Evaluation of irritation and sensitisation of two 50 microg/day oestrogen patches

To comparatively assess the irritation and sensitisation of the Estradot transdermal oestrogen patch, in healthy postmenopausal women, using the Menorest transdermal oestrogen patch, as a comparator.

In an open-label, single-centre, randomised, active-treatment, within-patient controlled study, 208 healthy postmenopausal women, age range 40-70 years, received and completed simultaneous treatment with a 5 cm(2) (50 microg/day) oestradiol patch (Estradot) and a 14.5 cm(2) (50 microg/day) oestradiol patch (Menorest). The treatment was given for 72 h, then 96 h, for eight successive applications during an induction phase, and for 72 h during a challenge phase. There was a 14-day resting period between phases. Skin irritation (measured by erythema on a scale of 0-4), topical sensitisation, patch adherence and local skin reaction, were assessed and recorded immediately before or after removal of each patch, as appropriate.

Most patients experienced a significant difference in irritation with Menorest than with Estradot (P < 0.0001) at the end of the induction phase. Patch loss was also significantly higher for Menorest as compared to Estradot (P = 0.0253) at the end of the induction phase. Most incidences of erythema were classified as slight (score of 1), and there was no significant difference in the percentage of topical sensitisation, or in the incidence of local skin reactions between Estradot and Menorest. Patch loss was low for both systems.

Estradot demonstrates reduced skin irritation, superior adhesion and a lower rate of patch loss compared to Menorest.