Rapidly absorbed after PO administration (food reduces absorption). Protein binding: 99%. Extensively metabolized in the liver. Primarily excreted in feces. Unknown if removed by hemodialysis. Half-life: 10 hr.
Readily absorbed from the GI tract (absorption decreased by food). Protein binding: less than 4%. Undergoes phosphorylation intracellularly to the active metabolite. Primarily excreted in urine. Removed by hemodialysis. Half-life: 1–3 hr; metabolite, 2.6–10 hr (increased in impaired renal function).
! Peripheral neuropathy (characterized by numbness, tingling, burning, and pain in the lower extremities) occurs in 17% to 31% of patients. These symptoms may be followed by sharp, shooting pain and progress to a severe, continuous, burning pain that may be irreversible if the drug is not discontinued in time.
PO: Rapid absorption, bioavailability 30%, peak plasma levels 1 hr, wide tissue distribution, rapid hepatic metabolism (CYP3A4 minor pathway), excretion in urine; heavy, high-fat meal significantly delays absorption