ISONIAZID SHOULD BE TAKEN ON AN EMPTY STOMACH!

.. . Bioavailability Is Reduced After Food, Regardless Of Acetylation Rate The bioavailability of isoniazid (INH) was strongly reduced with concomitant food intake in 9 healthy male volunteers. Peak concentration, mean concentration and the total amount ofiNH absorbed were diminished. 'Irrespective of the mechanism involved, the observations motivate a strictly defined dosage regimen for !NH in the treatment of tuberculosis. wilh 1he drug always given on an empty stomach. Moreover, the decision about dose size should be based 011 assessme11ts of single-dose kinetics of IN H. ' The 9 subjects aged 28-35 were given a single dose of INH I OOmg/ I Okg either with I OOml water or immediately after a standard breakfast.

'Whether he was a rapid or a slow acetylator, each subject had lower mean serum levels of INH when the drug had been ingested after the breakfast than when it had been taken on an empty stomach ... the acetylation rate as such may be an insufficient parameter for the proper adjustment of the dosage regimen/or IN H. hydralazine and other drugs subject to the same mode of biotransformation.'

Melander, A. c1 al.: Aclll Medica Scandinavica 200: 93 (No l-2. !976)

INPHARMA 4th December, 1976 p 16