Related to this topic: Medicines | Equipment | Books | Your Experience | Other resources | Glossaries
Print options: Printer friendly version of this leaflet (html)     Other options:  AddThis Social Bookmark Button (what's this?)

PatientPlus articles are written for doctors and so the language can be technical. However, some people find that they add depth to the articles found in the other sections of this website which are written for non-medical people.

Metronidazole and Tinidazole

These antibacterials work by entering bacterial cells and binding to bacterial DNA. This inhibits further replication. Metronidazole resistance is growing, and research has suggested that mechanisms other than genetics are involved. The emerging resistance of the B. fragilis group against several antimicrobial agents emphasise the importance of sensitivity testing of anaerobes in laboratories1.

Available Treatments
  • Metronidazole: is available as oral, intravenous, topical or suppository medication
  • Tinidazole: is available in tablet form only

Tinidazole is very similar to metronidazole, but has a longer duration of action.

Indications for Use

  • Surgical or gynaecological sepsis e.g. bacteroides fragilis
  • Pseudomembranous colitis
  • Trichomonal vaginitis. Treatment with oral metronidazole is effective, and T.vaginalis DNA disappears rapidly after treatment2. Metronidazole-resistant trichomoniasis is an infrequent but challenging problem with no universally successful treatment. High-dose tinidazole plus a broad-spectrum antibiotic, i.e. doxycycline or ampicillin, and clotrimazole pessaries, for 7--14 days can be used in this situation. The cure rate has been reported as high as 90%3.
  • Helicobacter pylori eradication. H. pylori-infected patients who are allergic to penicillin may be treated with a first-line treatment combining a proton-pump inhibitor, clarithromycin and metronidazole4. The effectiveness of these antiinfectives is limited by lack of compliance with treatment regimens, and increasing antibiotic resistance5.
  • Bacterial vaginosis- gardnerella vaginalis
  • Entamoeba histolytica
  • Giardia lamblia
  • Chronic sinusitis can be managed effectively with a combination of metronidazole and a penicillin6
  • Established cases of tetanus. Metronidazole, human tetanus immunoglobulin, and active immunization should be initiated on presentation7.
  • Odour reduction in presence of fungating tumour (topical preparation)
  • Acne rosacea (topical preparation).

It is also used as prophylaxis for abdominal ( colon/ rectum) and pelvic ( hysterectomy) surgery.

Cautions and Contraindications
  • Avoid alcohol whilst taking metronidazole. It causes a disulfiram-like reaction. Symptoms include nausea, vomiting, flushing, thirst, palpitations and chest pain, vertigo and hypotension.
  • Avoid in liver disease
  • Avoid in pregnancy and breastfeeding.( Tinidazole particularly in first trimester)
  • Laboratory monitoring is advisable if course of treatment last more than 10 days. Check FBC, LFT.
Adverse Effects
  • GI upset
  • Unpleasant taste
  • Urine darker colour
  • Hepatitis, pruritus and jaundice
  • Thrombocytopaenia, aplastic anaemia
  • Prolonged treatment may cause peripheral neuropathy, transient epilepsy or neutropenia.

Document References
  1. Schaumann R, Petzold S, Fille M, et al; Inducible metronidazole resistance in nim-positive and nim-negative bacteroides fragilis group strains after several passages metronidazole containing columbia agar plates.; Infection. 2005 Oct;33(5-6):368-72. [abstract]
  2. Van Der Pol B, Williams JA, Orr DP, et al; Prevalence, incidence, natural history, and response to treatment of Trichomonas vaginalis infection among adolescent women.; J Infect Dis. 2005 Dec 15;192(12):2039-44. Epub 2005 Nov 8. [abstract]
  3. Mammen-Tobin A, Wilson JD; Management of metronidazole-resistant Trichomonas vaginalis--a new approach.; Int J STD AIDS. 2005 Jul;16(7):488-90. [abstract]
  4. Gisbert JP, Gisbert JL, Marcos S, et al; Helicobacter pylori first-line treatment and rescue options in patients allergic to penicillin.; Aliment Pharmacol Ther. 2005 Nov 15;22(10):1041-6. [abstract]
  5. McLoughlin R, O'Morain C; Effectiveness of antiinfectives.; Chemotherapy. 2005 Aug;51(5):243-6. Epub 2005 Jul 26. [abstract]
  6. Brook I; Microbiology and antimicrobial management of sinusitis.; J Laryngol Otol. 2005 Apr;119(4):251-8. [abstract]
  7. Bassin SL; Tetanus.; Curr Treat Options Neurol. 2004 Jan;6(1):25-34. [abstract]
Internet and Further Reading AcknowledgementsEMIS is grateful to Dr Hayley Willacy for writing this article. The final copy has passed scrutiny by the independent Mentor GP reviewing team. ©EMIS 2007.
DocID: 363
Document Version: 1
DocRef: bgp25150
Last Updated: 16 Oct 2007
Review Date: 15 Oct 2008
Patient UK Current Health News








Disclaimer: Patient UK has no control over the content of any external links above. Inclusion does not imply endorsement by Patient UK.

Want to advertise on this site? Find out how >>







Disclaimer: Patient UK has no control over the content of any external links above. Inclusion does not imply endorsement by Patient UK.

Want to advertise on this site? Find out how >>

PS - Health and Poverty

Perhaps the biggest cause of ill health in the world is poverty. Help to Make Poverty History. For example, why not lend some of your money to disadvantaged communities to enable them to trade their way out of poverty through schemes such as Shared Interest.

See also MAKEPOVERTYHISTORY North East for details and links to campaigns against poverty.

^ Top of Page