VA’s Formulary May Have Curbed Misuse of Ivermectin for COVID-19

In contrast to retail pharmacies, there was only a minimal increase in ivermectin dispensing at Veterans Administration (VA) pharmacies during the COVID-19 pandemic, possibly due to the VA national formulary restriction on the antiparasitic drug, a cohort study suggested.

After March 2020, the slope change in retail pharmacies was greater than that seen in VA pharmacies, for a differential change of 2.17 additional prescriptions per 100,000 per month (95% CI 1.29-3.05), reported Nora V. Becker, MD, PhD, of the University of Michigan in Ann Arbor, and co-authors in a research letter published in JAMA Network Open.

Conversely, monthly ivermectin dispensing rates among VA pharmacies had a slight uptick of 0.14 prescriptions per 100,000 per month (95% CI 0.08-0.21) from March 2020 to September 2021, which decreased by 2.83 prescriptions per 100,000 (95% CI -3.80 to -1.86) following the VA formulary restriction on ivermectin prescribing in September 2021, which stated that “the patient should NOT receive ivermectin tablets” when they are to be used “as a treatment for COVID-19 infection without another appropriate indication.”

Becker and colleagues noted that “additional research is needed to determine why the surge in ivermectin dispensing seen in retail pharmacies did not occur in VA pharmacies. Local VA facility restrictions in ivermectin use may have existed before September 2021.”

“Another possibility is that inappropriate demand for ivermectin increased less among veterans compared with non-veterans,” they added. “Distinguishing between these possibilities could inform the design of interventions to decrease future provision of low-value care for COVID-19 and other conditions.”

The formulary restriction cites a CDC health advisory, which noted that ivermectin dispensing from retail pharmacies increased 24-fold in the summer of 2021 and calls to poison control centers across the country increased five-fold.

It also cites an FDA consumer update from September 2021 that warns that “the FDA has not authorized or approved ivermectin for the treatment or prevention of COVID-19 in people or animals. Ivermectin has not been shown to be safe or effective for these indications. There’s a lot of misinformation around, and you may have heard that it’s okay to take large doses of ivermectin. It is not okay.”

For this study, Becker and colleagues calculated monthly ivermectin dispensing data per 100,000 active annual veterans from the VA’s Corporate Data Warehouse from June 2019 to February 2022. Any veteran that had been hospitalized or filled a medication was counted.

U.S. retail pharmacy data were gathered from the IQVIA National Prescription Audit, which captures 92% of prescriptions dispensed. Monthly ivermectin dispensing was calculated per 100,000 U.S. residents.

There were 7,434 and 2,362, 572 ivermectin prescriptions dispensed by VA pharmacies and retail pharmacies, respectively, during the study period.

To assess the association between the VA formulary restriction and ivermectin dispensing, Becker and team conducted a single-group interrupted time series analysis using only VA ivermectin dispensing rates without a control group, which began in March 2020, since ivermectin dispensing before this time was infrequent.

Study limitations included the lack of a control group for the analysis of the VA formulary restriction and a lack of complete U.S. retail pharmacy data.