Tolbutamide (Oral)

Tolbutamide is an oral tablet that is prescribed to help prevent high blood sugar levels that have been increased by type 2 diabetes when diet alone is not proving effective.


In patients with type 2 diabetes, their body cannot properly deal with storing excess sugar, causing the sugar to remain in the bloodstream. Prolonged or chronic high blood sugar can lead to very serious health implications and should be treated quickly.

The most important first steps in managing type 2 diabetes are to introduce a proper diet or to clean up a diet high in sugary, fatty foods. More often than not, extra steps such as medications are needed to help the body cope.

Tolbutamide is part of a specific type of medications called sulfonylureas. Tolbutamide works by causing the pancreas to release extra insulin into the blood to deal with the excess sugars.

This medicine is available only with your doctor's prescription.

Condition(s) treated?

  • Type 2 Diabetes

Type of medicine?

  • Sulfonylureas

Side Effects

Although medicine will usually help fight the issues you are facing, it may cause some unwanted or unexpected side effects. You may not experience all of the following side effects, but if any do occur you may need to seek medical attention.

Contact your healthcare provider immediately if any of these rare side effects occur:

  • stomach pain
  • chills or
  • clay or light-colored stools
  • darker colored urine
  • dizziness
  • diarrhea
  • headache
  • fever
  • Feeling itchy
  • loss or lack of appetite
  • nausea
  • unusual rashes
  • unpleasant breath odor
  • unusual tiredness or weakness
  • vomiting of blood
  • 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 pain or pain in side
  • muscle pain or cramps
  • muscle twitching
  • nosebleeds
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • rapid weight gain
  • seizures
  • sensitivity to the sun
  • shortness of breath
  • ulcers or white spots on lips or inside the mouth
  • stupor
  • swelling of face, ankles, or hands
  • swollen glands
  • tight chest
  • unexplained bleeding
  • bruising
  • wheezing
  • yellow eyes or skin

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

  • Anxiety
  • blurred vision
  • cold sweats
  • cool, pale skin
  • increased hunger
  • nervousness
  • nightmares
  • shakiness
  • slurred speech

There are some side effects which may occur that usually will not need medical attention. These side effects mostly disappear during treatment, which is a normal side effect of your body adjusting to the medication. Also, your health care provider may be able to tell you about other ways to prevent or help to reduce some of these side effects.

Be sure to check with your health care provider if any of the following, more common, side effects become annoying, or if you have any further questions about them:

  • Belching
  • indigestion
  • pain in the chest below the breastbone
  • passing of gas
  • stomach pain, fullness, or discomfort
  • Less common
  • 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 the skin
  • severe sunburn

There are, of course, other side effects which are not listed that may also occur in some patients. If you notice any other effects, contact your healthcare provider for further information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.


The dosage of this medicine is always going to be different for each individual patient. Remember to follow your doctor or physician's orders and understand all of the directions on the label. The following information includes only average doses of this medicine for adults and children. If your dose is different you must not exceed or change it unless the doctor explicitly tells you to do so.

The amount of medicine that you take depends on the following factors; the strength of the medicine, the number of doses you must take each day, the time allowed between each dose and the duration of time you take the medicine for. All these factors are dependant on the medical issue for which you are taking the medicine.

For oral dosage form (tablets):

Adults: At the beginning of your treatment, 1000 to 2000 milligrams (mg) per day is taken in the morning or in equally divided doses. Your doctor or health provider may adjust this dose as needed. The dose will not usually exceed more than 3000 mg per day.

Children: The use and dosage of this medicine must be determined by your doctor.


Although there are certain medicines which should not be used together at all, there are other cases in which two different medicines can be used together, even if an interaction were to occur. In these cases, the doctor may want to alter the dose, or impose other precautions if necessary. If you are prescribed this medication by another doctor or health care provider, it is especially important that they know if you are actively taking any of the medicines in the list below. The following list of interactions have been noted on the basis of their potential significance, but these medications are not necessarily all-inclusive.

It is advised that using this medicine with any of the following medicines is usually not recommended but could be required in some cases. If both medications are prescribed at the same time, your doctor may change the dosage or how often you have to use one or both of these medicines.

