Metronidazole (Flagyl®) versus Tinidazole (Tindamax®)

Based on "Antibiotic and Chemotherapy"
written by Roger G. Finch

Difference between Metronidazole and Tinidazole

  Metronidazole Tinidazole
Drug class
Nitroimidazole antimicrobial
Available formulations Oral, topical, intravaginal, intravenous Oral
Indications • Amebiasis
• Trichomoniasis (tinidazole is useful in treating trichomoniasis that fails to respond to metronidazole)
• Bacterial vaginosis
Anaerobic Bacterial Infections:
• Intra-abdominal Infections (peritonitis, intra-abdominal abscess, liver abscess)
• Skin and skin structure infections
• Endometritis, endomyometritis, tubo-ovarian abscess, postsurgical vaginal infections
• Septicemia
• Meningitis, brain abscess
• Pneumonia, empyema, lung abscess
• Endocarditis
• Giardiasis
Tinidazole is more effective than metronidazole for giardiasis15
"Off-label" uses Giardiasis  
Half-life 8 hours 10-15 hours,
the longer half-life contributes to prolonged duration of action
Bioavailability Oral close to 100%3
Rectal 59%-90%
Vaginal 20%
Topical 2%
Cigarette smoking may decreases metronidazole bioavailability1
Oral close to 100%4
Excretion Via the urine - 60% to 80%, via feces- 6% to 15%
Excreted by the liver and the kidneys. Via the urine - 20-25%, via feces - 12%
Spectrum of activity: Bacteroides spp.
Gardnerella vaginalis
Mobiluncus spp.
Peptostreptococcus spp.
Gram-positive anaerobes
Clostridium species
Eubacterium species
Peptococcus species
Peptostreptococcus species
Gram-negative anaerobes
Bacteroides fragilis group
Fusobacterium species
Protozoal parasites
Entamoeba histolytica
Trichomonas vaginalis
Bacteroides spp.
Gardnerella vaginalis
Prevotella spp.

Anaerobic bacteria have greater susceptibility to tinidazole14

Protozoal parasites
Trichomonas vaginalis
Giardia duodenalis (G. lamblia)
Entamoeba histolytica

Tinidazole is active against some protozoa resistant to metronidazole12
Side effects, safety Side effects are very similar and include:
• Nausea
• Metallic taste
• Dyspepsia
• Encephalopathy
• Convulsive seizures
• Peripheral neuropathy2
Contraindications Hypersensitivity to nitroimidazole derivatives
First trimester of pregnancy
Pregnancy category B C
Special populations Treatment of amebiasis in children Treatment of amebiasis and giardiasis in children
Drug interactions Disulfiram
Food Food does not affect the oral bioavailability.
Both metronidazole and tinidazole can be taken with food to minimize gastrointestinal side effects


Both metronidazole and tinidazole, nitroimidazole antimicrobials, have similar mechanism of action, antimicrobial spectrum of activity, toxicity, and adverse effects.

The main distinguishing features are the half-life and a set of licensed indications. Tinidazole advantages over metronidazole are prolonged duration of action, and better tolerability.


Tinidazole is significantly more effective than metronidazole in the treatment of intestinal amoebiasis, and is better tolerated than metronidazole 5.

Results of clinical trial of metronidazole and tinidazole in intestinal amoebiasis 5 Metronidazole Tinidazole
Regimen 2 g once daily for 3 consecutive days
Cure rates, number of patients 15 patients (55.5%) 28 patients (96.5%)
Cure with partial relief of symptoms 1 patient
5 patients
Treatment failure 7 patients

Amebic liver abscess

In the treatment of amebic liver abscess tinidazole provides earlier symptoms improvement, shorter duration of treatment, and causes less side effects17.

Bacterial vaginosis

Seven days therapy of metronidazole or tinidazole provides equal cure rates in the treatment of bacterial vaginosis. Both medications show similar inhibitory activity against bacteria associated with bacterial vaginosis 11.

Results of clinical trial of metronidazole vs tinidazole in for bacterial vaginosis 6 Metronidazole Tinidazole
Regimen 500 mg twice daily for 7 days 500 mg twice daily, or 1 g twice, for 7 days
Cure rates at 14 days 76.8%
Cure rates at 1 month 64.5%

Tinidazole single dose regimen is more effective than metronidazole single dose in the treatment of bacterial vaginosis.

Results of comparative study of metronidazole and tinidazole in for bacterial vaginosis 9 Metronidazole Tinidazole
Regimen single 2 g dose
Cure rate at 4 weeks 77.9% 97.7%

Tinidazole 500 mg single dose provides better long-term cure rates than metronidazole 500 mg twice daily for 5 days and is more effective in preventing bacterial vaginosis relapses16.

See also:


Tinidazole is superior to metronidazole with regard to efficacy and tolerability. Resistance of Trichomonas vaginalis to metronidazole is higher than to tinidazole 10. Metronidazole-resistant cases of trichomoniasis can be successfully treated with tinidazole 12, 13.

