By Gina Shaw
Originally published by our sister publication Pharmacy Practice News
Numerous wrong-dose errors involving nirmatrelvir and ritonavir (Paxlovid, Pfizer) have been reported to the Institute for Safe Medication Practices (ISMP) over the past several months, with many of the errors involving confusion over renal dosing, according to a new ISMP alert.
Beginning in April 2022, nirmatrelvir and ritonavir became available in tablet form in two blister-pack configurations, with different dosing and a specific blister pack for patients who have moderate renal impairment.
For patients with normal renal function, it comes in a carton holding 30 tablets contained in five daily-dose blister cards. Each blister card contains four nirmatrelvir tablets (150 mg each) and two ritonavir tablets (100 mg each). Patients should take two tablets of nirmatrelvir (150 mg each, 300 mg total) and one?tablet of ritonavir (100 mg) in the morning, and the same doses in the evening.
For patients with moderate renal function, who must take only one tablet of nirmatrelvir (150 mg) along with one tablet of ritonavir (100 mg) together, twice daily, special reduced-dose blister packages are available. (Patients with severe renal impairment should not be prescribed this drug.)
Prior to April 2022, only the standard packaging was available, and pharmacy staff were asked to remove one of the nirmatrelvir tablets for each dose on all five blister cards, and put on manufacturer-supplied stickers to alert patients with moderate renal impairment to the removal of the unneeded tablets.
The ISMP report noted that many recently reported errors have involved patient self-administration, such as taking the wrong tablets or the entire day’s dose at one time. Others have been dispensing errors, many involving renal dosing modifications—even with the availability of the new reduced-dose blister packages.
“Dispensing errors involved providing the carton with reduced-dose blister packages intended for patients with moderate renal impairment to patients with normal renal function or mild renal impairment, or vice versa,” it said. “Several of the reported errors involved improper renal dosing, such as prescribing or dispensing Paxlovid to patients with severe renal impairment. Other prescribing errors included ordering the standard dose for patients with moderate renal impairment and vice versa, … and not checking or asking patients about renal function or concomitant drug use to avoid drug-drug interactions.”
To avoid errors, ISMP recommends the following:
• Educate prescribers and pharmacists about the reduced-dose blister package for patients with moderate renal impairment and who should receive it.
• Check electronic health record configuration. Ensure it is intuitive to select two of the 150-mg nirmatrelvir tablets to make up a 300-mg dose.
• Provide clinical decision support. Prescribing systems should include guidance for nirmatrelvir and ritonavir, if possible, such as an order sentence with dosing for patients with moderate renal impairment.
• Check and confirm renal function, and use the FDA’s screening checklist to identify significant drug interactions.
• When educating patients about how to take the drug, avoid communicating the dose by tablet or blister color, which can cause confusion. Instead, show them how it is labeled on the blister pack, and make sure they know which tablets to take at what time.
“ISMP is emphasizing the need to educate patients using the teach-back method, since blister-pack instructions can be quite confusing,” said ISMP President Rita K. Jew, PharmD, MBA, in a statement. “Providing patients with the Paxlovid Fact Sheet for Patients, Parents, and Caregivers (www.fda.gov/media/155051/download) is a requirement and provides printed instructions to follow; if patients have questions, they should contact their pharmacist.”
The full ISMP alert is available online.
