Oral Anticoagulants Often Inappropriately Prescribed for HIV Patients on ART

By Marilynn Larkin

April 02, 2020

NEW YORK (Reuters Health) - Direct oral anticoagulants (DOACs) are frequently prescribed for individuals on antiretroviral boosters, despite the risk of drug-drug interactions, researchers say.

"Several factors likely contribute to our finding that non-recommended DOAC/ART combinations were observed in study participants," Dr. Anne Monroe of George Washington University in Washington, DC, told Reuters Health by email. "Clinicians without HIV expertise prescribing DOACs may be less aware of the interactions between DOACs and antiretroviral therapy. Additionally, recommendations regarding management of DOAC/ART interactions vary between different information resources."

"Coordinated care involving the DOAC prescriber, the HIV clinician, and a clinical pharmacist can help avoid adverse events," she said. "Ongoing education and innovative ways to increase pharmacologic vigilance, such as clinical dashboards that alert to potential drug interactions, may also be beneficial."

Dr. Moore and colleagues analyzed oral anticoagulant prescribing among people with HIV registered in the DC Cohort Database from 2011-2017.

As reported in Clinical Infectious Diseases, among 8,315 participants, 236 anticoagulant prescriptions (96 DOAC; 140 warfarin) were reported for 206 individuals. Those receiving prescriptions had a median age of 56 at anticoagulant initiation, and were predominantly men (82%) and black (82%).

DOAC use increased from 3% of total anticoagulant prescribing in 2011 to 43% in 2016, when DOACs accounted for 64% of all newly recorded anticoagulant prescriptions.

Nineteen bleeding events were recorded among 16 individuals. Despite the U.S. Food and Drug Administration label recommendation to avoid use of rivaroxaban in those taking boosted ARVs, 41% of patients remained on boosted ARVs after rivaroxaban initiation.

Dr. Jeffrey Laurence, senior scientific consultant for programs at amfAR in Washington, DC, commented in an email to Reuters Health, "The major concern is that prescriptions for the DOACs are ever-increasing in the HIV-positive population without adequate ways of assessing whether people concomitantly taking ritonavir or cobicistat are receiving an appropriate dose of the DOAC (i.e., not overdosing). Levels can be measured, but they are not well standardized, and the tests not readily available."

Dr. Laurence noted that he recommends warfarin for maintenance or enoxaparin for initial treatment and maintenance rather than a DOAC. "If the patient absolutely insists on avoiding (warfarin), and will not self-inject (enoxaparin), even if it's only once per day, I recommend avoiding rivaroxaban, the DOAC most prominently prescribed in this study, and using apixaban instead," he said.

"Clinicians should engage their pharmacists in review of any potential conflicts between a specific ART regimen and a new drug," he added, "deciding on alternative medications or at least being aware to monitor for specific side-effects."

Douglas Jennings, clinical pharmacist for heart transplant and mechanical circulatory support at NewYork Presbyterian Columbia University Irving Medical Center in New York City, also commented by email.

"Warfarin has the same potential for drug interaction as the DOACs, therefore there is no perfect option for patients with HIV who require oral anticoagulation," he told Reuters Health.

"In non-HIV patient populations, the data demonstrating superior safety with DOACs over warfarin are overwhelming," he said. "I therefore believe that it would be more appropriate to use a DOAC over warfarin in most patients with HIV who are taking an interacting medication. This notion is supported by the findings of the current study, which reported that rates of bleeding were acceptably low and similar between the warfarin and DOAC groups."

There are several questions that still need to be addressed in larger cohorts of HIV patients," he noted. "These include how to optimize dosing of DOACs in the setting of these significant interactions, and what to do when faced with HIV patients with impaired renal function."

SOURCE: https://bit.ly/344qbMQ Clinical Infectious Diseases, online March 17, 2020.