Antitubercular Drug Management in Critically Ill Patients

Introduction to Antitubercular Therapy

The Infectious Diseases Society of America recommends adjusting dosing intervals, not doses, for antitubercular drugs in critically ill patients with renal impairment, as reducing doses compromises peak concentrations and treatment efficacy 1, 2, 3

In patients with renal impairment (CrCl <30 mL/min), the American Thoracic Society suggests increasing the dosing interval to three times weekly for pyrazinamide and ethambutol, rather than reducing the dose, to maintain therapeutic peak levels 1, 2, 3
The Centers for Disease Control and Prevention recommend that isoniazid and rifampin can be given at standard doses (300 mg and 600 mg, respectively) three times weekly in patients with renal impairment, as they are hepatically metabolized 1, 2, 3

For patients with advanced liver disease or baseline ALT >3× upper limit of normal, the World Health Organization recommends omitting pyrazinamide and using isoniazid, rifampin, and ethambutol for 2 months, followed by 7 months of isoniazid and rifampin (total 9 months) 5

The European Respiratory Society suggests measuring serum drug concentrations in all ICU patients with renal or hepatic impairment, as altered pharmacokinetics are universal in critical illness 4
The Infectious Diseases Society of America recommends collecting blood at 2 hours post-dose as the primary time point to capture peak concentrations (Cmax) for isoniazid, rifampin, pyrazinamide, and ethambutol 4

The American Thoracic Society recommends giving pyridoxine 25-50 mg daily with isoniazid to all ICU patients, as they universally meet high-risk criteria for neuropathy 7, 1

The Centers for Disease Control and Prevention advise against reducing doses in renal impairment, as it lowers peak concentrations and compromises concentration-dependent bacterial killing 2, 3, 4
The Infectious Diseases Society of America warns against assuming "normal" creatinine means normal renal function, as serum creatinine is misleading in elderly patients, those with low muscle mass, or patients on continuous renal replacement therapy (CRRT) 4
The World Health Organization emphasizes the importance of immediately stopping hepatotoxic drugs if bilirubin rises at any level, regardless of transaminase values 5