In case you notice the effects not listed here, contact your doctor or pharmacist. During the pregnancy this treatment should be used only when strongly necessary. Do not increase your dose or use this drug more often or for longer than prescribed. Before using doxepin, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death). A very serious allergic reaction rarely occurs.