Tolazamide

Primary Use

Tolazamide is prescribed to improve blood sugar control in adults with type 2 diabetes mellitus. It is intended to be used as part of a comprehensive treatment plan that includes a healthy diet and regular physical activity.

How It Works in Treatment

In people with type 2 diabetes, the body either does not produce enough insulin or cannot use it properly. Tolazamide helps by stimulating the pancreas to release more insulin, which allows the body to process sugar more effectively.

Important Limitations

• Type 1 Diabetes: Tolazamide is not used to treat type 1 diabetes, a condition where the body does not produce any insulin.
• Diabetic Ketoacidosis: This medication should not be used to treat diabetic ketoacidosis, which is a serious condition that requires treatment with insulin.

Controlling blood sugar is essential for reducing the risk of long-term complications associated with diabetes, such as nerve damage, kidney problems, and vision loss.

How Tolazamide Works

Tolazamide belongs to a class of medications known as sulfonylureas. It works primarily by triggering the beta cells in the pancreas to produce and secrete more insulin. Insulin is a hormone that allows the body to move sugar (glucose) from the blood into the cells, where it is used for energy.

Because this medication relies on the body's ability to produce insulin, it is only effective for people with type 2 diabetes whose pancreases still function. It is not used to treat type 1 diabetes, a condition where the body does not produce any insulin.

Additional Effects

While the main function of tolazamide is to increase insulin secretion, it may also help lower blood sugar through other mechanisms, especially with long-term use. These may include:

• Increasing the sensitivity of body tissues to insulin, allowing the body to use its own insulin more effectively.
• Reducing the amount of sugar that the liver produces and releases into the blood.

By keeping blood sugar levels within a target range, tolazamide helps manage diabetes and may reduce the risk of long-term health complications associated with high blood sugar.

Common Side Effects

Tolazamide may cause some mild side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• Nausea or heartburn
• A feeling of fullness or loss of appetite
• Skin rash, itching, or hives
• Increased sensitivity to sunlight

Serious Side Effects

Some side effects can be serious. If you experience any of the following, contact your doctor immediately:

• Signs of low blood sugar (hypoglycemia), such as shakiness, sweating, fast heartbeat, dizziness, confusion, or extreme hunger
• Yellowing of the skin or eyes
• Dark-colored urine or light-colored stools
• Unusual bruising or bleeding
• Fever, sore throat, or pale skin
• Unusual tiredness or weakness
• Swelling of the hands, feet, or lower legs

Low blood sugar is a common risk with this medication. It is important to know how to recognize the symptoms and follow your healthcare provider's instructions for treatment.

Major Warnings

Cardiovascular Risk: Some clinical studies have suggested that oral antidiabetic drugs may be linked to an increased risk of cardiovascular mortality compared to treatment with diet alone or diet plus insulin.

Hypoglycemia: All sulfonylureas, including tolazamide, can cause severe low blood sugar (hypoglycemia). This risk is increased by factors such as kidney or liver disease, inadequate caloric intake, strenuous exercise, or alcohol consumption.

Contraindications

• Type 1 diabetes mellitus.
• Diabetic ketoacidosis, with or without coma.
• Known hypersensitivity to tolazamide or other sulfonylurea medications.

Precautions

G6PD Deficiency: Treatment of patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency with sulfonylurea agents can lead to hemolytic anemia. Caution is advised for these individuals.

Loss of Blood Glucose Control: When a patient stabilized on any diabetic regimen is exposed to stress such as fever, trauma, infection, or surgery, a loss of glycemic control may occur. In such cases, it may be necessary to discontinue tolazamide and temporarily administer insulin.

Pregnancy and Nursing: Tolazamide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Because some reports suggest that prolonged hypoglycemia may occur in neonates born to mothers receiving a sulfonylurea at the time of delivery, the medication is often discontinued well before the expected delivery date. It is generally not recommended for use while breastfeeding.

Pregnancy

The use of tolazamide during pregnancy should be discussed with a healthcare provider. It is typically only used if the potential benefits justify the potential risks to the fetus. Many experts recommend using insulin during pregnancy to maintain blood glucose levels as close to normal as possible, as abnormal blood sugar levels are associated with a higher risk of congenital abnormalities.

If tolazamide is used during pregnancy, it is often discontinued at least two weeks before the expected delivery date. This precaution is taken because some newborns have experienced severe and prolonged low blood sugar (hypoglycemia) when the mother was taking similar medications at the time of delivery.

Breastfeeding

It is currently unknown if tolazamide passes into human breast milk. However, other medications in the same class (sulfonylureas) are known to be excreted in milk. Because of the risk of low blood sugar in the nursing infant, a decision must be made whether to stop nursing or stop the medication, depending on the mother's medical needs. If the medication is stopped, insulin therapy may be considered if diet alone is not enough to control blood sugar.

Available Forms

Tolazamide is available in the following form:

• Oral Tablet: This medication is taken by mouth.

The tablets are designed to be swallowed. The physical appearance, including color and shape, may vary depending on the manufacturer. Some tablets are scored, which allows them to be divided if necessary.

FDA Approval and Indications

Tolazamide is approved by the U.S. Food and Drug Administration (FDA) for the management of type 2 diabetes mellitus. It is indicated for use in adults to lower blood glucose levels when diet and exercise alone are insufficient. It is not indicated for the treatment of type 1 diabetes or diabetic ketoacidosis.

Cardiovascular Mortality Warning

The labeling for tolazamide includes a special warning regarding the risk of cardiovascular mortality. This warning is based on the University Group Diabetes Program (UGDP) study, which suggested that oral hypoglycemic agents may be associated with increased cardiovascular risks compared to treatment with diet alone or diet plus insulin. This warning is a standard requirement for drugs in the sulfonylurea class.

Pharmacogenomic Labeling

The FDA includes tolazamide in its records of drugs with pharmacogenomic biomarkers in the labeling. Specifically, patients with a glucose-6-phosphate dehydrogenase (G6PD) deficiency may be at a higher risk of developing hemolytic anemia while taking sulfonylureas. The FDA recommends caution when prescribing this medication to patients with this genetic condition, and healthcare providers may consider alternative treatments.

Generic Availability

Tolazamide is available as a generic drug. Generic medications are required to have the same active ingredients, strength, and dosage form as brand-name drugs, but they are usually sold at a lower price point.

Insurance and Medicare Coverage

Most health insurance plans and Medicare Part D programs cover generic tolazamide. The specific out-of-pocket cost or copayment depends on the individual's insurance plan and the drug's tier on their formulary list.

Factors Influencing Cost

The total price paid for tolazamide can vary based on several factors:

• Pharmacy Choice: Prices may differ between retail pharmacy chains, independent pharmacies, and mail-order services.
• Dosage and Quantity: The prescribed strength (such as 100 mg, 250 mg, or 500 mg) and the number of tablets dispensed will affect the final cost.
• Savings Programs: Patients may be able to reduce costs by using pharmacy discount cards or comparing prices at different locations.