I have allergies that are quite varied. Pollens, dust mites and other seasonal allergies. Food and pet allergies as well. I am taking Diphhenhydramine HCI to control the daily symptoms and have tailored my home/lifestyle to remove the rest of the things that effect me. I am wondering if there are any physical effects to long term use of this drug. I am experiencing some physical discomforts that may just be 'getting old' or 'influenza' symtoms but I would like to know if the daily use of this drug can cause problems in the long run.

Additionally, I am concerned about putting other things into my system that may react badly with Diphhenhydramine HCI. If I have a headache or muscle pain can I safely take a pain killer? What about mineral supplements and vitamins? Is there any risk with it reacting to the Diphhenhydramine HCI? If I am prescribed any medications in the future should I be wary of any specific families of drugs that do not mix well with this med?