What is the absorption rate constant of allopurinol?

The absorption rate constant of allopurinol varies based on individual factors and the specific formulation used. Generally, allopurinol is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 1.5 to 2 hours after oral administration. The exact rate constant can differ among studies, but it is typically in the range of 0.1 to 0.2 h⁻¹. For precise values, consulting pharmacokinetic studies specific to the formulation is recommended.