Flagyl ER (Oral)

Metronidazole is used to treat bacterial infections in various parts of the body. It is also used to treat infections from protozoa (like trichomoniasis and amebiasis) and infections from bacteria that do not need oxygen to survive. The extended-release tablets are used to treat women with vaginal infections (bacterial vaginosis).

Metronidazole is part of a group of medicines called antibiotics. It works by killing bacteria or stopping their growth. However, this medicine will not work for colds, flu, or other viral infections.

This medicine is available only with your doctor's prescription.

It is important for your doctor to check your progress during regular visits to ensure the infection is gone. Blood tests may be necessary to monitor for side effects.

If your symptoms do not get better within a few days after starting this medicine or if they worsen, contact your doctor.

Do not take metronidazole if you have taken disulfiram (Antabuse®) in the last 2 weeks. Taking these medicines together may cause serious side effects.

Drinking alcohol while using this medicine can lead to stomach pain, nausea, vomiting, headache, or flushing or redness of the face. Other products that contain alcohol (for example, elixirs, cough syrups, tonics) may also cause issues. These effects may last for at least one day after stopping metronidazole. This medicine may also change how alcoholic drinks taste. You should not drink alcohol or use other alcohol-containing products while taking this medicine and for at least 3 days after stopping it.

If you have trichomoniasis: Using this medicine while pregnant (especially during the first 3 months) can harm your unborn baby. Use an effective form of birth control to prevent pregnancy. If you think you might be pregnant while using this medicine, inform your doctor immediately.

If you are being treated for trichomoniasis (an infection of the sex organs), your doctor may want to treat your sexual partner at the same time, even if they have no symptoms. It may also be advisable to use a condom during sex. These steps will help prevent getting the infection back from your partner. If you have questions about this, consult your doctor.

Contact your doctor immediately if you experience burning, numbness, tingling, or painful sensations in your arms, hands, legs, or feet. These could indicate a condition called peripheral neuropathy.

Reach out to your doctor right away if you have dizziness, trouble with muscle control or coordination, shakiness or an unsteady walk, slurred speech, or difficulty speaking. These may be signs of a serious brain condition called encephalopathy.

Call your doctor right away if you experience confusion, drowsiness, fever, a general feeling of being unwell, headache, loss of appetite, nausea, stiff neck or back, or vomiting. These may be symptoms of a serious condition known as aseptic meningitis.

This medicine can increase your risk of serious liver problems, which may be life-threatening. This risk is higher if you have Cockayne syndrome (a rare form of dwarfism). Contact your doctor immediately if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellowing of the eyes or skin.

Metronidazole may cause dry mouth, an unpleasant or sharp metallic taste, and changes in taste sensation. For temporary relief of dry mouth, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. If your mouth remains dry for more than 2 weeks, consult your doctor or dentist. Ongoing dry mouth may increase the risk of dental issues, including tooth decay, gum disease, and fungal infections.

Serious skin reactions can occur with this medicine. Contact your doctor immediately if you experience blistering, peeling, or loosening of the skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills while using this medicine.

Do not take other medicines without discussing them with your doctor. This includes prescription or over-the-counter (OTC) medicines and herbal or vitamin supplements.

In deciding to use a medicine, you and your doctor need to consider the risks against the benefits. For this medicine, keep the following in mind:

Allergies

Inform your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also, tell your healthcare professional about any other allergies, such as to foods, dyes, preservatives, or animals. For over-the-counter products, read the label or package ingredients carefully.

Pediatric

There have not been enough studies on how metronidazole capsules, oral liquid, and tablets affect children, except for treating amebiasis. Safety and effectiveness in children have not been established.

Studies have not shown any pediatric-specific issues that would limit the use of metronidazole extended-release tablets for treating bacterial vaginosis in teenage girls, but these should not be used before menstruation begins.

Geriatric

Studies have not found any geriatric-specific problems that would limit the use of metronidazole in older adults. However, older patients are more likely to experience side effects and liver issues related to age, which may require careful monitoring and possible dose adjustments.

