Glipizide is the generic name for Glucotrol. Glucotrol is a diabetes medication that belongs to the class of drugs called sulfonylurea. It is available in 5mg and 10mg tablets. This medication was approved by the FDA in 1984 for the treatment of type 2 diabetes. It is supposed to be used in addition to exercise and diabetic diet.

Only a doctor or prescribing clinician can prescribe this medication. The doctor usually starts with a minimum dose. The starting dose for most patients is 5 mg every day before breakfast. The patients with liver problem may be started at 2.5mg. If a patient needs about 15mg or above of this medication, it should be divided into two doses, 30 minute before breakfast and 30 minutes before dinner. It is recommended that the total daily dose does not exceed 40mg. Blood glucose is checked several times a day during the introductory period to monitor the effectiveness of the medication and any need to increase dose. The doctor adjusts the dose accordingly until and effective dose is reached. Sometimes, a patient may not get blood sugar lowered, even at higher dose of this medication and this is called primary failure. In that instance, the doctor may stop using it for this patient.

How Glipizide works

Glucotrol works by causing the beta islet cells of the pancreas to release insulin. The insulin released is then used by the body to move glucose to the right places, that is, muscle, fat and liver for storage and then lower blood sugar. The beta islet cells of the pancreas have to be working for this diabetic medicine to work. If the beta islet cells are not working, as happens in type 1 diabetes, Glucotrol will not be able to work. 

Glucotrol tends to release more insulin after a person eats while keeping the fasting glucose level normal in many cases. This is good because it helps to reduce the incidence of hypoglycemia or low blood sugar because the insulin is not too much when a person is fasting.

This medication is absorbed faster when taken in an empty stomach, than when taken with food. It starts to work about 30 minutes after it is administered. It is recommended to take it about 30 minutes before a meal. It can work for up to 24 hours.

Glucotrol, like most sulfonylurea drugs, may stop working after some years of use. This occurrence in which a drug that had previously worked for a patient stops working anymore is called secondary failure.

Glucotrol is broken down by the liver, but those products produced by the breakdown or any parts of the medicine that did not get broken down are removed in urine by the kidney.

How to Use Glipizide

Take this diabetic medicine by mouth.

Take Glucotrol 30 minutes before meals as ordered. If it is once a day, take it thirty minutes before breakfast. If a second dose is ordered, take that 30 minutes before dinner.

Be familiar with the signs and symptoms of hypoglycemia or low blood sugar.

Patients should be checked regularly for evidence of cardiovascular complications.

Adverse Reactions of Glucotrol

There many adverse reactions or glipizide side effects. Some of them are mild and may be temporary and should not make the patient to stop taking this medication. However, some are serious and may persist over time and should cause the patient to stop taking the medication. The patient should therefore report all adverse reactions and side effects of glipizide to their physician immediately.

Below is a list of adverse reactions:

  • Hypoglycemia or low blood glucose can occur because of excess insulin release by the pancreas, caused by Glucotrol. Hypoglycemia can be made worse by the concurrent use of other medications that lower blood sugar, not eating enough, taking alcohol or excessive exercise.
  • Nausea
  • Diarrhea
  • Constipation
  • Abdominal pain
  • Jaundice – This is rare but serious side effect. This medication should be stopped and the doctor informed if it occurs.
  • Decreased white blood cells, which may be severe.
  • Anemia, or decreased red blood cells.
  • Total reduction in blood components, like red blood cells, white blood cells and platelets. When platelets are reduced, there will be problem with blood clothing.
  • This and other sulfonylureas can react with alcohol to produce an effect that resembles Antabuse or disulfiram. This is rare.
  • Allergic reactions include redness of the skin, rash, itch, and eczema and sensitiveness to sunlight. If these do not stop after some days, the patient should stop using glipizide.
  • Decrease in body sodium which can cause dehydration because sodium is needed to hold water in the body.
  • Syndrome of inappropriate antidiuretic hormone (SIADH), which can also cause dehydration.
  • Headache
  • Drowsiness
  • Dizziness


Glucotrol and all sulfonylurea medications now have a boxed warning. This is because research has shown that people who use this class of drugs are more likely to die of cardiovascular complications than those patients who use insulin, or just diabetic diet and exercise to control diabetes.

