Susie,
This is from drugs.com:
Less common:
Chills
constipation
cough, hoarseness, runny or stuffy nose, sinus problems, sneezing, or sore throat
diarrhea
dizziness
fast or pounding heartbeat
[b]increased thirst(meaning possible dry mouth, my thoughts)
irritability
loss of appetite
sexual problems in maleshttp://www.drugs.com/sfx/naltrexone-side-effects.htmlBut my first thought is your location and do you have your heat on? If you get stuff at night you might breathing through your mouth more which can cause a dry mouth. It might not be that noticeable, and if that is the case a humidifier could help. This time a year my mouth is dry because of the heated house, and we have a humidifier attached to our furnace. My allergies are a aggravated little, but not enough to take meds, but enough to cause a dry mouth. I would try sucking on something hard to eliminate it, and hopefully it will subside with time on its own.
I hope this answered your questions, or hopefully give you thought of another reason.
jaba