Breast Feeding

There are not enough studies in women to determine the risk to infants when using this medication while breastfeeding. Consider the potential benefits and risks before taking this medication while nursing.

Interactions with Medicines

Some medicines should never be used together, while others may be used together with caution. If you are taking this medicine, it is crucial for your healthcare professional to know if you are taking any of the medicines listed below. The following interactions are important and are not necessarily a complete list.

Using this medicine with any of the following medicines is not recommended. Your doctor may choose not to prescribe this medication, or may need to adjust some of the other medicines you take.

• Amprenavir
• Bepridil
• Cisapride
• Disulfiram
• Dronabinol
• Dronedarone
• Levoketoconazole
• Mesoridazine
• Pimozide
• Saquinavir
• Sparfloxacin
• Terfenadine
• Thioridazine
• Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some cases. If both medicines are prescribed, your doctor may adjust the dose or frequency of use for one or both.

• Acenocoumarol
• Adagrasib
• Alfuzosin
• Amiodarone
• Amitriptyline
• Anagrelide
• Apomorphine
• Aripiprazole
• Aripiprazole Lauroxil
• Arsenic Trioxide
• Asenapine
• Astemizole
• Atazanavir
• Azithromycin
• Bedaquiline
• Buprenorphine
• Bupropion
• Buserelin
• Busulfan
• Capecitabine
• Ceritinib
• Chloroquine
• Chlorpromazine
• Cholera Vaccine, Live
• Cimetidine
• Ciprofloxacin
• Citalopram
• Clarithromycin
• Clofazimine
• Clomipramine
• Clothiapine
• Clozapine
• Crizotinib
• Cyclobenzaprine
• Dabrafenib
• Dasatinib
• Degarelix
• Delamanid
• Desipramine
• Deslorelin
• Deutetrabenazine
• Dexmedetomidine
• Disopyramide
• Dofetilide
• Dolasetron
• Domperidone
• Donepezil
• Doxepin
• Doxifluridine
• Droperidol
• Ebastine
• Efavirenz
• Encorafenib
• Entrectinib
• Eribulin
• Erythromycin
• Escitalopram
• Famotidine
• Felbamate
• Fexinidazole
• Fingolimod
• Flecainide
• Fluconazole
• Fluorouracil
• Fluoxetine
• Formoterol
• Foscarnet
• Fosphenytoin
• Galantamine
• Gatifloxacin
• Gemifloxacin
• Glasdegib
• Gonadorelin
• Goserelin
• Granisetron
• Halofantrine
• Haloperidol
• Histrelin
• Hydroquinidine
• Hydroxychloroquine
• Hydroxyzine
• Ibutilide
• Iloperidone
• Imipramine
• Inotuzumab Ozogamicin
• Itraconazole
• Ivabradine
• Ivosidenib
• Ketoconazole
• Lapatinib
• Leuprolide
• Levofloxacin
• Lithium
• Lofexidine
• Lumefantrine
• Macimorelin
• Mebendazole
• Mefloquine
• Methadone
• Methotrexate
• Methotrimeprazine
• Mifepristone
• Mizolastine
• Mobocertinib
• Moricizine
• Moxifloxacin
• Mycophenolate Mofetil
• Mycophenolic Acid
• Nafarelin
• Nelfinavir
• Nilotinib
• Norfloxacin
• Octreotide
• Ofloxacin
• Olanzapine
• Ondansetron
• Osimertinib
• Oxaliplatin
• Ozanimod
• Pacritinib
• Paliperidone
• Panobinostat
• Papaverine Hydrochloride
• Paroxetine
• Pasireotide
• Pazopanib
• Pentamidine
• Perphenazine
• Phenobarbital
• Phenprocoumon
• Phenytoin
• Pimavanserin
• Pipamperone
• Piperaquine
• Pitolisant
• Ponesimod
• Posaconazole
• Primidone
• Probucol
• Procainamide
• Prochlorperazine
• Promethazine
• Propafenone
• Protriptyline
• Quetiapine
• Quinidine
• Quinine
• Ranolazine
• Relugolix
• Ribociclib
• Risperidone
• Ritonavir
• Selpercatinib
• Sertindole
• Sertraline
• Sevoflurane
• Siponimod
• Sodium Phosphate
• Sodium Phosphate, Dibasic
• Sodium Phosphate, Monobasic
• Solifenacin
• Sorafenib
• Sotalol
• Sulpiride
• Sultopride
• Sunitinib
• Tacrolimus
• Tamoxifen
• Tegafur
• Telaprevir
• Telavancin
• Telithromycin
• Tetrabenazine
• Tolterodine
• Toremifene
• Trazodone
• Trimipramine
• Triptorelin
• Vandetanib
• Vardenafil
• Vemurafenib
• Venlafaxine
• Vilanterol
• Vinflunine
• Voclosporin
• Voriconazole
• Vorinostat
• Warfarin
• Zotepine
• Zuclopenthixol

