title: Post-marketing experience with nevirapine extended release (XR) tablets: effectiveness and tolerability in a population-based cohort in British Columbia, Canada.
abstract: BACKGROUND
  Nevirapine 400 mg extended release tablets (nevirapine-XR) are a once-daily alternative to nevirapine 200 mg immediate release tablets (nevirapine-IR). Study objectives were to describe the effectiveness and tolerability of nevirapine-XR in clinical practice and, for patients who switched from once daily 2×200 mg nevirapine-IR to nevirapine-XR, compare virological suppression and plasma nevirapine concentrations during each treatment period.
  
  
  METHODS
  HIV-1-infected adults entered the study cohort if they initiated nevirapine-XR in British Columbia (BC) Canada between 1 April 2012 and 30 September 2012 and were followed until 30 September 2013. Demographic and clinical variables were abstracted from the BC Centre for Excellence in HIV/AIDS databases. Patients who switched from once daily nevirapine-IR to nevirapine-XR were monitored for 6 months pre- and post-switch with comparison of virological suppression (McNeamer's test) and median random plasma nevirapine concentrations (Wilcoxon-Mann-Whitney test) in each period.
  
  
  RESULTS
  The 536 nevirapine-XR-treated patients were 96% male, median (IQR) age 49.9 (44.0-56.9) years. Median follow-up was 15.6 (14.7-16.5) months, with 474/536 (88%) maintaining virological suppression. Emergent drug resistance developed in 5/536 (1%), adverse drug reactions in 17/536 (3%) and, although 31/536 (6%) reported 'whole' tablets in their stools, this was not associated with adverse outcomes. Among the 305 patients who switched from nevirapine-IR to nevirapine-XR, median (IQR) random plasma nevirapine concentration was higher during nevirapine-IR 5,000 (3,690-6,090) ng/ml than nevirapine-XR 3,930 (3,050-5,150) ng/ml (P<0.001), but there was no difference in virological suppression, 89% and 87% respectively (P=0.414).
  
  
  CONCLUSIONS
  This post-marketing study affirms the effectiveness and tolerability of nevirapine-XR as an alternative to nevirapine-IR in adults.
authors.affiliation: BC Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Lepik
authors.forename: Benita
authors.initials: B
authors.lastname: Yip
authors.forename: Rachel A
authors.initials: RA
authors.lastname: McGovern
authors.forename: Erin
authors.initials: E
authors.lastname: Ding
authors.forename: Adriana
authors.initials: A
authors.lastname: Nohpal
authors.forename: Birgit E
authors.initials: BE
authors.lastname: Watson
authors.forename: Junine
authors.initials: J
authors.lastname: Toy
authors.forename: Linda
authors.initials: L
authors.lastname: Akagi
authors.forename: P Richard
authors.initials: PR
authors.lastname: Harrigan
authors.forename: David M
authors.initials: DM
authors.lastname: Moore
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hogg
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
authors.forename: Rolando
authors.initials: R
authors.lastname: Barrios
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D023241:Antiretroviral Therapy, Highly Active; D001955:British Columbia / Q000453:epidemiology; D015331:Cohort Studies; D003692:Delayed-Action Preparations; D016903:Drug Monitoring; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology; D015497:HIV-1; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D019829:Nevirapine / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D011159:Population Surveillance; D011358:Product Surveillance, Postmarketing; D019233:Retreatment; D013607:Tablets; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D003692:Delayed-Action Preparations; D013607:Tablets; D019829:Nevirapine