title: Absence of clinically relevant pharmacokinetic interaction between ribavirin and tenofovir in healthy subjects.
abstract: This was a 36-day, open-label, fixed-sequence, multiple-dose drug interaction study in 23 healthy subjects to evaluate the effects of multiple doses of tenofovir disoproxil fumarate on the single-dose pharmacokinetics of ribavirin. Subjects received a 600-mg once-daily oral dose of ribavirin on days 1 and 22 and 300-mg once-daily oral doses of tenofovir disoproxil fumarate on days 17 through 24. Pharmacokinetic sampling was performed on days 1 through 4 and 22 through 25. Pharmacokinetics of ribavirin was not altered by its coadministration with tenofovir disoproxil fumarate as the point estimates (day 22 [test treatment]/day 1 [reference treatment]), and the 90% confidence interval for maximum observed concentration (0.95; 88.7-101) and area under the plasma concentration-time curve up to time of last measurable concentration (1.12; 106-117) were within the equivalence bounds of 80% to 125%. Tenofovir pharmacokinetics after ribavirin coadministration was similar to that observed in previous studies. These results indicate that coadministration of tenofovir disoproxil fumarate and ribavirin does not result in substantial changes to their individual pharmacokinetic profiles.
authors.affiliation: Gilead Sciences Inc, Foster City, CA 94404, USA. sramanathan@gilead.com
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Ramanathan
authors.forename: Andrew
authors.initials: A
authors.lastname: Cheng
authors.forename: Angelique
authors.initials: A
authors.lastname: Mittan
authors.forename: Ramin
authors.initials: R
authors.lastname: Ebrahimi
authors.forename: Brian P
authors.initials: BP
authors.lastname: Kearney
mesh_terms: D000225:Adenine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D000328:Adult; D000998:Antiviral Agents / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D004347:Drug Interactions; D005260:Female; D015658:HIV Infections; D006526:Hepatitis C; D006801:Humans; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D012254:Ribavirin / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D000068698:Tenofovir
chemical_list: D000998:Antiviral Agents; D063065:Organophosphonates; D012254:Ribavirin; D000068698:Tenofovir; D000225:Adenine