CYCLOSERINE
DOSAGE
Adults: Initially 250mg twice a day (oral), increased to 500mg twice a day depending on serum concentrations.
The usual target dose in adults is 10-20mg/kg/day once or twice per day. Maximum 1g per day.
Children: 15-20 mg/kg once daily. Maximum 1g per day.
All patients must be prescribed pyridoxine whilst receiving cycloserine. The usual dose ranges from 50 to 100mg daily, up to 50mg per 250mg of cycloserine.
PREPARATIONS
Oral: 250mg capsules.
DRUG LEVEL MONITORING
Indications for monitoring:
10 – 20mg/L
Timing of sample:
ADVERSE EFFECTS
COMMON:
Neurological: Confusion, disorientation, dizziness, somnolence (increased risk if peak serum level >35mg/L).
SERIOUS:
Cardiovascular: Sudden development of congestive heart failure (rarely reported at doses greater than 1 to 1.5g daily).
Dermatological: Rash and photosensitivity, Stevens-Johnson syndrome (rare).
Haematological: Vitamin B12 and/ or folic acid deficiency, megaloblastic anaemia or sideroblastic anaemia (rare).
Psychiatric: Depression, seizure, psychotic disturbances (increased risk if peak serum level >35mg/L).
ADVERSE EFFECTS: MONITORING
Routine tests as per generic MDR-TB treatment monitoring guidelines.
INTERACTONS
Alcohol: Increased risk of convulsions with cycloserine.
Isoniazid: Increased risk of CNS toxicity when given with cycloserine.
This information is not inclusive of all drug interactions. Please discuss with a pharmacist.
CONTRA-INDICATIONS & CAUTIONS
Contraindications:
Hypersensitivity: To cycloserine.
Neurological: Epilepsy, depression, severe anxiety, psychotic states.
Alcohol Dependence.
Renal Disease: Severe renal impairment.
Cautions:
Pregnancy & Breast-feeding
Neurological: Stop or reduce dose if symptoms of central nervous system toxicity such as convulsions, psychosis, somnolence, depression, confusion, hyper-reflexia, headache, tremor, vertigo, paresis or dysarthria.
Dermatological: Stop or reduce dose if allergic dermatitis develops.
Renal Disease: Use with caution. Reduce dose in severe renal impairment.
LABORATORY INFORMATION
Please find up to date information at www.assayfinder.com regarding individual providers of drug level monitoring tests. Click on the provider to discover contact details. Turnaround time varies depending on the test and whether it is run locally or sent to an external lab. By contacting laboratories in advance, turnaround time can significantly be reduced.
Adults: Initially 250mg twice a day (oral), increased to 500mg twice a day depending on serum concentrations.
The usual target dose in adults is 10-20mg/kg/day once or twice per day. Maximum 1g per day.
Children: 15-20 mg/kg once daily. Maximum 1g per day.
All patients must be prescribed pyridoxine whilst receiving cycloserine. The usual dose ranges from 50 to 100mg daily, up to 50mg per 250mg of cycloserine.
PREPARATIONS
Oral: 250mg capsules.
DRUG LEVEL MONITORING
Indications for monitoring:
- Ensure therapeutic dose.
- Ensure toxic levels are not reached.
- Renal impairment.
10 – 20mg/L
Timing of sample:
- Peak: 3-4 hours post dose.
- Repeat at 6 hours if suspect delayed absorption.
- Trough levels – taken immediately prior to a dose.
- Serum levels after 4 days at target dose.
- Repeat fortnightly for one month and until stable. Serum levels may increase over a 2-week period despite a stable dose due to accumulation of cycloserine.
- Repeat at least 6 monthly.
- Repeat if suspect malabsorption, treatment failure, or neuropsychiatric side effects (should be monitored monthly).
- Patients with reduced renal function require more frequent monitoring, initially weekly until stable.
- High Peak Level: Reduce dose if level >35mg/L. If level is 35 to 50mg/L, consider reducing dose by 25% per day. If level >50mg/L, consider halving the dose. Recheck level after four days.
- Low Peak Level: Increase dose if level <15mg/L.
- Trough levels: Cyloserine absorption may be slow and consequently a 2-hour peak level may not capture the true Cmax. It is rare to see elevated peak levels in the absence of elevated trough levels, therefore a raised trough level may indicate potentially toxic ‘true’ peak levels. Consider serial peak serum level assays (e.g. at 2, 4 and 6 hours post dose), and dose reduction.
ADVERSE EFFECTS
COMMON:
Neurological: Confusion, disorientation, dizziness, somnolence (increased risk if peak serum level >35mg/L).
SERIOUS:
Cardiovascular: Sudden development of congestive heart failure (rarely reported at doses greater than 1 to 1.5g daily).
Dermatological: Rash and photosensitivity, Stevens-Johnson syndrome (rare).
Haematological: Vitamin B12 and/ or folic acid deficiency, megaloblastic anaemia or sideroblastic anaemia (rare).
Psychiatric: Depression, seizure, psychotic disturbances (increased risk if peak serum level >35mg/L).
ADVERSE EFFECTS: MONITORING
Routine tests as per generic MDR-TB treatment monitoring guidelines.
INTERACTONS
Alcohol: Increased risk of convulsions with cycloserine.
Isoniazid: Increased risk of CNS toxicity when given with cycloserine.
This information is not inclusive of all drug interactions. Please discuss with a pharmacist.
CONTRA-INDICATIONS & CAUTIONS
Contraindications:
Hypersensitivity: To cycloserine.
Neurological: Epilepsy, depression, severe anxiety, psychotic states.
Alcohol Dependence.
Renal Disease: Severe renal impairment.
Cautions:
Pregnancy & Breast-feeding
Neurological: Stop or reduce dose if symptoms of central nervous system toxicity such as convulsions, psychosis, somnolence, depression, confusion, hyper-reflexia, headache, tremor, vertigo, paresis or dysarthria.
Dermatological: Stop or reduce dose if allergic dermatitis develops.
Renal Disease: Use with caution. Reduce dose in severe renal impairment.
LABORATORY INFORMATION
Please find up to date information at www.assayfinder.com regarding individual providers of drug level monitoring tests. Click on the provider to discover contact details. Turnaround time varies depending on the test and whether it is run locally or sent to an external lab. By contacting laboratories in advance, turnaround time can significantly be reduced.