Medicinal products listed are not considered a comprehensive list of all possible medicinal products that may interact with nirmatrelvir/ritonavir. Please consult with the Paxlovid (nirmatrelvir/ritonavir) SmPC and appropriate references for comprehensive information.

• Nirmatrelvir/ritonavir is a CYP3A substrate; therefore, medicinal products that induce CYP3A may decrease plasma concentrations of nirmatrelvir and ritonavir and reduce Paxlovid therapeutic effect
• PAXLOVID is a stong inhibitor of CYP3A and may increase plasma concentrations of medicinal products that are primarily metabolised by CYP3A
• Medicinal products that are extensively metabolised by CYP3A and have high first pass metabolism appear to be the most susceptible to large increases in exposure when coadminstered with nirmatrelvir/ritonavir 
  • Thus, coadministration of nirmatrelvir/ritonavir with medicinal products highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life threatening events is contraindicated 

Special warning and precautions for use :

Potential for interactions should be considered with other medicinal products prior to and during Paxlovid therapy; concomitant medicinal products should be reviewed during Paxlovid therapy and the patient should be monitored for the adverse reactions associated with the concomitant medicinal products. The risk of interactions with concomitant medications during the 5-day treatment period for Paxlovid should be weighed against the risk of not receiving Paxlovid.

Severe, life-threatening, and fatal adverse reactions due to drug interactions have been reported in patients treated with Paxlovid.

Hypersensitivity reactions
Anaphylaxis, hypersensitivity reactions, and serious skin reactions (including toxic epidermal necrolysis and Stevens-Johnson syndrome) have been reported with Paxlovid (see section 4.8 of SmPC). If signs and symptoms of a clinically significant hypersensitivity reaction or anaphylaxis occur, immediately discontinue Paxlovid and initiate appropriate medications and/or supportive care.

Coadministration of Paxlovid with calcineurin inhibitors and mTOR inhibitors
Consultation of a multidisciplinary group (e.g., involving physicians, specialists in immunosuppressive therapy, and/or specialists in clinical pharmacology) is required to handle the complexity of this coadministration by closely and regularly monitoring immunosuppressant blood concentrations and adjusting the dose of the immunosuppressant in accordance with the latest guidelines (see section 4.5 of SmPC).

• In patients with a history of clinically significant hypersensitivity to the active substances (nirmatrelvir/ritonavir) or to any of the excipients listed in section 6.1 of the SmPC
  
• ​​​​​​​In patients with severe hepatic or severe renal impairment
• With medicinal products that are:
  • Highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening reactions
  • Potent CYP3A inducers where significantly reduced plasma nirmatrelvir/ritonavir concentrations may be associated with the potential for loss of virologic response and possible resistance

Please see the SmPC for special warnings and precautions for use before prescribing Paxlovid.

Please see the SmPC for special warnings and precautions for use before prescribing Paxlovid. 

• In some circumstances, DDIs cannot be prevented by this approach, either because of persisting effects (ie. carbamazepine or rifampicin) or a very long half-life of the comedication (ie. amiodarone)
• These DDIs may result in inadequate exposure to nirmatrelvir or toxic drug levels
• An alternative COVID-19 treatment should be considered in such situations

• Ritonavir is used in combination with other antivirals to similarly inhibit drug metabolism