Administration of Seromycin should be discontinued or the dosage reduced if the patient develops
allergic dermatitis or symptoms of CNS toxicity, such as convulsions, psychosis, somnolence,
depression, confusion, hyperreflexia, headache, tremor, vertigo, paresis, or dysarthria.
The toxicity of Seromycin is closely related to excessive blood levels (above 30 μg/mL), as
determined by high dosage or inadequate renal clearance. The ratio of toxic dose to effective dose in
tuberculosis is small.
The risk of convulsions is increased in chronic alcoholics.
Patients should be monitored by hematologic, renal excretion, blood level, and liver function studies.
Before treatment with Seromycin is initiated, cultures should be taken and the organism’s susceptibility
to the drug should be established. In tuberculous infections, the organism’s susceptibility to the other
antituberculosis agents in the regimen should also be demonstrated.
Anticonvulsant drugs or sedatives may be effective in controlling symptoms of CNS toxicity, such as
convulsions, anxiety, and tremor. Patients receiving more than 500 mg of Seromycin daily should be
closely observed for such symptoms. The value of pyridoxine in preventing CNS toxicity from
Seromycin has not been proved.
Administration of Seromycin and other antituberculosis drugs has been associated in a few instances
with vitamin B12 and/or folic–acid deficiency, megaloblastic anemia, and sideroblastic anemia. If
evidence of anemia develops during treatment, appropriate studies and therapy should be instituted.
Blood levels should be determined at least weekly for patients with reduced renal function, for
individuals receiving a daily dosage of more than 500 mg, and for those showing signs and symptoms
suggestive of toxicity. The dosage should be adjusted to keep the blood level below 30 μg/mL.
Carcinogenesis, Mutagenicity, And Impairment Of Fertility
Studies have not been performed to determine potential for carcinogenicity. The Ames test and
unscheduled DNA repair test were negative. A study in 2 generations of rats showed no impairment of
fertility relative to controls for the first mating but somewhat lower fertility in the second mating.
Pregnancy Category C
A study in 2 generations of rats given doses up to 100 mg/kg/day demonstrated no teratogenic effect in
offspring. It is not known whether cycloserine can cause fetal harm when administered to a pregnant
woman or can affect reproduction capacity. Seromycin should be given to a pregnant woman only if
Because of the potential for serious adverse reactions in nursing infants from Seromycin, a decision
should be made whether to discontinue nursing or to discontinue the drug, taking into account the
importance of the drug to the mother.
Safety and effectiveness in pediatric patients have not been established.