Haemodialysis of pyrazinamide in uraemic patients

Pharmacokinetic Considerations in the Treatment of Tuberculosis in Patients with Renal Failure

Tuberculosis is re-emerging in patients with altered immune status, such as those with chronic renal failure. Clinicians should thus be aware of the pharmacokinetics and dosage adjustment of antitubercular drugs in patients with renal insufficiency. Among patients with renal insufficiency, those who are dialysed should be treated with special care. Indeed, dosage should always be closely adjusted in these patients and potential removal by dialysis must be taken into account. However reliable the dosage adjustment recommendations are for these drugs in patients with renal failure, further pharmacokinetic investigations need to be performed, especially in dialysis patients in whom the influence of haemodialysis and continuous ambulatory peritoneal dialysis on drug pharmacokinetics needs to be detailed. In the meantime, it could be generally advised to administer all antitubercular drugs after the haemodialysis session, even though some drugs are known to be non-dialysable.

Mycobacterial infections in patients with chronic renal disease

In this article, the authors have provided a comprehensive review of TB and MOTT infections in patients on renal dialysis and receiving kidney transplants. Because most published series are small retrospective studies or case reports, there are several uncertainties still involved in the diagnosis and treatment of such patients. Unanswered questions include selection of optimal dosage and duration of therapeutic agents; the best tests for screening and diagnosis, especially in high prevalence areas; and the best management of MOTT infections because of unavailability of highly effective therapy.

The effect of hemodialysis on isoniazid, rifampin, pyrazinamide, and ethambutol

This study examines hemodialysis clearances of isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol (EMB). Seven chronic hemodialysis patients were studied. Six were given single oral doses (INH 300 mg, RIF 600 mg, PZA 1000 mg, and EMB 25 mg/kg) 2 h before hemodialysis (Cobe Centrysystem 3 hemodialysis machine; Fresenius F80B dialyzer; median blood flow rate 400 ml/min; dialysate flow rate 600 ml/min; median hemodialysis time 3.5 h). The seventh subject, being treated for tuberculosis (TB), was studied with his usual regimen. Arterial and venous serum samples were collected at the beginning and end of hemodialysis, and hourly during hemodialysis. Dialysate was collected for the duration of hemodialysis. All samples were assayed for drug concentrations using high-performance liquid chromatography (HPLC) (INH, RIF) and gas chromatography/mass spectrometry (GC/MS) (PZA, EMB) methods. Median recoveries of drug in dialysate were 9% (INH), 4% (RIF), 45% (PZA), and 2% (EMB) of the doses administered. Median hemodialysis clearances calculated by dividing the amount recovered in dialysate by the serum area under the curve during hemodialysis were 124 (INH), 40 (RIF), 270 (PZA), and 46 (EMB) ml/min. INH, RIF, and EMB were not significantly removed by hemodialysis. PZA is significantly dialyzed and should be dosed after hemodialysis.