There are a number of oral prescription medications that may be used to help certain types of excessive sweating. The medications work in different ways to reduce sweating. They do this by helping to prevent the stimulation of sweat glands and thus decreasing overall sweating.
Oral hyperhidrosis medications are best suited for patients with certain types of excessive sweating, in which local therapies either haven’t been effective, or areas difficult to treat (craniofacial sweating). Probably the best form of excessive sweating that is suited for oral therapy is generalized hyperhidrosis, (sweating symptoms all over the body ). Compensatory sweating which occurs after ETS is a form of generalized hyperhidrosis, and if very bothersome, than it would also be appropriate to treat with oral therapy.
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.
There are other oral medications besides anticholinergics that have been used over the years to treat hyperhidrosis, the most common are beta blockers which act on the B-adrenergic receptors (block the effect of adrenaline), which lowers heart rates and lowers blood pressure, and anxiolytics (benzodiazepams), which help to reduce anxiety. Unfortunately, primary hyperhidrosis is not related to a central nervous system disorder, and these medications usually are ineffective in controlling symptoms and improving the quality of life in people with primary hyperhidrosis of the hands or feet. The rare individual with blushing disorder which like hyperhidrosis is a manifestation of overactive sympathetic activity can sometimes get relief by using an anticholinergic and beta blocker together prior to public speaking or other situation which tend to precipitate blushing.
These medications act on the central nervous system and are best for patients who experience episodic or event-driven hyperhidrosis (such as excessive sweating brought on by job interviews or presentations). Side effects limit their long-term use. For instance, benzodiazepines can be habit-forming and many patients cannot tolerate the sedative effects caused by both of these drug therapies.