Vioxx was designed to be the remedy for bleeding for drugs called non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDS inhibit two enzymes cyclo-oxygenase-1 (COX-1) and (COX-2). COX-1 is responsible for platelet inhibition (increased bleeding) and irritation of the stomach. COX-2 is responsible for pain relief. Prior to Vioxx and Celebrex the fact that there were 2 COX enzymes was unknown. When they found out that there were two, they were able to separate the effects. Therefore, these two drugs are able to relieve pain with a minimum of GI bleeding. Vioxx says in its package insert that it can cause a 10% rise in the INR. If your INR was 3.0 and you took Vioxx it might go up to about 3.3!! Big deal. However, I'm sure that some of the Celebrex people were only too happy to point this out to doctors. Of course as the drugs were used by millions of people there were some reports of bleeding. But whether or not this was truly related to the drugs is unknown. I would rate myself as very knowledgable in this area because I have given talks to groups of doctors about the relatively few interactions between Celebrex and warfarin. Of course, someone could turn this around and say that I was paid by Celebrex so my judgement is cloudy. But those of you who have followed what I write, know that I was not invited back by the Coumadin people because I would not say that there product was superior when I did not believe it. I would have done the same thing if I did not truly believe that these drugs are safe with warfarin.
Darvocet is a very interesting drug. The people who study it say that it is no better than a placebo. However, the World Health Organization wanted it declared a dangerous narcotic and banned from world trade. The difficulty in rating pain relievers is that pain is such a subjective issue. In other words, if it works for you, use it. I have not found any reliable reports of harm being caused by Darvocet and warfarin. I looked really hard too, because I wanted to find some. I haven't been a big fan of Darvon or Darvocet because when I was dispensing prescriptions, I had more people (3) die from this drug than anything else that I dispensed. They were all addicted and taking in excess of 25 a day. The first one was shortly after Darvon came out and we were told that it was non-addicting. He was taking about 50m every other day. The other two people took an entire month's worth at once.
Advil etc. does not raise the INR. Therein lies the problem. It just causes you to bleed with no warning such as an elevated INR would give.