  • Acarbose
  • Aspirin
  • Balofloxacin
  • Besifloxacin
  • Ceritinib
  • Ciprofloxacin
  • Disopyramide
  • Dulaglutide
  • Enoxacin
  • Entacapone
  • Fleroxacin
  • Flumequine
  • Gatifloxacin
  • Gemifloxacin
  • Levofloxacin
  • Lanreotide
  • Lomefloxacin
  • Lixisenatide
  • Moxifloxacin
  • Norfloxacin
  • Nadifloxacin
  • Ofloxacin
  • Octreotide
  • Pasireotide
  • Pazufloxacin
  • Prulifloxacin
  • Pefloxacin
  • Rufloxacin
  • Sparfloxacin
  • Thioctic Acid
  • Tosufloxacin

If you are using this medicine with any of the following listed medicines you may experience an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acebutolol
  • Atenolol
  • Betaxolol
  • Bisoprolol
  • Bitter Melon
  • Carteolol
  • Carvedilol
  • Celiprolol
  • Chloramphenicol
  • Dicumarol
  • Esmolol
  • Fenugreek
  • Fosphenytoin
  • Furazolidone
  • Ginkgo Biloba
  • Glucomannan
  • Guar Gum
  • Iproniazid
  • Isocarboxazid
  • Ketoconazole
  • Labetalol
  • Levobunolol
  • Linezolid
  • Methylene Blue
  • Metipranolol
  • Metoprolol
  • Moclobemide
  • Nadolol
  • Nebivolol
  • Nialamide
  • Oxprenolol
  • Penbutolol
  • Phenelzine
  • Phenytoin
  • Pindolol
  • Practolol
  • Procarbazine
  • Propranolol
  • Psyllium
  • Rasagiline
  • Rifapentine
  • Safinamide
  • Selegiline
  • Sulfaphenazole
  • Sotalol
  • Tranylcypromine
  • Timolol
  • Voriconazole
  • Trimethoprim


Certain medications should not be used when eating certain types of food since interactions can occur. The use of alcohol or tobacco with certain medications can also cause interactions to occur. The following interactions have been listed due to their potential significance and are not necessarily an all-inclusive list.

When using this medicine, use of any of the following is usually not recommended, but may be unavoidable in some cases. If these substances are used together, your doctor may change the dose or how often you use this medicine. They may also give you strict or special instructions about the use of food, alcohol, or tobacco with the medication.

  • Ethanol

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Alcohol intoxication
  • Underactive adrenal glands
  • Underactive pituitary glands
  • Undernourished condition
  • Weakened physical condition
  • Any other condition that is known to cause low blood sugar. Patients with these conditions may be more likely to develop low blood sugar while taking tolbutamide.
  • Diabetic ketoacidosis (ketones in the blood)
  • Type I diabetes. This medication should not be used in patients with this condition.
  • Fever
  • Infection
  • Surgery
  • Trauma. This condition may cause temporary problems with blood sugar control and your doctor may wish to treat you with insulin temporarily.
  • Heart disease. This medication should be used with caution as it may make this condition worse.
  • Kidney disorder
  • Liver disorder. Higher blood levels of this medicine may occur, which can cause serious problems.

It is very important that your doctor check your progress with regular visits to make sure that this medicine is working properly. Blood tests may be required to check for unwanted side effects.

It is extremely important to carefully complie with any instructions from your health care provider about the following:

  • The consumption of alcohol can cause severely lowered blood sugar levels. If you know you will be consuming alcohol you should discuss this further with your health care profession.
  • our family members may also need to learn how to counteract or help with side effects if they occur. Those diagnosed with diabetes may need specific counseling about any dosing changes which can occur due to lifestyle changes, for example any changes to the patient's exercise regime and diet. It is extremely important that counseling on contraception and pregnancy is received due to the problems that can occur in patients with diabetes during pregnancy.
  • Travel¬†- It is important to keep your recent prescription and your medical history with you at all times when travelling. It is wise to be prepared for an emergency while away from home as you would normally. Always make allowances for changing time zones and keep your meal times as close as possible to your usual meal times so as not to interfere with each dose taken.
  • n case of emergency¬†- It is possible that there may be a time when you need emergency care for a problem caused by your diabetes. It is important that you are prepared for any and all emergencies. It is a very good idea to always wear a medical identification bracelet or neck chain at all times that states you are diabetic. Also, always keep a copy of an ID card in your wallet or purse which states that you have diabetes, with a list of all of your medicines.

