As the omicron surge pummels a pandemic-weary nation, the first antiviral pills for Covid-19 promise desperately needed protection for people at risk of severe disease. Many people prescribed Pfizer’s or Merck’s new medications will require careful monitoring by doctors, reports NBC News.
The approval from FDA
The Food and Drug Administration authorized Pfizer’s Paxlovid for mild to moderate Covid in people as young as 12 who have underlying conditions that raise the risk of hospitalization and death from the coronavirus, such as heart disease or diabetes.
However, one of the two drugs in the antiviral cocktail could cause severe or life-threatening interactions with widely used medications, including statins, blood thinners and some antidepressants. And the FDA does not recommend Paxlovid for people with severe kidney or liver disease.
Because of experts’ concerns about the potential side effects of Merck’s molnupiravir, the FDA has restricted its use to adults and only in scenarios in which other authorized treatments, including monoclonal antibodies, are inaccessible or are not “clinically appropriate.”
About Paxlovid cocktail
The Paxlovid cocktail consists of two tablets of the antiviral nirmatrelvir and one tablet of ritonavir, a drug that has long been used as what is known as a boosting agent in HIV regimens.
Ritonavir suppresses a key liver enzyme called CYP3A, which metabolizes many medications, including nirmatrelvir. In the case of Paxlovid treatment, ritonavir slows the body’s breakdown of the active antiviral and helps it remain at a therapeutic level for longer.
The boosting effect was likely to have been crucial in driving Paxlovid’s high effectiveness in clinical trials.
Side effects
When Paxlovid is paired with other medications that are also metabolized by the CYP3A enzyme, the chief worry is that the ritonavir component may boost the co-administered drugs to toxic levels.
Complicating matters, the drugs that pose interaction risks are widely prescribed to people at the greatest risk from Covid because of other health conditions.
The medications include, but are not limited to: blood thinners; anti-seizure medications; drugs for irregular heart rhythms, high blood pressure and high cholesterol; antidepressants and anti-anxiety medications; immunosuppressants; steroids (including inhalers); HIV treatments; and erectile dysfunction medications.
In its fact sheet about Paxlovid, the FDA has published a detailed list of medications that may interact harmfully with ritonavir, including those that should not be paired with the Covid antivirals.
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Source: NBC News
