Open Study of Reservoir and Matrix Patches in a Tropical Environment

Abstract

Objective To determine the influence of temperature and humidity on skin reactions with continuous transdermal oestrogen therapy. Design Two prospective studies, each of 6 months’ duration. Setting Two centres in Western India. Range of temperature 20–38°C; humidity 55–90 per cent. Population 62 healthy menopausal women. Main outcome measures 61 women using a 50ug reservoir patch were assessed over 6 months about tolerability and skin reactions. In 26 women who had repeated complete detachment of, or significant skin reactions with the reservoir patch, a further study of 6 months’ duration was undertaken with a 50ug matrix patch. Results 64 per cent completed the first study and were happy to continue with the reservoir patch, while 36 per cent discontinued prematurely because of adverse effects. Ten per cent had problems of adhesion. Mild skin reactions occurred in 21 per cent, and moderate or severe in 38 per cent. The premature discontinuation rate because of problems of adhesion and skin reactions was 23 per cent, which was significantly higher than such rates in 4 other comparable studies conducted in temperature zones. However, the variations in temperature and humidity in Western India did not significantly influence the premature discontinuation rate as a consequence of skin reactions (Chi-Square test, P = 0.4, and P = 1.0, respectively). From the 26 women subsequently using the matrix patch, none complained of the patch falling off, although 4 per cent had partial detachment. None complained of moderate or severe skin reactions. Twelve per cent had mild itching. Conclusions Because of frequent and severe skin irritation, transdermal therapy with the reservoir patch is not accepted favourably by some women in hot, humid climates. In contrast, because of the superior adhesive properties and minimal mild skin reactions, women in Western India are found to readily accept therapy with the matrix patch.