One of the most anticipated new medications on the market to fight COVID-19 is Paxlovid. Made by Pfizer, it is an oral medication that can reduce the severity of a COVID infection when taken early enough.

The FDA has given emergency approval for its use, and the federal government recently contracted to buy 10 million courses of treatment and will provide it for free.

It’s a very effective medication, but hasn’t been widely used yet simply because it hasn’t been available. Paxlovid reduced the risk of hospitalization or death by 88% when taken within five days of symptom onset compared with a placebo in non-hospitalized, high-risk adults with COVID-19.

Paxlovid is now available with a prescription for adults and children 12 or older with a positive COVID test and who are at high risk for progression to severe infection including hospitalization or death.

But this doesn’t mean it’s a substitute for vaccination. Because not everyone should take this powerful medicine.

The FDA has published a fact sheet for health care providers on Paxlovid. Much more than a sheet, it’s actually 29 pages crammed with facts – and 12 of those pages list potential side effects.

Here’s the irony: Some of the preexisting conditions that make a COVID infection especially dangerous — such as high blood pressure, diabetes, heart failure and arrhythmias — often are treated with multiple medicines that could also make Paxlovid dangerous.

Some of the common cardiac medications that you cannot take with Paxlovid include amiodarone, flecainide, Plavix, Brilinta, and some statins. Some of these can be stopped for the five-day course of Paxlovid. But other meds, such as amiodarone, hang around in the body for quite a while, and adding Paxlovid is completely contraindicated.

Paxlovid is a combination drug (nirmatrelvir with ritonavir). It inhibits an enzyme in the body essential to produce cholesterol, steroids, and prostacyclins, and can increase the concentration of many other medications

What’s more, many people might not even realize that they could be harmed by this new medication. Because at least 40% of American adults are considered obese, 14% smoke, and more than 10% have diabetes, there are a lot of people at high risk even though they may feel well. They are all potential candidates to develop severe COVID and may need therapy, and an unknown number are taking multiple medications that can interact with Paxlovid.

In light of this information, taking Paxlovid is not an easy decision. It is very effective in the studies done so far, especially in the unvaccinated. However, the drug interferes with so many medications that are used for chronic medical conditions that it needs to be used carefully.

I would be very reluctant to recommend its use for patients taking multiple medications, all of which should be checked for interactions before use. It is not a panacea. Getting vaccinated to reduce the risk of life-threatening complications and hospitalization seems a much safer option.

David Becker is a board-certified cardiologist with Chestnut Hill Temple Cardiology in Flourtown. He has been in practice for more than 25 years.