Cycloserine
Cycloserine (Seromycin)
Cycloserine
(sye-kloh- SEE-reen)
Pregnancy Category: C Seromycin (Rx)

Classification: Antitubercular agent for retreatment regimens

Action/Kinetics: Produced by a strain of Streptomyces orchidaceus or Garyphalus lavendulae. Acts by inhibiting cell wall synthesis by interfering with the incorporation of the amino acid alanine. Well absorbed from the GI tract and widely distributed in body tissues. Time to peak plasma levels: 3-8 hr. CSF levels are similar to those in plasma. t 1/2: 10 hr. From 60% to 70% is excreted unchanged in urine.

Uses: With other drugs to treat active pulmonary and extrapulmonary tuberculosis only when primary therapy cannot be used. To treat UTIs when other therapy has failed or if the organism has demonstrated sensitivity.

Contraindications: Hypersensitivity to cycloserine, epilepsy, depression, severe anxiety, psychosis, severe renal insufficiency, and alcoholism. Lactation.

Special Concerns: Safe use during pregnancy and in children has not been established.

Side Effects: CNS: Drowsiness, headache, mental confusion, tremors, vertigo, loss of memory, psychoses (possibly with suicidal tendencies) character changes, hyperirritability, aggression, increased reflexes, seizures paresthesias, paresis, coma. Neurotoxic effects depend on blood levels of cycloserine. Hence, frequent determinations of cycloserine blood levels are indicated, especially during the initial period of therapy. Other: Sudden development of CHF, skin rashes, increased transaminase.

Overdose Management: Symptoms: CNS depression, including drowsiness, mental confusion, headache, vertigo, paresthesias, dysarthrias, hyperirritability, psychosis, paresis, seizures and coma. Treatment: Supportive therapy. Charcoal may be more effective than emesis or gastric lavage. Hemodialysis may be used for life-threatening toxicity. Pyridoxine may treat neurotoxic effects.

Drug Interactions: Ethanol / Risk of epileptic episodes Isoniazid / Risk of cycloserine CNS side effects (especially dizziness)

How Supplied: Capsule: 25 mg

Dosage
?Capsules
Adults, initially: 250 mg q 12 hr for first 2 weeks; then, 0.5-1 g/day in divided doses based on blood levels. Dosage should not exceed 1 g/day. Pediatric: 10-20 mg/kg/day, not to exceed 0.75-1 g/day. NOTE: Pyridoxine, 200-300 mg/day may prevent neurotoxic effects.