Topical glycopyrrolate should not be overlooked in treatment of focal hyperhidrosis

Abstract

Conflicts of interest: none declared. Sir, The recent review article by Lowe et al.1 on the place of botulinum toxin type A in the treatment of focal hyperhidrosis omits the topical antimuscarinic agent, glycopyrronium bromide. Topical glycopyrrolate (0·5–4% cream, solution or pads) is indicated mainly for the head and neck2, 3 and various types of gustatory sweating (compensatory,4 diabetic5 and Frey's)6 and, in our experience, is effective and well tolerated. EP and USP grade glycopyrrolate powder can be imported into the U.K. and the desired formulation prepared by ‘Special Order Manufacturers’ (SOMs). The cream formulation should use an acidic base, e.g. Unguentum M, to reduce drug hydrolysis and extend stability; a 3‐month expiry is given by some SOMs. The solution, on the other hand, has a shorter expiry, of 1 month, if pH‐stabilized and refrigerated. Glycopyrrolate may be used twice daily, but it is more usually applied at night. Care should be taken to avoid the nose, mouth, and particularly the eyes, where an inadvertent splash can cause failure to accommodate. Patients often experience a dry mouth and throat, and should be warned about that also. We advise not to wash treated skin for 3–4 h after application, and to store the drug in a cool place. If local prescribing authorities do not allow for provision of glycopyrrolate, it may be obtained by mail from Canada (at http://www.pharmacy.ca).