Management of DR-TB ADR: Vestibular Toxicity

Vestibular toxicity is one of the Adverse Drug Reactions (ADRs) that results in damage of the balance structure in the inner ear leading to loss of balance for the patient.

Suspected agent(s): Amikacin (Am), Cycloserine (Cs), Fluoroquinolones (FQs), Isoniazid (H), Ethionamide (Eto), Linezolid (Lzd)

Suggested Management Strategies

• If early symptoms of vestibular toxicity appear, there may be a need to change the dosing of the injectable agent to twice/ thrice a week.
• Consider using Capreomycin (Cm) if an aminoglycoside was the prior injectable in the regimen. 
• If tinnitus and unsteadiness worsen with the above adjustment, stop the injectable agent. 
• This is one of the few adverse events that may cause permanent intolerable toxicity and can necessitate the discontinuation of a class of agents.

Points to Note

• Ask the patient about tinnitus and unsteadiness every week, especially in elderly patients.
• Fullness in the ears and intermittent ringing are early symptoms of vestibular toxicity.
• A degree of disequilibrium can be caused by Cs, FQs, Eto, H or Lzd.
• Some clinicians will stop all drugs for several days to see if symptoms are attributed to these drugs.
• Symptoms of vestibular toxicity generally do not improve on withholding medications.

Resources

• Guidelines for Programmatic Management of Drug-resistant Tuberculosis in India, March 2021.
• Ready Reckoner for Medical Officers - Adverse Drug Reactions Associated with Anti-TB Drugs Identification and Management, 2019.

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