Excretion hydrocodone

Figure 34-37 Hydrocodone and hydromorphone metabolic transformations.The figures in parenthesis are percent of a dose of hydrocodone excreted in urine. Rapid metabolizers excrete more hydromorphone conjugates (5.9%) compared with slow metabolizers (1.0%). Hydrocodo and hydromorphoi exist as 6-a and jl-stereiosomers. 6-a-hydrocodol is dihydrocodeine 6-a-hydromorphoi is dihydromorphine. For hydromorphone administration, 6% of the dose is excreted as the free parent drug and 30% as conjugates. Only trace amounts of hydromorphoi conjugates are formed.

Codeine is excreted via the kidneys mainly unchanged or as the conjugate with glucuronic acid. Amounts of norcodeine (10-20%) and morphine (5-15%) considerably exceed the amounts of the other metabolites (normorphine, hydrocodone, dihydrocodeine), which are present only in traces [43,44],... 

Hydrocodone has a half-life of 3.8 boms, peak effect at 1.3 hours, and a duration of 4.6 hours. It is metabolized by the liver and excreted primarily in urine. Hydrocodone is oxidized to hydromorphone by cytochrome P450 2D6. The extended-release formulation has measurably different pharmacokinetics following a single dose of 1,2 or 3 HC/ APAP CR tablet(s), the mean maximum plasma concentration (C ) ranged from 13.3 to 36.8 ng/mL for HC and 2.01 to 6.68 ng/mL for APAP. The mean time to reach (T ) was 6.0-6.7 hours for HC and 1.1-1.3 hours for APAP. Following twice-daily dosing of 2 HC/APAP CR tablets for 3 days, steady-state HC/APAP concentrations were attained by 24 hours [3,4]. The mean on day 3 was 37.0 ng/mL for HC and 4.96 ng/mL for APAP. Systemic exposures of HC and APAP demonstrated a dose-proportional increase from one to three tablets. Steady-state concentrations were reached by 24 hours with minimal accumulation following twice-daily administration. Thus, it can be taken every 12 hours [4]. 

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