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Flagyl IV Side Effects

Generic Name: metronidazole

Note: This page contains information about the side effects of metronidazole. Some of the dosage forms included on this document may not apply to the brand name Flagyl IV.

For the Consumer

Applies to metronidazole: oral capsule, oral powder for suspension, oral suspension, oral tablet, oral tablet extended release

In addition to its needed effects, some unwanted effects may be caused by metronidazole (the active ingredient contained in Flagyl IV). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking metronidazole:

More common:
  • Agitation
  • back pain
  • blindness
  • blurred vision
  • burning, numbness, tingling, or painful sensations in the hands or feet
  • changes in speech patterns
  • confusion
  • convulsions
  • decreased vision
  • depression
  • dizziness
  • drowsiness
  • eye pain
  • fever
  • hallucinations
  • headache
  • irritability
  • lack of coordination
  • nausea
  • 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 or stools
  • body aches or pain
  • chills
  • clumsiness or unsteadiness
  • difficulty with breathing
  • ear congestion
  • feeling of pelvic pressure
  • frequent or painful urination
  • loss of voice
  • nasal congestion
  • pinpoint red spots on the skin
  • runny nose
  • skin rash, hives, redness, or 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-colored 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

Minor Side Effects

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

More common:
  • Abdominal or stomach cramps
  • dizziness or lightheadedness
  • feeling of constant movement of self or surroundings
  • heartburn
  • sensation of spinning
  • trouble sleeping
  • weight loss
Less common or 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

For Healthcare Professionals

Applies to metronidazole: compounding powder, intravenous powder for injection, intravenous solution, oral capsule, oral suspension, oral tablet, oral tablet extended release

General

The most serious side effects reported were convulsive seizures, encephalopathy, aseptic meningitis, and optic and peripheral neuropathy (characterized by numbness or paresthesia of an extremity).[Ref]

Nervous system

Very common (10% or more): Headache (up to 18%)
Common (1% to 10%): Taste metallic, dizziness
Rare (0.01% to 0.1%): Drowsiness, ataxia, peripheral neuropathy, transient epileptiform seizure, encephalopathy
Very rare (less than 0.01%): Acute cerebellar syndrome, paralysis, dysarthria, gait impaired, nystagmus, tremor, convulsion, incoordination
Frequency not reported: Convulsive seizure, headache, syncope, paresthesia, optic neuritis, peripheral sensory neuropathy[Ref]

Gastrointestinal

Very common (10% or more): Nausea (up to 10%)
Common (1% to 10%): Abdominal pain, diarrhea, dry mouth, vomiting, stomatitis, glossitis
Rare (less than 0.1%): Pancreatitis, mucositis, epigastralgia
Frequency not reported: Epigastric pain/distress, abdominal cramping, constipation, furry tongue, glossitis, stomatitis, oral mucositis, taste disorder, dyspepsia, pseudomembranous colitis, tongue discolored[Ref]

Genitourinary

Very common (10% or more): Vaginitis (15%)
Common (1% to 10%): Pruritus genital, urine abnormal, dysmenorrhea, moniliasis, urinary tract infection
Rare (less than 0.1%): Darkened urine
Frequency not reported: Vaginal dryness, vulva dryness, dysuria, polyuria, incontinence, pelvic pressure, cystitis, candida infection proliferated, dyspareunia, procitiits, pyuria[Ref]

Other

Common (1% to 10%): Bacterial infection, influenza-like symptoms, weakness
Rare (less than 0.1%): Fever, aseptic meningitis
Frequency not reported: Vertigo, tinnitus, hearing impaired, hearing loss, sensorineural hearing loss, overgrowth of Candida, disulfiram-like reaction[Ref]

Respiratory

Common (1% to 10%): Upper respiratory tract infection, rhinitis, sinusitis, pharyngitis
Frequency not reported: Nasal congestion, hiccup[Ref]

Hematologic

Uncommon (0.1% to 1%): Leukopenia
Rare (less than 0.1%): Neutropenia, neutropenia reversible, thrombocytopenia, pancytopenia, agranulocytosis, blood dyscrasia
Frequency not reported: Bone marrow aplasia, bone marrow depression[Ref]

Cardiovascular

Frequency not reported: Flat T-wave, flushing, QT interval prolonged[Ref]

Dermatologic

Common (1% to 10%): Pruritus
Rare (0.01% to 0.1%): Stevens-Johnson Syndrome, toxic epidermal necrolysis, skin rash, erythema multiforme, pustulosis, Quincke edema
Very rare (less than 0.01%): Fixed drug eruption
Frequency not reported: Erythematosus rash, pruritus, urticaria, mild erythematous eruption, pustular eruption, angioedema[Ref]

Local

Frequency not reported: Thrombophlebitis[Ref]

Psychiatric

Very rare (less than 0.01%): Confusion, hallucination, psychotic disorder
Frequency not reported: Irritability, depression, insomnia, libido decreased, psychosis, disorientation, psychotic reaction, depressed mood[Ref]

Ocular

Rare (0.01% to 0.1%): Optic neuropathy, diplopia, myopia
Very rare (less than 0.01%): Light sensitivity, vision disorder
Frequency not reported: Vision blurred, visual acuity decreased, color vision change[Ref]

Metabolic

Rare (less than 0.1%): Anorexia[Ref]

Musculoskeletal

Common (1% to 10%): Myalgia
Very rare (less than 0.01%): Stiff neck, arthralgia
Frequency not reported: Fleeting joint pain[Ref]

Oncologic

Frequency not reported: Breast cancer, colon cancer[Ref]

Hepatic

Rare (0.01% to 0.1%): Cholestatic hepatitis, liver function test abnormal
Very rare (less than 0.01%): Mixed hepatitis, hepatocellular injury, jaundice, liver failure, liver transplant
Frequency not reported: Drug-induced hepatitis, liver enzymes increased[Ref]

Immunologic

Rare (less than 0.1%): Anaphylaxis, anaphylactic shock, Herxheimer reaction
Frequency not reported: Reaction serum sickness-like, hypersensitivity reaction[Ref]

References

1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. "Product Information. Flagyl (metronidazole)." Searle, Skokie, IL.

3. Cerner Multum, Inc. "Australian Product Information." O 0

Not all side effects for Flagyl IV may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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