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Reduced valproate plasma levels possible after introduction of efavirenz in a bipolar patient
Author(s) -
Saraga Michael,
Preisig Martin,
Zullino Daniele Fabio
Publication year - 2006
Publication title -
bipolar disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.285
H-Index - 129
eISSN - 1399-5618
pISSN - 1398-5647
DOI - 10.1111/j.1399-5618.2006.00331.x
Subject(s) - efavirenz , epilepsy , pharmacokinetics , concomitant , medicine , pharmacology , plasma levels , human immunodeficiency virus (hiv) , antiretroviral therapy , endocrinology , psychiatry , viral load , virology
The case of a bipolar patient with concomitant multidrug addiction is described who presented a decrease in valproate plasma level of more than 50% shortly after antiretroviral therapy was initiated. Despite important dose augmentations of up to 4 g/day, plasma levels were difficult to raise to the target concentration of 50 mg/dL. The possible mechanisms underlying the observed pharmacokinetic changes are discussed: (i) a uridine diphosphate‐glucuronosyl transferase induction by efavirenz; and (ii) a plasma protein displacement of valproate by efavirenz with subsequent increased elimination of the free fraction.