Single-dose tinidazole for the treatment of giardiasis

Abstract

Sixty-three expatriate residents and travellers in Bangladesh, infected with Giardia lamblia, participated in two studies to compare the therapeutic efficacy of tinidazole and metronidazole. In the first trial 33 randomly selected patients were treated with tinidazole (50 mg/kg of body weight to a maximum of 2 g) or metronidazole (60 mg/kg of body weight to a maximum of 2.4 g) in a single oral dose. Patients were followed for 4 weeks after the end of therapy for the presence of G. lamblia in their stools. Sixteen (94%) of 17 patients receiving tinidazole were free of G. lamblia during that period, compared to only 9 (56%) of 16 patients who had received metronidazole (P < 0.02). In the second trial patients were randomly allocated to a treatment schedule of either metronidazole as a single dose on 3 successive days (50 mg/kg of body weight to a maximum of 2 g daily) or tinidazole as a single oral dose (50 mg/kg of body weight to a maximum of 2 g). All 15 patients treated with tinidazole and 14 (93%) of 15 patients treated with metronidazole were free of G. lamblia during the 4-week follow-up period. A single oral dose of tinidazole is a highly effective treatment for giardiasis and is equal in efficacy to a 3-day therapy with metronidazole.

Treatment of Patients with Refractory Giardiasis

“…There are a number of drugs whose efficacies are well studied and that have been accepted for the treatment of patients with this infection. The published rates of cure vary for different regimens, but they are frequently reported to be 190% [1,[3][4][5][6][7]. Nevertheless, some individuals experience treatment failure, despite having received successive courses of treatment that have been documented to result in a cure for most patients.…”

Treatment of Giardiasis

“…One dose of tinidazole (Fasigyn) was successfully used in 1971 in a group of Swedish students who acquired giardiasis during a visit to Russia (11). This single, 2-g dose (or equivalent in children) has consistently proven to have a clinical efficacy of 80 to 100% with a median efficacy of 92% (Table 1) (16,126,130,131,146,151,193,222,229,261 (93,130,229,261). There is also improved compliance with this dosing schedule.…”

“…These regimens are generally less efficacious, particularly if only one dose of metronidazole is given. The efficacy of single-dose therapy ranges from 36 to 60% if the drug is given for 1 day (16,93,127,130,220,229) and rises to 67 to 80% if the drug is given for 2 days (Table 1) The high-dose regimens may also carry more side effects (127).…”

Antiparasitic Drugs in Children

“…In addition, adverse effects tend to be milder, although infants often fmd the syrup formulation unpalatable (Speelman 1985).…”