title: The disposition of antituberculous drugs in plasma of elderly patients. II. Isoniazid, rifampicin and pyrazinamide.
abstract: The pharmacokinetics of isoniazid (INH), rifampicin (RIF) and pyrazinamide (PZA) were studied in 18 elderly patients (67-89 years of age) and 19 young adult patients (19-59 years of age) on the first day and at one month of treatment for pulmonary tuberculosis. Elderly patients exhibited more side effects but there were no age-related changes in the pharmacokinetics of any of the three drugs when used in this combination. The clearance for INH and RIF at steady-state were significantly lower than after first-dose, while that of PZA remained unchanged. At steady-state the clearances for INH and RIF were not characteristic of polymorphic metabolism and auto-enzyme induction, respectively. Elderly patients are more sensitive to antituberculous (anti-TB) drugs; therefore, a modification in the dosage for this patient group should be considered.
authors.affiliation: Department of Pharmacology, Chinese University of Hong Kong, Shatin.
authors.forename: A
authors.initials: A
authors.lastname: Walubo
authors.forename: K
authors.initials: K
authors.lastname: Chan
authors.forename: J
authors.initials: J
authors.lastname: Woo
authors.forename: H S
authors.initials: HS
authors.lastname: Chan
authors.forename: C L
authors.initials: CL
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D005260:Female; D006801:Humans; D007538:Isoniazid / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011718:Pyrazinamide / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D012293:Rifampin / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D011718:Pyrazinamide; D007538:Isoniazid; D012293:Rifampin