du Bouchet et al, 1997

Lewis et al., 1997; Watson and Pattman, 1996; Walker et al.,

1997; Chen et al., 1999 Lewis et al., 1997; du Bouchet et al., 1997 Sikorski et al., 1992

Livengood and Lossick, 1991; Antonelli et al., 2000 Lewis et al., 1997; Nyirjesy et al., 1998; Poppe, 2001 Wong et al., 1990; Yu and Tak Yin, 1993

Bouree and Issoire, 1992

Ziomko and Kuczynska, 1994

Narcisi and Secor, 1996

Riley and Krieger, 1996

Katiyar et al., 1994

Bouma et al., 1998

*AVC pessaries contain sulphanilamide, aminacrine HCl and allantoin. +A single oral dose of 2g metronidazole cured 36/45 cases. 1Gynalgin contains metronidazole, chloroquine and citric acid. ^High incidence of local side effects.

metallic taste, disulfiram-like reaction to alcohol) may be more noticeable. Cure rates in women are similar (about 95%) with both regimens if male sexual partners are also treated, but appear to be lower with the single-dose regimen if they are not. Only the 7 day regimen has been extensively evaluated in males, where it is just as effective as in women.

The acute toxicity of metronidazole is low, but it is a mutagen and long-term, high-dose administration to mice can produce lung tumours. Follow-up of treated women has failed to show any malignancies and any risk from short-term treatment appears to be very small. Similarly, there is no evidence that the drug is teratogenic, but it does cross the placenta and it seems only prudent to avoid its use during the first trimester if at all possible. Local treatments or simple douching have very disappointing long-term cure rates but may be of value in controlling symptoms during pregnancy until metronidazole can be used.

Treatment failures with any of the 5-nitroimi-dazole drugs are uncommon and are usually due to non-compliance. Failure to absorb the drug and inactivation by vaginal flora are other, rare causes, but a small but slowly growing proportion of treatment failure is due to genuinely resistant isolates. Careful measurement of sensitivity in vitro, using specified media and controlled oxygen tension, is necessary to obtain consistent results (Ackers, 1995) but a high level of resistance can be shown in some isolates. The mechanism of this resistance is, to some extent, understood (Edwards, 1993). Most such cases can be managed by increased and repeated doses but if that fails, no really effective alternative drugs are available, although occasional successes with a variety of preparations have been reported (Table 11.4) and discussed in a recent article (Lewis et al., 1997).

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