From Cat
Chemical structure of secnidazole

Secnidazole is a benzimidazole anti-infective which has recently been tested in cats for treatment of Giardia spp infections.

Secnidazole is structurally related to the commonly used 5-nitroimidazoles metronidazole and tinidazole. Once the drug enters the parasite it becomes activated by the reduction of the nitro group and binds covalently to DNA molecules, resulting in irreversible helical damage and death of the organism[1]. Secnidazole is rapidly and completely absorbed after oral administration and has a longer terminal elimination half-life (approximately 17 to 29 hours) than commonly used drugs in this class[2]. It appears to have anti-protozoan and antibacterial effects[3][4].

Secnidazole has the advantage of being a single dose treatment and in humans treated with a single dose of secnidazole (30 mg/kg), it achieved up to 98% cure[5]. Researchers, in a comparative study between secnidazole and metronidazole found a curative rate of 100% for secnidazole and 96% for metronidazole[6]. However, when metronidazole was used in a single dose, its curative rate was reduced to 36–54%[7][8]. On the other hand, a single dose of secnidazole reaches the same response achieved with multiple dosage regimens of metronidazole or tinidazole.

In cats treated with secnidazole, 100% cure rates aganst G. duodenalis were reported. Minor blood parameter changes were noted, primarily elevation in liver enzymes in some cats, but no clinical signs of toxicity were reported[9]. The main advantage of this treatment is that only a single dose is required, which is interesting in animals hard to handle like cats.

No reported cases of the use of secnidazole in cats infected with Tritrichomonas spp are observed in the literature, but the sensitivity of this protozoan to other benzimidazoles suggests its likely sensitivity to this drug as well. Further research is required in this area of study.

The recommended dose in cats is 30 mg/kg given as a single dose, used off-label.

This drug can be compounded to 30 mg (kitten) and 100mg (adult) capsules by compounding pharmacies.

See also

Secnidazole for the treatment of giardiasis in naturally infected cats


  1. Payne PA & Artzer M (2009) The biology and control of Giardia spp and Tritrichomonas foetus. Vet Clin North Am Small Anim Pract 39:993–1007
  2. Girginkardeşler, N et al (2003) Dientamoeba fragilis, a neglected cause of diarrhea, successfully treated with secnidazole. Clin Micro Infect 9(2): 110–113
  3. Zhang HJ et al (2011) Synthesis, molecular modeling and biological evaluation of β-ketoacyl-acyl carrier protein synthase III (FabH) as novel antibacterial agents. Bioorg Med Chem 19(15):4513-4519
  4. De Backer, E et al (2009) In vitro activity of secnidazole against Atopobium vaginae, an anaerobic pathogen involved in bacterial vaginosis. Clin Micro Infect 16(5):470–472
  5. Di Prisco MC et al (2000) Clinical trial with Secnidazole in a single dose in Venezuelan children infected by Giardia intestinalis. Invest Clin 41:179–88
  6. Rastegar-Lari A & Salek-Moghaddam A (1996) Single-dose secnidazole versus 10-day metronidazole therapy of giardiasis in Iranian children. J Trop Pediatr 42:184–185
  7. Bassily S et al (1987) Treatment of intestinal E. histolytica and G. lamblia with metronidazole in the treatment of trichomoniasis, giardiasis and amoebiasis. J Trop Med Hyg 90:9–12
  8. Nigram P et al (1991) Clinical profile of giardiasis and comparison of its therapeutics response to metronidazole and tinidazole. J Assoc Physicians 39:6–8
  9. Da Silva AS et al (2011) Secnidazole for the treatment of giardiasis in naturally infected cats. Parasitol Int Jul 8