tolbutamide at a glance
Medicine class
Sulfonylurea blood-glucose-lowering treatment
Main use
Type 2 diabetes inadequately controlled by dietary measures
Food
Take with or immediately after a meal, following the prescribed instructions
Important risk
Can cause low blood glucose, particularly in older or debilitated people
What is tolbutamide used for?
Tolbutamide is licensed for adults with type 2 diabetes.
Treatment when dietary measures alone have not adequately controlled blood glucose.
It complements rather than replaces dietary management.
How does tolbutamide work?
Tolbutamide blocks ATP-sensitive potassium channels in functioning pancreatic beta cells, increasing insulin release. Its continuing effect may also involve reduced liver glucose production and improved sensitivity to available insulin.
tolbutamide preparations and strengths
Tablet
Route: Oral
Strengths: 500 mg
How to take tolbutamide
Take tolbutamide exactly as prescribed, by mouth with or immediately after a meal. Maintain the dietary plan agreed with the diabetes team.
Swallow the tablet as directed.
The scoreline is not intended for breaking the tablet.
Avoid alcohol because it may cause flushing and make you feel unwell.
Do not stop treatment without discussing it with the prescriber.
tolbutamide side effects
Common or expected effects
- Low blood glucose, with sweating, shaking, hunger, dizziness, palpitations, blurred vision or confusion
- Nausea, vomiting, diarrhoea or constipation
- Appetite changes or weight gain
- Headache or tingling sensations
- Skin rash or increased sensitivity to sunlight
Get urgent medical advice
- Severe hypoglycaemia causing abnormal behaviour, seizure, marked drowsiness or unconsciousness
- Facial, lip, tongue or throat swelling, or difficulty breathing or swallowing
- Unexpected bruising or bleeding, persistent fever, sore throat or recurrent infections
- Yellow skin or eyes
- A severe or spreading skin reaction
tolbutamide in pregnancy
Tolbutamide is generally avoided during pregnancy because evidence is limited and placental transfer may cause prolonged neonatal hypoglycaemia. Obtain prompt diabetes-specialist review when planning pregnancy or after discovering a pregnancy. Do not stop diabetes treatment before review because uncontrolled glucose is also harmful.
tolbutamide while breastfeeding
The selected UK product contraindicates tolbutamide during breastfeeding. Small quantities have been detected in milk, with a theoretical risk of infant hypoglycaemia. Insulin or metformin are generally preferred, subject to individual assessment.
tolbutamide interactions
Some medicines can strengthen or weaken tolbutamide’s glucose-lowering effect. Check all prescribed, pharmacy and herbal products with a clinician or pharmacist.
Warfarin and other coumarin anticoagulants
May markedly increase hypoglycaemia risk; the product information advises against co-administration.
Beta-blockers
May enhance glucose lowering and make hypoglycaemia warning symptoms harder to recognise.
Sulfonamide antibiotics, especially sulfafurazole
May cause severe hypoglycaemia; sulfafurazole should not be co-administered.
Common questions about tolbutamide
Answers are fully visible for fast scanning and source review.
Can tolbutamide cause low blood sugar?
Yes. Warning symptoms include sweating, shaking, hunger, dizziness, palpitations, blurred vision and confusion. Treat suspected hypoglycaemia promptly according to the diabetes team’s plan.
Can I drink alcohol while taking tolbutamide?
Alcohol should be avoided because it can cause facial flushing, make you feel unwell and complicate glucose control.
Can I drive while taking tolbutamide?
Do not drive while experiencing hypoglycaemia or impaired concentration. Ensure glucose is adequately controlled and follow current DVLA requirements.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.