I have dry mouth as a result of radiation to the head and neck. I know that there are several medications that cause it and a few that relieve it but nothing lasts for extended periods. Taking water with you everywhere can help but better still are the gels like Oral 7 or Oralieve. Xylimelts are effective at night. You have to be more cautious with your teeth with dry mouth as teeth need to be bathed in saliva in order to build themselves up continuously.