Comparison of single-dose and multiple-dose pharmacokinetics between two formulations of hydrocodone bitartrate/acetaminophen: immediate-release versus biphasic immediate-release/extended release.

Objective: This study aimed to compare the single-dose and steady-state pharmacokinetics (PK) of biphasic immediate-release (IR)/extended-release (ER) hydrocodone bitartrate (HB)/acetaminophen (APAP) and IR HB/APAP. Setting: The study was conducted in a contract research center. Participants: The study included healthy adults. Interventions: In a three-way crossover study, Study 1, participants received the following treatments: (A1) a single dose of IR/ER HB/APAP 7.5/325 mg one tablet, followed by one tablet every 12 hours (q12h); (B1) a single dose of IR/ER HB/APAP 7.5/325 mg two tablets, followed by two tablets q12h; (C1) a single dose of IR HB/APAP 7.5/325 mg two tablets (one tablet at hours 0 and 6), followed by one tablet q6h. In a two-way crossover study, Study 2, participants received the following treatments: (A2) an initial dose of IR/ER HB/APAP 7.5/325 mg three tablets, followed by two tablets q12h; (B2) three doses of IR HB/APAP 7.5/325 mg one tablet q4h, followed by one tablet q6h. Main outcome measures: PK values were compared, and adverse events were assessed. Results: Single-dose and steady-state area under the concentration-time curves for hydrocodone and APAP were similar for IR/ER and IR HB/APAP; the steady-state peak plasma concentrations (C-max) at steady state were also similar, but single-dose Cmax for hydrocodone was lower for IR/ER HB/APAP. For most PK parameters, 90% confidence intervals for geometric least squares mean ratios were not meaningfully different (80%-125%). Steady state was achieved in 2-3 days for IR/ER HB/APAP and in 2 days for IR HB/APAP. Median time to Cmax was longer for IR/ER HB/APAP versus IR HB/APAP (P<0.05). Adverse events were similar across treatments. Conclusion: PK outcomes and tolerability were similar for IR/ER HB/APAP and IR HB/APAP.