I had taken 2 vicodin's the other day for my back pain. The very next day I came down with a flu/cold virus, but had a very bad migraine that whole day, which I feel was intensified from being sick. Now, this has happen to me before from taking vicodin. I've also had a migraine the next day from taking Theraflu, which also has a high dose of acetaminophen-500mg. Now, I also smoke marijuana for a medical condition. I've finally concluded that if I've previously taken something with the acetaminophen, and smoke marijuana, I have a major migraine the next day. I'm not one that has migraines. My question, is why is this? I obviously won't do that again, but has anyone else suffered from migraines, or just a bad headache after taking acetaminophen?