE trial (n=6,522 Chinese patients with IGT and CHD) showed 18% reduction in diabetes incidence. Particularly useful in Asian populations where postprandial hyperglycemia predominates. Not absorbed systemically, acting entirely in the GI lumen. PMID: 12119174, 20831680.
Indications
- Type 2 diabetes mellitus with prominent postprandial hyperglycemia
- Impaired glucose tolerance (IGT) / prediabetes prevention (STOP-NIDDM trial)
- Add-on therapy for residual postprandial glucose spikes despite other agents
- Patients on high-carbohydrate diets (particularly effective in Asian dietary patterns)
- Dumping syndrome post-gastric surgery (off-label)
Mechanism of Action
Complex carbohydrates are rapidly digested by alpha-glucosidase enzymes in small intestine, causing rapid glucose absorption and post-meal glucose spikes
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Acarbose (Precose) | 25 mg | Three times daily with first bite of each meal | Starting dose for 2-4 weeks to minimize GI side effects |
| Acarbose (Precose) | 50 mg | Three times daily with first bite of each meal | Standard maintenance dose after 4-8 weeks titration |
| Acarbose (Precose) | 100 mg | Three times daily with first bite of each meal | Maximum dose; for patients >60kg only; increased GI and hepatic side effects |
Evidence Grade
GRADE A
Safety & Contraindications
- Not systemically absorbed - acts locally in GI tract; minimal systemic side effects
- GI side effects are primary limitation: flatulence (77%), diarrhea (33%), abdominal pain (21%) - dose-dependent, usually improve with continued use
- Must be taken with first bite of each meal to be effective
- Hypoglycemia treatment: if hypoglycemia occurs (with concurrent insulin/SU), must treat with GLUCOSE (dextrose) tablets, not sucrose/table sugar (acarbose blocks sucrose digestion)
- Contraindicated in inflammatory bowel disease, intestinal obstruction, or hepatic cirrhosis
- Rare hepatotoxicity with doses >100mg TID; monitor LFTs if using maximum dose