Tol-Tab Side Effects
Generic name: tolbutamide
Medically reviewed by Drugs.com. Last updated on Mar 22, 2025.
Note: This document provides detailed information about Tol-Tab Side Effects associated with tolbutamide. Some dosage forms listed on this page may not apply specifically to the brand name Tol-Tab.
Applies to tolbutamide: oral tablet.
Precautions
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.
It is very important to follow carefully any instructions from your health care team about:
- Alcohol—Drinking alcohol may cause severe low blood sugar. Discuss this with your health care team.
- Counseling—Other family members need to learn how to prevent side effects or help with side effects if they occur. Also, patients with diabetes may need special counseling about diabetes medicine dosing changes that might occur because of lifestyle changes, such as changes in exercise and diet. Furthermore, counseling on contraception and pregnancy may be needed because of the problems that can occur in patients with diabetes during pregnancy.
- Travel—Keep your recent prescription and your medical history with you. Be prepared for an emergency as you would normally. Make allowances for changing time zones and keep your meal times as close as possible to your usual meal times.
- In case of emergency—There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says you have diabetes and a list of all of your medicines.
Check with your doctor right away if you start having chest pain or discomfort; nausea; pain or discomfort in arms, jaw, back, or neck; shortness of breath; sweating; or vomiting while you are using this medicine. These may be symptoms of a serious heart problem, including a heart attack.
Tolbutamide can cause low blood sugar. However, this can also occur if you delay or miss a meal or snack, drink alcohol, exercise more than usual, cannot eat because of nausea or vomiting, take certain medicines, or take tolbutamide (the active ingredient contained in Tol-Tab) with another type of diabetes medicine. The symptoms of low blood sugar must be treated before they lead to unconsciousness (passing out). Different people feel different symptoms of low blood sugar. It is important that you learn which symptoms of low blood sugar you usually have so you can treat it quickly.
Symptoms of low blood sugar include anxiety; behavior change similar to being drunk; blurred vision; cold sweats; confusion; cool, pale skin; difficulty in thinking; drowsiness; excessive hunger; fast heartbeat; headache (continuing); nausea; nervousness; nightmares; restless sleep; shakiness; slurred speech; or unusual tiredness or weakness.
If symptoms of low blood sugar occur, eat glucose tablets or gel, corn syrup, honey, or sugar cubes; or drink fruit juice, non-diet soft drink, or sugar dissolved in water. Also, check your blood for low blood sugar. Glucagon is used in emergency situations when severe symptoms such as seizures (convulsions) or unconsciousness occur. Have a glucagon kit available, along with a syringe or needle, and know how to use it. Members of your household also should know how to use it.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Common side effects of Tol-Tab
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 side effects
- belching
- indigestion
- pain in the chest below the breastbone
- passing of gas
- stomach pain, fullness, or discomfort
Less common side effects
- flushing or redness of skin
- unusually warm skin
Incidence not known
- change in taste or bad, unusual, or unpleasant (after)taste
- increased sensitivity of skin to sunlight
- redness or other discoloration of skin
- severe sunburn
Serious side effects of Tol-Tab
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:
Rare side effects
- abdominal or stomach pain
- chills
- clay-colored stools
- dark urine
- diarrhea
- dizziness
- fever
- headache
- itching
- loss of appetite
- nausea
- rash
- unpleasant breath odor
- unusual tiredness or weakness
- vomiting of blood
Incidence not known
- agitation
- back or leg pains
- bleeding gums
- blood in urine or stools
- bloody, black, or tarry stools
- chest pain
- coma
- confusion
- convulsions
- cough or hoarseness
- decreased urine output
- depression
- difficulty breathing
- fast or irregular heartbeat
- fatigue
- fever with or without chills
- fluid-filled skin blisters
- general body swelling
- general feeling of tiredness or weakness
- high fever
- hostility
- increased thirst
- irritability
- lethargy
- light-colored stools
- lower back or side pain
- muscle pain or cramps
- muscle twitching
- nosebleeds
- painful or difficult urination
- pale skin
- pinpoint red spots on skin
- rapid weight gain
- seizures
- sensitivity to the sun
- shortness of breath
- sore throat
- sores, ulcers, or white spots on the lips or in the mouth
- stupor
- swelling of face, ankles, or hands
- swollen or painful glands
- tightness in the chest
- unexplained bleeding or bruising
- wheezing
- yellow eyes or skin
Get emergency help immediately if any of the following symptoms of overdose occur while taking tolbutamide:
Symptoms of overdose
- anxiety
- blurred vision
- cold sweats
- cool, pale skin
- increased hunger
- nervousness
- nightmares
- shakiness
- slurred speech
For healthcare professionals
Applies to tolbutamide: intravenous powder for injection, oral tablet.
General adverse events
The most commonly reported adverse reactions have included gastrointestinal disturbances such as nausea, epigastric fullness, and heartburn.[Ref]
Cardiovascular
- 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
- Common (1% to 10%): Nausea, epigastric fullness, heartburn
- Frequency not reported: Anorexia, diarrhea, vomiting, constipation[Ref]
Gastrointestinal disturbances such as nausea, epigastric fullness, and heartburn tend to be dose related and may disappear when dosage is reduced.[Ref]
Metabolic
- Frequency not reported: Hypoglycemia, increased appetite, weight gain
- Frequency not reported: Hepatic porphyria, disulfiram-like reactions[Ref]
Hypersensitivity
- Rare (less than 0.1%): Cholestatic jaundice
- Frequency not reported: Hepatic function disturbances[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]
Dermatologic
- Frequency not reported: Photosensitivity
Sulfonylureas:
- Frequency not reported: Porphyria cutanea tarda[Ref]
Other
- Frequency not reported: Tinnitus, alcohol intolerance[Ref]
Nervous system
- Frequency not reported: Headache, taste disturbances, paraesthesia[Ref]
Hematologic
- Rare (less than 0.1%): Leukopenia, agranulocytosis, thrombocytopenia, hemolytic anemia, aplastic anemia, pancytopenia[Ref]
Hepatic
- Rare (less than 0.1%): Cholestatic jaundice
- Frequency not reported: Hepatic function disturbances[Ref]
Endocrine
- Frequency not reported: Hyponatremia, syndrome of inappropriate antidiuretic hormone (SIADH) secretion[Ref]
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References
1. (2016) "Product Information. Tolbutamide (tolbutamide)." Mylan Pharmaceuticals Inc
More about Tol-Tab (tolbutamide)
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- During pregnancy
- Drug class: sulfonylureas
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Further information
Tol-Tab side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.