title: Sino-implant (II)® continuation and effect of concomitant tenofovir disoproxil fumarate-emtricitabine use on plasma levonorgestrel concentrations among women in Bondo, Kenya.
abstract: OBJECTIVE
  The objective was to assess associations between tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) exposure and levonorgestrel (LNG) concentrations among Kenyan HIV prevention trial participants using Sino-implant (II) LNG implants for contraception.
  
  
  METHODS
  Women were offered implants among other contraceptive methods, were randomized to daily TDF-FTC or placebo, and followed monthly up to 56weeks. Associations between TDF-FTC exposure and mean LNG values were analyzed with linear mixed models.
  
  
  RESULTS
  Of 739 women, 29 (3.9%) received implants with no incident pregnancies and one discontinuation. Mean LNG concentrations over 56weeks among 28 women contributing data ranged between 214.0 and 659.8pg/mL with no significant difference between TDF-FTC and placebo arms or between variable levels of TDF-FTC adherence.
  
  
  CONCLUSIONS
  Concomitant TDF-FTC use was not associated with a significant change in plasma LNG concentrations among women using Sino-implant (II) in the first year of use.
authors.affiliation: FHI 360, Durham, NC, USA. Electronic address: CTodd@fhi360.org.
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Todd
authors.affiliation: FHI 360, Durham, NC, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Deese
authors.affiliation: FHI 360, Durham, NC, USA.
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.affiliation: FHI 360, Durham, NC, USA.
authors.forename: David
authors.initials: D
authors.lastname: Hubacher
authors.affiliation: FHI 360, Durham, NC, USA.
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Steiner
authors.affiliation: Impact Research and Development Organization, Kisumu, Kenya.
authors.forename: Sheila
authors.initials: S
authors.lastname: Otunga
authors.affiliation: The Bill & Melinda Gates Foundation, Seattle, WA, USA(2).
authors.forename: Lut
authors.initials: L
authors.lastname: Van Damme
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000494:pharmacology*; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004338:Drug Combinations; D004343:Drug Implants; D000068679:Emtricitabine; D005260:Female; D015658:HIV Infections / Q000517:prevention & control; D006801:Humans; D007630:Kenya; D016912:Levonorgestrel / Q000008:administration & dosage* / Q000097:blood*; D008137:Longitudinal Studies; D063065:Organophosphonates / Q000494:pharmacology*; D019338:Polypharmacy; D011446:Prospective Studies; D000068698:Tenofovir; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D003271:Contraceptive Agents, Female; D004338:Drug Combinations; D004343:Drug Implants; D063065:Organophosphonates; D003841:Deoxycytidine; D016912:Levonorgestrel; D000068698:Tenofovir; D000068679:Emtricitabine; D000225:Adenine
keywords: Levonorgestrel implant; Levonorgestrel levels; Long-acting reversible contraception; Preexposure prophylaxis; Prospective study; Sino-implant (II)