Tolazamide | Side Effects, Dosage, Uses & More
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Generic Name:

tolazamide, Oral tablet

All Brands

  • Tolinase (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.
SECTION 1 of 5

Highlights for tolazamide

Oral tablet
1

Tolazamide is an oral drug that’s used to treat type 2 diabetes. It’s given if you can’t control your blood sugar levels with diet and exercise alone.

2

Your dose depends on your age, blood sugar levels, and how you respond to the medication. Your doctor will decide a dose that’s right for you.

3

Common side effects include nausea, vomiting, decreased appetite, heartburn, and feeling full.

4

You’ll need to learn how to use a blood glucose monitor to test your blood sugar regularly at home. You’ll also need to learn to spot the signs of low and high blood sugar, and treat these reactions when needed. Your doctor will teach you how to do this.

5

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

IMPORTANT INFORMATION

Fatal heart events warning

Another drug in the same class as tolazamide has been shown to raise your chance of fatal heart problems. Studies show that the risk of this happening is higher in people who treat their diabetes with glucose-lowering drugs when compared to those who treat it with diet alone or diet plus insulin. Ask your doctor if tolazamide is right for you.

Risk of very low blood sugar

You may have a greater risk for dangerously low blood sugar if you skip meals, drink alcohol, exercise for long periods of time, or if you’re taking other drugs that lower your blood sugar. Not everyone will react the same way to low blood sugar, so you should learn how to spot your own symptoms when your blood sugar is low. Severe low blood sugar can lead to injuries, coma, and may even be fatal.

Low sodium levels warning

Tolazamide may rarely cause low sodium levels and syndrome of inappropriate antidiuretic hormone secretion (SIADH). In SIADH, 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.

What is tolazamide?

Tolazamide 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

Tolazamide is used to treat type 2 diabetes. It’s given if you can’t control your blood sugar levels with diet and exercise alone.

How it works

Tolazamide belongs to a class of drugs called sulfonylureas. A class of drugs refers to medications that work similarly.

More Details

How it works

Tolazamide belongs to a class of drugs called sulfonylureas. A class of drugs refers to medications that work similarly. They have a 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). Tolazamide lowers blood sugar levels by triggering your pancreas to release more insulin.

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SECTION 2 of 5

tolazamide Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with tolazamide include:

  • nausea

  • vomiting

  • decreased appetite

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.

  • low blood sugar (hypoglycemia). Symptoms may include:

    • shakiness
    • nervousness or anxiety
    • sweating, chills, or clamminess
    • irritability or impatience
    • confusion or delirium
    • fast heart rate
    • hunger
    • nausea
    • sleepiness
    • blurred vision
    • tingling or numbness in your lips or tongue
    • headaches
    • weakness of fatigue
    • anger, stubbornness, or sadness
    • lack of coordination
    • nightmares or crying out in your sleep
    • seizures
    • unconsciousness

    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.

  • liver disease. Symptoms may include:

    • yellowing of your skin or the whites of your eyes
    • fatigue or tiredness
    • nausea or vomiting
    • itching
    • clay-colored or white stools
    • dark-colored urine
    • pain in the right upper part of your stomach
  • 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. This leads to lower sodium levels in your blood. 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

Tolazamide doesn’t cause drowsiness.

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
  • 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.
SECTION 3 of 5

tolazamide May Interact with Other Medications

Oral tablet

Tolazamide 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.

Food interactions

Tolazamide causes your body to make more insulin to remove the sugar from your blood. If you skip a meal while taking this drug, your body will still make the extra insulin. This could cause you to have low blood sugar.

Alcohol interaction

Limit drinking alcohol and avoid drinking it on an empty stomach while taking tolazamide, because it may increase your risk of low blood sugar.

Medications that might interact with this drug

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 tolazamide 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 tolazamide.

Non-steroidal anti-inflammatory drugs (NSAIDs)

Examples are:

  • ibuprofen
  • naproxen

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

Drug used to treat gout
  • probenecid

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

Blood thinner
  • warfarin

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

Drugs used to treat depression

Monoamine oxidase inhibitors (MAOIs), such as:

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

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

Drug used to treat fungus
  • miconazole

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

Diuretics

Examples are:

  • thiazides

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

Corticosteroids

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

Drugs to treat seizures
  • phenytoin

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

Drugs to treat psychotic disorders
  • phenothiazines

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

Thyroid drugs

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

Examples are:

  • levothyroxine
  • Amour thyroid
  • Thyrolar

Estrogens

Examples are:

  • oral birth control
  • hormone replacement therapy

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

Nicotinic acid
  • niacin

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

Sympathomimetics

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

  • albuterol

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 tolazamide and cause high blood sugar (hyperglycemia).

