ISMP issues warning about possible safety issues with newly authorized antiviral

To encourage the appropriate use of Pfizer’s COVID-19 antiviral drug nirmatrelvir/ritonavir (Paxlovid), the Institute for Safe Medication Practices (ISMP) released an alert for dispensing pharmacists.

ISMP stated that a dose reduction is necessary for patients with moderate renal impairment, and patients with severe renal impairment should not receive the drug.

Paxlovid, which received emergency use authorization (EUA) from the federal government, is designed to treat patients with positive COVID-19 viral testing results and who are at high risk for progression to severe disease.

The drug is only available in a carton containing 5 blister cards, each with daily morning and evening doses comprising 2 tablets of nirmatrelvir and one tablet of ritonavir. For patients with moderate renal impairment, pharmacists should remove one of the nirmatrelvir tablets for both the morning and evening doses from each blister card before being dispensed. The empty blisters on all 5 cards should be covered with manufacturer-supplied stickers.

ISMP said other possible safety issues include drug–drug interactions and patients failing to take both tablets together. Providers should report errors with the medication within their health care organizations and to FDA’s MedWatch reporting program, which is mandatory for products under an EUA. ISMP also requests providers report medication errors to its medication error reporting program.