O#17   Hypertrichosis in females applying minoxidil topical solution and in normal controls

Rodney P.R. Dawber1 and Jan Rundegren2. 1Churchill Hospital, Oxford,UK and 2Pharmacia, Helsingborg, Sweden

Hypertrichosis has been reported more frequently in females than males who use minoxidil topical solution (MTS) for the treatment of androgenetic alopecia (AGA). To study this in detail, data from placebo-controlled clinical trials in women (up to 5% MTS) were analysed based on spontaneous reports of hypertrichosis / facial hair and investigators enquiries (solicited) about the presence of any new hair growth on body parts other than the scalp.
In the clinical trials involving 1333 females, spontaneous reports of hypertrichosis / facial hair were noted in 50 (4%) in a dose-related pattern of response (5%MTS > 2%MTS > placebo). 9 females (7 in 5% and 2 in 2%MTS group) discontinued treatment because of hypertrichosis / facial hair. Solicited reports of excessive hair growth also showed a dose-related pattern of response. Post-marketing safety data showed a lower occurence (0.5%) of hypertrichosis / facial hair than in clinical trials. Of interest, in one clinical trial 27% of the females enrolled (MTS and placebo-treated) had facial hair growth reported at baseline. Some women may have hair follicles that are very sensitive to MTS and should use the lowest MTS strength (2%) to minimize unwanted hair growth. The hypertrichotic effect of MTS on sites other than the scalp, including the face, is reversible and does not always require discontinuation of therapy.