martes, 1 de noviembre de 2011

Clarification of off label prescribing and an update on Dr. Gleason

After the lively exchange triggered by my recent post on off label promotion of pharmaceuticals I thought this follow up might be useful. A commenter was concerned by my statement that off label prescribing was legitimate: “Yet, off label prescribing is, by definition, prescription to treat conditions for which there is NO EVIDENCE that such prescription works.” Thus the question is raised---does “evidence based” equate to “FDA approved”?

Not necessarily. I cited metformin for polycystic ovary syndrome, viagra cialis online pharmacy pharmacy for pulmonary hypertension, anticonvulsants and tricyclic antidepressants for neuropathic pain and caspofungin for invasive candidiasis as examples of evidence based treatments, all of which lack FDA approval for those uses. In other words, current examples of legitimate off label prescribing. Another example is the use of vasopressin in cardiac arrest---fully in accordance with ACLS protocols yet off label. And if memory serves, there are past examples in which evidence based prescribing preceded eventual FDA approval for particular indications. Thus, angiotensin converting enzymes were validated and used for heart failure at a time when they were only approved for hypertension.

The flip side is FDA approved (on label) prescribing which is not evidence based. Doxazosin, for example, (Cardura) is FDA approved as monotherapy for hypertension despite strong evidence from ALLHAT that such use is inappropriate. Old farts like me may remember phenformin (Ciba-Geigy’s DBI, the granddaddy of metformin) which remained on label and FDA approved for years despite clear evidence of harm. How many thousands of patients died of lactic acidosis before the FDA finally took action? So much for the FDA as the guardian of evidence based medicine!

That said, I’m sure there are widespread instances of off label prescribing that are non-evidence based and even harmful. One more point about inappropriate prescribing: off label prescribing is to be distinguished from on label prescribing which ignores warnings and contraindications in product labeling. I have blogged about this unfortunately widespread practice here and here.

On to Dr. Gleason. The commenter seems to have misperceived me as defending Dr. Gleason’s promotional activities and questioned my basis for stating that he did nothing clearly illegal. Having no legal expertise of my own, I merely cited experts quoted in the Times article who made that point. If this is a fuzzy area of the law subject to prosecutorial discretion, or zeal, it could be a dangerous precedent of concern to all who speak at CME events.

A discussion forum concerning Dr. Gleason has been set up here for those who wish to keep abreast or weigh in.