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Flagyl is an antibiotic utilized to combat various infections stemming from bacteria and other microorganisms. Flagyl is particularly effective against anaerobic bacteria, which are bacteria that do not require oxygen to survive. Flagyl is also active against certain parasites, including Trichomonas vaginalis.

Some common side effects of generic Flagyl include nausea, vomiting, diarrhea, and stomach pain. Other potential side effects may include loss of appetite, headache, dizziness, and weakness. In rare cases, Flagyl may cause more serious side effects such as allergic reactions, changes in blood cell counts, and liver damage.

Price in Canada

The cost of Flagyl in Canada can differ according to whether one opts for the brand-name or the generic form. Flagyl is a medication that is available in both brand-name and generic form. The brand-name version is made by Pfizer and tends to be more expensive than the generic version. The cost of brand-name Flagyl can vary based on the dosage and quantity prescribed. For example, a package of 14 500mg tablets may cost around $20.

On the other hand, the generic version of Flagyl is usually much less expensive than the brand-name version. Generic medications are made by pharmaceutical companies other than the original manufacturer and are designed to be chemically equivalent to the brand-name medication. The price of generic Flagyl may vary depending on the manufacturer and the pharmacy where you purchase it, but it is usually significantly cheaper than the brand-name version. For example, a package of 14 500mg tablets may cost around $5.

It’s important to note that the price of Flagyl can also vary depending on your insurance coverage. Some insurance plans may cover the cost of Flagyl, either partially or fully, while others may not cover it at all. If you have insurance, it’s a good idea to check with your insurance provider to see what your coverage is for Flagyl.

Indications of Flagyl Generic

Flagyl (metronidazole) is a medication that treats infections caused by bacteria and other microorganisms. It is particularly effective against anaerobic bacteria, which are bacteria that do not require oxygen to survive. Flagyl is also active against certain parasites, including Trichomonas vaginalis. Below, we will review the various indications for Flagyl.

  • A parasitic infection caused by the organism Entamoeba histolytica.
  • Intra-Abdominal Infections. Infections that occur within the abdomen and can be caused by bacteria or other microorganisms. If left untreated, these infections can lead to serious complications.
  • Skin and Skin Structure Infections. Flagyl may be used to treat certain types of infections affecting the skin and surrounding tissues, including abscesses, cellulitis, and wound infections.
  • Gynecologic Infections. Flagyl may be used to treat certain gynecologic infections, such as bacterial vaginosis and pelvic inflammatory disease.
  • Bacterial Septicemia. A serious infection that occurs when bacteria enter the bloodstream and spread throughout the body. This condition, also known as sepsis, can lead to organ damage and can be life-threatening if not treated promptly.
  • Bone and Joint Infections. Flagyl may be used to treat certain types of infections affecting the bones and joints, such as osteomyelitis.
  • Central Nervous System Infections. Flagyl may be used to treat certain types of infections in the central nervous system, including meningitis and brain abscesses.
  • Lower Respiratory Tract Infections. Flagyl may be used to treat certain types of infections affecting the lower respiratory tract, such as pneumonia.
  • Symptomatic Trichomoniasis. Trichomoniasis is an STI caused by the parasite Trichomonas vaginalis. Symptoms can include itching and burning in women, and discharge from the penis, burning after urination or ejaculation, and itching in men. Flagyl is a commonly prescribed medication for the treatment of symptomatic trichomoniasis in both men and women.
  • Asymptomatic Trichomoniasis. In some cases, an individual may be infected with Trichomonas vaginalis but not experience any symptoms. This is known as asymptomatic trichomoniasis. Flagyl may be prescribed for individuals with asymptomatic trichomoniasis to prevent the transmission of the infection to sexual partners and reduce the risk of complications.

Dosage and Administration

Flagyl is available in several forms, including tablets, capsules, and a suspension for oral use, as well as a cream for external use. In this article, we will review the dosage and administration guidelines for Flagyl, including specific recommendations for the treatment of trichomoniasis, amebiasis, and anaerobic bacterial infections. We will also discuss dosage adjustments that may be necessary for patients with severe hepatic impairment or those undergoing hemodialysis.


For the treatment of trichomoniasis, the recommended adult dosage of Flagyl is 2 grams orally as a single dose. This can be administered as either a single 2-gram tablet or capsule, or as two 1-gram tablets or capsules taken at the same time.


For the treatment of amebiasis, the recommended adult dosage of Flagyl is 750 mg. In children, the dosage is 35 to 50 mg/kg/day, with a maximum daily dose of 1 gram.

Dosage Adjustments

In certain situations, the dosage of Flagyl may need to be adjusted to ensure the safe and effective use of the medication.

