Pharmacokinetic Profile of Isoniazid and Acetylator Status in Patients with Systemic Lupus Erythematosus: Implications for Tuberculosis Prevention Therapy in Indonesia.

Introduction: Systemic Lupus Erythematosus (SLE) is a chronic autoimmune inflammatory disease with a high risk of tuberculosis (TB) infection, especially in those living in TB-endemic areas. Isoniazid (INH), an anti-tuberculosis drug, is recommended as preventive therapy in TB susceptible groups, however, its use in SLE is still controversial. SLE patients are more likely to have compromised liver function which can influence the kinetic of INH. The aim of the study was to explore the pharmacokinetic profile of INH and acetylator status in SLE patients.

Methods: This was a descriptive observational study with a purposive sampling technique, including adult female SLE at Dr. Hasan Sadikin Hospital Bandung, conducted in January - August 2023. Inclusion criteria were SLE patients in remission with no TB infection; whereas the exclusion criteria were INH allergy, liver or kidney disorders, pregnant or lactating patients, and malignancy. Pharmacokinetic data was collected from six blood collection time points (0, 1, 2, 3, 4, and 8 hours) after 10 days of daily INH 300 mg administration on an empty stomach.

Results: In total, 20 female SLE patients were included. The C_max value was 8.73 (2.55-18.27) mg/L and AUC_0-24 was 28.01 (8.82-79.40) mg.h/L.

Conclusion: In terms of pharmacokinetic features, preventive isoniazid (INH) daily use of 300mg in SLE is sufficient to provide the prospect of protection from TB. These findings suggest that INH prophylaxis may be a viable strategy for TB prevention in SLE patients, warranting further investigation into long-term safety and efficacy.