Spectinomycin

Teratogenic Effects. Pregnancy Category B.

Spectinomycin was not teratogenic or embryocidal when orally or subcutaneously administered to rats at doses of 300 mg/kg/day (equivalent to the recommended maximum human dose based on mg/m²). No teratogenic effects were observed when spectinomycin was administered intraperitoneally to mice or rats at dose levels of 400 or 1600 mg/kg/day, respectively. Spectinomycin was administered intramuscularly or subcutaneously to pregnant rabbits at dose levels up to 300 mg/kg/day (equivalent to the recommended maximum human dose based on mg/m²). Embryonic and fetal development were unaffected by treatment. Since there are no controlled studies of spectinomycin in pregnant women, and because animal reproduction studies are not always predictive of human responses, spectinomycin should be used during pregnancy only if clearly needed.

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when spectinomycin is administered to a nursing woman.

Genotoxicity of spectinomycin hydrochloride was evaluated in six assay test systems including two Ames tests, two micronucleus tests in mice, unscheduled DNA synthesis in rat primary hepatocytes, and a chromosomal aberration test in Chinese hamster ovary cells. Spectinomycin was not shown to be mutagenic or genotoxic in these tests.

No adverse effects on fertility or general reproductive performance were observed when spectinomycin was administered subcutaneously to rats at dose levels up to 300 mg/kg (equivalent to the recommended maximum human dose based on mg/m²). A threegeneration reproduction study in rats administered spectinomycin hydrochloride orally at dose levels up to 400 mg/kg (equivalent to the recommended maximum human dose based on mg/m²) produced no evidence of drug-induced toxicity during growth, gestation, or lactation periods of any parental generation. Pregnancy rates of the 400 mg/kg/day groups were consistently lower than those of the control groups. A histopathological examination of the testes and ovaries of the third generation animals was normal.

Dizziness and fever have been reported by some patients.

Adverse reactions are listed below, by system organ class and by frequency. Frequencies are defined as: Very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), rare (≥1/10,000 to <1/1,000), very rare (<1/10,000) and not known (cannot be estimated from available data).