Acitretin (Ro 10-1670, Neotigason), a second-generation monoaromatic r
etinoid, is the main acid derivative and active metabolite of etretina
te (Ro 10-9359, Tigason), Three patients who were unresponsive to trea
tment with acitretin but who responded to etretinate are reported, Twe
nty-nine patients in the U.K. are currently receiving etretinate on a
named-patient basis. Possible explanations for the functional discrepa
ncy between the two drugs are discussed.