If you experience any of the following symptoms, contact your health care provider immediately;

  • chest pain or discomfort
  • nausea
  • pain or discomfort in arms, neck, back or jaw.
  • shortness of breath
  • sweating
  • vomiting

These also may be the symptoms of a serious heart problem, including a heart attack.

Taking Tolbutamide can cause low blood sugar but this can also happen if you delay or miss a meal snack, consume any alcohol, exercise more than you usually do, do not eat due to nausea or vomiting, if you are taking certain medicines, or you take tolbutamide with any other type of diabetes medication. If this happens the symptoms of low blood sugar should be treated quickly before they lead the patient to become unconsciousness or start to pass out. Different patients will feel different symptoms to low blood sugar so it is important that you learn which symptoms of low blood sugar you usually feel or have so they can treat it quickly.

Symptoms of low blood sugar include the following:

  • anxiety
  • behavioral changes that resemble being drunk
  • blurry vision
  • cold sweats
  • confusion
  • cool or pale skin
  • difficulty thinking
  • drowsiness
  • increased or excessive hunger
  • fast or unusual heartbeat
  • headaches
  • nervousness
  • nausea or vomiting
  • nightmares
  • a restless sleep
  • shakiness
  • slurred speech
  • unusual tiredness or weakness

If any symptoms of low blood sugar occur you should eat glucose (either tablets or gel), foods rich in sugar, honey, fruit juice, soda (not diet soda) or sugar water. It is also important to check your blood for low blood sugar throughout the day. It is important to always have a glucagon kit available, along with a syringe or needle, and know how to use it in case severe symptoms such as seizures or unconsciousness occur. Other members of your household also should know or be taught how to use it.


  • Store at room temperature.
  • Store in a dry place, protected from light
  • Do not store in a bathroom.
  • Keep all drugs in a safe place out of the reach of children and pets.
  • Contact your pharmacist about how to discard unused drugs.


In general, this medication is used treat type 2 diabetes in adults by helping to control the blood sugar levels. This is achieved through making the patients pancreas secrete more insulin into the blood stream. While diet should always be the first step in any issue stemming from high blood sugar levels, medication is regularly needed in combination to drastically reduce the risk of further serious health problems.

There are significant benefits of being on this medication, which primarily include better control of blood sugar levels which in turn, reduces the risk of further complications. By helping to control the high blood sugar levels in a patient, it will also help to prevent or reduce kidney damage, nerve problems blindness, loss of any limbs and impotence. By maintaining control of your diabetes, you may also reduced your chances of a heart attack or stroke.

Tolbutamide should be used in conjunction with a proper or balanced diet and an exercise program to control high blood sugar in people with type 2 diabetes. Tolbutamide, under certain circumstances, may also be used with other diabetes medications.

This medication will only help to lower the blood sugar in people whose bodies will produce insulin naturally. This means that Tolbutamide should not be used to treat type 1 diabetes, which is different for type 2 in that the body does not produce insulin naturally and, therefore, cannot control the amount of sugar in the blood. It can also not be used in those suffering from diabetic ketoacidosis, which is a serious condition that may occur when the blood sugar remains high for a prolonged amount of time untreated.

After prolonged use of tolbutamide, it may not control the blood sugar levels as well as it did at the beginning of the patient's treatment. A doctor or health provider may adjust the dosage of the medication when this is needed so that it will work best for you. It is important to always tell your doctor how you feel and of any side effects, you experience. It is also important to tell your doctor about your blood sugar test results if they have been either higher or lower than normal at any time during your treatment.

Last Reviewed:
December 22, 2017
Last Updated:
April 26, 2018