In a Phase 2 HPA clinical study [see Pharmacodynamics ], pharmacokinetics was evaluated in a subgroup of 12 adult subjects. On Day 8, blood was taken just prior to and at 1, 2, 4, 6, 8, and 12 hours following the last application. Plasma concentration of halobetasol propionate was measureable in all subjects. Based on the geometric mean plasma concentrations at 12 hour post-application across time, steady-state was achieved by Day 8. The mean (±standard deviation) Cmax concentrations for ULTRAVATE lotion on Day 8 was ± pg/mL, with the corresponding median Tmax value of 3 hours (range 0 – 6 hours); mean area under the halobetasol propionate concentration versus time curve over the dosing interval (AUCτ) was 1632 ± 1147 pg•h/mL.
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.