The trade name for diphenhydramine, an antihistamine used to treat allergies.
                                                            
                                                     
                        
                                                
                        
                        
                            A medication administered frequently prior to the administration of blood products and other treatments to prevent reactions. This may also be used to reduce itching or as a sleeping medication.
                                                            
                                                     
                        
                                                
                        
                        
                            Brand name for an antihistamine.