Acitretin (Ro 10-1670 or Neotigason), a free acid and the main metabolite o
f etretinate (Ro 10-9359 or Tigason), is the most recent of the retinoids u
sed orally in the treatment of psoriasis and numerous other dermatoses exhi
biting disorders of keratinization. In the majority of cases, its side-effe
cts are similar to those of hypervitaminosis A.