The most commonly used medications for managing excessive sweating are anticholinergics. Glycopyrolate® or Robinul® is the most commonly prescribed anticholinergic that is used to treat excessive sweating. It works by blocking the acetycholine receptor on the sweat glands and thereby reducing sweat production. Unfortunately, there are acetylcholine receptors on most vital organs under the control of the autonomic nervous system, and therefore there are many side effects associated with their use. The impact on sweating and the development of side effects are dose dependent. Taken at sufficient doses to reduce sweating, most patients will develop side effects such as; dry mouth, urinary retention, constipation, dry eyes, blurred vision, heart burn, heat intolerance and occasionally tachycardia or rapid heart rates. These side effects can be improved by reducing the daily dosage, but than the sweating symptoms recur. As a result of these common side effects few patients get significant relief of their sweating symptoms from taking anticholinergics.
Patients with generalized hyperhidrosis caused by an underlying medical disorder (secondary hyperhidrosis), should not use an anticholinergic for sweating to treat their symptoms. The underlying medical disorder should be addressed and managed appropriately. Similarly, patients with a known history of GERD, irritable bowel, glaucoma, or a heart issues should not take an anticholinergic for sweating.
Studies are ongoing to develop medications that improve the symptoms of excessive sweating without causing severe side effects, but as yet there are no FDA approved medications that fit the role. In fact using anticholinergics to treat hyperhidrosis is an off label indication.