In summary, the three bioequivalence approaches that are currently consistently accepted by regulatory authorities are bioequivalence studies with clinical endpoints, in-vivo pharmacodynamic studies (in particular VCA for topical corticosteroid products), and waivers for topical solutions. Also, most require pharmacokinetic studies if there are safety concerns relating to systemic exposure. However, it is refreshing to see that the regulatory authorities are giving credence to alternative science-based methods for demonstration of bioequivalence, rather than insistence on clinical endpoint studies.
The most common side effect of topical corticosteroid use is skin atrophy. All topical steroids can induce atrophy, but higher potency steroids, occlusion, thinner skin, and older patient age increase the risk. The face, the backs of the hands, and intertriginous areas are particularly susceptible. Resolution often occurs after discontinuing use of these agents, but it may take months. Concurrent use of topical tretinoin (Retin-A) % may reduce the incidence of atrophy from chronic steroid applications. 30 Other side effects from topical steroids include permanent dermal atrophy, telangiectasia, and striae.
A common mistake is to be too cautious about topical steroids. Some parents undertreat their children's eczema because of an unfounded fear of topical steroids. They may not apply the steroid as often as prescribed, or at the strength needed to clear the flare-up. This may actually lead to using more steroid in the long term, as the inflamed skin may never completely clear. So, you may end up applying a topical steroid on and off (perhaps every few days) for quite some time. The child may be distressed or uncomfortable for this period if the inflammation does not clear properly. A flare-up is more likely to clear fully if topical steroids are used correctly.