Did a little net surfing as you do when something new is suggested.
Just mentioned this to (klo) over coffee and sent her the link.
As with all medications you should check with your doctors
first. There may be Precautions,Side effects and Contraindications

FDA Approves Glycopyrrolate Oral Solution for Chronic Severe Drooling
http://www.medscape.com/viewarticle/726048
At the bottom is another link to;
Drooling (Otolaryngology and Facial Plastic Surgery)

History Leukoplakia bx 8/2006 SCC floor mouth T3N0M0- Verrucous Carcinoma.
14 hour 0p SCC-Right ND/excision/marginal mandibulectomy 9/2006, 4 teeth removed, flap from wrist, trach-ng 6 days- no chemo/rad.
6 ops and debulking (flap/tongue join) + bx's 2006-2012.
bx Jan 2012 Hyperkeratosis-Epithelial Dysplasia
24cm GIST tumour removed 8/2013. Indefinite Oral Chemo.

1/31/16 passed away peacefully surrounded by family