Drug to treat tuberculosis
  • isoniazid

This drug can reduce the effect of tolazamide 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.
Tolazamide warnings
kidney disease
People with kidney disease

Tolazamide is mostly removed from your body by your kidneys. If your kidneys aren’t working as well as they should, this drug 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.

liver disease
People with liver disease

You may be more sensitive to this medication if you have liver disease. This may cause severe low blood sugar. Your doctor will start you at a lower dose and slowly increase your dose if needed.

pregnant women
Pregnant women

Tolazamide 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. Tolazamide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

breastfeeding
Women who are breast-feeding

It isn’t known whether tolazamide passes through breast milk. If it does, it may cause low blood sugar in a breastfeeding child.

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

seniors
For seniors

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

children
For children

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

Keep tolazamide and all medicine out of the reach of children. Taking too much of this medication can cause severe low blood sugar. This can lead to coma, seizure, or other brain problems may that will require hospitalization.

allergies
Allergies

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

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

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

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How to Take tolazamide (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

What are you taking this medication for?

Type 2 diabetes
Form: Oral tablet
Strengths: 250 mg and 500 mg
Adult dosage (ages 18-64 years)
  • If your fasting blood sugar reading is <200, your starting dose may be 100 mg taken by mouth once per day.
  • If your fasting blood sugar reading is >200, your starting dose may be 250 mg taken by mouth once per day.
  • Take tolazamide with breakfast or your first major meal of the day.
  • If your total daily dose is 500 mg or less, take it once per day.
  • If your total daily dose is over 500 mg, split it into two equal doses and take it twice a day with meals.
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)

Seniors may be more likely to have low blood sugar while taking tolazamide. Your doctor may start you at a lower dose.

Special considerations

Kidney Disease: Your doctor may start you at a lower dose and slowly increase your dose if needed.

Liver Disease: Your doctor may start you at a lower dose and slowly increase your dose if needed.

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

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

If you don't take it at all or if you stop taking it suddenly

If you don’t take tolazamide or stop taking it suddenly, you may still have high blood sugar. Over time, high blood sugar can harm your eyes, kidneys, nerves, or heart.

If you take too much

If you take too much tolazamide, you may have low blood sugar. This can lead to serious complications, including coma and death. Symptoms include:

  • shakiness
  • nervousness or anxiety
  • sweating, chills, and clamminess
  • irritability or impatience
  • confusion, including delirium
  • fast heart rate
  • lightheadedness or dizziness
  • hunger and nausea
  • sleepiness
  • blurred or impaired vision
  • tingling or numbness in your lips or tongue
  • headaches
  • weakness or fatigue
  • anger, stubbornness, or sadness
  • lack of coordination
  • nightmares or crying out during your sleep
  • seizures
  • unconsciousness

You can treat mild low blood sugar by drinking or eating something sugary right away (fruit juice, sugar candies, or glucose tablets).

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

Tolazamide is a long-term drug treatment.

Important considerations for taking tolazamide

Store tolazamide at room temperature

Keep it at 68–77°F (20–25°C).

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

Keep it away from light and high temperature.

Store this drug in a childproof container.

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.

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
    • 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
    • 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 is back in the normal range, eat a small snack if your next planned meal or snack is more than 1 hour later.

While taking tolazamide, 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 monitoring machine
  • needle container for safe disposal of lancets

Clinical monitoring

Before starting and while taking tolazamide, 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 diet

Don’t skip meals while taking this drug. Tolazamide causes your body to make more insulin to remove the sugar from your blood. If you skip a meal while taking this drug, your body will still make the extra insulin, and it could cause you to have low blood sugar.

Sun sensitivity

Tolazamide 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

If you’re testing your blood sugar at home, you may 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 monitoring machine
  • 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 tolazamide Cost?

Oral tablet

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Lowest price for tolazamide

Walmart $48.86
Walgreens $85.23
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These prices represent the lowest priced national pharmacies for tolazamide on GoodRx. They may be lower than your insurance.

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These prices represent the lowest priced national pharmacies for tolazamide 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 30, 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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