New roles for systemic retinoids.

Acitretin, the only oral retinoid indicated for the treatment of psoriasis, has shown activity when used in combination, rotational, and sequential therapy regimens with other therapies. When used with phototherapy, significantly greater activity has been observed at lower doses than with either approach as monotherapy. While initial anecdotal evidence is promising, clinical trials are needed to evaluate whether sequential or rotational use of biologic agents with acitretin may yield improved efficacy and an acceptable safety profile with decreased risk of immunosuppression. Acitretin and other retinoids also work as chemopreventative agents in psoriasis patients with extensive exposure to psoralen ultraviolet A (PUVA) and in solid-organ transplant patients where a number of studies have reported decreased numbers of squamous cell cancers when treated with acitretin.