II. Indications
- Conditions
- Anaerobic Infections
- Intraabdominal Infections (e.g. Diverticulitis)
- Pelvic Inflammatory Disease
- Bacterial Vaginosis
- Helicobacter Pylori
- Trichomoniasis
- Amebiasis
- Giardiasis
- Pseudomembranous colitis (Clostridioides difficile)
- Organisms
III. Contraindications
- Cockayne Syndrome
- Risk of lethal hepatotoxicity with Metronidazole
IV. Mechanism
- Nitroimidazole Antibiotic (includes tindazole, secnidazole)
- Inhibits Protein synthesis in susceptible organisms by disrupting DNA helix, resulting in DNA breakage
V. Medications
- Metronidazole Systemic
- Intravenous Solution
- Tablets: 250, 375 and 500 mg
- Extended Release: 750 mg
- Metronidazole Topical (e.g. Metrogel): 1% and 0.75% gels, creams and lotions
- See Roseacea
- Metronidazole Vaginal (e.g. Metrogel Vaginal): 0.75% gel
- A 1.3% gel is also available (Nuvessa)
- See Bacterial Vaginosis
VI. Dosing: Adult
- See Helicobacter Pylori
- See Bacterial Vaginosis
- See Diverticulitis
- See Pelvic Inflammatory Disease
- See Amoeba Histolytica Dysentery and Amebic Liver Abscess
- See Pseudomembranous colitis (Clostridioides difficile)
- Taking with food decreases gastric irritation
- Anaerobic Bacterial Infection
- Intravenous (administer each IV dose over 1 hour)
- Loading dose: 15 mg/kg up to 1000 mg IV
- Maintenance dose: 7.5 mg/kg up to 500 mg IV every 6 to 8 hours
- Oral
- Take 250 to 750 mg orally three to four times daily
- Intravenous (administer each IV dose over 1 hour)
VII. Dosing: Child
- See Amoeba Histolytica Dysentery and Amebic Liver Abscess
- Taking with food decreases gastric irritation
- Anaerobic Bacterial Infection
- Intravenous (administer each IV dose over 1 hour)
- Load: Metronidazole 15 mg/kg IV (up to 1000 mg) over 1 hour
- Maintenance: Metronidazole 7.5 mg/kg/dose (up to 500 mg/dose) IV every 8 hours
- Decrease dosing interval to every 12 hours in age <1 week old
- Oral
- Give 7.5 to 12.5 mg/kg/dose (up to 500 to 750 mg/dose) three times daily
- Intravenous (administer each IV dose over 1 hour)
VIII. Pharmacokinetics
- Half-Life: 8 hours
- Some of drug is metabolized via Glucuronidation
- Renal excretion (mostly unchanged in the urine)
IX. Adverse Effects
- Carcinogenic in mice and rats (FDA Black box warning)
-
Disulfiram Reaction (Antabuse Effect)
- Alcohol induced Flushing, Vomiting and Headache
- Since the 1960s, Alcohol has been strictly cautioned against when taking Metronidazole
- More recent data suggests no inhibition of aldehyde dehydrogenase as is seen with Disulfiram
- Safest to avoid Alcohol with Metronidazole, but interactions appear to be very uncommon
- (2021) Presc Lett 28(10): 58
- Gastrointestinal intolerance
- Neurotoxicity (stop immediately if these occur)
- Seizures
- Encephalopathy
- Aseptic Meningitis
- Optic Neuropathy
- Cerebellar dysfunction (e.g. Ataxia, Dizziness)
- Peripheral Neuropathy (e.g. distal Paresthesias)
- Other effects
- Urine Color change
- Darker Urine
- Urine Color change
X. Drug Interactions
-
Alcohol or Disulfiram
- See Disulfiram reaction under adverse effects above
- Avoid Alcohol for 3 days after last dose
- Avoid Disulfiram for 2 weeks after last dose
-
Warfarin
- Increases INR
- Other interactions
XI. Safety
- Pregnancy Class B Medication
- Avoid in first trimester pregnancy
- Unknown safety in Lactation
- However, generally avoided in Lactation
- May resume Breast Feeding at 12 to 24 hours after a single Metronidazole dose
XII. Resources
- Metronidazole Tablet (DailyMed)
- Metronidazole Intravenous Solution (DailyMed)
XIII. References
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 110-1
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
- Burtin (1995) Am J Obstet Gynecol 172:525-9 [PubMed]
Images: Related links to external sites (from Bing)
Related Studies
| metronidazole (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| METRONIDAZOLE 0.75% CREAM | Generic | $0.56 per gram |
| METRONIDAZOLE 0.75% LOTION | Generic | $1.90 per ml |
| METRONIDAZOLE 250 MG TABLET | Generic | $0.10 each |
