Liverpool COVID-19 Interactions

Do Not Coadminister

Nirmatrelvir/ritonavir (5 days)

Dihydroergotamine

Quality of Evidence: Very Low

Summary:

Coadministration is contraindicated as it may increase dihydroergotamine concentrations which may result in serious and/or life-threatening reactions such as acute ergot toxicity. Dihydroergotamine should be paused during nirmatrelvir/ritonavir treatment and for at least 3 days after the last dose of nirmatrelvir/ritonavir. After stopping nirmatrelvir/ritonavir, the CYP3A4 inhibitory effect takes several days to resolve.

Description:

Coadministration is contraindicated. Ritonavir coadministration is likely to result in increased plasma concentrations of ergot derivatives. Increased plasma concentrations of ergot derivatives leading to acute ergot toxicity, including vasospasm and ischaemia.

Paxlovid GB Summary of Product Characteristics, Pfizer Ltd, December 2024.

Coadministration is contraindicated. Ritonavir coadministration is likely to result in increased plasma concentrations of ergot derivatives and is therefore contraindicated as elevated plasma concentrations are associated with serious and/or life-threatening reactions.

Paxlovid EU Summary of Product Characteristics, Pfizer, February 2025.

Co-administration may increase concentrations of ergot derivatives. Co-administration contraindicated due to potential for acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system.

Paxlovid US Prescribing Information, Pfizer Inc, February 2025.