The technical name for a dry mouth is called xerostomia. Xerostomia is the subjective feeling of oral dryness, which may or may not be associated with a problem with the salivary glands.
Xerostomia most commonly occurs as a side effect of medications. When the site of the medication being used acts upon the autonomic nervous system, there is a possibility the individual will have a dry mouth. Drug types which have been related with xerostomia include antihistamines, antihypertensives, tricyclic antidepressants, and sedatives.Consuming a greater number of medications results in a higher chance of having a dry mouth. Recreational drugs such as marijuana and heroin may also cause temporary or permanent reduction in saliva flow depending on usage and other factors.