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.