Tolbutamide

Medication Information Leaflet

What is this medication for?

Tolbutamide is used in the treatment of diabetes. It works together with lifestyle changes, such as having a healthy diet and regular exercise, to reduce blood sugar levels. It helps the pancreas to release more insulin to bring your blood sugar levels down.

How should I take or use this medication?

Take the tablet(s) as directed by your doctor immediately before meal(s).
 
Do not miss or delay meals after taking the medication.

What should I do if I forget to take or use this medication?

If you missed a dose, take your next dose immediately before your next meal and skip the dose you missed. 

Do not double your dose or use extra medication to make up for the missed dose.


What precautions should I take when taking or using this medication?

Inform your healthcare professional if you:
  • Are allergic to this medication or any of the other ingredients of this medication
  • Are allergic to sulfonamide drugs such as sulfamethoxazole or have a “sulfa” allergy 
  • Have Glucose-6 Phosphate Dehydrogenase (G6PD) deficiency, a genetic condition in which your red blood cells break down faster than they are made
  • Are pregnant, planning to become pregnant or breastfeeding
  • Have heart, kidney or liver problems
  • Drink alcohol often
  • Are eating less than usual due to sickness as your medication dosage may need to be changed
  • Are exercising more than usual or making changes to your usual diet as your blood sugar levels may be affected
  • Are an elderly above 65 years old as you have a higher risk of having side effects from this medication

What are some common side effects of this medication?

Like all medications, this medication may cause some possible side effects but not everyone experiences them. Consult your healthcare professional if any of the side effects becomes severe and bothersome.

The common side effects of Tolbutamide include:
  • Low blood sugar (hypoglycemia)
    • If you experience low blood sugar, read below to manage your symptoms 
  • Weight gain
    • Exercise regularly to prevent weight gain associated with this medication

Symptoms of low blood sugar include:
  • Weakness 
  • Dizziness 
  • Hunger
  • Sweating
  • Trembling 
  • Blurred vision
  • Walking unsteadily 
  • Fast heartbeat
If you experience any of these low blood sugar symptoms, do the following immediately: 
    Step 1: Check your blood sugar level with a home blood sugar meter (glucometer) if available. If your blood sugar level is less than 4 mmol/L, take 15 grams of fast-acting sugar. Examples of 15 grams of fast-acting sugar are:
    • 3 glucose tablets or 
    • Half a glass of fruit juice (200ml) or
    • Half a can of soft drink or sweetened drink (175ml) or
    • 1 can of less sugar soft drink (330ml) or
    • 3 teaspoons of sugar, honey or syrup

    Step 2: Monitor yourself for 15 minutes. If you have a glucometer (home blood sugar meter), check your blood sugar level again after 15 minutes. 

    Step 3: If your blood sugar level is still less than 4 mmol/L or you still have symptoms of low blood sugar, you should take another 15 grams of fast-acting sugar as per Step 1.

    If your symptoms do not go away, see a doctor or go to the hospital immediately.

    Step 4: Take your meal or snack if your blood sugar level is 4 mmol/L and above after consuming the fast-acting sugar earlier on. 

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:
  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body
If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

See a doctor or go to the hospital immediately if your blood sugar level is always low (less than 4mmol/L) or you continue to experience symptoms of low blood sugar even after taking some sugar (see instructions above for management of low blood sugar).

What food or medication should I avoid when I take or use this medication?

Avoid taking alcohol with this medication as it may cause symptoms such as flushing, nausea, vomiting, headache, fast heartbeat, fast breathing and giddiness.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How do I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin.

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Disclaimer

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup, and supported by the Ministry of Health. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Please visit www.moh.gov.sg/knowyourmeds and www.ndf.gov.sg for more information on medication.

Last updated on May 2023

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