Description: Tolbutamide lowers blood glucose concentration principally by stimulating the secretion of endogenous insulin from pancreatic β-cells. It may enhance peripheral sensitivity to insulin and reduce basal hepatic glucose production during long-term admin.

Onset: 1 hr.

Duration: 6-24 hr.


Absorption: Readily absorbed from the GI tract. Time to peak plasma concentration: W/in 3-5 hr.

Distribution: Distributed into breast milk. Volume of distribution: 0.15 L/kg. Plasma protein binding: Approx 95%.

Metabolism: Metabolised in the liver via hydroxylation mediated by CYP2C9 isoenzyme.

Excretion: Via urine (75-85%) mainly as metabolites and faeces. Half-life: 4-7 hr.

Tolbutamide, a sulfonylurea, controls high blood sugar with a proper diet and exercise program in people with type 2 diabetes. It works by causing the release of your body’s natural insulin and may help to restore your body’s proper response to insulin.

How to use tolbutamide

Take this medication by mouth as directed by your doctor, usually once daily in the morning. Your daily dose may also be divided into smaller doses to be taken several times a day, especially if this medication causes stomach upset. Follow your doctor’s instructions carefully. The dosage is based on your medical condition and response to treatment.

To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor’s instructions carefully.

If you are already taking another anti-diabetic drug (such as chlorpropamide), follow your doctor’s directions carefully for stopping the old drug and starting tolbutamide.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

Tell your doctor if your condition does not improve or if it worsens (your blood sugar levels are too high or too low).

Not available.

Tell your doctor or pharmacist promptly if any of these effects persist or worsen:

  • stomach upset/fullness
  • nausea
  • headache
  • weight gain

Tell your doctor right away if you have any serious side effects, including:

  • dark urine
  • easy bleeding/bruising
  • persistent nausea
  • severe stomach/abdominal pain
  • signs of infection (such as persistent sore throat, fever)
  • yellowing eyes/skin

This medication can cause low blood sugar (hypoglycemia).

Tell your doctor immediately if Symptoms of high blood sugar (hyperglycemia) occur, such as:

  • thirst
  • increased urination
  • confusion
  • drowsiness
  • flushing
  • rapid breathing
  • fruity breath odor

A very serious allergic reaction to this drug is rare.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.


  • Allergic reaction to this medication
  • Patients with medical history of:
    • kidney disease
    • liver disease
    • low sodium blood level (hyponatremia)
    • certain hormonal conditions (adrenal/pituitary insufficiency, thyroid disease, syndrome of inappropriate antidiuretic hormone-SIADH)
  • You may experience blurred vision, dizziness, or drowsiness
  • Limit alcohol
  • harder to control your blood sugar when your body is stressed (such as due to fever, infection, injury, or surgery)
  • More sensitive to the sun
  • Tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before having surgery
  • Older adults may be more sensitive to low blood sugar
  • Used only when clearly needed during pregnancy
  • Consult your doctor before breast-feeding

Consult your doctor regarding the precautions mentioned above.


Beta-blocker medications (including metoprolol, propranolol, glaucoma eye drops such as timolol) may prevent the fast/pounding heartbeat you would usually feel when your blood sugar level falls too low (hypoglycemia).

Check the labels on all your medicines (such as cough-and-cold products) because they may contain ingredients that could affect your blood sugar.

This medication may interfere with certain laboratory tests, possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.


If overdose is suspected, contact a poison control center or emergency room immediately. Symptoms of overdose may include: shakiness, fast heartbeat, sweating, loss of consciousness.


Do not share this medication with others.

Attend a diabetes education program to learn more about diabetes and the important aspects of its treatment, including medications, diet, exercise, and getting regular eye/foot/medical exams.

Learn the symptoms of high and low blood sugar and how to treat low blood sugar. Check your blood sugar levels regularly as directed.

Keep all regular medical and laboratory appointments. Laboratory and/or medical tests (such as liver and kidney function tests, fasting blood glucose, hemoglobin A1c, complete blood counts) should be performed periodically to monitor your progress or check for side effects.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.


Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.


There are no brands containing this molecule.

Related Articles


Perazine is a phenothiazine antipsychotic agent used in the treatment of acute and chronic psychotic disorders. Use this medication precisely [...]


Niceritrol is a nicotinic acid and pentaerythritol ester. It has been utilized as a vasodilator and a lipid-lowering drug since [...]


Pentoxyverine is a centrally acting cough suppressant, mainly used for non-productive cough. It is often used in a form of [...]