Over the last few months, Mifepristone has been the subject of laws and court cases centering on its role in medication abortion. Some people are calling for the drug to be banned altogether, with one argument being that it poses a safety risk to patients. That argument has made it all the way to the US Supreme Court. However, some abortion rights advocates and patients say that if anything, the drug should be easier to get. After all, they argue, why should mifepristone be tightly regulated when it’s actually safer to take than many other drugs on the market? And the talking point they’re using is “Mifepristone is safer than Viagra?”
So today we’re going to try and get to the bottom of this particular talking point. But we’re also going to look at the science behind why we know mifepristone, or any drug, is safe. Mifepristone is sold under the brand name Mifeprex, and it’s the first pharmaceutical in a pair typically used for medication abortion. It has other uses too, but this is the one we’ll focus on. It blocks the effects of progesterone, a hormone that’s important in pregnancy. Without progesterone, the fetus detaches from the uterine wall, and the pregnancy is terminated.
A patient will typically take mifepristone and then follow it up immediately or up to 48 hours later with a series of doses of misoprostol, which causes contractions. Taking mifepristone and misoprostol together can be up to 98% effective if taken early enough in pregnancy. A second dose, as needed, makes that number more like 99% overall. This combo is also used for managing early miscarriages.
When a miscarriage happens in the first trimester, a patient has three options: medication management, a physical procedure, or just waiting for it to pass naturally from the body. Doctors used to only use misoprostol if a patient selected the medication route, but in about 30% of cases, the patients would need further doses or a physical procedure to pass their miscarriage. So now doctors prescribe the mifepristone and misoprostol combo as the standard of care, and it’s much more effective, even though this technically isn’t an FDA-approved way to treat miscarriage.
So mifepristone definitely works, and is used to provide care to a variety of people who need it. But that’s only half of what scientists and regulators want to know when deciding if a drug should be made available to folks. The other half is whether it’s safe to use, and regulatory processes are designed to find that out. Mifepristone was developed in the 1980s and first approved in China and France in 1988. After reviewing studies conducted here and abroad, the FDA approved mifepristone in the US in the year 2000, and it’s currently approved in more than 90 countries. And in the US, medication abortions account for over half of all abortions.
Which creates a ton of opportunity to collect data on the safety of mifepristone, which should make it easy to know if it is actually safer than, our thesis here, taking Viagra. Except it’s not quite that simple. Because no one does clinical trials, or even indirect comparisons, between two totally different drugs used for two different purposes. Comparing Drug A for Use A to Drug B for Use B would cost a lot of effort and money, and wouldn’t tell doctors anything that would help patients. Instead, clinical studies often compare whatever intervention is being tested to the standard of care. Standard of care can mean a lot of things, but in the case of abortion medications, we’re generally looking at the other things that may happen to patients who are pregnant: surgical abortions and live birth.
And what shakes out from that research is that medication abortion has a slightly higher rate of complications than surgical abortion, and a much lower rate of complications than giving birth. In case it is not clear, no one is saying that one of these outcomes is better than the others. The FDA keeps track of adverse events after taking a drug in the FDA Adverse Event Reporting System (FAERS). This system is not perfect, as drug companies have to report any adverse effects that they know about but there is no rule that doctors or patients have to report events. Therefore, FAERS likely undercounts adverse events, especially minor ones. FAERS is the best way to compare the safety of two totally different types of drugs. As of June 2022, FAERS reports 28 deaths in patients in the US who had taken mifepristone in the more than 20 years since it’s been approved, with a death rate of between 0.35 and 0.65 per 100,000, depending on which cases are counted. Drugs in the group that includes Viagra have a death rate of around 4 per 100,000 users, eight times higher than mifepristone. Mifepristone is currently more regulated than most other drugs, as it is under what the FDA calls a Risk Evaluation and Mitigation Strategy (REMS). This program is meant to make sure that providers are prescribing the most dangerous drugs safely and properly monitoring the patients on them. In the wake of the pandemic, the FDA has made some changes that make mifepristone easier to get, if it remains legal. Patients can now get a prescription through a telehealth appointment and receive the drug by mail, and retail pharmacies can choose to become certified to dispense mifepristone. While that doesn’t mean every corner pharmacy now has it, these changes have made medication abortions more accessible to many patients. Some hoops remain; you have to find the right pharmacy if you don’t want to go the mail-order route, and only certain healthcare providers may prescribe mifepristone. Patients also have to sign a form saying that they understand all the possible risks. None of which are necessarily bad things, but they are things that we don’t do with most other drugs. And the drugs we do do them with tend to be much riskier than mifepristone; carrying a risk of addiction, for example.
At this point, mifepristone has been studied for more than thirty years in hundreds of thousands of people worldwide. This video has been pretty America-centric because we’re the ones currently arguing about it, but mifepristone is being used safely in plenty of other nations too. So if it was an especially dangerous drug, we’d know, and either a regulatory agency or the manufacturer would likely have pulled it from the market. It does happen. Sometimes, despite our best efforts, clinical trials will miss something important that comes out after a drug hits the market. For example, look at Vioxx, a painkiller that was approved by the FDA in 1999 based on clinical trials of about 5000 people. After it was approved, the manufacturer conducted a few studies to learn even more about the drug. Long story short, they discovered an increased risk of heart attack and stroke, and the manufacturer pulled Vioxx from the market in 2004.
But in the case of Mifepristone, all of the available evidence points to the same place: it’s safe. Saying that it’s safer than Viagra is a splashy, but messy, way to make that point. But we know that there is rigorous evidence that the FDA and medical providers are tracking to support their policy and prescribing decisions. Basically, the methods we use to approve and prescribe drugs are based on science. Science is a human endeavor, and that means it is sometimes flawed. But it’s also the best thing we’ve got going to make sure things are safe for everybody. The next step is to make sure they’re fair, too.
We hope you enjoyed this video and I hope that you know that it would not be possible to tackle tricky subjects like this head-on without the support of our patrons. It might sound like I’m just saying that, but I am not just saying that; you help us do what we do every day; you make this possible, especially when it’s less ad-friendly! As a thank you, patrons get access to a few neat perks, like bloopers and behind-the-scenes peeks. If you’d like to join our community of supporters, you can get started at patreon.com/scishow. [♪ OUTRO]