Can a GLP-1 Drug Cut Your Other Prescriptions? Danish Data, Blood Pressure Trials, and the Doses That Need Adjusting

Researchers at the University of Southern Denmark had an unusual way to see what happens to the rest of a person's medicine cabinet after they start a GLP-1 drug. Denmark records every prescription filled in the country, so the team followed 189,392 adults who started semaglutide for weight management between December 2022 and December 2024. They tracked 10 groups of medicines for two years before each person's first semaglutide fill and one year after, then compared what people actually filled with what their earlier trend predicted.

A year in, several kinds of prescriptions were running below the forecast. Asthma medicines were 18% lower than expected, and painkillers and antidepressants about 7% lower. Steroid creams, psoriasis treatments, and antifungal creams were 8% to 9% lower. Blood pressure prescriptions still went up, but more slowly than predicted. One group went the other way: prescriptions for anti-anxiety medicines were 16% higher than expected and were still elevated two years after people started. The study was published in Diabetes, Obesity and Metabolism on October 25, 2026.

A study like this shows a change that followed the first semaglutide prescription. It cannot show that semaglutide caused it. People who start a weight-loss drug may also change their diet, see their doctor more often, or have their other prescriptions reviewed. The researchers included a comparison group as a check, and it flagged one result in particular. Diabetes medicines fell by 13% after semaglutide, but a similar drop showed up in the comparison group, so that change may have little to do with the drug.

Blood pressure is where the trial evidence is strongest. In Novo Nordisk's main Wegovy weight-loss trial, the Wegovy label reports that systolic blood pressure (the top number) fell by 6.2 mmHg over 68 weeks on semaglutide 2.4 mg, compared with 1.1 mmHg on placebo. In a Yale-led analysis of Eli Lilly's SURMOUNT-1 trial of tirzepatide (Zepbound), published in Heart in 2024, most of the drop happened in the first 24 weeks and then leveled off. At 72 weeks, tirzepatide lowered systolic pressure by 6.8 mmHg and diastolic pressure by 4.2 mmHg more than placebo, and 58% of people on tirzepatide had normal blood pressure, compared with 35% on placebo. By the authors' estimate, weight loss accounted for about two-thirds of the drop.

Fewer trials have counted how often people actually cut back their pills. One that did is REDEFINE 1, Novo Nordisk's trial of CagriSema, a combination of semaglutide and cagrilintide that the FDA has not yet approved. Among people taking blood pressure medicine during the 68-week study, 39.6% on CagriSema reduced or stopped it, compared with 18.8% on placebo, according to an analysis published in Hypertension. The analysis does not say which pills were changed or why, and the drug's pending FDA review means these figures come from a trial, not from routine care.

The flip side of a falling blood pressure is a pill dose that is suddenly too strong. The Wegovy label reports low blood pressure, including dizziness on standing, in 1.3% of adults in its weight-loss trials versus 0.4% on placebo, and fainting in 0.8% versus 0.2%. Some of those cases followed vomiting or diarrhea, and the label notes they were more common in people who were also taking blood pressure medicine. The Heart analysis of SURMOUNT-1 found the same direction: low-blood-pressure side effects were uncommon but more frequent on tirzepatide.

Dehydration adds a second risk. Both the Wegovy and Zepbound labels describe reports of acute kidney injury, some severe enough to need dialysis, mostly in people who became dehydrated from nausea, vomiting, or diarrhea. The labels tell patients to take steps to avoid losing fluids and to report persistent nausea, vomiting, or diarrhea promptly. For someone whose blood pressure is already falling on a pill dose set months earlier, a bad week of stomach side effects is the time to call.

For people with type 2 diabetes, the warning is printed in the drug interaction section of every label we checked. Wegovy, Ozempic, Zepbound, and Mounjaro all tell prescribers to consider lowering the dose of insulin or of a sulfonylurea, an older class of pills such as glipizide or glyburide, when the GLP-1 drug is started.

The trial numbers show why. In the Wegovy trial in adults with type 2 diabetes who were not using insulin, blood sugar below 54 mg/dL was reported in 6.2% of people on Wegovy versus 2.5% on placebo, and the label says the risk was higher in people also taking a sulfonylurea. In Zepbound's trial in adults with type 2 diabetes, the figure was 4.2% versus 1.3%. Wegovy's label adds that its use alongside insulin has not been studied. Metformin, the most common diabetes pill, is not named in this warning.

GLP-1 drugs slow the rate at which the stomach empties, which can change how other pills are absorbed. For most medicines this does not matter much. The Ozempic label says semaglutide injections did not affect the absorption of other oral medicines to any clinically relevant degree in its studies. A few medicines are more sensitive.

Levothyroxine, the standard thyroid hormone pill, is one. In a drug interaction study with semaglutide tablets, the body's exposure to levothyroxine was 33% higher, and both the Rybelsus and Wegovy labels cite that result and advise extra monitoring for medicines with a narrow margin between too little and too much. The Zepbound and Mounjaro labels name warfarin, a blood thinner, as an example of a drug to monitor more closely. They also advise people on birth control pills to switch to a non-oral method, or add a barrier method, for four weeks after starting tirzepatide and for four weeks after each dose increase, a rule explained in our pregnancy and birth control guide.

Zepbound is the only GLP-1-based drug in this group approved to treat moderate to severe obstructive sleep apnea in adults with obesity, and its label is direct about what its trials did not test. In one 52-week study of 234 people who could not or would not use a CPAP-style machine, the apnea-hypopnea index, the number of breathing pauses or drops per hour of sleep, fell by about 25 events per hour on Zepbound versus 5 on placebo. In a second study of 235 people who kept using their machines, it fell by about 29 versus 5.5, measured after a one-week break from the machine.

The label then states that the trials did not evaluate the timing or appropriateness of stopping positive airway pressure therapy in people already using it. So a better sleep score on Zepbound is a reason to ask about a repeat sleep study. It is not, on its own, evidence that the machine can go back in the closet.

The rise in anti-anxiety prescriptions in the Danish data is the result that does not fit the story of a lighter medicine cabinet. The study does not explain it, and the authors stop at recommending that prescribing patterns keep being watched. Prescription records cannot tell a new anxiety problem apart from an old one that was treated differently, or from a doctor visit that happened to include a new prescription. Anyone who notices a change in mood or anxiety after starting a GLP-1 drug should raise it with their prescriber, and the research on emotional changes is still thin.

The reductions in the trials above happened because doctors adjusted doses as readings changed. That is the model to copy. Before or soon after starting a GLP-1 drug, these questions can help:

Do I take insulin or a sulfonylurea, and should either dose change now, before I start?

How often should I check my blood pressure at home, and what reading should prompt a call?

Which of my pills need extra monitoring because of slower stomach emptying, such as levothyroxine or warfarin, and when should my levels be rechecked?

If I use birth control pills, what backup method should I use, and for how long?

If I use a CPAP machine, when would a repeat sleep study make sense?

What should I do with my other medicines on days I cannot keep fluids down?

Stopping or cutting a medicine on your own can backfire, even when your numbers look better. A pharmacist can review the full list. Readers over 65, who often take the most medicines, may also want the guide to GLP-1 drugs after 65; the dosing schedule guide covers how fast doses rise.