How long for an allergy to occur?

Can an allergy to a medication (Vicodin) occur after the medication is used long term?

• Greetings. I have been taking Vicodin (5 mg hydrocodone/ 500 APAP "tylenol") for about 2 months now due to a back injury endured in the military. About 1 week ago, I started getting itchy knees, but didn't think much of it. Well I ran out of medication for roughly 24 hours the other day, and when I took 2 vicodin, it felt like my troat was swelling up. O could still breathe ok, but it was uncomfortable. The itchiness got worse. I took a bath this morning and it turned my skin red. I have stopped using the medication and will be seeing a professional to get switched up for medication. How is it possible that I developed an allergy to a medication 2 months into taking it? What is a good alternative medicine? (please don't say NSAIDS because I have bad stomach issues from years of overusing them). And #3, for you medical savvy people, what is more likely to cuase the reaction, the APAP or the hydrocodone? Thanks in advance. My back thanks you too :0)

• Answer:

  Hydrocodone and acetaminophen allergies are not very common. You might try taking the acetaminophen alone (get a bottle of Tylenol) to see if that’s the culprit. If it’s the hydrocodone, there’s always codeine (T3) or morphine. Darvocet doesn’t really do anything, nor does Ultram. Fentanyl patches help some people. Oxycontin would probably be your best bet. The difficulty is finding a doctor who is comfortable prescribing pain medications. If it is the acetaminophen and not the hydrocodone, a compounding pharmacy can make up capsules that contain just the hydrocodone. But it is not a typical request.