Side effects of Advil PM include daytime drowsiness, memory impairment, ringing in the ears, itching or rash, and dry mouth, nose or throat, according to Drugs.com. Other side effects include heartburn, diarrhea, upset stomach and constipation. Some people taking Advil PM feel nervous or restless.
Signs of an allergic reaction to Advil PM requiring emergency medical assistance include chest pain, problems with vision or balance, slurred speech, convulsions and shortness of breath, states Drugs.com. An overdose can damage the intestines or stomach. People with uncontrolled heart disease, glaucoma, asthma or overactive thyroid should not take Advil PM. The active ingredients in Advil PM are diphenhydramine and ibuprofen.