 Cyproheptadine has both antihistamine and antiserotonergic and has side effects related to these mechanisms. These side effects include drowsiness or sleepiness, confusion, excitement, fatigue, insomnia, hallucinations, blurred vision, tinnitus, dizziness, tachycardia, increase perspiration, appetite stimulation, weight gain, constipation, diarrhea, changes in frequency of urination, thickening of secretions, and dry mucus membranes. Over-dosage can results in atropine-like effects as well as central nervous depression, convulsions. 