A very serious allergic reaction rarely occurs. Consult your doctor or pharmacist for more details. Read the Medication Guide provided by your pharmacist before you start taking doxepin and each time you get a refill. Older adults may be more sensitive to the side effects of this drug, especially dry mouth, dizziness, drowsiness, confusion, difficulty urinating and QT prolongation (see above). It may help improve mood and feelings of well-being, relieve anxiety and tension, help you sleep better, and increase your energy level. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.