Have you seen the television commercials for Rinvoq (upadacitinib)? Ads for this rheumatoid arthritis (RA) drug have been in heavy rotation recently. In one, you see a woman kickstarting a motorcycle as the announcer says: “Your mission: Stand up to moderate to severe rheumatoid arthritis and take it on with Rinvoq!” She roars off and the scene shifts to women welding and drilling heavy metal bars for a large sculpture.

In another commercial, a woman clips her harness onto a zipline and swings high above a green valley. Then we see her speeding along in an all-terrain vehicle as she drives through a stream with reckless abandon.

The message is clear. Rinvoq will allow you to participate in vigorous and highly demanding leisure-time activities.

Of course, there is the standard list of scary side effects. While people onscreen are distracting us with their strenuous activities, the announcer warns: “Rinvoq can lower your ability to fight infections, including tuberculosis. Serious infections and blood clots, sometimes fatal, have occurred, as have certain cancers including lymphoma and tears in the stomach or intestines and changes in lab results.”

If you think that sounds dangerous, the Food and Drug Administration has just issued new worrisome warnings for Rinvoq and other drugs in the same class. These medications are called JAK (Janus kinase) inhibitors.

Another highly advertised medicine in this category is Xeljanz (tofacitinib). Doctors prescribe it for rheumatoid arthritis, psoriatic arthritis and ulcerative colitis. Olumiant (baricitinib) for RA is also subject to the FDA’s heightened cautions.

What prompted this new safety concern? When the Food and Drug Administration first approved Xeljanz, it required the manufacturer (Pfizer) to conduct further safety research on the medication.

This is what the agency refers to as a Phase 4 study. In the case of Xeljanz, the FDA wanted to compare this JAK inhibitor to an older class of anti-inflammatory drugs called TNF blockers such as Humira (adalimumab) or Enbrel (etanercept).

The results are now in, and they aren’t pretty. The FDA saw more blood clots and deaths with Xeljanz compared to the older TNF blocker drug for rheumatoid arthritis.

Because of this study, the FDA is strengthening the black box warnings: “We are requiring revisions to the Boxed Warning, FDA’s most prominent warning, for Xeljanz/Xeljanz XR, Olumiant, and Rinvoq to include information about the risks of serious heart-related events, cancer, blood clots, and death ... In addition, to ensure the benefits of these three medicines outweigh the risks in patients who receive them, we are limiting all approved uses to certain patients who have not responded or cannot tolerate one or more TNF blockers.”

In other words, doctors are not supposed to prescribe drugs like Rinvoq unless they have first prescribed a medicine such as Humira and it has not worked. The industry insider publication FiercePharma suggests that the new precautions could throw a monkey wrench into Rinvoq’s “megablockbuster” ambitions.

The moral to this tale: Serious side effects are often revealed after FDA drug approval. Slick TV commercials that make a new medicine seem fabulous may need to be tempered by evidence.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email them via their website: www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”

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