- Medicine to treat heart conditions can become unsafe when taken with Paxlovid
- Coronary heart disease drugs prescribed with it mean a higher risk of blood clots
- And alongside immunosuppressants it can cause plasma to rise to toxic levels
Pfizer’s flagship Covid drug can have dangerous interactions with common medications, a review has found.
Paxlovid gained emergency use authorization in the US in December last year as an antiviral drug to treat mild to moderate Covid in high-risk patients.
It has been given to millions of vulnerable Americans with underlying health conditions — reducing their risk of death by up to 90 per cent.
But Paxlovid can cause serious health problems when coupled with common heart disease medication such as statins and blood thinners.
Researchers from Lahey Hospital and Medical Center, Harvard Medical School and other US institutions found the Covid drug can increase the risk of developing blood clots when taken with blood thinners.
It can also cause an irregular heartbeat when combined with drugs for heart pain and when taken alongside statins it can be toxic to the liver.
Dozens of medications such as aspirin are safe to take with Paxlovid, the researchers stress. But doctors need to be aware that other drugs can be dangerous and should be discontinued or adjusted while a patient is being treated for Covid.
When President Joe Biden, 79, tested positive for Covid and started Paxlovid in July, his physician Dr Kevin O’Connor temporarily stopped him from taking the statin Crestor and stroke prevention drug Eliquis.
Pfizer’s CEO Dr Albert Bourla, 60, also took a course of Paxlovid when he caught the virus in August
Dr. Sarju Ganatra, director of the cardio-oncology program at Lahey Hospital and Medical Center in Massachusetts, said: ‘Awareness of the presence of drug-drug interactions of Paxlovid with common cardiovascular drugs is key.
‘System-level interventions by integrating drug-drug interactions into electronic medical records could help avoid related adverse events.
‘The prescription of Paxlovid could be incorporated into an order set, which allows physicians, whether it be primary care physicians or cardiology providers, to consciously rule out any contraindications to the co-administration of Paxlovid.
‘Consultation with other members of the health care team, particularly pharmacists, can prove to be extremely valuable.
‘However, a health care provider’s fundamental understanding of the drug-drug interactions with cardiovascular medications is key.’
Paxlovid is made of two antivirals, nirmatrelvir and ritonavir.
Dr Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, who was not involved in the new paper, told CNN: ‘The second drug, ritonavir, is a nonspecific drug that inhibits metabolism and increases the dose of the other drug.
‘But the ritonavir in Paxlovid also can inhibit the metabolism of other drugs. So you have to be really careful when you prescribe Paxlovid for people who are on certain blood thinners, cardiac medications, statins and other drugs,” Barouch said. “So it’s not just a free pass.’
Paxlovid is intended for use by patients who are considered likely to become seriously ill from the deadly virus, such as seniors and people with pre-existing conditions like heart disease.
Millions of doses have been prescribed to Americans since it was rolled out this year.