A Weight-Loss Drug Became the First Medicine for Sleep Apnea

For decades, the treatment for obstructive sleep apnea has been mechanical. A CPAP machine pushes air through a mask to keep the airway open at night. It works well for people who use it, but many find the mask uncomfortable and stop. Others try oral appliances or, less often, surgery.

On December 20, 2024, the FDA approved² the first medicine for the condition. It was not a new sleep drug. It was Zepbound, the version of tirzepatide sold for weight management.

What obstructive sleep apnea does

In obstructive sleep apnea, the soft tissue at the back of the throat collapses during sleep and partly or fully blocks the airway. Breathing stops or becomes shallow, oxygen levels dip and the brain briefly wakes the sleeper to restore airflow. This can happen dozens of times an hour without the person remembering it.

Severity is measured with the apnea hypopnea index, or AHI, which counts those events per hour. Fifteen or more is moderate, and 30 or more is severe. Loud snoring is the classic sign, but many people notice only daytime sleepiness, morning headaches or trouble concentrating. Untreated apnea is linked with high blood pressure, atrial fibrillation and other cardiovascular problems.

Excess weight is one of the strongest risk factors, because fat around the neck and tongue narrows the airway.

What the trials found

The approval rested on two trials known as SURMOUNT-OSA, published in the New England Journal of Medicine¹. Together they enrolled 469 adults with obesity and moderate to severe apnea. People with diabetes were excluded. One trial included people who could not or would not use CPAP. The other included people who were already using it.

Participants took the highest dose of tirzepatide they could tolerate, 10 or 15 milligrams once a week, or a placebo, for 52 weeks. At the start, they averaged about 50 breathing events an hour, which is severe apnea.

By the end, the results were clear³. In the trial without CPAP, AHI fell by 25.3 events an hour on tirzepatide and 5.3 on placebo. In the trial with CPAP, it fell by 29.3 compared with 5.5. That was a reduction of up to about 59 percent from where people started. The drug also lowered blood oxygen dips, blood pressure and a marker of inflammation, and people reported feeling less sleepy.

Many participants improved enough to change category. According to Eli Lilly's announcement⁴ of the approval, after one year 42 percent of people taking tirzepatide alone and 50 percent of those also using CPAP had either no apnea or mild apnea without symptoms. On placebo, those figures were 16 and 14 percent.

The most common side effects were nausea, diarrhea and other digestive problems, mostly mild to moderate and most frequent while the dose was being increased.

Who it is for

The approval is specific. It covers adults with moderate to severe obstructive sleep apnea who also have obesity, and the drug is meant to be used with a reduced calorie diet and more physical activity. Much of the benefit comes from weight loss, so people with apnea who are not overweight are unlikely to gain as much.

It also does not make CPAP obsolete. Many trial participants still had apnea at the end of a year, even if it was milder. For someone with severe apnea, CPAP works from the first night, while the drug takes months to reach full effect. A sleep physician may recommend both, at least at first, and then reassess with a new sleep study after weight loss.

Coverage and cost

The new indication changed the coverage picture. Medicare drug plans are barred by law from covering medicines used only for weight loss, but in January 2025 CMS confirmed⁵ that Part D plans can cover Zepbound when it is prescribed for sleep apnea. Commercial insurers set their own rules, which commonly require a recent sleep study and prior authorization.

What happens if you stop

Tirzepatide is meant to be taken long term. In other trials of the drug, people who stopped regained much of the weight they had lost, and because the apnea benefit is tied to weight, it is reasonable to expect breathing problems to return as well. That makes the decision closer to starting a chronic medication than taking a short course.

The first step is still a diagnosis

Sleep apnea remains badly underdiagnosed. If a partner has noticed loud snoring or pauses in your breathing, or if you are sleepy during the day despite a full night in bed, the place to start is a sleep evaluation. Home sleep tests are now widely used and are often covered. Treatment choices, including whether a medication makes sense, follow from what that test shows.