A drug allergy is an allergic reaction to a medication and can cause a rapid heartbeat and difficulty breathing. Symptoms of drug dependence and abuse include bloodshot eyes, frequent nosebleeds, drowsiness, and more. Esophagitis, an inflammation of the lining of the esophagus, causes chest pain, nausea, and more. Labyrinthitis, an infection and swelling in the inner ear, and may cause vertigo or hearing loss. Narcotic abuse can cause fatigue, shallow breathing, anxiety, euphoria, vomiting, confusion, and constipation.