Friday, April 16, 2010

Reqiem for a Heavyweight

One of the things I get to do now as department head is to advise pharmacy on formulary additions and deletions. Today I got an email asking me to comment on whether we should keep Sodium Pentothol on the formulary.

Now Pentothal AKA Thio AKA STP has been used in anaesthesia since the late 1930s. Despite a bit of trouble after Pearl Harbour when its use in sub lethal doses by untrained personnel lead to allegedly more deaths than caused by the Japanese Pentothol was the undisputed champion of induction agents until the mid 1990s. There were challengers along the way, methohexital, ketamine, etomidate, alphathesin (which I would love to see formulated in intralipid), midazolam, sufentanyl and alfentanyl all came and were unable to supplant Pentothal as the dominant induction agent. Millions of people went to sleep (and woke up after) hearing, "You'll get a taste of onions or garlic...."

Propofol finally supplanted Thio. It wasn't easy though. I remember in the early 1990s when Propofol was first introduced. We presented it to our pharmacy committee who balked at the cost of $8 vs 50 cents for the equivalent dose of Thio. Propofol was unquestionably better but not 16 times better. At first pharmacy allowed that we could use it for Pentothal allergies or porphyria. Later they allowed us 6 vials per person per week. This lead to my practice of what I called "President's Choice" propofol (President's Choice was the house brand at a grocery chain) where I took 10 cc of propofol and topped it up with enough pentothal. It also lead to a lot of stealing from other people's carts.

It was later understood that while propofol was clearly better for day surgery, pentothal should be used longer cases. Gradually propofol became used more and more, pentothal less and less. A few years ago the multidose bottles of pentothal disappeared, leaving only single dose bottles which were a hassle to reconstitute.

Currently while propofol now generic costs $3 for 20cc the equivalent dose of pentothal goes for $14. The question was, whether we should keep pentothal. I felt that for a drug which is clearly not as good, only used on principle by a small group of diehards and which costs almost 5 times more, it would be hard to justify it. That doesn't mean I don't feel guilty about it.

Pentothal joins a large list of anaesthetic drugs which have fallen into the dustbin during my lifespan including Halthane, Enflurane, Isoflurane, Curare and Pancuronium (still available but only ever used to scare residents).


burnttoast said...

The last time I had to use pentothal, it was because a neurosurgeon demanded we place someone in barb coma after an aneurysm clipping. ? Pharmacy had a fit, and it took just short of an act of God. So before you trash it, see if you have anyone on surgery staff that thinks it has magic properties...
I use iso on inpatients commonly. I think the cardio team still uses pancuronium. I do too, on the eon lengthed surgery. What is almost funnier, is how a drug gets repped like crazy, shows up, and poof, disappears very quietly. Rapacuronium, I think. Hopefully some of the rep action will quit now. What a waste of time and money.

Bleeding Heart said...

We put a patient in a barbiturate coma as a resident using pentothal. The problem is that after a couple of days, pentothal which has a very long elimination half life and is very lipid soluble hangs around the patient will never wake up.

One of our neurosurgeons liked to use methohexital in his awake seizure surgeries. It was not available in Canada at that time so we got some by special access. I gave some during a case and pharmacy hounded me for months to fill out numerous forms.

So when your neurosurgeon wants a barbiturate coma, he can organize it himself.