Reduced valproate plasma levels possible after introduction of efavirenz in a bipolar patient.
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.
Saraga
Michael
M
University Department of Adult Psychiatry, Lausanne, Switzerland. michael.saraga@inst.hospvd.ch
Preisig
Martin
M
Zullino
Daniele Fabio
DF
D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000927:Anticonvulsants / Q000097:blood* / Q000627:therapeutic use; D048588:Benzoxazines; D001714:Bipolar Disorder / Q000097:blood* / Q000150:complications / Q000821:virology; D003521:Cyclopropanes; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D015658:HIV Infections / Q000097:blood / Q000150:complications / Q000188:drug therapy; D006801:Humans; D008297:Male; D010078:Oxazines / Q000494:pharmacology* / Q000627:therapeutic use; D019966:Substance-Related Disorders / Q000097:blood / Q000150:complications / Q000821:virology; D014635:Valproic Acid / Q000097:blood* / Q000627:therapeutic use
D000480:Alkynes; D019380:Anti-HIV Agents; D000927:Anticonvulsants; D048588:Benzoxazines; D003521:Cyclopropanes; D010078:Oxazines; D014635:Valproic Acid; C098320:efavirenz