Monday, May 03, 2010

When Drugs Become Extinct

Doctors are all familiar with marketing efforts to promote new drugs, but once the new drugs displace older drugs in the medical marketplace, who serves as advocates for the continued manufacture of older FDA-approved drugs?

In a short answer: no one.

For those of us dealing in cardiac arrhythmia management, this presents difficult challenges to patient care if people are unable to take the newer drugs due to side effects. These patients no longer have a fall-back option to turn to for medical therapy when the older drugs have become extinct on the marketplace.

Examples of antiarrhythmics that have reached extinction status in the US include many of our older antiarrhythmic drugs such as procainamide, mexilentine or quinaglute.

Take for instance a recent case: A older person with recurrent ventricular tachycardia and congestive heart failure and ICD implantation who has experienced several appropriate shocks for hemodynamically-significant ventricular tachycardia from their ICD. They were not in heart failure and had a consistent ideal body weight. Beta blocker medications have been maximized. This same person is pacemaker dependent and allergic to Amiodarone and iodine. Sotalol was not tolerated and dronedarone is contraindicated because of heart failure. Their creatinine clearance is 40. The patient was placed on mexilentine in the hospital and did well, only to find after discharge that no pharmacies could obtain the drug any longer. Oral procainamide, I have found, has suffered the same fate long ago. Few options remain: dofetilide as an inpatient?


Still, the issue of drug extinction is a challenging one: not enough market to justify the drug's manufacture, yet still a rare patient out there who might need an older medication. Even generic drug manufacturers won't manufacture these niche drugs - there's just not enough of a market to justify their manufacture and the regulatory environment precludes a small start-up company from even trying to meet the very small demand.

I wish I had an answer to this conundrum. How do others handle this situation?



Marco said...

Custom synthesis and formulation? Although that's got to be pricey...


Anonymous said...

lobbying teva to continue to make mexilitene. local pharmacies cannot get enough. we begged the hospital to buy whatever it could acquire for now.

DrJohnM said...

Mexiletine is a problem for us too. Gosh, it is still pretty useful. We just keep calling pharmacies until we find one that has it, but I suspect this tactic will eventually fail.

Jay said...

I'm still mourning the loss of procainamide. Many of my amio refractory VT patients would do well when this was added.

Mexitil has been less of a problem, but will be missed if it really goes away forever (maybe I'm in denial, but I'm still hopeful). I've also thought of this drug as "chicken soup" for arrhythmias. Doesn't really help or hurt, but it makes us all feel better.

I guess we'll all have to get better at VT ablation.