Differences in nevirapine biotransformation as a factor for its sex-dependent dimorphic profile of adverse drug reactions.
OBJECTIVE
Nevirapine is widely used for the treatment of HIV-1 infection; however, its chronic use has been associated with severe liver and skin toxicity. Women are at increased risk for these toxic events, but the reasons for the sex-related differences are unclear. Disparities in the biotransformation of nevirapine and the generation of toxic metabolites between men and women might be the underlying cause. The present work aimed to explore sex differences in nevirapine biotransformation as a potential factor in nevirapine-induced toxicity.


METHODS
All included subjects were adults who had been receiving 400 mg of nevirapine once daily for at least 1 month. Blood samples were collected and the levels of nevirapine and its phase I metabolites were quantified by HPLC. Anthropometric and clinical data, and nevirapine metabolite profiles, were assessed for sex-related differences.


RESULTS
A total of 52 patients were included (63% were men). Body weight was lower in women (P = 0.028) and female sex was associated with higher alkaline phosphatase (P = 0.036) and lactate dehydrogenase (P = 0.037) levels. The plasma concentrations of nevirapine (P = 0.030) and the metabolite 3-hydroxy-nevirapine (P = 0.035), as well as the proportions of the metabolites 12-hydroxy-nevirapine (P = 0.037) and 3-hydroxy-nevirapine (P = 0.001), were higher in women, when adjusted for body weight.


CONCLUSIONS
There was a sex-dependent variation in nevirapine biotransformation, particularly in the generation of the 12-hydroxy-nevirapine and 3-hydroxy-nevirapine metabolites. These data are consistent with the sex-dependent formation of toxic reactive metabolites, which may contribute to the sex-dependent dimorphic profile of nevirapine toxicity.
Centro de Estudos de Doenças Crónicas (CEDOC), NOVA Medical School, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal.
Aline T
AT
Marinho
Patrícia M
PM
Rodrigues
Umbelina
U
Caixas
Alexandra M M
AM
Antunes
Teresa
T
Branco
Shrika G
SG
Harjivan
M Matilde
MM
Marques
Emília C
EC
Monteiro
Sofia A
SA
Pereira
D000328:Adult; D019380:Anti-HIV Agents / Q000009:adverse effects* / Q000097:blood*; D001711:Biotransformation / Q000187:drug effects / Q000502:physiology; D064420:Drug-Related Side Effects and Adverse Reactions / Q000097:blood* / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019829:Nevirapine / Q000009:adverse effects* / Q000097:blood*; D012727:Sex Characteristics
D019380:Anti-HIV Agents; D019829:Nevirapine
nevirapine metabolism; nevirapine toxicity; sex differences; sex-dependent pharmacokinetics