Does botulinum toxin decrease frequency and severity of sialorrhea in Parkinson's disease?

This study analysed if botulinum toxin type A (BTX-A) decreases drooling in 21 Parkinson's disease patients. BTX-A injections were given in the parotid glands. The severity of drooling decreased in 18 (86%) patients, while frequency was reduced in 8 (38%). In 11(52%) patients, the frequency of drooling remained constant, which may reflect more difficulties in swallowing, compared to the group that presented such improvement. Future trials assessing the level of swallowing dysfunction may be important to establish a prognosis for patients who keep the frequency of drooling in spite of decreased severity after BTX injection.