Zileuton
Zileuton. 5-lipoxygenase inhibitor — blocks leukotriene biosynthesis upstream of CysLT1 receptor. Asthma maintenance; less used than… Oral half-life 2.3 h.
5-lipoxygenase inhibitor — blocks leukotriene biosynthesis upstream of CysLT1 receptor. Asthma maintenance; less used than montelukast. CYP1A2 inhibitor (raises theophylline + propranolol). Hepatotoxicity warning requires LFT monitoring.
PK: THE VOLUME IS VERBATIM AND THE ABSTRACT OWN WORDING MAKES IT APPARENT — "apparent total plasma clearance, and APPARENT terminal phase volume of distribution values after the q8h and q6h regimens were ... 793 +/- 233 and 579 +/- 162 ml/min, and 179 +/- 126 and 115 +/- 29L, respectively" — so pairing it with an independent bioavailability divided by that quantity twice. THE DIRECTION WAS CHECKED BEFORE ACTING, as the contract requires, AND HERE FIXING F ALONE MAKES THE RECORD BETTER: implied clearance moves from 1.15x high to 0.92x of the paper own figure. Note the stored volume is also the q6h ARM ONLY, where the q8h arm is 179 L. The half-life was stated nowhere in that abstract, which reports only peak concentration, peak time, clearance and volume; the value adopted is that paper own volume over its own clearance for the same arm. ka 1.5 is removed for a reason worth recording: the abstract verbatim peak time is "1.5 +/- 0.9 and 1.5 +/- 0.9 hours", NUMERICALLY IDENTICAL TO THE STORED RATE, which is the confirmed collision shape — although 1.5 is also a catalog default on two dozen routes, and it does not even reproduce that peak time. THE DOSE BLOCK IS SEPARATELY WRONG and is corrected: it mixed an immediate-release unit dose, a controlled-release unit dose and a daily total. DOSING: THE BLOCK MIXED THREE DIFFERENT QUANTITIES. Its minimum was the immediate-release unit dose, its typical was the CONTROLLED-RELEASE unit dose, and its maximum was A DAILY TOTAL RATHER THAN A UNIT DOSE AT ALL — under a citation that studied only 600 mg immediate-release, four and six hourly. The value most surfaces read, the typical, was the one with no support. The block is narrowed to the dose its citation actually studied.
Pharmacokinetics
- Oral — t½ 2.3 h · F 100% · ka 1.315 h⁻¹ · Vd 115 L
Sources: PMID:8620668