Results of randomized, comparative trial of tinidazole and metronidazole for trichomonal vaginitis 7 Metronidazole Tinidazole
Regimen single 2 g dose
Parasitological cure 64%
(32 patients of 50)
94% (47 patients of 50)
Satisfactory clinical response 72%
(36 patients of 50)
(48 patients of 50)
Severity and frequency of side-effects significantly less with tinidazole than with metronidazole

Helicobacter pylori

Results of randomized study comparing efficacy of a metronidazole-based versus a tinidazole-based treatment for Helicobacter pylori8 Metronidazole Tinidazole
Regimen Metronidazole 250 mg 4 times a day, amoxicillin 1 g twice a day, and PPI standard dose for 7, 10 or 14 days. Tinidazole 500 mg twice a day, amoxicillin 1 g twice a day, and PPI standard dose for 7, 10 or 14 days.
H. pylori eradication after 7 days 23 patients of 30
20 patients of 27
H. pylori eradication after 10 days 20 patients of 26
20 patients of 26
H. pylori eradication after 14 days 25 patients of 32
21 patients of 27

Further reading


  • 1. Montalli VA, Bergamaschi Cde C, Ramacciato JC, Nolasco FP, Groppo FC, Brito RB Jr, Haas DA, Motta RH. The effect of smoking on the bioavailability of metronidazole in plasma and saliva. J Am Dent Assoc. 2012 Feb;143(2):149-56. PubMed
  • 2. Kato H, Sosa H, Mori M, Kaneko T. Clinical Characteristics of Metronidazole-induced Encephalopathy. Kansenshogaku Zasshi. 2015 Sep;89(5):559-66. PubMed
  • 3. Mandell GL, Bennett JE, Dolin R. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 8th Ed., Saunders. pp. 350-360
  • 4. Fung HB, Doan TL. Tinidazole: a nitroimidazole antiprotozoal agent. Clin Ther. 2005 Dec;27(12):1859-84. PubMed
  • 5. Swami B, Lavakusulu D, Devi CS. Tinidazole and metronidazole in the treatment of intestinal amoebiasis. Curr Med Res Opin. 1977;5(2):152-6. PubMed
  • 6. Schwebke JR, Desmond RA. Tinidazole vs metronidazole for the treatment of bacterial vaginosis. Am J Obstet Gynecol. 2011 Mar;204(3):211.e1-6. PubMed
  • 7. Anjaeyulu R, Gupte SA, Desai DB. Single-dose treatment of trichomonal vaginitis: a comparison of tinidazole and metronidazole. J Int Med Res. 1977;5(6):438-41. PubMed
  • 8. Berrutti M, Pellicano R, Astegiano M, et al. Helicobacter pylori eradication: metronidazole or tinidazole? Minerva Gastroenterol Dietol. 2008 Dec;54(4):355-8. PubMed
  • 9. Thulkar J, Kriplani A, Agarwal N. A comparative study of oral single dose of metronidazole, tinidazole, secnidazole and ornidazole in bacterial vaginosis. Indian J Pharmacol. 2012 Mar;44(2):243-5. PubMed
  • 10. Schwebke JR, Barrientes FJ. Prevalence of Trichomonas vaginalis isolates with resistance to metronidazole and tinidazole. Antimicrob Agents Chemother. 2006 Dec;50(12):4209-10. PubMed
  • 11. Austin MN, Meyn LA, Hillier SL. Susceptibility of vaginal bacteria to metronidazole and tinidazole. Anaerobe. 2006 Oct-Dec;12(5-6):227-30. PubMed
  • 12. Hager WD. Treatment of metronidazole-resistant Trichomonas vaginalis with tinidazole: case reports of three patients. Sex Transm Dis. 2004 Jun;31(6):343-5. PubMed
  • 13. Sobel JD, Nyirjesy P, Brown W. Tinidazole therapy for metronidazole-resistant vaginal trichomoniasis. Clin Infect Dis. 2001 Oct 15;33(8):1341-6. PubMed
  • 14. Kałowski M, Dybicki J, Kedzia A, Lukiański M. Study of obligate anaerobic bacterial sensitivity to tinidazole and metronidazole (determination of minimal inhibiting concentration--MIC) Wiad Lek. 1993 Mar;46(5-6):211-5. PubMed
  • 15. Nigam P, Kapoor KK, Kumar A, Sarkari NB, Gupta AK. Clinical profile of giardiasis and comparison of its therapeutic response to metronidazole and tinidazole. J Assoc Physicians India. 1991 Aug;39(8):613-5. PubMed
  • 16. Raja IM, Basavareddy A, Mukherjee D, Meher BR. Randomized, double-blind, comparative study of oral metronidazole and tinidazole in treatment of bacterial vaginosis. Indian J Pharmacol. 2016 Nov-Dec;48(6):654-658. PubMed
  • 17. Pandey S, Gupta GK, Wanjari SJ, Nijhawan S. Comparative study of tinidazole versus metronidazole in treatment of amebic liver abscess: A randomized control trial. Indian J Gastroenterol. 2018 May;37(3):196-201

Published: December 17, 2015
Last updated: August 14, 2018


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