I had my Ingrezza upped to 80mg, and I have had a pretty bad cold lately. I decided to take NyQuil last night after reading the back and the drug interactions and such. About 30-45 minutes later, my muscles completely tensed up, I couldn't move or speak. When my husband moved my legs I shook. I could think somewhat but I couldn't form words or move my jaw. I could mumble. He called the pharmacy that handles my Ingrezza and they didn't know what to do because they hadn't heard of that side effect before, and because I have had serotonin syndrome and seizures before my husband decided he wanted to take me to the ER to be safe. He had to dress me but by the time we got there I was able to talk and walk with assistance. The doctor also didn't really know what to do other then give me fluids and keep me there until I felt ok. I eventually felt better, just extremely tired and they discharged me.
My husband is pharmaceutical major and he looked up the compounds and the side effects of both the cold medicine and Ingrezza and they seem to interact. I submitted the complication to the FDA so hopefully they figure it out so it doesn't happen to another person, but it was scary. I am now afraid to take any over the counter medications.