I am an adult female, 67, 5'2", 150# and have been taking Niaspan at night for about 6 months, along with my other meds which I have been taking for years. Soon after beginning Niaspan, I had a reaction which I can only describe as a fire inside my skull - no neurologic symptoms, just burning pain. This began within minutes of me taking Excedrin extra strength for my arthritis in order to sleep more easily. The symptoms lasted only about 10 minutes, subsided, and did not return. I had this reaction twice more - each time immediately after I had used a product containing aspirin, or aspirin itself. Last night I had a much more severe reaction which began just like the previous ones -- like a forest fire surrounding my brain, only it began 3 hours after taking my evening meds, and I had not taken any foot or drink or additional OTC meds. This time the reaction was much more severe and did not subside, but spread from inside my head to my face, and eventually all over my body in a bright red rash that looked and felt like sunburn. (I had not been outside all day.) I finally took some benadryl and eventually fell asleep, but this reaction scared me very much last night.