Clobetasol propionate for psoriasis: are ointments really more potent?

Abstract

Background: Clobetasol propionate is the most common topical therapy used for psoriasis in the US. Conventional dermatologic wisdom is that ointment preparations provide the highest potency (due to their occlusive nature and moisturizing ability) and are best suited for psoriasis. However, patients often find application of ointment to be messy, raising concerns about both short-term and long-term adherence to treatment. This article reviews the current literature and assesses the relative potency of clobetasol propionate ointment compared to other clobetasol propionate preparations in the treatment of psoriasis. Relevant literature was identified by PubMed and Google searches. We included studies of psoriasis that reported the percentage of subjects that achieved desired efficacy endpoints, as well as studies that reported the subjects' mean change in symptoms from baseline. We excluded studies conducted before 1980 and those that allowed concomitant treatments.

Observations: Efficacy rates ranged from 17% to 80% for the different vehicles: ointment, solution, foam, cream, lotion, shampoo, and emollient.

Conclusions: Clobetasol propionate is a very effective treatment for psoriasis. Ointment preparations have similar efficacy to other preparations in clinical trial situations. In clinical practice, a situation in which patient preferences are more likely to affect compliance, it may be best to choose whichever vehicle patients find preferable.

Introduction

Psoriasis is a lifelong disease characterized by emotionally and physically devastating exacerbations and remissions. Topical corticosteroids are used frequently as treatment for psoriasis to decrease inflammation and manage itching. (1) Patients find many topical agents messy and time-consuming to apply. The need for long-term application may be a daunting task for many patients. Poor adherence to treatment over time, due to an undesirable vehicle, may result in poor treatment outcomes.

Ointments are commonly prescribed for psoriasis, in part because of the perception that they are more potent and in part because of the perception that moisturizing psoriasis plaques is inherently beneficial. (2) Nevertheless, ointment-based vehicles are among the least appealing to patients due to their messiness and greasy feel. Bothersome aspects of the vehicle likely reduce patients' adherence to treatment. (3)

The purpose of this study is to review the literature in order to test the conventional wisdom that ointment vehicles are better for psoriasis by comparing the published potencies of clobetasol propionate in different vehicles.

Methods

Double-blind, randomized, controlled psoriasis studies determining the efficacy of clobetasol propionate (in the forms of ointment, cream, lotion, solution, foam, shampoo, and emollient) were searched for using PubMed and Google. PubMed search terms consisted of "clobetasol propionate" and "psoriasis." Google search terms consisted of "clobetasol propionate (CP) 0.05%" in conjunction with either "ointment," "solution," "shampoo," "foam," "lotion," "cream," or "emollient." The Google search was advanced to include only sites that reported the phrase in that exact order.

We included studies that measured efficacy by the percentage of subjects whose symptoms met a desired outcome such as "clear/almost clear" after at least 2 weeks of clobetasol propionate treatment. We also included studies that measured efficacy by the subject population's mean improvement in symptoms from baseline after treatment. Only those trials that involved more than 50 adult subjects with moderate to severe baseline disease, based on erythema, plaque thickness, scaling, and pruritus, were included. We evaluated studies of scalp and non-scalp psoriasis separately.

We excluded studies that allowed application of other topical therapies, mixtures of vehicles, and hydrocolloid occlusive dressings during the trial as well as those conducted before 1980. Placebo efficacy rates of several studies were taken into account when reporting outcomes. Efficacy values were reported in 2 separate ways.

Efficacy was first assessed by…