Generic Name

Cycloserine

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Classification

FDA Approved Indications

• Treatment of tuberculosis caused by susceptible strains when used in combination with other antituberculosis agents

Mechanism of Action

Cycloserine inhibits bacterial cell wall synthesis by inhibiting the enzyme alanine racemase and D-Ala-D-Ala ligase, essential for peptidoglycan synthesis in mycobacterial cell walls.

Dosage and Administration

Adult: 250-500 mg orally twice daily, adjusted based on response and tolerability

Pediatric: Not commonly used in pediatric populations; dosing is weight-based and determined by clinician

Geriatric: Careful monitoring recommended due to potential neurotoxicity; dosage adjustments may be necessary

Renal Impairment: Reduce dose in patients with renal impairment due to renal clearance of the drug

Hepatic Impairment: Use with caution; no specific dosage adjustment established

Pharmacokinetics

Absorption: Well absorbed orally

Distribution: Widely distributed in body tissues and fluids, including cerebrospinal fluid

Metabolism: Minimal hepatic metabolism

Excretion: Primarily excreted unchanged in urine

Half Life: ~10 hours

Contraindications

• History of seizure disorder
• Concurrent use with drugs lowering the seizure threshold

Precautions

• Neurotoxicity (psychosis, depression, seizures)
• Renal impairment may increase toxicity risk, monitor renal function closely

Adverse Reactions - Common

• Neurotoxicity (psychosis, depression, confusion) (Common)
• Seizures (Less common)

Adverse Reactions - Serious

• Neurotoxicity leading to psychosis or seizures (Possible, especially at higher doses or in predisposed individuals)

Drug-Drug Interactions

• CNS depressants (may enhance neurotoxicity)
• Drugs lowering seizure threshold (e.g., imipramine, carbamazepine)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed
• Report any mental changes, seizures, or new neurological symptoms immediately
• Avoid alcohol and CNS depressants during therapy
• Stay hydrated and maintain hydration to support renal function

Special Considerations

Black Box Warnings:

• Neurotoxicity, including psychosis and seizures, especially in predisposed patients

Genetic Factors: No known genetic contraindications

Lab Test Interference: Potential false elevation of blood urea nitrogen (BUN) and creatinine

Overdose Management

Signs/Symptoms: Seizures, confusion, hallucinations, coma

Treatment: Supportive care; administer benzodiazepines for seizures; monitor electrolytes and renal function; maintain airway

Storage and Handling

Storage: Store at room temperature, away from moisture and light

Stability: Stable as per package insert; discard after expiration date