Clobex Shampoo

CLINICAL PHARMACOLOGY

Like other topical corticosteroids, CLOBEX® (clobetasol propionate) Shampoo, 0.05%, has anti-inflammatory, antipruritic, and vasoconstrictive properties. The mechanism of the anti-inflammatory activity of the topical steroids, in general, is unclear. However, corticosteroids are thought to act by the induction of phospholipase A2 inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor, arachidonic acid. Arachidonic acid is released from membrane phospholipids by phos-pholipase A2.

Pharmacokinetics

The extent of percutaneous absorption of topical corticosteroids is determined by many factors, including the vehicle, the integrity of the epidermal barrier and occlusion. Topical corticosteroids can be absorbed from normal intact skin, while inflammation and/or other disease processes in the skin may increase percutaneous absorption.

Due to the fact that circulating levels of corticosteroids are usually below the limit of detection following application, there are no human data regarding the pharmacokinetics of topical corticosteroids. In such cases pharmacodynamic end points, including both hypothalamic-pituitary-adrenal (HPA) axis testing and topical vasoconstriction, are used as surrogates in the assessments of systemic exposure and relative potency, respectively.

In studies evaluating the potential for hypothalamic-pituitary-adrenal (HPA) axis suppression, use of CLOBEX® (clobetasol propionate) Shampoo, 0.05%, resulted in demonstrable HPA axis suppression in 5 out of 12 (42%) adolescent patients (See PRECAUTIONS).

CLOBEX® Shampoo (clobetasol propionate shampoo) is in the super-high range of potency in vasoconstrictor studies.

Clinical Studies

The safety and efficacy of CLOBEX® (clobetasol propionate) Shampoo, 0.05%, has been evaluated in two clinical trials involving 290 patients with moderate to severe scalp psoriasis. In both trials, patients were treated with either CLOBEX® Shampoo (clobetasol propionate shampoo) or the corresponding vehicle applied once daily for 15 minutes before lathering and rinsing for a period of 4 weeks. Efficacy results are presented in the table below.

  CLOBEX® Shampoo
n (%)
CLOBEX® Shampoo Vehicle
n(%)
  Study A Study B Study A Study B
Total Number of Patients 95 99 47 49
Success Rate1
-at Endpoint2
40 (42.1%) 28 (28.3%) 1 (2.1%) 5 (10.2%)
Subjects with Scalp Psoriasis Parameter Clear (None) at Endpoint        
Erythema3 17 (17.9%) 12 (12.1%) 3 (6.4%) 1 (2.0%)
Scaling3 21 (22.1%) 15 (15.2%) 0 (0%) 2 (4.1%)
Plaque Thickening3 35 (36.8%) 34 (34.3%) 5 (10.6%) 5 (10.2%)
1Success rate defined as the proportion of patients with a-0 (clear) or 1 (minimal) on a 0 to 5 point physician's Global Severity Scale for scalp psoriasis.
2At four (4) weeks or last observation recorded for a subject during the treatment period (baseline if no post-baseline data were available).
3Patients with 0 (clear) on a 0 to 3 point scalp psoriasis parameter scale.

Clinical studies of Clobetasol Propionate Shampoo, 0.05%, did not include sufficient numbers of non-Caucasian patients to determine whether they respond differently than Caucasian patients with regards to efficacy and safety.

Last reviewed on RxList: 12/1/2008
This monograph has been modified to include the generic and brand name in many instances.

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