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both may be the best option for you. If both medicines are prescribed together, your doctor may adjust the dose or how often you take one or both.

• Carbamazepine
• Cholestyramine
• Cyclosporine
• Milk Thistle

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be taken around the time of eating or with certain foods due to possible interactions. Using alcohol or tobacco with some medicines may also cause interactions. The following interactions are important and are not necessarily a complete list.

Using this medicine with any of the following is not recommended. Your doctor may choose not to prescribe this medication, change some of the other medicines you take, or give you special instructions regarding food, alcohol, or tobacco.

• Ethanol

Other Medical Problems

Other medical issues may affect how this medicine works. Be sure to tell your doctor about any other medical problems you have, especially:

• Blood or bone marrow problems, or history of or
• Brain disease (e.g., aseptic meningitis, encephalopathy) or
• Leukopenia (low white blood cells), history of or
• Optic neuropathy (eye disease with vision changes), history of or
• Oral thrush (Candida infection) or
• Peripheral neuropathy (nerve problem), history of or
• Seizures, history of or
• Vaginal yeast infection (Candida infection)—Use with caution. This may worsen these conditions.

• Cockayne syndrome (genetic disorder)—Should not be used in patients with this condition.

• Kidney disease, end-stage or
• Liver disease, severe—Use with caution. The effects may be stronger because the body removes the medicine more slowly.

Along with its needed effects, a medicine may cause some unwanted effects. Not all of these side effects may occur, but if they do, they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

• Agitation
• back pain
• blindness
• blurred vision
• burning, numbness, tingling, or painful sensations in the hands or feet
• changes in speech patterns
• confusion
• decreased vision
• depression
• dizziness
• drowsiness
• eye pain
• fever
• headache
• irritability
• lack of coordination
• nausea
• seeing or hearing things that are not there
• seizures
• shakiness and unsteady walk
• slurred speech
• stiff neck or back
• trouble speaking
• unsteadiness, trembling, or other problems with muscle control or coordination
• unusual tiredness or weakness
• vomiting
• weakness in the arms, hands, legs, or feet

Less common

• Black, tarry stools
• blood in the urine
• body aches or pain
• burning while urinating
• chills
• clumsiness or unsteadiness
• difficulty with breathing
• ear congestion
• fainting
• feeling of pelvic pressure
• frequent or painful urination
• irregular heartbeat
• loss of voice
• nasal congestion
• pinpoint red spots on the skin
• runny nose
• skin rash, hives, redness, itching
• sneezing
• stomach and back pain (severe)
• unusual bleeding or bruising
• vaginal irritation, discharge, or dryness not present before taking the medicine

Rare

• Bleeding gums
• bloating
• chest pain
• constipation
• cough
• dark urine
• fast heartbeat
• indigestion
• loss of appetite
• painful or difficult urination
• pains in the stomach, side, or abdomen, possibly radiating to the back
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swollen glands
• yellow eyes or skin

Incidence not known

• Blistering, peeling, or loosening of the skin
• bloody or cloudy urine
• burning while urinating
• continuing diarrhea
• continuing stomach pain
• diarrhea
• feeling of warmth
• increased volume of pale, dilute urine
• joint or muscle pain
• loss of bladder control
• red skin lesions, often with a purple center
• red, irritated eyes
• redness of the face, neck, arms, and occasionally, upper chest
• redness of the skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Dizziness or lightheadedness
• feeling of constant movement of self or surroundings
• heartburn
• sensation of spinning
• stomach cramps
• trouble sleeping
• weight loss

