By Alex Janin

Jeanette Witten recently rummaged through her pantry for Red Hots, the cinnamon-flavored

candy.

The 56-year-old in Montclair, N.J., was looking for a reprieve from a persistent residual taste—“like your mouth is just clenched around a grapefruit rind”—that came after she took Paxlovid, Pfizer’s antiviral drug to treat Covid-19.

Ms. Witten is one of many people who have scouted remedies for what is informally known as Paxlovid mouth, a taste that can linger for as long as you take the drug. Patients who have taken Paxlovid have described it as sun-baked trash-bag liquid, a mouthful of dirty pennies and rotten soymilk. They have tried to erase the taste with salves from cinnamon to milk to pineapple. They are also trading strategies online.

A Pfizer spokesperson acknowledged the side effect, called dysgeusia, and pointed to a study that found the symptom occurred 5.6% of the time people took the drug. The study was funded by Pfizer. The company said most patients’ dysgeusia symptoms were mild.

The culprit is likely ritonavir, a part of the drug that is used to boost levels of antiviral medicines, doctors say. Ritonavir has a known association with dysgeusia. It is a small price to pay given the nearly 90% reduction in hospitalization and death among those at risk for severe disease from Covid-19, say doctors and people who have taken the medication.

But it’s still hard for many patients to stomach.

Lisa Crawford, 35, scoured the internet for potential remedies after the taste hit her: “It was like the smell that hot garbage has, but in your mouth.”

Ms. Crawford, who lives in Phoenix, and has asthma, says she spent the night in and out of sleep after being woken up by the bad taste. She came across a comment on Reddit recommending pineapple and asked her father to pick some up.

She considered stopping the course altogether, but the fruit provided some relief. She snacked on it every 10 to 15 minutes, day after day.

“I probably have no tooth enamel left,” she says, “but it was the only thing that saved my sanity.”

Unless a patient cannot keep the medication down, even with anti-nausea medication, or is displaying signs of an allergic reaction, they should stay the course, doctors say. Stopping the drug too early could increase the likelihood of a rebound case.

“If you do not take the full course, you are adding an opportunity for the virus to hang around with less drug presence to block replication,” says Yale School of Medicine infectious disease specialist Scott Roberts.

If a patient is vomiting or experiencing an allergic reaction, they should stop the course and talk to their doctor about other antivirals. In some cases, doctors may prescribe medication to help treat other potential side effects of Paxlovid, such as nausea.

Otherwise, Dr. Roberts suggests people try sucking on things that bind to the mouth’s taste receptors, such as lozenges and mints. Shivanjali Shankaran, a doctor and infectious disease specialist at Rush University Medical Center in Chicago, recommends sipping chocolate milk or eating a spoonful of peanut butter to coat the mouth before taking each dose.

Cinnamon gum is also effective for two reasons: The flavor is overpowering and almost numbing, and the gum helps improve the flow of saliva, which can prevent dryness that can worsen the taste.

While holed up in a Chicago hotel room with Covid in May, Jacklyn Grace Lacey, 36, tweeted about taking Paxlovid. She got a direct message from a former student recommending mouthwash and other mint-flavored things. She opened a food-delivery app and “ordered, like, every mint item they had,” she said.

She also ordered a half gallon of milk in hopes that it would help coat her throat. To fit the milk in the hotel’s minibar refrigerator, she had to take out the hotel-stocked bottles.

“I called down to the front desk and I was like, ‘Listen, it’s going to look like we just drank the entire minibar of alcohol, but I actually just removed everything because I’m storing milk,’” she recalls.

Chantal McLaughlin ended up forgoing the drug altogether.

“I actually strained my neck because the gag response was so strong,” she recalls.

Despite the label’s instructions to ingest the pills whole, she crushed the first dose up and stirred it into a glass of lemon water. Ms. McLaughlin, who is 51 and based in New York City, has a condition that makes it difficult for her to swallow large pills.

“The minute I took a sip, my taste buds just rejected it,” she says. She tried the same process in a thick peanut butter-banana smoothie. She only managed to get a few sips down.

The FDA and Pfizer advise that the tablets should be taken whole and not chewed, broken or crushed. A Pfizer spokesperson said the company is working to develop a different formulation of the drug for people who have difficulty swallowing pills.

Andrea Freire, a paralegal in Tampa, Fla., says she downed four bottles of strawberry-flavored Pedialyte daily for three to four days to try to mask the taste.

For Mrs. Freire, 40, who has a heart defect, it was still a no-brainer to take the drug a second time when she got Covid-19 a month later.

“I would take it again 100 times over,” she says.