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Tolbutamide Side Effects

Medically reviewed by Last updated on Mar 12, 2023.

Applies to tolbutamide: oral tablet.

Serious side effects of Tolbutamide

Along with its needed effects, tolbutamide may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking tolbutamide:


Incidence not known

Get emergency help immediately if any of the following symptoms of overdose occur while taking tolbutamide:

Symptoms of overdose

Other side effects of Tolbutamide

Some side effects of tolbutamide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

Incidence not known

For Healthcare Professionals

Applies to tolbutamide: intravenous powder for injection, oral tablet.


The most commonly reported adverse reactions have included gastrointestinal disturbances such as nausea, epigastric fullness, and heartburn.[Ref]


Frequency not reported: Increased cardiovascular mortality[Ref]

In the University Group Diabetes Program (UGDP) study, cardiovascular mortality rate was approximately 2.5 times higher in patients treated for 5 to 8 years with diet plus tolbutamide 1.5 g per day compared with that of patients treated with diet alone. The UGDP study was a long-term prospective clinical trial designed to evaluate the effectiveness of glucose lowering drugs in preventing or delaying vascular complications in patients with type 2 diabetes mellitus (n=823). Tolbutamide was stopped based on the increase in cardiovascular mortality; a significant increase in total mortality was not observed, but stopping the drug may have limited the ability to measure that.[Ref]


Gastrointestinal disturbances such as nausea, epigastric fullness, and heartburn tend to be dose related and may disappear when dosage is reduced.[Ref]

Common (1% to 10%): Nausea, epigastric fullness, heartburn

Frequency not reported: Anorexia, diarrhea, vomiting, constipation[Ref]


Frequency not reported: Hypoglycemia, increased appetite, weight gain


Frequency not reported: Hepatic porphyria, disulfiram-like reactions[Ref]


Hypersensitivity reactions usually develop within 6 to 8 weeks of starting therapy. Allergic skin reactions may occur and progress rarely to erythema multiforme exfoliative dermatitis, and fever.[Ref]

Rare (less than 0.1%): Cholestatic jaundice

Frequency not reported: Hepatic function disturbances[Ref]


Frequency not reported: Photosensitivity


Frequency not reported: Porphyria cutanea tarda[Ref]


Frequency not reported: Tinnitus, alcohol intolerance[Ref]

Nervous system

Frequency not reported: Headache, taste disturbances, paraesthesia[Ref]


Rare (less than 0.1%): Leukopenia, agranulocytosis, thrombocytopenia, hemolytic anemia, aplastic anemia, pancytopenia[Ref]


Rare (less than 0.1%): Cholestatic jaundice

Frequency not reported: Hepatic function disturbances[Ref]


Frequency not reported: Hyponatremia, syndrome of inappropriate antidiuretic hormone (SIADH) secretion[Ref]


1. Product Information. Tolbutamide (tolbutamide). Mylan Pharmaceuticals Inc. 2016.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.