A pharmacokinetic evaluation of single and multiple doses of extended-release hydrocodone bitartrate in subjects experiencing surgical or osteoarthritic pain.

OBJECTIVES: To assess the single-dose and steady-state pharmacokinetics of a single-entity hydrocodone extended-release (ER) formulation in patients enrolled in two separate phase 2 clinical studies.

SETTING: Both studies were multicenter clinical studies.

SUBJECTS AND INTERVENTIONS: In study 1, 115 subjects with postsurgical pain (bunionectomy) received single doses of 10, 20, 30, or 40 mg hydrocodone-ER, 10 mg hydrocodone/325 mg acetaminophen immediate-release (IR), or placebo. In study 2, 37 subjects with osteoarthritic pain received doses of 10, 20, 30, or 40 mg of hydrocodone- ER twice-daily for 7 days. Venous blood samples were taken periodically up to 24 hours postdosing after the single dose (study 1) or after 7 days of dosing (study 2) and were assayed for concentrations of hydrocodone and its major metabolites.

MAIN OUTCOME MEASURES: Standard pharmacokinetic parameters were estimated by noncompartmental analysis methods.

RESULTS: Following a single dose of hydrocodone-ER, Tmax was prolonged to approximately 6 hours at all dose levels of hydrocodone-ER compared with 2.9 hours for the IR formulation. All doses of hydrocodone-ER formulations provided prolonged and sustained release of hydrocodone throughout the 12-hour dosing interval with reduced peak-to-trough fluctuation at steady state compared with hydrocodone/acetaminophen-IR comparator. Both single-dose and steadystate mean Cmax and AUClast values showed reasonable dose-proportionality. Norhydrocodone and hydromorphone plasma concentrations were 32-38 percent and <2.1 percent, respectively, of hydrocodone concentrations in both studies.

CONCLUSIONS: The sustained plasma concentrations of hydrocodone support twice-daily dosing with a 12-hour dosing interval.