Administration of cycloserine 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 cycloserine 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.
There is currently no manufacturer warning information available for this drug.
Cycloserine is indicated in the treatment of active pulmonary and extrapulmonary tuberculosis (including renal disease) when the causative
organisms are susceptible to this drug and when treatment with the primary medications (streptomycin, isoniazid, rifampin, and ethambutol) has proved inadequate. Like all antituberculosis drugs, cycloserine should be administered in conjunction with other effective chemotherapy and not as the sole therapeutic agent.
Cycloserine may be effective in the treatment of acute urinary tract infections caused by susceptible strains of gram–positive and gram–negative bacteria, especially Enterobacter spp. and Escherichia coli. It is generally no more and is usually less effective than other antimicrobial agents in the treatment of urinary tract infections caused by bacteria other than mycobacteria. Use of cycloserine in these infections should be considered only when more conventional therapy has failed and when the organism has been demonstrated to be susceptible to the drug.
Cycloserine, 3-isoxazolidinone, 4-amino –, (R)– is a broad–spectrum antibiotic that is produced by a strain of Streptomyces orchidaceus and has also been synthesized. Cycloserine is a white to off–white powder that is soluble in water and stable in alkaline solution. It is rapidly destroyed at a neutral or acid pH.
Cycloserine has a pH between 5.5 and 6.5 in a solution containing 100 mg/mL. The molecular weight of cycloserine is 102.09, and it has an empirical formula of C3H6N2O2.
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