Before taking doxepin, tell your doctor or pharmacist if you are allergic to it; or to other tricyclic antidepressants (such as nortriptyline); or if you have any other allergies. The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. However, it may take up to 3 weeks before you feel the full effect. Tell your doctor right away if you get sunburned or have skin blisters/redness. Doxepin should not be used by pregnant/nursing women or children as well as by the patients having demonstrated a reaction of hypersensitivity to Doxepin. During pregnancy, this medication should be used only when clearly needed.