A Comparative Study of Tar and Betamethasone Valerate in Chronic Plaque Psoriasis: A Study in Thailand
Prasutr Thawornchaisit MD*, Kitiphong Harncharoen PhD**
Affiliation : * Department of Medicine, Lerdsin General Hospital ** Department of Epidemiology, Faculty of Public Health, Mahidol University
Objective : Evaluate and compare the efficacy, safety, and tolerability of coal tar (10% LCD, liquor carbonis
detergens), with betamethasone valerate in the therapy of large plaque-type psoriasis.
Materials and Methods : Patients with stable, mild to moderate plaque psoriasis at the Department of Medicine,
Lerdsin General Hospital, Bangkok, Thailand were randomized for treatment with either coal tar (10% LCD)
cream or betamethasone valerate cream (0.1%). All patients entered a 2 week wash-out period followed by the
creams being applied twice daily until completion at 6 weeks. The patient severity of psoriasis was assessed
using the modified Psoriasis Area and Severity Index (PASI) score at baseline and after 2, 4, and 6 weeks of
treatment.
Result: At the end of the trial, the mean reduction of the PASI score from baseline was 38.39% with the coal tar
group and 69.36% with the betamethasone valerate group. The mean percentage of the PASI score reduction
was statistically significant in both groups but the betamethasone valerate group was significantly superior
to the coal tar group. Both drugs’ adverse effects were limited to mild irritation localized to the skin without
systemic side effects. The Betamethasone valerate cream was safe, effective, and well-tolerated while the coal
tar cream was described as messy, malodorous, and with a tendency to staining clothes.
Conclusion : The investigator’s overall assessment of the treatment response at completion of the trial demon-
strated that the betamethasone valerate group achieved significantly greater clearance and marked improve-
ment compared with the coal tar group.
Keywords : Coal tar, Betamethasone valerate, Plaque type psoriasis
