Management of DR-TB ADR: Seizures

Adverse Drug Reactions (ADRs), such as seizures, may occur from the Drug-resistant TB (DR-TB) treatment regimen.

Suspected agent(s): Cycloserine (Cs), Isoniazid (H), Fluoroquinolone (FQ)

Suggested Management Strategies

• Withhold Cs, FQ and H pending resolution of seizures.
• Initiate anticonvulsant treatment: Carbamazepine, Phenytoin or Valproic acid (relatively safe with Bdq) are most commonly used. 
• Check serum electrolytes including potassium, sodium, bicarbonate, calcium, magnesium and chloride. 
• When seizures have resolved, restart the medication, one at a time.
• Cs should not be restarted unless it is absolutely essential to the regimen. If Cs is re-initiated, start a dose one weight band lower.

Points to Note

• An anticonvulsant is generally continued until DR-TB treatment is completed.
• History of previous seizure disorder is not a contraindication if the seizures are well controlled and/or the patient is receiving anticonvulsant treatment.
• Do not include Cs if an alternative drug is available.
• Patients with a history of previous seizures may be at increased risk for developing seizures during DR-TB treatment.
• Always check creatinine in patients with a new-onset of seizures. A decrease in renal function can result in high blood levels of Cs, which can cause seizures. Adjusting the dose of Cs in the presence of low creatinine may be all that is needed to control the seizures.

Resources

• Guidelines for Programmatic Management of Drug-resistant Tuberculosis in India, March 2021.
• WHO Consolidated Guidelines on Tuberculosis: Module 4 - Treatment: Drug-resistant TB Treatment, 2020.
• Technical and Operational Guidelines for TB in India, 2016.

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