Cycloserine
Mechanism :
Cycloserine is an analog of the amino acid D-alanine. It interferes with an early step in bacterial cell wall synthesis in the cytoplasm by competitive inhibition of two enzymes, L-alanine racemase, which forms D-alanine from L-alanine, and D-alanylalanine synthetase, which incorporates D-alanine into the pentapeptide necessary for peptidoglycan formation and bacterial cell wall synthesis.
Indication :
- Mycobacterium avium complex (MAC)
- Multi-drug resistant tuberculosis (TB).
Contraindications :
Hypersensitivity; Alcohol use; Renal dysfunction, severe; History of seizure disorder, mental depression, severe anxiety or psychosis.
Dosing :
15-20 mg/kg/day (Oral) in divided doses upto 1 g/day for a period of 18-24 months.
Adverse Effect :
Confusion, dizziness, headache, somnolence, seizure, vertigo, arrhythmias and heart failure.
Interaction :
Ethanol: May increase risk of cycloserine-assoc. CNS toxicity, seizures (additive toxicity).
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | 250–500 mg every 12–24 hours. Monitor blood levels weekly |
| 10-20 | 250–500 mg every 12–24 hours. Monitor blood levels weekly |
| <10 | 250–500 mg every 24 hours. Monitor blood levels weekly |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unknown dialysability. Dose as in GFR<10 mL/min |
| HD | Dialysed. Dose as in GFR<10 mL/ min |
| HDF/High flux | Dialysed. Dose as in GFR<10 mL/ min |
| CAV/VVHD | Likely dialysability. Dose as in GFR=10–20 mL/min |
Hepatic Dose :
No dosage adjustments are recommended.