Pfizer’s antiviral drug may not be compatible with other medications

Antiviral pills by Pfizer consisting of two drugs is undergoing scrutiny as one of it is suspected to cause severe interactions with some of the widely used prescriptions such as blood thinners, statin and antidepressants.

As Omicron variant continues to spread rapidly across nation suffering from the pandemic hit, the first antiviral Covid-19 pills offer hope for people at higher risk of serious diseases.

Even so, experts urge caution and constant monitoring for patients prescribed with Pfizer’s or Merck’s new pill by doctors or pharmacists.

Pfizer’s cocktail, dubbed as Paxlovid, received authorization from the Food and Drug Administration (FDA) for drug delivery to people as young as 12 with mild to moderate Covid and underlying conditions that elevate the susceptibility towards coronavirus, such as diabetes or heart disease.

Eventually, one of the two drugs in Pfizer’s antiviral cocktail emerged to be controversial with concerns of its ability to catalyze life-threatening interactions with other commonly prescribed treatments.

Imperative to note, FDA does not approve Paxlovid delivery to patients suffering from severe liver or kidney diseases.

Following concerns raised by experts, on the potential side effects of Merck’s molnupiravir, the FDA has deployed a stringent eligibility criteria focusing on adults that are not clinically appropriate – or have no access to other authorized treatments, such as monoclonal antibodies.

The Paxlovid cocktail is packed with one tablet of ritonavir and two pills of the antiviral nirmatrelvir, with the former showcasing years of therapeutic application as a boosting agent in HIV regimens.

Apparently, ritonavir works as an enzyme inhibiter by suppressing CYP3A, which is a key liver enzyme that metabolizes nirmatrelvir and other medications.

During Paxlovid treatment, ritonavir slows the bodily breakdown of active antiviral and helps keep it at a therapeutic level for prolonged duration, which was anticipated to be key in ensuring the drugs high effectiveness during clinical trials.

While it is impressive, when Paxlovid is combined with other medications that also use CYP3A enzyme as a metabolizing catalyst, the primary drawback is ritonavir’s capabilities to scale up the co-administered drug to toxic levels.

Source Credits: https://www.nbcnews.com/health/health-news/pfizer-covid-pills-covid-symptoms-may-risky-drugs-rcna9683