Tolbutamide | Side Effects, Dosage, Uses & More

Generic Name:

tolbutamide, Oral tablet

All Brands

  • Orinase (Discontinued)
A discontinued drug is a drug that has been taken off the market due to safety issues, shortage of raw materials, or low market demand.
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Highlights for tolbutamide

Oral tablet
1

Tolbutamide is an oral drug that’s used to treat type 2 diabetes.

2

Tolbutamide is used along with diet and exercise to control your blood sugar level.

3

Your dose depends on your blood sugar levels, other medical conditions you have, and how you respond to the medication.

4

Common side effects include nausea, stomach fullness or bloating, heartburn, headache, and low blood sugar (hypoglycemia).

5

This drug may raise your risk of heart problems that can be fatal. Ask your doctor if this medication is right for you.

IMPORTANT INFORMATION

Type 1 diabetes

You shouldn’t use tolbutamide alone if you have type 1 diabetes. Don’t use this drug if you have diabetic ketoacidosis. You’ll need to take this drug along with insulin.

Low blood sugar

Tolbutamide can cause low blood sugar (hypoglycemia). If you don’t treat low blood sugar, you can have a seizure, pass out, and possibly develop brain damage. Low blood sugar can even be fatal. If you pass out because of a low sugar reaction or cannot swallow, someone will have to give an injection of glucagon to treat the low sugar reaction. You may need to go to the emergency room.

Fatal heart problems

Tolbutamide has been shown to raise your risk of fatal heart problems. Studies show that the risk of this happening is higher in people who treat their diabetes with oral diabetes medications. Ask your doctor if tolbutamide is right for you.

Drug features

Tolbutamide is a prescription drug. It’s available as an oral tablet.

This drug may be used as part of a combination therapy. That means you need to take it with other drugs.

Why it's used

Tolbutamide is used to decrease high blood sugar in adults with type 2 diabetes. It’s given along with diet and exercise.

How it works

Tolbutamide belongs to a class of drugs called sulfonylureas.

More Details

How it works

Tolbutamide belongs to a class of drugs called sulfonylureas. A class of drugs refers to medications that work similarly. They have similar chemical structure and are often used to treat similar conditions.

Insulin is a chemical that your body makes that helps to move sugar (glucose) into your body’s cells. Once the sugar enters your cells, they use it as fuel for your body. If your body doesn’t make enough insulin on its own or if it can't use the insulin that it makes properly, the sugar will stay in your bloodstream. This causes high blood sugar levels (hyperglycemia). Tolbutamide lowers blood sugar levels by triggering your pancreas to release more insulin.

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tolbutamide Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with tolbutamide include:

  • nausea

  • stomach fullness or bloating

  • heartburn

  • headache

  • low blood sugar (hypoglycemia)

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • severe low blood sugar (less than 35–40 mg/dL). Symptoms may include:

    • mood changes, such as irritability, impatience, anger, stubbornness, or sadness
    • confusion, including delirium
    • lightheadedness or dizziness
    • sleepiness
    • blurred or impaired vision
    • tingling or numbness in your lips or tongue
    • headaches
    • weakness or fatigue
    • lack of coordination
    • nightmares or crying out during sleep
    • seizures
    • unconsciousness
  • allergic skin reactions. Symptoms may include:

    • itching
    • redness
    • hives
    • bumpy rashes
  • sensitivity to sunlight. Symptoms may include:

    • getting sunburned easily
    • skin rash when you’re out in the sun
  • low red blood cells (anemia). Symptoms may include:

    • fast heart rate
    • chest pain
    • trouble breathing when exerting yourself
    • lightheadedness or dizziness
  • low white blood cells

  • low platelets. This could lead to bleeding.

  • low sodium levels (hyponatremia) and syndrome of inappropriate antidiuretic hormone secretion (SIADH). In SIADH, your antidiuretic hormone is increased, and your body is unable to urinate (get rid of) excess water. If the amount of water you drink exceeds the amount of water you urinate, your body will keep that extra water. This leads to lower sodium levels in your blood (hyponatremia). This is dangerous. Symptoms may include:

    • nausea and vomiting
    • headache
    • confusion
    • loss of energy and fatigue
    • restlessness and irritability
    • muscle weakness, spasms, or cramps
    • seizures
    • coma
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Tolbutamide doesn’t cause drowsiness.

This drug will decrease your blood sugar levels. Tolbutamide can cause your blood sugar level to drop too low (hypoglycemia). If you have a low blood sugar reaction, you need to treat it.

