Acarbose
Acarbose is an **oral antihyperglycemic agent** used primarily as an adjunctive treatment for diabetes mellitus in dogs and cats. * **Primary Use:** It reduces the rate and amount of glucose absorbed from the gastrointestinal tract after a meal, making it useful for mild reductions in blood glucose (typically in the 250-350 mg/dL range). * **Clinical Pearl:** Acarbose is highly unlikely to provide adequate glycemic control when used as a sole therapy. It is best utilized in conjunction with dietary management (e.g., low-carbohydrate diets) and primary antihyperglycemic agents like **insulin**. * **Administration:** Because its action depends on the presence of food in the gut, it must be given with meals (preferably right before) and is generally ineffective for animals fed *ad libitum*.
Mechanism: Acarbose acts locally within the gastrointestinal tract and does not stimulate insulin secretion. * It competitively inhibits pancreatic **alpha-amylase** and intestinal brush-border **alpha-glucosidases** (such as sucrase, maltase, and isomaltase). * **Mechanism Pathway:** Inhibition of these enzymes → delayed digestion of complex carbohydrates and disaccharides into absorbable monosaccharides → glucose is absorbed further down the GI tract at a slower rate → blunts the postprandial blood glucose spike → reduces overall insulin requirements. * **Note:** Acarbose has no inhibitory effect on lactase.
Dosing by species
- Improve glycemic control and reduce insulin dependence · 12.5-25 mg (total dose) PO with meals. · PO · with meals · When acarbose is used with a low carbohydrate diet it may improve glycemic control and reduce insulin dependence.
- Reduce insulin dosage and thereby reduce hypoglycemia occurrence · 12.5 mg per cat PO twice daily with meals. · PO · twice daily
- Adjunctive glycemic control · 12.5-20 mg (total dose) per meal PO · PO · per meal
- For dogs poorly controlled with insulin and dietary therapy when another reason for the poor control cannot be identified · Initially 12.5-25 mg total dose per dog PO with each meal. May increase dose after two weeks to 50 mg per dog and then to 100 mg per dog (in large dogs, >25 kg) if response has been inadequate. · PO · with each meal · Give only at the time of feeding. There is a greater chance of diarrhea at the higher dosages.
- Adjunctive glycemic control · 12.5-20 mg (total dose) per meal PO · PO · per meal
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Underweight animals (may have deleterious effects on nutritional status)
- Known hypersensitivity to acarbose
- Diabetic ketoacidosis
- Inflammatory bowel disease
- Colonic ulceration
- Partial intestinal obstruction or predisposition to obstruction
- Chronic intestinal disease with marked disorders of digestion or absorption
- Conditions where excessive gas formation would be detrimental
Adverse effects
- Flatulence
- Soft stools
- Diarrhea (dose-dependent)
- Weight loss (reported in dogs)
- May contribute to hypoglycemia if used concurrently with other hypoglycemic agents (e.g., insulin)
Drug interactions
- Charcoal · Intestinal adsorbents may reduce the efficacy of acarbose.
- Digoxin · Acarbose may reduce digoxin blood concentrations.
- Hyperglycemic Agents (corticosteroids, thiazides, estrogens, phenothiazines, thyroid hormones, calcium channel blockers) · May negate the antihyperglycemic effects of acarbose.
- Pancreatin, Pancrelipase, or Amylase · Exogenous enzyme formulations may reduce the efficacy of acarbose.
Monitoring
- Serum glucose concentrations
- Adverse GI effects (diarrhea, flatulence, weight loss)
- Serum aminotransferase levels (rarely elevated with long-term high-dose use)
Overdose
Acute overdosages are likely to cause only **diarrhea and flatulence**. No specific treatment should be necessary for the GI upset. > **Hypoglycemia Warning:** Should acute hypoglycemia occur secondary to concurrent use of other antihypoglycemics (like insulin), **parenteral glucose** should be administered. If treating orally, you MUST use **glucose/dextrose** (do not use sucrose/table sugar, as acarbose prevents its breakdown and absorption).
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.