Does Tolinase (tolazamide) cause side effects?

Tolinase (tolazamide) is a prescription diabetes medication used with diet and exercise to reduce blood glucose levels in adult patients with type 2 diabetes mellitus. Other diabetes drugs are sometimes used in combination with Tolinase. Tolinase’s initial effect is to increase beta-cell insulin secretion. 

Tolinase causes the pancreas to produce insulin and increases the body's response to it. Tolinase also may decrease the rate of hepatic glucose production, increase insulin receptor sensitivity, and increase the number of insulin receptors. The brand name Tolinase is discontinued. 

Common side effects of Tolinase include:

Serious side effects of Tolinase include:

Drug interactions of Tolinase include quinolone antibiotics, which may result in abnormal changes in blood glucose. 

Tolinase may increase blood levels of methotrexate by interfering with the binding of methotrexate to blood proteins. 

Anti-retroviral protease inhibitors, a type of anti-HIV medication, may decrease the effectiveness of Tolinase and consequently worsen blood glucose control. 

There are no adequate studies of the effects of Tolinase for pregnant women. It is unknown if Tolinase is secreted in breast milk. Consult your doctor before breastfeeding.

What are the imporant side effects of Tolinase (tolazamide)?

Side effects associated with tolazamide therapy include:

  1. Dizziness
  2. Fatigue
  3. Headache
  4. Malaise
  5. Vertigo
  6. Increase sensitivity to the sunlight (photophobia),
  7. Itching
  8. Rash
  9. Hives
  10. Anorexia
  11. Constipation
  12. Diarrhea
  13. Sensations of stomach fullness
  14. Heartburn
  15. Nausea
  16. Vomiting
  17. Muscle weakness
  18. Water loss from the body (diuresis)

Possible serious side effects of tolazamide include:

  1. Disulfiram (Antabuse)-like reactions (for example, severe flushing accompanied by low blood pressure (hypotension) and tachycardia
  2. Low blood glucose
  3. Low blood sodium
  4. Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
  5. Blood disorders
  6. Liver dysfunction

Tolinase (tolazamide) side effects list for healthcare professionals

Tolinase (tolazamide) Tablets have generally been well tolerated. In clinical studies in which more than 1,784 diabetic patients were specifically evaluated for incidence of side effects, only 2.1% were discontinued from therapy because of side effects.

Hypoglycemia: See prescribing information.

Gastrointestinal Reactions: Cholestatic jaundice may occur rarely; Tolinase (tolazamide) Tablets should be discontinued if this occurs. Gastrointestinal disturbances, eg, nausea, epigastric fullness, and heartburn, are the most common reactions and occurred in 1% of patients treated during clinical trials. They tend to be dose-related and may disappear when dosage is reduced.

Dermatologic Reactions: Allergic skin reactions, eg, pruritus, erythema, urticaria, and morbilliform or maculopapular eruptions, occurred in 0.4% of patients treated during clinical trials. These may be transient and may disappear despite continued use of Tolinase (tolazamide) ; if skin reactions persist, the drug should be discontinued.

Porphyria cutanea tarda and photosensitivity reactions have been reported with sulfonylureas.

Hematologic Reactions: Leukopenia, agranulocy-tosis, thrombocytopenia, hemolytic anemia, aplas-tic anemia, and pancytopenia have been reported with sulfonylureas.

Metabolic Reactions: Hepatic porphyria and disul-firam-like reactions have been reported with sul-fonylureas; however, disulfiram-like reactions with Tolinase (tolazamide) have been reported very rarely.

Cases of hyponatremia have been reported with tolazamide and all other sulfonylureas, most often in patients who are on other medications or have medical conditions known to cause hyponatremia or increase release of antidiuretic hormone. The syndrome of inappropriate antidiuretic hormone (SIADH) secretion has been reported with certain other sul-fonylureas, and it has been suggested that these sul-fonylureas may augment the peripheral (antidiuretic) action of ADH and/or increase release of ADH.

Miscellaneous: Weakness, fatigue, dizziness, vertigo, malaise and headache were reported infrequently in patients treated during clinical trials. The relationship to therapy with Tolinase (tolazamide) is difficult to assess.

What drugs interact with Tolinase (tolazamide)?

The hypoglycemic action of sulfonylureas may be potentiated by certain drugs including nonsteroidal anti-inflammatory agents and other drugs that are highly protein bound, salicylates, sulfonamides, chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, and beta-adrenergic blocking agents.

When such drugs are administered to a patient receiving Tolinase (tolazamide), the patient should be closely observed for hypoglycemia. When such drugs are withdrawn from a patient receiving Tolinase (tolazamide) , the patient should be observed closely for loss of control.

Certain drugs tend to produce hyperglycemia and may lead to loss of control. These drugs include the thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympa-thomimetics, calcium channel blocking drugs, and isoniazid. When such drugs are administered to a patient receiving Tolinase (tolazamide), the patient should be closely observed for loss of control. When such drugs are withdrawn from a patient receiving Tolinase (tolazamide) , the patient should be observed closely for hypoglycemia.

A potential interaction between oral miconazole and oral hypoglycemic agents leading to severe hypoglycemia has been reported. Whether this interaction also occurs with the intravenous, topical or vaginal preparations of miconazole is not known.


In a bioassay for carcinogenicity, rats and mice of both sexes were treated with tolazamide for 103 weeks at low and high doses. No evidence of car-cinogenicity was found.


Teratogenic Effects:

Pregnancy Category C. Tolinase (tolazamide) , administered to pregnant rats at ten times the human dose, decreased litter size but did not produce terato-genic effects in the offspring. In rats treated at a daily dose of 14 mg/kg no reproductive aberrations or drug related fetal anomalies were noted. At an elevated dose of 100 mg/kg per day there was a reduction in the number of pups born and an increased perinatal mortality.

There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, Tolinase (tolazamide) is not recommended for the treatment of the pregnant diabetic patient. Serious consideration should also be given to the possible hazards of the use of Tolinase (tolazamide) in women of child bearing age and in those who might become pregnant while using the drug.

Because recent information suggests that abnormal blood glucose levels during pregnancy are associated with a higher incidence of congenital abnormalities, many experts recommend that insulin be used during pregnancy to maintain blood glucose levels as close to normal as possible.

Nonteratogenic Effects:

Prolonged severe hypoglycemia (four to ten days) has been reported in neonates born to mothers who were receiving a sulfonylurea drug at the time of delivery. This has been reported more frequently with the use of agents with prolonged half-lives. If Tolinase (tolazamide) is used during pregnancy, it should be discontinued at least two weeks before the expected delivery date.

Nursing Mothers

Although it is not known whether tolazamide is excreted in human milk, some sulfonylurea drugs are known to be excreted in human milk. Because the potential for hypoglycemia in nursing infants may exist, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. If the drug is discontinued and if diet alone is inadequate for controlling blood glucose, insulin therapy should be considered.

Pediatric Use

Safety and effectiveness in children have not been established.

Geriatric Use

Elderly patients are particularly susceptible to the hypoglycemic action of glucose lowering drugs. Hypoglycemia may be difficult to recognize in the elderly. The initial and maintenance dosing should be conservative to avoid hypoglycemic reactions.

Elderly patients are prone to develop renal insufficiency, which may put them at risk of hypoglycemia. Dose selection should include assessment of renal function.


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Medically Reviewed on 5/19/2020
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Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.