  • For mild hypoglycemia (55–70 mg/dL), treatment is 15–20 grams of glucose (a type of sugar). You need to eat or drink one of the following:
    • 3–4 glucose tablets
    • a tube of glucose gel
    • ½ cup of juice or regular, non-diet soda
    • 1 cup of nonfat or 1% cow’s milk
    • 1 tablespoon of sugar, honey, or corn syrup
    • 8–10 pieces of hard candy, such as lifesavers
    • Once your blood sugar level is back in the normal range, eat a small snack if your next planned meal or snack is more than 1 hour later.
  • Test your blood sugar 15 minutes after you treat the low sugar reaction. If your blood sugar is still low, then repeat the above treatment.
  • Once your blood sugar level is back in the normal range, eat a small snack if your next planned meal or snack is more than 1 hour later.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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tolbutamide May Interact with Other Medications

Oral tablet

Tolbutamide can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol interaction

Drinking alcohol while taking tolbutamide may affect your blood sugar levels. They can either increase or decrease. Limit your alcohol intake while you take this medication. Avoid drinking alcohol on an empty stomach.

Medications that might interact with this drug

Nonsteroidal anti-inflammatory drugs (NSAIDs)

Examples are:

  • ibuprofen
  • ketorolac
  • meloxicam
  • naproxen

These drugs can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Salicylates

Examples are:

  • aspirin
  • salsalate

These drugs can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Sulfonamides

Examples are:

  • sulfasalazine
  • sulfamethoxazole/trimethoprim

These drugs can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Drugs that treat infections
  • chloramphenicol

This drug can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Drugs used to treat gout
  • probenecid

This drug can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Blood thinner
  • warfarin

This drug can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Drugs used to treat depression

Monoamine oxidase inhibitors, such as:

  • isocarboxazid (Marplan)
  • phenelzine (Nardil)
  • tranylcypromine (Parnate)

These drugs can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Heart and blood pressure medications (beta blockers)

Examples are:

  • acebutolol (Sectral)
  • atenolol (Tenormin)
  • bisoprolol (Zebeta)
  • esmolol (Brevibloc)
  • metoprolol (Lopressor, Toprol XL)
  • nadolol (Corgard)
  • nebivolol (Bystolic)
  • propranolol (Inderal LA)

These drugs change how your body manages blood sugar. Taking them with tolbutamide can cause high or low blood sugar. These medications may also mask your symptoms of low blood sugar. Your doctor will watch you closely if you take these drugs with tolbutamide.

Drugs used to treat fungus
  • miconazole 

This drug can increase the effect of tolbutamide and cause low blood sugar (hypoglycemia).

Diuretics

Examples are:

  • thiazides 

These drugs can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Corticosteroids

These drugs can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Drugs to treat seizures
  • phenytoin

This drug can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Drug to treat psychotic disorders
  • phenothiazines

This drug can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Thyroid drugs
  • levothyroxine
  • Armour thyroid
  • Thyrolar

These drugs can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Estrogens

Examples are:

  • oral birth control
  • hormone replacement therapy

These drugs can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Nicotinic acid
  • niacin

This drug can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Sympathomimetics

Examples are:

  • albuterol
  • epinephrine
  • dopamine

These drugs can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

High blood pressure or heart medications (calcium channel blockers)

Examples are:

  • verapamil (Calan, Veralan)
  • diltiazem (Cardizem, Cartia XT)

These drugs can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Drugs to treat tuberculosis
  • isoniazid

This drug can reduce the effect of tolbutamide and cause high blood sugar (hyperglycemia).

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

People with type 1 diabetes

Don’t use tolbutamide alone if you have type 1 diabetes. You’ll need to take it along with insulin.

People with diabetic ketoacidosis

You shouldn’t use tolbutamide if you have diabetic ketoacidosis. You’ll need to be treated with insulin.

People with enzyme deficiency

If you have glucose 6-phosphate dehydrogenase (G6PD) deficiency, this drug increases your risk of hemolytic anemia. Hemolytic anemia occurs when your body destroys its red blood cells. Your doctor may give you another type of drug for your diabetes if you have this condition.

People with kidney disease

Tolbutamide is removed from your body by your kidneys. If your kidneys aren’t working as well as they should, tolbutamide may build up in your body and cause low blood sugar (hypoglycemia). Your doctor may start you at a lower dose and slowly increase your dose if needed.

People with liver disease

Tolbutamide is processed by your liver. If you have liver disease, levels of this drug can increase in your blood. You may be more sensitive to the blood sugar-lowering (hypoglycemic) action of tolbutamide. Your doctor may start you at a lower dose and slowly increase your dose if needed.

Pregnant women

Tolbutamide is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. Tolbutamide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Women who are breast-feeding

It isn’t known if tolbutamide passes through breast milk, but other sulfonylureas can pass through breast milk. If it does, it may cause low blood sugar (hypoglycemia) in breastfeeding children.

You and your doctor may need to decide if you’ll take tolbutamide or breastfeed.

For seniors

Seniors may be more likely to experience low blood sugar or low blood sodium when using tolbutamide. Kidney problems, drug interactions, and a poor diet may also increase the risk of these side effects in seniors.

For children

The safety and effectiveness of tolbutamide in people younger than 18 years old haven’t been established.