| METRONIDAZOLE 500 MG TABLET | Generic | $0.14 each |
| METRONIDAZOLE TOP 1% GEL PUMP | Generic | $0.69 per gram |
| METRONIDAZOLE TOPICAL 0.75% GL | Generic | $0.46 per gram |
| METRONIDAZOLE TOPICAL 1% GEL | Generic | $1.06 per gram |
| METRONIDAZOLE VAGINAL 0.75% GL | Generic | $0.47 per gram |
Ontology: Metronidazole (C0025872)
| Definition (CHV) | a drug that treats bacterial and fungal infection |
| Definition (CHV) | a drug that treats bacterial and fungal infection |
| Definition (NCI) | A synthetic nitroimidazole derivative with antiprotozoal and antibacterial activities. Although its mechanism of action is not fully elucidated, un-ionized metronidazole is readily taken up by obligate anaerobic organisms and is subsequently reduced by low-redox potential electron-transport proteins to an active, intermediate product. Reduced metronidazole causes DNA strand breaks, thereby inhibiting DNA synthesis and bacterial cell growth. |
| Definition (NCI_NCI-GLOSS) | A drug that is used to treat infection and is being studied in the treatment of cancer. It is a type of antibacterial, antiprotozoal, and anthelmintic. |
| Definition (MSH) | A nitroimidazole used to treat AMEBIASIS; VAGINITIS; TRICHOMONAS INFECTIONS; GIARDIASIS; ANAEROBIC BACTERIA; and TREPONEMAL INFECTIONS. It has also been proposed as a radiation sensitizer for hypoxic cells. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985, p133), this substance may reasonably be anticipated to be a carcinogen (Merck, 11th ed). |
| Definition (CSP) | antiprotozoal and antibacterial effective against obligate anaerobes. |
| Definition (PDQ) | A synthetic nitroimidazole derivative with antiprotozoal and antibacterial activities. Although its mechanism of action is not fully elucidated, un-ionized metronidazole is readily taken up by obligate anaerobic organisms and is subsequently reduced by low-redox potential electron-transport proteins to an active, intermediate product. Reduced metronidazole causes DNA strand breaks, thereby inhibiting DNA synthesis and bacterial cell growth. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39503&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39503&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C651" NCI Thesaurus) |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | D008795 |
| SnomedCT | 326285001, 332974000, 1222004, 372602008 |
| LNC | LP14997-8, MTHU002300 |
| English | 1H-Imidazole-1-ethanol, 2-methyl-5-nitro-, Metronidazole [skin], 2 Methyl 5 nitroimidazole 1 ethanol, 2-Methyl-5-nitroimidazole-1-ethanol, Metronidazole, metronidazole, Metronidazole [vaginal], METRONIDAZOLE, metronidazole (medication), Metronidazole [Chemical/Ingredient], metronidazole vaginal, metroNIDAZOLE, MetroNIDAZOLE, Metronidazole [vaginal] (product), Metronidazole [skin] (product), Metronidazole product, Metronidazole (product), Metronidazole (substance), METRO, Metronidazole [skin] (substance), Metronidazole [vaginal] (substance) |
| Swedish | Metronidazol |
| Czech | metronidazol |
| Finnish | Metronidatsoli |
| Russian | METRONIDAZOL, МЕТРОНИДАЗОЛ |
| Japanese | フラジール, フラギル, 安息香酸メトロニダゾール, クロント, ダニゾール, メトロニダゾールホスファート, 塩酸メトロニダゾール, メトロニダゾール塩酸塩, メトロニダゾールベンゾアート, アスゾール, メトロニダゾール, メトロニダゾールリン酸, トリカゾール, ギネフラビル, トリバゾール |
| Polish | Metronidazol |
| Norwegian | Metronidazol |
| Croatian | Metronidazol |
| Spanish | metronidazol [uso vaginal], metronidazol (uso dermatológico) (producto), metronidazol [uso vaginal] (producto), metronidazol (uso dermatológico), metronidazol (piel) (producto), metronidazol (piel), metronidazol (producto), metronidazol (sustancia), metronidazol, Metronidazol |
| French | Métronidazole |
| German | Metronidazol |
| Italian | Metronidazolo |
| Portuguese | Metronidazol |
Ontology: Flagyl (C0699678)
| Definition (CHV) | brand name of an antibiotic |
| Definition (CHV) | brand name of an antibiotic |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | D008795 |
| English | flagyl, flagyl [brand name], Flagyl |
