EMA’s safety committee (PRAC) is reminding healthcare professionals of the risk of serious and potentially fatal adverse reactions with Paxlovid (nirmatrelvir, ritonavir) when used in combination with certain immunosuppressants that have a narrow safe dosage range (where small changes in the dose can lead to serious adverse reactions), due to drug-drug interactions reducing the body’s ability to eliminate these medicines.

The PRAC reviewed all available evidence, including reports of serious adverse reactions, some of which were fatal, resulting from drug-drug interactions between Paxlovid and these immunosuppressants. In several cases, blood levels of these immunosuppressants increased rapidly to toxic levels resulting in life-threatening conditions. Therefore, the PRAC agreed on a direct healthcare professional communication (DHPC) to remind healthcare professionals of the risk of these interactions, which is known and already described in the product information for this medicine.