When to call the doctor

If tolbutamide isn’t working well enough to control your diabetes, you’ll have signs of high blood sugar (hyperglycemia). Call your doctor if you have the any of these symptoms:

  • frequent urination
  • intense thirst
  • intense hunger, even though you’re eating
  • extreme fatigue
  • blurry vision
  • cuts or bruises that are slow to heal
  • tingling, pain, or numbness in your hands or feet

Allergies

Tolbutamide can cause a severe allergic reaction. Symptoms may include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives
  • skin rash

Don’t take tolbutamide again if you’ve ever had an allergic reaction to it. Taking it again could be fatal.

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How to Take tolbutamide (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose
  • changes in your diet
  • illness
  • stress

What are you taking this medication for?

Type 2 diabetes
Form: Oral tablet
Strengths: 500 mg
Adult dosage (ages 18-64 years)
  • The standard starting dose is 1–2 grams taken by mouth 1–3 times per day. Your doctor may increase or decrease your dose, depending on how you respond to this medication.
  • The standard maintenance dose is 0.25–3 grams taken by mouth. Take this medication in the morning or in divided doses throughout the day. Divided doses may be better for you if you’re having stomach-related side effects.
  • The maximum daily dose is 3 grams per day.
Child dosage (ages 0-17 years)

This medicine hasn’t been studied in children and shouldn’t be used in people younger than 18 years old.

Senior dosage (ages 65 years and older)

Your body processes this drug more slowly. Your doctor may start you on a lowered dose so that too much of this drug doesn’t build up in your body. Too much drug in your body can lead to dangerously low blood sugar levels (hypoglycemia).

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Tolbutamide comes with serious risks if you don't take it as prescribed.

If you don’t take it at all

If you don’t take tolbutamide at all, you may experience high blood sugar levels and all the symptoms associated with it. Over time, elevated blood sugar levels can harm your eyes, kidneys, nerves, or heart. Severe issues include heart attack, stroke, blindness, kidney failure and dialysis, and amputation of your limbs.

If you take too much

If you take too much tolbutamide, your blood sugar may fall to dangerously low levels (hypoglycemia).

You can treat mild low blood sugar by drinking or eating something sugary right away (fruit juice, sugar candies, or glucose tablets). It’s important to treat low blood sugar as soon as possible because it could cause you to have a seizure, pass out, or get brain damage. It can even be fatal.

What to do if you miss a dose

If you forget to take your dose, take it as soon as you remember. If it’s just a few hours before your next dose, then skip the missed dose and only take one dose at that time.

Never try to catch up by taking two doses at once. This could cause low blood sugar.

How to tell if the drug is working

If tolbutamide is working, your symptoms of high blood sugar should decrease. You may not urinate as often or be as thirsty or hungry.

Tolbutamide is a long-term drug treatment.

Important considerations for taking tolbutamide

Store tolbutamide at room temperature

Keep it at 68–77°F (20–25°C).

Keep this drug away from light and high temperature.

Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry your medication with you or in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt this medication.
  • You may need to show your pharmacy’s label to clearly identify the medication. Keep the original prescription label with you when traveling.
  • Don’t leave this medicine in the car, especially when the temperature is hot or freezing.
  • Lancets need to be used to test your blood glucose. Check for special rules about traveling with medicine and lancets.

Self-management

You’ll need to learn how to do the following:

  • use a blood glucose monitor to test your blood sugar regularly at home
  • recognize the signs and symptoms of high and low blood sugar
  • treat high and low blood sugar reactions

While taking tolbutamide, your doctor may have you regularly test your blood sugar levels at home. You’ll need to purchase the following:

  • sterile alcohol wipes
  • lancing device and lancets (a needle used to obtain drops of blood from your finger to test your blood sugar)
  • blood sugar test strips
  • blood glucose monitor
  • needle container for safe disposal of lancets

Clinical monitoring

Before starting and while taking tolbutamide, your doctor may check your:

  • blood sugar levels
  • glycosylated hemoglobin (A1C) levels. This test measures your blood sugar control over the last 2–3 months.
  • liver function
  • kidney function

Your doctor may also do these tests to check for complications of high blood sugar:

  • eye exam at least once a year
  • foot exam at least once a year
  • dental exam at least once a year
  • tests for nerve damage
  • cholesterol levels
  • blood pressure and heart rate

Your diet

Making healthy food choices and tracking your eating habits can help you manage your diabetes. Follow the nutrition plan that your doctor, registered dietician, or diabetes educator recommended.

Sun sensitivity

Tolbutamide may cause increased sensitivity to the sun (photosensitivity). Use sunscreen, wear protective clothing, and limit how often you’re in the sun while taking this medication.

Hidden costs

While taking tolbutamide, your doctor may have you regularly test your blood sugar levels at home. You’ll need to purchase the following:

  • sterile alcohol wipes
  • lancing device and lancets (a needle used to obtain drops of blood from your finger to test your blood sugar)
  • blood sugar test strips
  • blood glucose monitor
  • needle container for safe disposal of lancets

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

What does the pill look like?

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How Much Does tolbutamide Cost?

Oral tablet

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Lowest price for tolbutamide

Walgreens $46.16
CVS Pharmacy $81.77
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These prices represent the lowest priced national pharmacies for tolbutamide on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on July 31, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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