It is a significant problem in Intensive Care Units. Recently my colleague anaesthetist raised similar question as they have a problem with saliva hypersecretion in patients with tracheostomy.
This is a significant issue when it comes to neck dissection done for oral cancer. A 'salivary leak' is due to the failure to create a surgical separation after resection between the oral cavity and the neck. It's better avoided than 'managed' in post surgical period.
Antisialogogues like atropine (oral / injectable) or Injection Glycopyrrolate may help combined with a pressure thick dressing to soak secretions.
The risk of carotid burst / rupture / infection is high in these patients. Also, radiation therapy may complicate / cause recurrence of the salivary leak with ingress of oral bacteria into the neck and can cause infections and erosive complications. I would say this problem is best prevented by better surgical care taken to 'reconstruct' the floor of the mouth with local flaps or free flaps or any means possible in the first chance (during the primary surgery itself!).
I give Tablet. Artane 2mg twice a day, can step up to three times a day (max 6mg). Daily dose is not so effective. One can see the secretions lesser and wound more dry within Day 3 of administration. If for some reason this is not enough, I inject Botox into the salivary gland. Hope this helps, thank you.