The INR won't budge from 6, that's therapeutic right?

So last post I left a teaser of how my first tour on clinical duty at the hospital would pan out.

At Wyandotte, the inpatient (IP) pharmacist staff is not sub-specialized to different departments like bigger hospitals (although we are trying to hire in an ID specialist). All the pharmacists rotate between order entry and typical IP maintenance, and clinical duty for the floors. Most of the time they will be upstairs in the various pharmacy offices for the floors, but if we're short on a given day they will just manage clinical from the clinical office in the IP pharmacy.

I started out my first clinical day in the clinical office the entire day, because that day happened to be a short staff day...and the clinical manager who was going to train me got in a car accident that morning. So I was pretty much stuck reading the pharmacy policies regarding dosing guidelines the rest of the day. That day was just boring except for one part. The clinical care coordinator and our new P4 were going over sticky details of how to best administer liposomal amphotericin B for a new admit, who had happened to just come in from a double lung transplant and wouldn't be able to use the common nebulizer for the amphotericin. The answer was pretty inventive; using a certain type of open-air nebulizer and a negative pressure room. The logistics behind this decision actually require some of the engineering department to get in on the discussion. Unfortunately I never did get to see how that worked out.

The rest of the first month or so went much better and I would rotate with the floor pharmacists and basically train on each floor. Aside from answering questions on everything the medical and nursing staff can throw at us, the main priorities the floor pharmacists have are to monitor the anticoag and antibiotic therapies of the patients on their floor. The most difficult and time consuming I would learn, Coumadin, was also the most fascinating.

Coumadin therapy is rather straightforward; for a given risk of developing clots, Coumadin is prescribed (sometimes with bridging heparin) to decrease this risk. In almost any case that isn't a post-op, these patients will be on Coumadin for years if not the rest of their lives. And Coumadin is scary. The therapeutic interval is extremely small, and there's a fine line for if the INR is 1.0 too low, there’s no effect, and 1.0 too high, the patient will bleed. Add to this the fact that pretty much everybody responds to Coumadin differently and hundreds of medications interact with it, Coumadin is a headache for even veteran pharmacists.

There are guidelines for how to deal with dosing Coumadin (if INR goes up, do this to dose, etc.) but they have proven to be useless for how many interindividual differences there are. One pharmacist explained it best to me; heparin therapy is like checkers, defined moves and each move has its direct consequence, and you can only go forward and back. Coumadin is more like chess; we have to think 3-4 steps ahead each dose just to attain a simple form of steady state (which by the way, the INR will never be at a steady state unless you have the text book patient, which by the way you will never have). Predicting how a patient may react is also key, but sometimes misleading. At first glance, an 85yo lady on synthroid and amiodarone might look like a 1mg patient, but then you realize it takes almost 15mg a day to keep her therapeutic. Or a 45yo 150kg male might get an INR of 5 from his first 2mg dose. To say the least, Coumadin therapy is tricky, but never, never the same.