A 58-year-old man with type 2 diabetes takes acarbose with meals and glimepiride once daily. One evening he becomes diaphoretic, tremulous and confused. His wife gives him a glass of orange juice, but after 15 minutes he shows no improvement. The most likely explanation for this poor response is:
- A Acarbose inhibits alpha-glucosidase, so the sucrose in juice cannot be split into absorbable glucose ✓
- B Orange juice contains fructose, which acarbose converts to a non-absorbable complex
- C Glimepiride has blocked intestinal glucose transporters
- D Hypoglycaemia under these circumstances can only be corrected intravenously
Correct answer: A. Acarbose inhibits alpha-glucosidase, so the sucrose in juice cannot be split into absorbable glucose
Explanation
Acarbose reversibly inhibits intestinal alpha-glucosidase enzymes, preventing hydrolysis of dietary disaccharides such as sucrose into monosaccharides. During hypoglycaemia in a patient taking acarbose, correction requires pure glucose (dextrose) or lactose-free monosaccharide sources, since table sugar and fruit juices will not raise blood glucose effectively. Intravenous dextrose is reserved when the patient cannot swallow safely.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
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Written and medically reviewed by the StethoPrep medical team.