Unintended consequences

We must always worry about both errors of comission and errors of omission. The NY Times today reports on an interesting article in today’s NEJM – Study: Heart Drug Use Resulted in Deaths

This is an old story which I covered in a talk last year – Update 2003 – Congestive Heart Failure

This is the problem:

• The RALES study found that treating Class III and IV CHF with spironalactone can save lives
• The investigators provided strict rules for dosing and monitoring
• Patients need to have serum potassium and creatinine followed carefully
• Patients with creatinine greater than 2.5 should not receive spironalactone
• Patients with hyperkalemia (5.5 or greater) should have spironalactone stopped
• Physicians are used to using spironalactone for cirrhotic ascites – but using much higher dosing

Quoting from the NY Times

The researchers say their findings illustrate what can happen when doctors apply drug-study results to their own patients. They suggest that some of the patients probably shouldn’t have been given the heart failure drug and that doctors weren’t checking for dangerous potassium buildup.

“I have no doubt that in the right patients and with careful monitoring that this is still a good drug combination,” said Dr. David N. Juurlink, one of the Canadian researchers. “It’s just when we prescribe it more widely and maybe we don’t monitor patients quite as closely as we should, then that’s where we get into trouble.”

This unfortunate study raises a cautionary note. Everything that we do in medicine has risks and benefits. We have the challenge of balancing those risks and benefits.

It is likely that the complications of spironalactone occurred because physicians were trying to practice excellent up to date medicine. Unfortunately, they knew just enough to get patients in trouble. I encourage interested readers to review slides 47-49 from my 2003 talk.