How does this medication work? What will it do for me?

Gliclazide belongs to the class of medications known as oral hypoglycemics. It is used for the control of blood glucose in people with type 2 diabetes. It is used when diet, exercise, and weight reduction have not been found to control blood glucose well enough without medication. Gliclazide increases the amount of insulin released by the pancreas and helps the body use insulin more efficiently.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

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What form(s) does this medication come in?

Each white, bevelled-edged, round tablet, marked with "GZ" over "80" on one side and cross-scored on the other, contains gliclazide 80 mg. Nonmedicinal ingredients: lactose, magnesium stearate, microcrystalline cellulose, povidone, sodium starch glycolate, and talc.

How should I use this medication?

The recommended dose of gliclazide ranges from 80 mg to 320 mg daily. Doses of 160 mg and above should be taken in two equally divided doses. Gliclazide should be taken with meals if possible. The daily dose should not exceed 320 mg.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

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Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to gliclazide or any ingredients of the medication
  • are allergic to other sulfonylureas (such as glyburide) or sulfonamides (such as sulfamethoxazole)
  • are pregnant or breast-feeding
  • are taking some forms of miconazole (ask your doctor or pharmacist for details)
  • are undergoing surgery or have suffered from recent severe trauma
  • have a serious infection
  • have severely reduced kidney or liver function
  • have type 1 diabetes
  • have unstable diabetes or ketoacidosis (high ketones in urine)
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What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • back, muscle, or joint pain
  • constipation
  • diarrhea
  • dizziness
  • headache
  • heartburn
  • increased skin sensitivity to sun
  • nausea
  • vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • skin rash or hives
  • swelling of the legs symptoms caused by low blood sugar:
    • anxiousness
    • blurred vision
    • cold sweats
    • confusion
    • difficulty concentrating
    • drowsiness
    • fast heart rate
    • feeling drunk
    • headache
    • hunger
    • nausea
    • nervousness
    • nightmares
    • shakiness
    • slurred speech
    • unusual tiredness
  • signs of  liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • unexpected weight gain

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • chest pain or pressure and/or shortness of breath
  • seizures
  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
  • signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
  • unconsciousness

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

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Are there any other precautions or warnings for this medication?

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take this medication.

Alcohol use: Gliclazide can cause an unpleasant "intolerance reaction" to alcohol. People taking gliclazide may experience flushing, warmth, nausea, giddiness, and possibly increased heart rate when they use alcohol. To prevent this reaction, avoid drinking alcohol.

Anemia: If you have a condition called glucose-6-phosphate dehydrogenase (G6PD) deficiency, gliclazide may cause hemolytic anemia (an abnormal breakdown of red blood cells). If you have G6PD deficiency, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Diabetes complications: Similar to other medications for diabetes, the use of gliclazide will not prevent the development of complications of diabetes.

Hypoglycemia (low blood sugar): Gliclazide, like other sulfonylurea drugs, can cause symptoms of hypoglycemia (low blood sugar) including dizziness, lack of energy, drowsiness, headache, and sweating have been observed. Weakness, nervousness, shakiness, and numbness or tingling have also been reported. Severe hypoglycemia can result from taking any of the sulfonylurea drugs. Seniors, those with reduced liver or kidney function, and those who are fragile or malnourished are more likely to have low blood sugar with these drugs. Low blood sugar is more likely to occur when food intake is inadequate or after strenuous or prolonged physical exercise. Monitor your blood glucose regularly and keep an emergency glucose (and glucagon kit) available in case you need to increase your blood sugar levels.

Illness/stress: People on gliclazide therapy may experience loss of blood sugar control during illness or stressful situations such as trauma or surgery. Under these conditions, your doctor may consider stopping the drug and prescribing insulin until the situation improves.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Gliclazide may reduce liver function. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Proper diet: The use of gliclazide must be considered as treatment in addition to proper diet and not as a substitute for diet.

Worsening of condition: Over time, gliclazide may become less effective because of your diabetes worsening. If gliclazide no longer controls blood glucose to target levels, it should be stopped and another medication added. Talk to your doctor if you find that your blood sugar levels are not controlled.

Pregnancy: Gliclazide may cause harm to the developing baby if it is taken by the mother during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if gliclazide passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

Seniors: Seniors may be more likely to experience side effects of this medication, particularly low blood sugar.

What other drugs could interact with this medication?

There may be an interaction between gliclazide and any of the following:

  • abiraterone
  • acetylsalicylic acid (ASA)
  • ACE inhibitors (e.g., enalapril)
  • alcohol
  • amiodarone
  • aprepitant
  • angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
  • "azole" antifungal medications (e.g., fluconazole, miconazole, voriconazole)
  • barbiturates (e.g., phenobarbital, thiopental)
  • beta-blockers (e.g., metoprolol, propranolol)
  • bosentan
  • buserelin
  • capecitabine
  • carbamazepine
  • inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
  • oral corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
  • cyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • cyclosporine
  • dabrafenib
  • danazol
  • other diabetes medications (e.g., chlorpropamide, glipizide, glyburide, insulin, metformin, nateglinide, rosiglitazone)
  • diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
  • exenatide
  • fenofibric acid
  • fluorouracil
  • fluvastatin
  • fosphenytoin
  • gemfibrozil
  • goserelin
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delaviridine, efavirenz, etravirine, nevirapine)
  • H2 receptor antagonists (e.g., ranitidine, famotidine, cimetidine)
  • leflunomide
  • leuprolide
  • methyltestosterone
  • mifepristone
  • milk thistle
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
  • nandrolone
  • nilotinib
  • nonsteroidal anti-inflammatory drugs (e.g., ibuprofen, naproxen)
  • octreotide
  • omeprazole
  • oral contraceptives
  • peginterferon Alfa-2b
  • phenytoin
  • porfimer
  • primidone
  • probenecid
  • pyrimethamine
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
  • rifampin
  • rifapentine
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
  • somatropin
  • sorafenib
  • antibiotics ("sulfas"; e.g., sulfisoxazole, sulfamethoxazole)
  • testosterone
  • ticagrelor
  • trimethoprim
  • triptorelin
  • warfarin
  • zafirlukast

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.