Rare

• Change in taste sensation
• congestion
• dry mouth
• pain or tenderness around the eyes and cheekbones
• tender, swollen glands in the neck
• trouble with swallowing
• unpleasant or sharp metallic taste
• voice changes

Incidence not known

• Decreased interest in sexual intercourse
• inability to have or keep an erection
• loss in sexual ability, desire, drive, or performance
• painful sexual intercourse

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

In the U.S.

• Flagyl
• Flagyl ER
• Likmez

Available Dosage Forms:

• Tablet
• Capsule
• Powder for Suspension

Therapeutic Class: Antibiotic

Chemical Class: Nitroimidazole

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine comes with a patient information leaflet. Read and follow the instructions carefully. Ask your doctor if you have any questions.

The capsules can be taken with or without food. If the medicine upsets your stomach, it is best to take it with a meal or snack.

The extended–release tablet must be taken without food, 1 hour before or 2 hours after a meal.

Swallow the extended-release tablet whole. Do not break, crush, or chew it.

To use the suspension: Shake the bottle well before using. Measure the oral liquid medicine with a marked oral syringe or medicine cup. Do not use a household measuring cup.

To help clear up your infection completely, keep using this medicine for the full time of treatment, even if you begin to feel better after a few days. If you stop using this medicine too soon, your infection may return.

This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times during the day. If you need help planning the best times to take your medicine, check with your doctor.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage forms (capsules or tablets): For amebiasis: Adults— For acute intestinal amebiasis: 750 milligrams (mg) 3 times a day for 5 to 10 days. For amebic liver abscess: 500 to 750 mg 3 times a day for 5 to 10 days. Children—Dose is based on body weight and must be determined by your doctor. The dose is usually 35 to 50 milligrams per kilogram of body weight (mg/kg) per day, divided into 3 doses, for 10 days. For bacterial infections: Adults—Dose is based on body weight and must be determined by your doctor. The dose is usually 7.5 milligrams per kilogram of body weight (mg/kg) every 6 hours for 7 to 10 days. Your doctor may increase your dose as needed. However, the dose is usually not more than 4 grams (g) per day. Children—Use and dose must be determined by your doctor. For trichomoniasis infections: Adults— Capsule: 375 milligrams (mg) 2 times a day for 7 days. Tablet: One-day treatment: 2 grams (g) given as a single dose or 1 g given in 2 doses per day. 7-day course treatment: 250 mg 3 times a day for 7 days. Children—Use and dose must be determined by your doctor.
• For oral dosage form (extended-release tablets):For bacterial vaginosis: Adults—750 milligrams (mg) once a day for 7 days. Children—Use and dose must be determined by your doctor.
• For oral dosage form (suspension): For amebiasis: Adults— For acute intestinal amebiasis: 750 milligrams (mg) or 7.5 milliliters (mL) 3 times a day for 5 to 10 days. For amebic liver abscess: 500 to 750 mg or 5 to 7.5 mL 3 times a day for 5 to 10 days. Children—Dose is based on body weight and must be determined by your doctor. The dose is usually 35 to 50 milligrams per kilogram of body weight (mg/kg) per day, divided into 3 doses, for 10 days. However, the dose is usually not more than 2250 mg per day. For bacterial infections: Adults—Dose is based on body weight and must be determined by your doctor. The dose is usually 7.5 milligrams per kilogram of body weight (mg/kg) every 6 hours for 7 to 10 days. However, the dose is usually not more than 4 grams or 40 mL per day. Children—Use and dose must be determined by your doctor. For trichomoniasis: Adults— One-day treatment: 2 grams (g) or 20 milliliters (mL) given as a single dose or 1 g or 10 mL given in 2 divided doses per day. 7-day course treatment: 250 milligrams (mg) or 2.5 milliliters (mL) 3 times a day for 7 days. Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

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