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Paxlovid - COVID-19 antiviral treatment

In 2022, Paxlovid was made available in Ireland as an antiviral option to treat COVID-19. 

Paxlovid consists of two separate tablets – one is called PF-07321332 and the other is called Ritonavir. PF-07321332 works by reducing the ability of the virus to multiply in the body while Ritonavir works to prolong the action of PF-07321332.

The treatment is specifically targeted only at patients who could be at risk of developing severe COVID-19 symptoms. Therefore, Paxlovid is not expected to be a widely used drug in the community.

For people with epilepsy who are taking anti-epileptic drugs (AEDs), there are a number of other important issues to be aware of, which are likely to limit the use of Paxlovid in practice. These are contained within the medication’s patient information leaflet, and we have summarised these key points below:

  • Paxlovid should not be used (contraindicated) in patients taking Carbamazepine (Tegretol), Phenytoin (Epanutin), Phenobarbitone (Phenobarbital), Primidone (Mysoline), Midazolam (Epistatus/ Buccolam), Clozepam (Rivotril) and other benzodiazepines sometimes used in the treatment of epilepsy. This is because some of these drugs cause Paxlovid to be ineffective and also there is a risk that Paxlovid can increase the blood levels of some of these drugs resulting in a potential increased risk of toxicity. 
  • Paxlovid may cause a significant reduction in blood levels of Lamotrigine (Lamictal) and Phenytoin (Epanutin) and may put patients at increased risk of developing seizures and therefore is not recommended.
  • In relation to Pregabalin (Lyrica), Gabapentin (Neurontin), Valproate (Epilim) and other anti-convulsants there is little safety data available at the moment. A lack of evidence does not imply that co-administration of these dugs with Paxlovid is safe. As Paxlovid is new to the market there is very little data to definitively recommend co-administration.

If you are on any of the AEDs mentioned above (or any other epilepsy treatment) and you are prescribed Paxlovid, please ensure that you inform your doctors and pharmacist about your epilepsy treatment and ensure that they have checked all available safety information. 

Remember to always have an up-to-date list of your medications with you at all times. This will ensure that your doctor/nurse or pharmacist will have all the correct information when making decisions.

While it is highly unlikely that you would be inappropriately prescribed Paxlovid, it is important that people with epilepsy and their family members be aware of this information.

Other medicines are available that might be used where Paxlovid is not suitable e.g.  Sotrovimab, which has the same indication as Paxlovid and is given in hospital by infusion.