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Precose Side Effects

Generic Name: acarbose

Note: This page contains side effects data for the generic drug acarbose. It is possible that some of the dosage forms included below may not apply to the brand name Precose.

It is possible that some side effects of Precose may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to acarbose: oral tablet

As well as its needed effects, acarbose (the active ingredient contained in Precose) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking acarbose, check with your doctor or nurse as soon as possible:

  • Yellow eyes or skin

Some acarbose side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Abdominal or stomach pain
  • bloated feeling or passing of gas
  • diarrhea

For Healthcare Professionals

Applies to acarbose: oral tablet


In general, systemic side effects have been rare and unexpected because of the very low systemic bioavailability of acarbose (the active ingredient contained in Precose) [Ref]


Gastrointestinal side effects in large scale clinical trials have shown that 58% of patients complain of side effects. Of these patients with side effects, over 90% experienced gastrointestinal (GI) effects. GI side effects usually developed within the first few weeks of therapy, were usually mild to moderate in severity, and typically decreased over time. The most common GI side effects were due to the fermentation of unabsorbed carbohydrates and resultant gas production. The following side effects have been reported in large studies of patients treated with dosages ranging from 300 to 600 mg/day for periods up to 2 years: flatulence in 50% to 70%, and abdominal spasm, tenesmus, or general abdominal pain in 8% of patients. Intractable constipation, nausea, vomiting, ileus, or gastric complaints have been reported in 5% of patients or less. Pneumatosis cystoides intestinalis has also been reported.[Ref]

The severity of GI symptoms may be decreased by dosage reduction and by avoidance of gas-producing foods and sucrose. Most studies have demonstrated that GI side effects decrease in severity over time.

Acarbose can cause a mild degree of carbohydrate malabsorption. It may adversely affect the absorption and metabolism of other nutrients and minerals as well. Data are available regarding significantly increased GI iron, chromium, and calcium losses. In some cases, iron-deficient anemia has resulted.

Coadministration of metronidazole or guar gum has not improved the GI tolerance of acarbose.[Ref]

Nervous system

Nervous system side effects are uncommon and have included somnolence, weakness, dizziness, headache, and vertigo.[Ref]


Acarbose (the active ingredient contained in Precose) may have a potentially beneficial effect on the lipid profile of patients with diabetes. Specifically, a trend towards decreased plasma triglycerides, total cholesterol, and apolipoprotein B and significant reductions in plasma apolipoproteins AI and AII have been reported. Interestingly, these effects have not been observed in nondiabetic subjects.[Ref]

Endocrine side effects have included hypoglycemia, which was infrequently reported and was more likely to occur when insulin or sulfonylureas were coadministered. Approximately 2% of patients treated with acarbose, alone or in combination with sulfonylureas or insulin, developed hypoglycemia. Another 3% exhibited symptoms suggesting of hypoglycemia. In general, addition of acarbose to insulin typically resulted in decreased insulin requirements, reducing the risk of hypoglycemia.[Ref]


Hepatic side effects have included isolated cases of elevated serum transaminases, indicating possible hepatic toxicity, in 3.8% of treated patients. These elevations were typically asymptomatic and reversible. Such elevations have also been more common in females, African-Americans, obese individuals (body mass index greater than 29), and those who have had diabetes for more than five years. Most cases of transaminase elevation have not been associated with other evidence of hepatic dysfunction. Fulminant hepatitis with fatal outcome has also been reported.[Ref]

Data from large clinical trials have shown that the incidence of elevated serum transaminases at doses of 50 to 100 mg TID was the same as with placebo. In long-term trials of up to 12 months, however, elevations of AST and/or ALT occurred in 15% of patients.[Ref]


Hematologic side effects have included anemia, which was probably due to decreased gastrointestinal iron absorption as a result of acarbose (the active ingredient contained in Precose) therapy. Sustained iron deficient anemia that required treatment has been reported in less than 1% of patients. Thrombocytopenia has also been reported.[Ref]


Dermatologic side effects are rare and have included pruritus in 0.1% and exanthema in 0.3% of treated patients.[Ref]


Other side effects have included reports that acarbose (the active ingredient contained in Precose) administration may have lead to an acute state of carbohydrate malabsorption that decreased with continued use.[Ref]


Hypersensitivity side effects have included one case of generalized erythema multiforme. Additional hypersensitivity side effects reported from worldwide post marketing experience include hypersensitive skin reactions (e.g. rash, erythema, exanthema and urticaria), edema, ileus/sibilus, jaundice and/or hepatitis and associated liver damage.[Ref]


1. "Product Information. Precose (acarbose)." Bayer, West Haven, CT.

2. Nishii Y, Aizawa T, Hashizume K "Ileus: a rare side effect of acarbose." Diabetes Care 19 (1996): 1033

3. Hollander P "Safety profile of acarbose, an alpha-glucosidase inhibitor." Drugs 44 Suppl 3 (1992): 47-53

4. Clissold SP, Edwards C "Acarbose. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential." Drugs 35 (1988): 214-43

5. Balfour JA, McTavish D "Acarbose. An update of its pharmacology and therapeutic use in diabetes mellitus [published erratum appears in Drugs 1994 Dec;48(6):929]." Drugs 46 (1993): 1025-54

6. Couet C, Ulmer M, Hamdaoui M, Bau HM, Debry G "Metabolic effects of acarbose in young healthy men." Eur J Clin Nutr 43 (1989): 187-96

7. Zimmerman BR "Preventing long term complications. Implications for combination therapy with acarbose." Drugs 44 Suppl 3 (1992): 54-60

8. Reaven GM, Lardinois CK, Greenfield MS, Schwartz HC, Vreman HJ "Effect of acarbose on carbohydrate and lipid metabolism in NIDDM patients poorly controlled by sulfonylureas." Diabetes Care 13 Suppl 3 (1990): 32-6

9. Andrade RJ, Lucena MI, Rodriguezmendizabal M "Hepatic injury caused by acarbose." Ann Intern Med 124 (1996): 931

10. DiazGutierrez FL, Ladero JM, DiazRubio M "Acarbose-induced acute hepatitis." Am J Gastroenterol 93 (1998): 481

11. Andrade RJ, Lucena M, Vega JL, Torres M, Salmeron FJ, Bellot V, GarciaEscano MD, Moreno P "Acarbose-associated hepatotoxicity." Diabetes Care 21 (1998): 2029-30

12. Sobajima H, Mori M, Niwa T, Muramatsu M, Sugimoto Y, Kato K, Naruse S, Kondo T, Hayakawa T "Carbohydrate malabsorption following acarbose administration." Diabetic Med 15 (1998): 393-7

13. Kono T, Hayami M, Kobayashi H, Ishii M, Taniguchi S "Acarbose-induced generalised erythema multiforme." Lancet 354 (1999): 396-7

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