Alcohol may interact with the first generation sulfonylureas, especially chlorpropamide, to cause moderate to severe facial flushing (increased flow of blood to the face) and an increase in facial temperature.

Chlorpropamide may prolong the action of barbiturates including phenobarbital. Probenecid (Benemid) may increase the hypoglycemic effect of chlorpropamide. Blood levels of digoxin (Lanoxin) may be increased by sulfonylureas, and, therefore, digoxin should be used cautiously with chlorpropamide and other first generation sulfonylureas.

Beta-blocking drugs including propranolol (Inderal) may interact with the first generation sulfonylureas, especially tolbutamide. Beta-blockers may lower or increase glucose levels when used alone. When used with sulfonylureas, beta-blocking drugs may interfere with glucose lowering by the sulfonylureas. In addition, beta-blockers can blunt some of the body's protective responses to hypoglycemia, for example, increased heart rate, thus making it difficult for patients to recognize hypoglycemia. This notwithstanding, beta-blockers have been used successfully in diabetic patients and have been associated with improved survival in diabetics with high blood pressure.

PREGNANCY: Very high doses of first generation sulfonylureas have been harmful to fetuses in animal studies. No adequate safety and efficacy studies have been conducted in humans. Therefore, sulfonylureas generally are not a good choice for pregnant women.

NURSING MOTHERS: Chlorpropamide and tolbutamide are excreted in breast milk. It is not known if acetohexamide and tolazamide are excreted in breast milk. Because hypoglycemia may occur in the infant who breastfeeds from a mother taking sulfonylureas, either formula feedings or discontinuation of sulfonylureas is strongly recommended in nursing mothers.

SIDE EFFECTS: The most common side effects of the first generation sulfonylureas are nausea, vomiting, heartburn, diarrhea and headache. These symptoms usually are avoided if the drug is ingested with a meal.

Hypoglycemia may occur during first generation sulfonylurea therapy. Symptoms and signs include hunger, nausea, tiredness, perspiration, headache, heart palpitations, numbness around the mouth, tingling of the fingers, tremors, muscle weakness, blurred vision, sensation of cold, excessive yawning, irritability, confusion or loss of consciousness.

First generation sulfonylureas may cause weight gain, sun sensitivity (skin rash), and allergic-type skin-reactions such as itching and hives. Rarely, blood disorders occur, for example, low white cell counts or low red cell counts. Jaundice, hepatitis and a low blood sodium concentration, which can lead to retention of fluid and swelling of the body, rarely occur

Reference: FDA Prescribing Information

Suggested Reading by Our Doctors

• Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
• Diabetes - Learn about type 1 and 2 diabetes (Diabetes Mellitus) symptoms including increased urination, thirst, weight loss, fatigue, nausea, vomiting, skin infections, and blurred vision. Causes and diagnosis information is provided in the information.
• Drugs: What You Should Know About Your Drugs - Find out what you should know about your drugs such as side effects, warnings and precautions, storage information, and if a generic version is as good as the brand name.

Read more chlorpropamide related articles »

Latest Medical News

• Metformin vs. Sulfonylureas for Diabetes