Do not

  • Do not use to manage type 1 diabetes mellitus because there is no insulin available in the pancreas to be released.
  • Do not fast while on Glucotrol because may result in severe hypoglycemia.
  • Maintain regular exercise, but do not exercise excessively as this can result in hypoglycemia in people who take Glucotrol.
  • Do not use this and other sulfonylurea medications to manage diabetic ketoacidosis or diabetic non-ketotic coma. IV rapid-acting or short-acting insulin should be used for those in a hospital setting.
  • Do not use in pediatric patients because its safety in children has not been proved.
  • Do not use in patients who are allergic to Glucotrol or any derivative of sulfonamides. Those who are allergic to any of the inactive ingredients Glucotrol should not take this medication. The inactive ingredients are silicone dioxide, lactose, cellulose, starch and stearic acid.
  • Do not take Glucotrol while fasting.
  • Do not use this diabetic medicine for gestational diabetes unless the doctor decides otherwise.

Glipizide Drug Interactions

  • Some drugs can increase the glucose lowering effects of Glucotrol and that can result in hypoglycemia. These drugs include aspirin, Chloramphenicol, NSAID like ibuprofen, Coumadin, MOAI drugs, Probenecid, beta blockers and others.
  • Beta blockers may cover up the symptoms of hypoglycemia in people who are also taking Glucotrol.
  • Some drugs decrease the glucose lowering effect of glipizide and may result in hyperglycemia. Some of these drugs are those that raise blood glucose. They include steroids like prednisone, thyroid medications like Synthroid, Dilantin, calcium channel blockers, diuretics, nicotinic acid, isoniazid, oral contraceptives and others.
  • Glucotrol interacts with oral miconazole to produce hypoglycemia which can be severe. This is because miconazole causes increase in the blood concentration of glipizide. Patients who have to take miconazole should have their Glucotrol doses reduced and blood sugar closely monitored.

Special Considerations in the Use of Glipizide

  • Use with caution in patients with liver problems because Glucotrol is broken down by the liver.
  • Use with caution in patients with kidney problems because this drug is eliminated from the body by the kidney in urine.
  • Liver and/or kidney problems can cause high blood levels of glipizide and also lower the ability of the liver to release glucose to the blood causing severe hypoglycemia.
  • If a liver and/or kidney problem causes a patient on glipizide to go into hypoglycemia, be prepared to treat the hypoglycemia for a long period because it may be prolonged because the drug will be present in the blood for a long time.
  • Use with caution in elderly patients and those with adrenal or pituitary problems. These patients are more prone to hypoglycemia while on Glucotrol.
  • When used in combination with insulin or any other drug that lowers glucose, the dose of insulin or that other drug should be lowered.
  • Be cautious with alcohol intake while on glipizide as alcohol can cause hypoglycemia in people taking glipizide.
  • When patients on Glucotrol are sick with infection or surgery, or other sickness that causes reduced activity, Glucotrol may temporarily lose its ability to control blood glucose. In such instance, subcutaneous insulin may be used until the sickness resolves.
  • Be aware of possibility of secondary failure, which is when the drug stops working after some years of effective use.
  • Use with caution in patients with Glucose-6-Phosphate dehydrogenase (G6PD) deficiency, because of risk of hemolytic anemia in this population of patients
  • Glucotrol should not be used in pregnant women. In any event that it is used in pregnancy, it should be discontinued about one month before the baby is born because of risk of severe hypoglycemia to the new baby.
  • Use with caution in breastfeeding mothers as this diabetic medicine, like other sulfonylureas, may be released into human milk. Consider using insulin, instead of Glucotrol while breast-feeding.
  • Use with caution in elderly patients because this population is more likely to have liver, kidney or heart disease.

Glipizide overdose

Overdose of Glucotrol can result in hypoglycemia or low blood sugar. Patients in hypoglycemia who are conscious should be given foods that provide quick release of glucose to the blood, like glucose tablets, orange juice, skim milk or regular sugar. Patients who are unconscious should be referred to emergency personnel by calling the appropriate emergency number or taken to the nearest emergency room. Patients in hypoglycemia who are unconscious are usually treated with IV fluid with 50% concentration of glucose, glucagon or both. 10% glucose IV may be given after the initial 50% dose, if the overdose and the resulting hypoglycemia are expected to be prolonged. Patients should be monitored for some time after hypoglycemia and treatment continued until hypoglycemia is completely resolved. It may take 24 to 48 hours for the patient to be out of danger of hypoglycemia.

Lab Tests

Patients on glipizide should monitor their blood glucose or urine glucose as directed by their doctor. Hemoglobin A1C should be checked every three months or as directed by the doctor.

Return from Glipizide to diabetes

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