Selecting & Utilizing a DOAC for VTE Prophylaxis
Considerations for transitioning patients from heparin over to a direct oral anticoagulant for venous thromboembolism prophylaxis, and strategies that can help health care professionals better manage patients through a drug shortage.
Manesh R. Patel, MD: I think it’s always unique in thinking about how the FDA looks at data. And I think the importance here is that there is a group of patients, however we identify them, and I think the key way of identifying them is to try to understand the bleeding risk and certainly their VTE [venous thromboembolism] risk. There’s a group of patients [who] seem to get a benefit. Considering the heparin shortage, where we’re looking for a therapy in these patients [for whom] you’re trying to avoid heparin, I think there’s an opportunity potentially to be thinking about the therapy there. And one might ask—and I guess I would ask is if I was going to use—what are some of the ways in which I would use it? How do I transition somebody who’s on an injectable, whether it’s heparin sub Q [subcutaneous] or low-molecular weight heparin? How would you say I should start with either rivaroxaban or betrixaban? How would I start that agent in somebody who is on an injectable from IV [intravenous] or sub Q?
Sarah A. Spinler, PharmD, FCCP, FAHA, FASHP, AACC, BCPS, AQ-Cardiology: For most of those agents, we typically would use them once a day. My guess is it probably would be in the evening. That way, if you do your procedures, most people decide those things in the morning. And if you look in terms of the potentially evening dose, it’s just basically stopping the subcutaneous heparin and starting the next day with your oral agent. Again, you’re trying to limit it to those types of patients [who] are high-risk for bleeding for some of the trials, and they excluded patients with active cancer, patients [who] had previous active bleeds in the last 3 months, patients [who] have active gastrointestinal ulcers, patients on dual antiplatelet therapy potentially, and patients with pulmonary cavitation. If you look at that percentage of patients, hospitalized patients, it wasn’t that much in terms of looking at those specific criteria compared [with] the general medical patients at risk [who] are hospitalized in the United States.
Manesh R. Patel, MD: Yeah, I think that’s right. And I think you’re right, that we would probably transition to once-a-day dosing and we would probably start that patient whenever you stop that agent, or you could start it a little before you stop the IV just to make sure the transition worked. A lot of people do that.
What about other parenteral agents with this shortage? Argatroban, bivalirudin, Fondaparinux—what are your thoughts about [those]?
Sarah A. Spinler, PharmD, FCCP, FAHA, FASHP, AACC, BCPS, AQ-Cardiology: Argatroban and bivalirudin have typically been restricted: bivalirudin to the catheterization lab, argatroban to the heparin-induced thrombocytopenia patients only. Fondaparinux, now its primary use is in venous thromboembolism prophylaxis in patients with a history of heparin-induced thrombocytopenia. All those products are more expensive than rivaroxaban or betrixaban, so probably [they] will unlikely be used for venous thromboembolism prophylaxis.
Manesh R. Patel, MD: Now that we have an antidote for say some of the Xa inhibitors, do you think the lack of an antidote for 1 of those parenteral agents affects you? Obviously, you mentioned cost. Any other things? Does the antidote affect you?
Sarah A. Spinler, PharmD, FCCP, FAHA, FASHP, AACC, BCPS, AQ-Cardiology: Oh, sure. There’s no antidote currently for either argatroban or bivalirudin. Granted, both have a shorter half-life—in terms of bivalirudin, almost shorter than heparin—so that’s an advantage for those. But certainly, Fondaparinux also has a very long half-life.
Manesh R. Patel, MD: One of the other ways we might be able to affect our utilization of things, [is] we’ve now [gone] from the world of writing [an order] on a piece of paper to electronically managing our pharmacy inventory to thinking about other ways. Are there other things we should be thinking about that we could put in place as we get more digital about potential shortages?
Sarah A. Spinler, PharmD, FCCP, FAHA, FASHP, AACC, BCPS, AQ-Cardiology: Sure. I think the electronic alerts and health medical records can do a tremendous service to help make practitioners aware, especially if you’re going to shift practice. If you want practitioners to use certain drugs for venous thromboembolism, you’ll get a certain list of medications that you can use. But some of the issues related to that are if you’re going to move the practice to something people aren’t familiar with.
One of the big concerns about the heparin shortage currently is that the drugs that are purchased usually are bought the same units per volume. The bags are all the same concentrations. The vials and the injections are all the same concentrations. But if those concentrations aren’t available, you’re changing. And if you don’t tell the nurse the doses may change and the nurse is giving them an injection, they’re not aware that the dose may change. Or [that] the pumps, [even though] they’re set or they’re smart pumps, there’s a higher likelihood for medication errors to occur once you switch products.
The other good part about the alert is that you can make individuals aware and, say, switch to bivalirudin in the catheterization lab, as an example. Or you can put something about using rivaroxaban as your choice where it wasn’t a choice before. But there’s a lot that goes into that, and you must communicate that to the providers, so medication errors don’t happen.