Originally posted March 29, 2018: On July 3, 2018, the FDA approved Xeomin (incobotulinumtoxinA) for drooling. Read more about the therapy below.

In Parkinson's disease (PD), many things slow down. One of the most noticeable is walking speed, but people also may blink or swallow less frequently. Swallowing less often can lead to saliva build-up, which, in turn, can lead to drooling, especially in later years with PD. Drooling can be embarrassing and interfere with social interactions. When significant, drooling also can affect the skin near the mouth and even cause infection.

Treatments are, unfortunately, somewhat limited. Doctors may prescribe medications you take by mouth, such as Robinul (glycopyrrolate). Or they might inject a drug called Myobloc (rimabotulinumtoxinB) or Botox (onabotulinumtoxinA), both of which are made from the bacteria that causes botulism, into the salivary glands to temporarily block saliva production. But there aren't any U.S. Food and Drug Administration (FDA) approved therapies specifically for drooling in PD.

That may soon change. The FDA is now reviewing an application for Xeomin (incobotulinumtoxinA) -- also made from the bacteria that causes botulism -- to treat chronic drooling. Drugs like Xeomin, which are called botulinum toxins, prevent the release of the chemical acetylcholine to decrease saliva production temporarily (for about three or four months). The FDA's decision on whether to approve this therapy for drooling in PD is expected by the end of 2018.

Researchers assessed Xeomin's benefit on drooling with a placebo-controlled, double-blind Phase III trial of 184 people. Some volunteers got placebo while others received one of two Xeomin doses injected into the salivary glands. Those who got the higher dose had less saliva and reported less drooling. Neither the participant nor the researcher knew who was getting placebo or study drug. (That's the "double-blind" part.) A placebo-controlled, double-blind design helps give more confidence in the results.

Xeomin is already FDA-approved and used to treat other conditions, including cervical dystonia (muscle contractions that cause abnormal head position and neck pain). If Xeomin is approved for drooling, it'd be the first and only botulinum with that specific indication.

Read more about drooling in Parkinson's.

Learn about a trial testing Robinul (glycopyrrolate) for drooling in PD.