Ready, set, go! Let's see how long it takes us to stop using N-acetylcysteine post-ACT

Today's ACT trial should have laid to rest the long-held practice of utilizing N-acetylcysteine (Mucomyst, Bristol-Myers Squibb) for prophylaxis against contrast-induced nephropathy. We've all done it. I've even made my dad swallow the rotten-egg–flavored liquid bid the day before contrast, twice the day of contrast, and twice more the day after. We have a slick protocol at our facility to ensure everyone gets the same uniform "protection." In truth, it makes me feel better to prescribe it, although I've had my doubts about it working for at least eight years. I guess ordering it comes under the adage, "Don't just stand there, do something." Sometimes I think it's not only the "something" we can do for the patient that makes us feel better but also serves as a subconscious defense maneuver in case we ever encounter a nice hopeful plaintiff's attorney.

ACT did not demonstrate any signal of harm, but it absolutely did not demonstrate any benefit, either. Although not powered to look at bicarbonate's roll in prophylaxis against contrast-induced nephropathy, it also failed to demonstrate any trend toward efficacy. Hopefully the upcoming ACT II trial planned to launch in the next 12 months will send bicarbonate packing in the same direction as it did N-acetylcysteine.

It's not that N-acetylcysteine is costly. I checked with my pharmacy today, and we've utilized our protocol 84 times since January 2010. Our hospital has around 120 beds, but our census runs anywhere from 40 to 90. According to Kevin Adams, pharmacy director of TJ Samson Community Hospital in Glasgow, KY, the cost is only $18 per treatment period, amounting to around $1600 total for our hospital this year in patient charges for the drug only. But imagine how many times it's been utilized in larger hospitals annually, and add the cost of an extra day's length of stay for each encounter. Since it's common for nearly any nephrologist or cardiologist to spend a day delivering this prophylactic protocol, the cost of this practice quickly adds up. If you assign the cost of a day's stay in the hospital anywhere from $400 to $ 1000 depending upon which reference you believe, the cost this year at TJ Samson Hospital for premedication against contrast-induced nephropathy was $33 600 to $84 000.

I commented to a friend today that "I keep writing the same line describing many trials at this year's AHA meeting." "This is the largest trial to date" is an adequate descriptor for many of the studies presented this week. The next statement is that "this trial is negative" or "this trial was neutral." I don't think this is a coincidence. Although it's not practical to perform a 10 000-strong study on every compound early in its development, it's apparent that many of the things we do for patients are garnered from small trials not adequately powered that produce completely the wrong conclusions. The N-acetylcysteine story is no different. Not only are patients confused by the mixed signals we identify, but physicians are as well. Once you get physicians going in a certain prescribing pattern, like Pavlov's salivating dogs, we can hardly seem to help ourselves. Perhaps some negative-conditioning program like a hot stick administered routinely by the hospital pharmacist might be a workable solution.

So next time you see me, if I have a bit of what seems like a nervous twitch, you'll know I convinced my pharmacist to help me with a little negative conditioning in order to make me practice evidence-based medicine. Now, get ready, set, go: See how long it takes you to change your practice.

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Your comments

	Ready, set, go! Let's see how long it takes us to stop using N-acetylcysteine post-ACT
	# 1 of 4	November 17, 2010 10:36 (EST)
	William Blanchet	Stick a fork in it, it's done.
	# 2 of 4	November 17, 2010 12:16 (EST)
	Melissa	I believe you are correct Wiliiam!!! Melissa
	# 3 of 4	November 17, 2010 10:19 (EST)
	Jan Pattanayak	I think its hard to argue that in addition to avoiding dehydration and hypotension the best way to avoid CIN is to minimize contrast usage.  We just switched to a power injector in our cath lab and it has cut down contrast use significantly.  Maybe because I grew up playing with those radio controlled cars I'm injecting about 3-4 cc per left coronary injection and 1-2cc for the right.  The LV gram takes 12-15 cc for a total of 30-40 cc.  (It also has the added benefit of allowing me to stand an extra 5 feet away from the patient for the diagnostic portion.  Alas I still get toasted during the intervention).  I could not endorse the power injector more strongly.
	# 4 of 4	November 17, 2010 10:28 (EST)
	Melissa	Jan, I've toyed with the idea of getting an injector, especially since I developed arthritis in the base of my thunb.  My only concern is that I've always anchored the catheter on the patient's leg to keep from having any play of the catheter in the ostium.  I personally think that's a good way to keep the catheter from getting sucked down into the vessel and helps to avoid dissection.  I'm a little nervous about using an injector for that reason but sounds like I need to re think it. Melissa

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