Cycloserine (Cs) or terizidone (Trd)

Update: January 2022

Forms and strengths

• 250 mg and 125 mg capsules

Dosage

• Child under 30 kg: 7.5 to 10 mg/kg 2 times daily (or 15 to 20 mg/kg once daily if tolerated)
• Child 30 kg and over and adult: 5 to 7.5 mg/kg 2 times daily (or 10 to 15 mg/kg once daily if tolerated)
• Maximum dose: 1000 mg daily
• Renal insufficiency: 250 mg once daily or 500 mg 3 times a week

Contra-indications, adverse effects, precautions

• Avoid in patients with epilepsy, depression, psychosis, severe anxiety, history of nervous system or psychiatric disorders, chronic alcohol use. However, if essential to the regimen, it can be administered under close monitoring.
• May cause:
  • nervous system and psychiatric disorders: seizure, headache, lethargy, confusion, mood change, drowsiness, anxiety, psychosis, depression, suicidal ideation, peripheral neuropathy; rarely, vestibular toxicity;
  • hypersensitivity reactions.
• For the management of adverse effects, see Appendix 17.
• Avoid or monitor combination with isoniazid and thionamides (increased risk of neurotoxicity).
• Administer concomitantly pyridoxine (vitamin B₆); child: 1 to 2 mg/kg (usual range: 10 to 50 mg) once daily; adult: 100 mg once daily.
• Pregnancy: use only if the benefits outweigh the risks. Administer pyridoxine to the mother (as above).
• Breastfeeding: no contra-indication. Administer pyridoxine to the mother (as above) and the breast-fed neonate or infant (1 to 2 mg/kg once daily).

Monitoring

• Symptomatic monitoring.

Patient instructions

• Take capsules with water before or after meals.
• Avoid alcohol during treatment.

Remarks

• To increase tolerance, start with a low dose (e.g. 250 mg daily in adults), then increase over 1 to 2 weeks to achieve the requested dose.

Storage