The limitations of conventional
therapy for
psoriasis are reviewed, and the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, dosing and therapeutic monitoring of
etretinate and other
retinoids are described. Traditional treatments for
psoriasis include topical application of
anthralin and
coal tar ointments; systemic
therapy with
corticosteroids or
methotrexate; and systemic or
methotrexate; and systemic
psoralens combined with exposure to ultraviolet light (PUVA). The topical
therapies are beneficial but aesthetically displeasing to patients; the systemic treatments are associated with severe adverse reactions.
Etretinate provides another option in the treatment of
psoriasis.
Etretinate and
acitretin, an investigational
retinoid, appear to be effective oral
therapies for severe variants of
psoriasis, especially pustular
psoriasis.
Retinoids generally do not offer substantial therapeutic advantages over other treatments for chronic-plaque
psoriasis. The most common adverse effects of
etretinate are
cheilitis,
alopecia, desquamation of the skin, drying of mucous membranes, and
pruritus. Use of low-dose etretinae in combination with other forms of
therapy, such as
corticosteroids or PUVA, may minimize the frequency of adverse effects.
Etretinate is a known
teratogen. Its elimination half-life is prolonged to 100-120 days with long-term use.
Acitretin, the
carboxylic acid derivative of
etretinate, has a much shorter elimination half-life than
etretinate (50 hours after multiple doses). Its adverse-effect profile is similar to that of
etretinate.
Etretinate and
acitretin appear to be clinically effective for
therapy of severe variants of
psoriasis.
Etretinate should not be used to treat mild
psoriasis because of the high incidence of serious adverse effects.