Because sulfonamides are absorbed from the vaginal mucosa, the usual precautions for oral sulfonamides apply. Patients should be observed for skin rash or evidence of systemic toxicity, and if these develop, the medications should be discontinued.
Deaths associated with administration of oral sulfonamides have reportedly occurred from hypersensitivity reactions, agranulocytosis, aplastic anemia, and other blood dyscrasias.
Goiter production, diuresis, and hypoglycemia have reportedly occurred rarely in patients receiving oral sulfonamides. Cross-sensitivity may exist with these agents. Rats appear to be especially susceptible to the goitrogenic effects of sulfonamides, and long-term administration has reportedly produced thyroid malignancies in this species.
Vaginal applicators or inserters should be used with caution after the seventh month of pregnancy.
Information For Patients
The doctor should advise the patient that in the event unusual local itching and burning occur, or other unusual symptoms develop, medication should be discontinued and not restarted without further consultation.
Drug interactions have not been documented with AVC.
Carcinogenesis, Mutagenesis, Impairment of Fertility
No data are available on long-term potential of AVC for carcinogenicity, mutagenicity, or impairment of fertility in animals or humans.
Teratogenic Effects. Pregnancy Category C: Animal reproductive studies have been conducted with sulfonamides, including sulfanilamide (see below). It is not known whether AVC can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. AVC should be given to a pregnant woman only if clearly needed.
Sulfonamides, including sulfanilamide, readily pass through the placenta and reach fetal circulation. The concentration in the fetus is from 50-90% of that in the maternal blood and if high enough, can cause toxic effects. The safe use of sulfonamides, including sulfanilamide, in pregnancy has not been established. The teratogenic potential of most sulfonamides has not been thoroughly investigated in either animals or humans. However, a significant increase in the incidence of cleft palate and other bony abnormalities of offspring has been observed with certain sulfonamides of the short-, intermediate- and long-acting types (including sulfanilamide) when given to pregnant rats and mice at high oral doses (seven to 25 times the human therapeutic oral dose.)
Sulfanilamide should be avoided in nursing mothers because absorbed sulfonamides will appear in maternal milk and have caused kernicterus in the newborn. Because of the potential for serious adverse reactions in nursing infants from sulfonamides, a decision should be made whether to discontinue nursing or to discontinue the drug.
Safety and effectiveness of AVC in pediatric patients have not been established.