This medication belongs to a class of medications called tricyclic antidepressants. Avoid drinking alcohol and smoking while being treated with this medication. 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. Your doctor may need to adjust your diabetes medication, exercise program, or diet. If you think you have used too much of this medicine seek emergency medical attention right away. Use the dropper that comes with the medication to measure out the prescribed amount.