Many physicians have been reluctant to prescribe Merck's COVID-19 antiviral, molnupiravir, because it's less effective at preventing severe outcomes, NPR reported Feb. 22.
"It's an alternative rather than a first-line drug, and I think that's why utilization is lower," said Rajesh Gandhi, MD, an infectious diseases physician at Boston-based Massachusetts General Hospital who helped develop COVID-19 treatment guidelines for the National Institutes of Health and the Infectious Diseases Society of America.
The FDA's emergency use authorization was more limited for molnupiravir than Pfizer's COVID-19 antiviral, Paxlovid. Data submitted to the FDA showed molnupiravir lowered the risk of hospitalization or death among high-risk patients by 30 percent, down from 48 percent in an earlier analysis. Paxlovid was shown to reduce the risk of hospitalization or death by 89 percent.
The FDA's authorization for molnupiravir also said it should be used when alternative treatments are "not accessible or clinically appropriate," and it comes in last on the agency's short list of recommended treatments for patients at high risk of progressing to severe illness.
Some pharmacies "are running into issues with storage space on molnupiravir and not moving the product that quickly," Derek Eisnor, MD, who oversees the government's distribution of COVID-19 drugs, said on a call with state health officials, NPR reports.
Still, molnupiravir has a place in the current treatment landscape. There is a list of common drugs Paxlovid cannot be taken with, while monoclonal antibody treatment sotrovimab and the antiviral remdesivir are intravenous treatments that must be administered in settings where clinicians can treat a severe infusion reaction in the rare instance one occurs.
Thus, molnupiravir is meant "as an alternative when one of those other drugs can't be given, because of drug interactions or feasibility issues," Dr. Gandhi said.
Federal data has also shown many courses of antiviral pills sit idle on pharmacy shelves. Physicians have said the number of steps involved in order to get a prescription (getting tested, visiting a healthcare provider, getting a prescription and finding a pharmacy to fill the treatments) is likely another factor in low utilization.
Some pharmacists are also pushing back against low reimbursement for COVID-19 treatment pills — a penny to $10 per prescription — saying they will not stock them at the current reimbursement rates.
Editor's note: This article was updated March 16 at 2:10 p.m. CT to clarify that remdesivir is an antiviral medication.