  • Severe Hepatic Impairment. The dosage of Flagyl should be reduced to avoid the risk of neurotoxicity. The recommended adult dosage is 250 mg, with a maximum daily dose of 750 mg.
  • Hemodialysis. The dosage of Flagyl should be adjusted to account for the decreased clearance of the medication. The recommended adult dosage is 500 mg orally after each hemodialysis session.

It is important to follow the instructions of your healthcare provider when taking Flagyl and to take the medication exactly as prescribed. Do not alter the dosage or frequency of the medication without first consulting your healthcare provider.

Drug Interactions

It is important to be aware of potential drug interactions with Flagyl as they can affect the effectiveness of the medication or cause adverse effects. The following are some notable drug interactions to be aware of when taking Flagyl.

  • Disulfiram. Disulfiram can interact with Flagyl and cause severe reactions when combined. Symptoms may include vomiting, dyspepsia, headache, flushing, and shortness of breath. It is important to avoid drinking alcohol while taking Flagyl, as this can also cause similar reactions.
  • Alcoholic Beverages. As mentioned, it is important to avoid consuming alcoholic beverages while taking Flagyl. This includes drinks with small amounts of alcohol, such as wine or beer, as they can cause the same reactions as disulfiram.
  • Warfarin and Other Oral Anticoagulants. Flagyl may increase the effect of warfarin and other oral anticoagulants, increasing the risk of bleeding. It is important to monitor bleeding risk and adjust warfarin dosage as necessary when taking Flagyl.
  • Lithium. Flagyl may increase the levels of lithium in the body. Close monitoring of lithium levels is necessary when taking these medications together.
  • Busulfan. Combining Flagyl with busulfan may increase the risk of bone marrow suppression. Close monitoring is necessary when taking these medications together.
  • Drugs That Inhibit CYP450 Enzymes. Flagyl is metabolized by CYP450 enzymes in the liver. Certain medications that inhibit these enzymes, such as ciprofloxacin and norfloxacin, may increase the levels of Flagyl in the body, increasing the risk of adverse effects.
  • Drugs That Induce CYP450 Enzymes. On the other hand, medications that induce CYP450 enzymes, such as rifampin and phenobarbital, may decrease the levels of Flagyl in the body, potentially reducing its effectiveness.
  • Drugs That Prolong the QT interval. Flagyl may prolong the QT interval, a measure of the time it takes for the heart to contract and relax. Combining Flagyl with other medications that also prolong the QT interval, such as certain antidepressants and antiarrhythmic medications, may increase the risk of dangerous heart rhythms. Close monitoring is necessary when taking these medications together.

Flagyl Warnings

Metronidazole (Flagyl) can have effects on the nervous system. These effects can include encephalopathy, a condition characterized by ataxia, dizziness, and dysarthria, as well as peripheral neuropathy, which is characterized by numbness or tingling in the extremities. In some cases, these conditions have been reversible after discontinuing metronidazole therapy.

Cases of aseptic meningitis have also been reported with metronidazole. Symptoms of aseptic meningitis may appear within hours of taking the medication and generally resolve after stopping the treatment.

Convulsive seizures have also been reported in patients taking metronidazole. It is important to quickly determine the benefit to risk ratio of continuing therapy if abnormal neurologic signs and symptoms occur.

Overdose & Contraindications

While Flagyl is generally safe and effective when taken as directed, it is important to be aware of the potential risks and side effects of this medication, including the possibility of overdose and contraindications.


Taking too much Flagyl can lead to serious and potentially life-threatening side effects. Symptoms of Flagyl overdose may include nausea, vomiting, stomach pain, loss of appetite, dizziness, drowsiness, and seizures.

  • Treatment of Overdose. If you or someone you know has taken an overdose of Flagyl, it is important to seek medical attention immediately. Treatment may involve supportive care, such as administering fluids and electrolytes to help restore balance to the body. In severe cases, the stomach may need to be emptied through induced vomiting or by using a procedure called gastric lavage.


There are certain conditions and situations in which Flagyl should not be used due to the risk of serious side effects or interactions with other medications.

  • Hypersensitivity. Flagyl should not be used in people who have a known hypersensitivity or allergy to metronidazole or any of the other ingredients in the medication.
  • Psychotic Reaction with Disulfiram. Flagyl should also not be used in combination with the medication disulfiram (Antabuse), as it may cause a severe and potentially life-threatening psychotic reaction.
  • Interaction with Alcohol. Flagyl should not be taken with alcohol, as it may cause a reaction that can result in severe nausea, vomiting, flushing, and headache.
  • Cockayne Syndrome. Flagyl should be used with caution in people with Cockayne syndrome, a rare genetic disorder that affects the body’s ability to repair DNA. Long-term use of Flagyl may increase the risk of serious side effects in people with this condition.


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