Sir,
I read with interest the paper on Isoniazid induced cerebellitis by Shah VS and Sardana V in the recent AIAN journal.[1] The authors described a patient with chronic renal disease, on 375 mg of isoniazid without pyridoxine supplements, who developed cerebellar toxicity. His MRI showed classical dentate signal changes and he made clinical and radiological recovery following withdrawal of isoniazid and addition of pyridoxine. Certainly, the paper is an important reminder for clinicians to be cautious of this complication in renal disease. However, two statements in the discussion section could confuse the clinicians on the appropriate dose of isoniazid in renal disease. The authors initially, and rightly, state that no dose modification of isoniazid is needed in renal disease. But, in the concluding remarks, they infer from this particular case that a dose modification of ‘anti tubercular drugs’ is indeed needed.
A literature search revealed that the available guidelines advise no dose modification of isoniazid in patients with renal disease, even if they are on hemodialysis.[2] Similarly, no dose modification is needed for rifampicin, pyrazinamide, moxifloxacin and linezolid.[2,3] Ethambutol can be given in standard doses in stage 1 to 3 Chronic Kidney Disease (CKD) and in patients on hemodialysis, but in stage 4 and 5, 15–25 mg/kg 3×/week (maximum 2.5 g) is recommended. Specific dosing guidelines for other drugs are also available.[3] All drugs need to be given 4–6 hours before the scheduled hemodialysis or after the completion of hemodilaysis. Adherence to the standard guidelines minimizes the risk of drug toxicities as well as under treatment of this serious infection.
To conclude, clinicians can safely use the standard dose of isoniazid in renal disease, which is 5 mg/kg/day, with a maximum of 300 mg/day.
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REFERENCES
- 1.Shah VS, Sardana V. A case of isoniazid induced cerebellitis in a patient with chronic renal failure. Ann Indian Acad Neurol. 2021;24:95–7. doi: 10.4103/aian.AIAN_547_19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Milburn H, Ashman N, Davies P, Doffman S, Drobniewski F, Khoo S, et al. Guidelines for the prevention and management of Mycobacterium tuberculosis infection and disease in adult patients with chronic kidney disease. Thorax. 2010;65:557–70. doi: 10.1136/thx.2009.133173. [DOI] [PubMed] [Google Scholar]
- 3.Guideline – Treatment of tuberculosis in renal disease. Version 3. 0. Available from: https://www.health.qld.gov.au/__data/assets/pdf_file/0024/444507/tb-guideline-renal.pdf .