ACARBOSE
Clinical safety rating
cautionComprehensive clinical and safety monograph for ACARBOSE (ACARBOSE).
Comprehensive clinical and safety monograph for ACARBOSE (ACARBOSE).
Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitusOff-label: Prevention of type 2 diabetes in individuals with impaired glucose tolerance
Acarbose is a complex oligosaccharide that competitively and reversibly inhibits α-glucosidase enzymes in the brush border of the small intestine. This delays the digestion and absorption of complex carbohydrates and disaccharides, thereby reducing postprandial hyperglycemia.
| Metabolism | Acarbose is metabolized exclusively within the gastrointestinal tract, primarily by intestinal bacteria and digestive enzymes. Approximately 35% of the dose is absorbed as metabolites, which are excreted via the kidneys. The parent drug is not significantly metabolized by hepatic enzymes. |
| Excretion | Primarily excreted unchanged in feces (approximately 50% of an oral dose) and as metabolites via the gastrointestinal tract; less than 2% of the dose is recovered in urine as active drug or metabolites. Renal excretion is minimal. |
| Half-life | Terminal elimination half-life is approximately 2.5 to 3 hours for the parent compound, but the drug acts locally in the GI tract; systemic half-life is not clinically relevant for its pharmacodynamic effect. |
| Protein binding | Negligible to low protein binding; less than 1-2% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is not well defined due to minimal systemic absorption; estimated to be less than 0.3 L/kg, reflecting limited distribution beyond the gastrointestinal lumen. |
| Bioavailability | Oral: Systemic bioavailability is very low (approximately 0.5-2%) due to local action in the GI tract and minimal absorption. The drug acts locally in the intestine; systemic levels are negligible. |
| Onset of Action | Oral: Onset of action occurs within 15-30 minutes after oral administration, corresponding to the inhibition of intestinal α-glucosidases during carbohydrate digestion. |
| Duration of Action | Oral: Duration of action is approximately 4-6 hours after a single dose, corresponding to the time the drug remains active in the gastrointestinal tract. Clinical effect is dependent on timing of carbohydrate ingestion. |
| Molecular Weight | 645.6 |
Initial: 25 mg orally 3 times daily with first bite of each main meal; maintenance: 50-100 mg 3 times daily; max 100 mg 3 times daily.
| Dosage form | TABLET |
| Renal impairment | No specific dose adjustment required for GFR ≥25 mL/min; contraindicated in GFR <25 mL/min (creatinine clearance <25 mL/min). |
| Liver impairment | No specific dose adjustment for mild-to-moderate hepatic impairment; contraindicated in severe hepatic impairment (Child-Pugh class C). |
| Pediatric use | Not recommended for use in pediatric patients; safety and efficacy not established. |
| Geriatric use | Initiate at the lowest dose (25 mg 3 times daily); titrate slowly based on tolerance and glycemic control, as elderly patients may have reduced renal function and higher risk of gastrointestinal adverse effects. |
| 1st trimester | Acarbose is not absorbed systemically to a significant extent; however, data on use in the first trimester are limited. Based on animal studies and limited human data, no teratogenic effects have been reported, but caution is advised. |
| 2nd trimester | Pregnant women with diabetes should maintain glycemic control. Acarbose has minimal systemic absorption, and no adverse fetal effects have been reported in animal studies. Use if clearly needed. |
| 3rd trimester | During the third trimester, acarbose can be used for glycemic control. It does not cross the placenta significantly, and no harm to the fetus has been documented. Monitoring maternal glucose is recommended. |
Clinical note
Comprehensive clinical and safety monograph for ACARBOSE (ACARBOSE).
| Placental transfer | Acarbose has minimal placental transfer due to its high molecular weight and low lipid solubility. Studies in animals show negligible transfer, and human data are lacking but suggest minimal passage. |
| Breastfeeding | Acarbose is excreted into breast milk in very low amounts (less than 1% of maternal dose) due to its poor oral bioavailability. It is unlikely to affect the nursing infant. However, caution is advised in infants with gastrointestinal issues. |
| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | Acarbose is classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies; limited human data. Minimal systemic absorption (<2%) suggests low fetal exposure. Risk cannot be excluded in first trimester. Second and third trimester: no known fetal risks, but use only if clearly needed. |
| Fetal Monitoring | Monitor maternal blood glucose levels regularly. No specific fetal monitoring required beyond standard prenatal care. Assess for gastrointestinal adverse effects in mother. |
| Fertility Effects | No known adverse effects on fertility. Acarbose does not affect reproductive hormones or gamete function based on animal studies. |
■ FDA Black Box Warning
None
| Serious Effects |
Diabetic ketoacidosisInflammatory bowel diseaseColonic ulcerationPartial intestinal obstructionChronic intestinal diseases associated with marked disorders of digestion or absorptionHypersensitivity to acarbose or any of its componentsSevere renal impairment (creatinine clearance <25 mL/min)Cirrhosis of the liver
| Precautions | Risk of hepatotoxicity: rare cases of severe hepatocellular injury, including fulminant hepatitis, reported, especially at higher doses (≥300 mg/day); monitor liver enzymes periodically., Use with caution in patients with renal impairment (eGFR <25 mL/min/1.73 m²): insufficient data; avoid use., May cause hypoglycemia when used in combination with sulfonylureas or insulin; treat hypoglycemia with oral glucose (dextrose) rather than sucrose (acarbose inhibits sucrose digestion)., Gastrointestinal adverse effects (flatulence, diarrhea, abdominal pain) are common due to undigested carbohydrate fermentation in the colon; may subside with continued use., Acute porphyria: acarbose has been associated with acute attacks in susceptible patients. |
| Food/Dietary | Acarbose delays digestion of complex carbohydrates and sucrose. To reduce gastrointestinal side effects, avoid high-sucrose foods and drinks. Simple sugars like glucose and fructose can still be absorbed and used to treat hypoglycemia. Alcohol may increase the risk of hypoglycemia when combined with acarbose, especially if taken with other antidiabetic agents. |
| Clinical Pearls | Acarbose delays carbohydrate absorption by inhibiting alpha-glucosidase in the brush border of the small intestine. It should be taken with the first bite of each main meal. Its efficacy is limited by gastrointestinal side effects (flatulence, diarrhea) due to undigested carbohydrates reaching the colon. Not recommended in patients with inflammatory bowel disease or colonic obstruction. Hypoglycemia from acarbose (rare in monotherapy) must be treated with oral glucose or milk, not sucrose or complex carbohydrates, since their digestion is blocked. Acarbose can cause isolated transaminase elevations; monitor LFTs if symptoms occur. |
| Patient Advice | Take acarbose with the first bite of each main meal; do not take it between meals. · Common side effects include gas, bloating, and diarrhea, which may improve over time. · If you experience low blood sugar, treat it with glucose tablets, juice, or regular soda, not candy or fruit juice (acarbose blocks their digestion). · Tell your doctor if you develop jaundice or abdominal pain, as liver problems can occur. · This medication is not for weight loss and does not affect insulin secretion. |
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