Interpreting the Nuances of DOAC Therapies for Patients With NVAF: The Pharmacist’s Role

In this companion commentary to the live webinar “An Untapped Resource: Pharmacists’ Role in Improving Screening and Management of NVAF,” we discuss the pharmacist’s perspective on screening for nonvalvular atrial fibrillation (NVAF), the nuances of direct oral anticoagulant (DOAC) dosing, and navigating barriers to treatment access.

Screening for NVAF
An opportunistic approach to screening for undiagnosed NVAF is reasonable for community and ambulatory care pharmacists. For example, if you are already seeing patients who are aged 65 years or older and filling prescriptions for blood pressure medicine, ask them if they have talked to their providers about screening for NVAF. Even something as simple as putting NVAF on patients’ radar might encourage them to be screened more frequently in various healthcare settings. It is important to reiterate to patients that repeated screening is more beneficial than when it is done at a single time point. When they return to pick up refills, ask them if they followed up with their provider about screening for NVAF.

In addition, if the pharmacist feels comfortable performing pulse palpation screening, then it is reasonable to do so. Pharmacists can also teach the patient how to do pulse palpation to check for any kind of rhythm irregularities. We should remember that suspected results of pulse palpation checks need to be confirmed by a provider for official diagnosis; pharmacists should ensure that patients are able to follow up with either their primary care provider or cardiologist and that patients know what to do next if they detect any kind of irregularity. Although pulse palpation is reasonable for pharmacists to use, having a handheld single-lead ECG device provides more accuracy in terms of detecting an irregular rhythm.

Dosing of DOAC Therapy
Both underdosing and overdosing of DOACs are associated with poor outcomes for patients. Therefore, DOAC doses should be adjusted over time as needed, as a patient gets older or with changes in renal function. Healthcare professionals need to be diligent about assessing the dose every time they interact with patients, making sure that the dose is still correct. On the other hand, pharmacists should also make sure that we are not initiating therapy at a wrong dose. We should not be empirically dose-reducing DOACs (eg, apixaban) unless the patient meets dose reduction criteria, even for patients with frailty and a high risk for falls. For apixaban, the dose reduction criteria specify that 2 of 3 of the following must be met: serum creatinine at or above 1.5 mg/dL and either aged 80 years or older or have a body weight of 60 kg or less. Proper prescribing at initiation and throughout the entire course of therapy is important.

In addition, the pharmacist can have an important role here by educating other healthcare professionals about the potential problems of underdosing DOACs and how this can lead to increased systemic embolic events and mortality, but doesn’t decrease the risk of bleeding. The pharmacist can present the literature, explain the clinical trial outcomes, and why it is important to follow what was done in those clinical trials when changing the DOAC dose.

For example, when using concomitant P2Y12 inhibitors, rivaroxaban may require dose reduction, whereas other DOACs do not. The rivaroxaban dose was reduced to 10 mg/day in the PIONEER AF-PCI study for patients with a creatinine clearance of 30-50 mL/min. If dose reducing rivaroxaban during dual therapy with a P2Y12 inhibitor, healthcare professionals should be mindful to re-evaluate and adjust the dose to either 15 mg/day or 20 mg/day, depending on the patient’s renal function, when the P2Y12 inhibitor is stopped.

Dosing and Body Weight
In the program “Stroke Prevention With Evidence-Based DOAC Therapy,” we highlighted that the guidelines for venous thromboembolism have been updated, and now there are sufficient data to support using rivaroxaban or apixaban for anticoagulation treatment regardless of weight or BMI. The data are starting to support that in the setting of NVAF as well. Patients should be presented with the options of warfarin or DOAC for their anticoagulation and be asked, “What do you think is going to work best for you?” If frequent clinic visits are not feasible, a DOAC is going to be the safer and potentially more effective agent for them. Similarly, the data in patients with lower weight are also suggestive of improved safety profiles and equal efficacy for DOAC therapy. Therefore, body weight has become much less of a concern when it comes to choosing therapies, and choosing a particular DOAC should always involve a patient discussion.

Striving for Access and Care Coordination
Upon therapy initiation, using a 1-month free trial card for a DOAC can be helpful, particularly because there are no restrictions on who qualifies to use them. We use them often for patients in the cardiac care unit to help with therapy continuity as they transition to the clinic.

Ensuring the patient has trustworthy follow-up before the 1-month free period is completed is imperative. The healthcare team should use that time to make certain a formulary agent is prescribed, prior authorization is completed if necessary, and the patients can acquire the medication consistently, prior to them running out of medication. If this doesn’t happen, patients may stop therapy after that month, and then suddenly, they have a stroke. It is important to avoid that lapse in time where patients could develop a clot and potentially embolize. Pharmacists can also help by accessing and providing resources to reduce out-of-pocket costs thereafter with copay assistance cards (if the patients have private or commercial insurance) or medication assistance (if they are in the Medicare Part D coverage gap).

As we just discussed, we try to be mindful that patients have their medications in hand before they leave the hospital. For example, if we use a copay card for DOAC therapy and we know that the patients will eventually want their prescriptions sent elsewhere, we either try to include the copay card information within the electronic prescription or make sure they leave with a physical copy of their copay card. This way, the information is more likely brought to the attention of other pharmacists.

Your Thoughts
Do you find opportunistic screening for NVAF valuable in your pharmacy practice? Please elaborate on your experience in the comment section below. Answer the polling questions and leave a comment in the box below.