WARNINGS
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.
PRECAUTIONS
GENERAL
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.
LABORATORY TESTS
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.
DRUG INTERACTIONS
Concurrent administration of ethionamide has been reported to potentiate neurotoxic side effects.
Alcohol and Seromycin are incompatible, especially during a regimen calling for large doses of the latter. Alcohol increases the possibility and risk of epileptic episodes.
Concurrent administration of isoniazid may result in increased incidence of CNS effects, such as dizziness or drowsiness. Dosage adjustments may be necessary and patients should be monitored closely for signs of CNS toxicity.
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 Seromycin 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 clearly needed.
NURSING MOTHERS
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.
USAGE IN PEDIATRIC PATIENTS
Safety and effectiveness in pediatric patients have not been established.
|
