Acitretin

Absorption	Oral absorption of acitretin is optimal when given with food, and is linear and proportional with increasing doses from 25 to 100 mg. Approximately 72% (range 47% to 109%) of the administered dose was absorbed after a single 50 mg dose of acitretin was given to 12 healthy subjects.
Volume of distribution	Not Available
Protein binding	Over 99.9% bound to plasma proteins, primarily albumin.
Metabolism	Following oral absorption, acitretin undergoes extensive metabolism and interconversion by simple isomerization to its 13-cis form (cis-acitretin). Both parent compound and isomer are further metabolized into chain-shortened breakdown products and conjugates, which are excreted.
Route of elimination	Both parent compound and isomer are further metabolized into chain-shortened breakdown products and conjugates, which are excreted. The chain-shortened metabolites and conjugates of acitretin and cis-acitretin are ultimately excreted in the feces (34% to 54%) and urine (16% to 53%).
Half life	49 hours (range 33 to 96 hours)
Clearance	Not Available
Toxicity	Oral, rat: LD50 = >4000 mg/kg. Symptoms of overdose include headache and vertigo.
Affected organisms	Humans and other mammals
Pathways	Not Available