Analog of D-alanine
Broad spectrum, Staphylococcus aureus and some gram-negative bacilli, such as Escherichia coli, although no longer used for these pathogens. Primary use is against M. tuberculosis.
Cycloserine disrupts D-alanine incorporation into peptidoglycan during bacterial cell wall synthesis.
Cycloserine is generally bacteriostatic, and based on its mechanism of action being 2 steps upstream from penicillin’s, cycloserine likely is time-dependent.
Cmax: 20-35 mg/L; Tmax: 1-2 hours; Bioavailability: not known, but likely is high; Protein binding: not known, but likely is very low
Central nervous system disturbances, including lethargy, difficulty concentrating, and altered behavior
PO: 250 mg capsules
Usual dose: 250-500 mg once or twice daily, rarely exceeding 1000 mg
Hepatic failures: No specific recommendations
Renal failures: Adjustment required. Depending upon the degree of impairment, usual doses given once daily or every other day should initially be employed.
Precautions: Renal impairment
No known interactions based on clearance. May exacerbate other agents that have CNS effects.
Category C: Risk unknown. Human studies inadequate
Toxic: baseline serum creatinine
Seromycin (Lilly/Dura)