Effects of antipsoriatic therapies on hepatic microsomal enzyme activity in patients with psoriasis.

OBJECTIVE

The influence of several antipsoriatic therapies on microsomal enzyme activity was assessed by comparing measurements of antipyrine kinetics prior to and two weeks after initiation of therapy.

METHODS

Serum and urine analysis was carried out by means of high performance liquid chromatography (HPLC). Each form of therapy was examined separately. 10 patients were treated with etretinate. The groups treated with 8-methoxypsoralene (8-MOP) in combination with UVA irradiation (PUVA), etretinate in combination with PUVA (RePUVA), anthralin, or combined UVA and UVB irradiation (SUP) consisted of 7 patients each.

RESULTS

Neither anthralin nor SUP therapy led to any significant changes in antipyrine kinetics. Antipyrine clearance under the other regimens was, however, reduced. It was 23% lower in PUVA-treated patients, 20% lower in those receiving retinoids and 28% lower in those under RePUVA (p<0.05 - 0. 01).

CONCLUSIONS

PUVA, etretinate and RePUVA inhibit microsomal enzyme activity in the liver. Possible drug interactions with other P subset450 inducing or inhibiting agents should be considered in the therapy of psoriatic patients.