Does Tylenol Raise Blood Sugar? Here’s Why It Can Cause False CGM Readings

A continuous glucose monitor (CGM) is a device that monitors glucose (sugar) in your body’s tissues. CGMs help people better manage diabetes. But sometimes medications can affect their accuracy. This includes common medications like acetaminophen (Tylenol) and aspirin as well as others like vitamin C and hydroxyurea.

While Tylenol doesn’t actually raise your blood sugar, an inaccurate CGM reading can lead to issues with safety and blood sugar management. Let’s take a closer look at why these false readings can happen and what to do to stay safe.

Does Tylenol raise your blood sugar?

No, Tylenol doesn’t affect glucose levels. But Tylenol can affect CGM readings with some versions of Medtronic and Dexcom CGM systems. The same is true for all products that contain acetaminophen, including many over-the-counter (OTC) and prescription medications.

Should you avoid taking Tylenol before a glucose test?

No. Tylenol will not affect a blood glucose test result. Tylenol affects the way the CGM reads glucose levels, but it doesn’t affect how much glucose is actually in your blood and tissues. And it won’t affect the result you get from a lab blood test or a blood reading with a traditional glucometer. 

Can other medications cause a false reading on your CGM?

Tylenol isn’t the only medication that can interfere with CGMs and affect their accuracy. While device companies provide medication warnings, it can be hard to keep track of it all. 

If you wear a CGM, take precautions with these medications:

• Hydroxyurea: This medication is used to treat sickle cell anemia, and it can cause falsely high glucose readings.

• Vitamin C (ascorbic acid): This can also falsely raise CGM readings depending on how much you take. Vitamin C is in multivitamins, supplements, and cold remedies. Most people get enough of it from a balanced and nutritious diet. So taking it as a supplement may not be necessary. Sometimes, people need to take vitamin C as an injection to treat digestive problems (malabsorption) or extensive burns. But this isn’t common. 

• Salicylic acid: This is the active ingredient in aspirin. It may cause falsely low glucose readings. But salicylic acid doesn’t affect all CGM systems. So talk with your care team about whether this is something to consider. 

Some research suggests that other common medications and substances may have the potential to affect CGM readings, including: 

• Lisinopril: Lisinopril is a common blood pressure medication.

• Albuterol: Albuterol is a common asthma medication.

• Red wine: Red wine can interfere with CGM readings. White wine, on the other hand, hasn’t been shown to affect CGM readings.

Ibuprofen (Advil) seems to be a safe alternative to acetaminophen and aspirin in terms of effects on CGM readings. 

Medications that affect Dexcom, Abbott, Medtronic, and Senseonic CGM systems

The effect a medication can have on a CGM depends on the type of CGM you’re using. How much medication you take can also affect the accuracy of your CGM. And the effect may vary from person to person. If in doubt, check your blood glucose with a glucometer before making any treatment decisions.

Let’s break down the medications you’ll need to be careful with according to the CGM brand.

How to get an accurate CGM reading

Your CGM can provide valuable insights and make everyday life with diabetes easier. But there are a few things to consider and troubleshoot to make sure you get accurate results. 

Good to know: If the way you’re feeling isn’t matching your CGM values, check your blood glucose with a glucometer. You may have a false CGM result. This can be a temporary problem that corrects over time. Or there may be steps you can take to correct it. Each CGM system is different, so be sure to read your manual for details.

Other issues can also affect the accuracy of your CGM, such as:

• Sensor issues: Your sensor may need calibration, or it may have been placed incorrectly. There can also be compression of the sensor area. This can happen if you sleep on the sensor or you wear a tight belt over it.

• Dehydration: This can happen if you haven’t had enough fluids or if you have an infection.

• Interference: This can happen from X-rays, CT scans, or MRI.

To improve CGM accuracy, make sure to:

• Stay well hydrated.

• Calibrate or change the sensor.

• Remove pressure from the sensor by changing your sleep position or tight clothing.

• Avoid medications that can affect the CGM sensor.

• Avoid exposing CGM equipment to radiation or strong magnetic fields. 

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Written by:

Jewels Doskicz, RN, BA

Jewels Doskicz, RN, is an Arizona-based registered nurse with more than 20 years of hospital-wide clinical nursing experience. She has spent over a decade in medical writing and editing, with a focus on diabetes and autoimmune disease.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Farzon A. Nahvi, MD

Farzon Nahvi, MD, is an emergency medicine physician and author of “Code Gray: Death, Life, and Uncertainty in the ER.” He works at Concord Hospital in Concord, New Hampshire, and teaches at the Geisel School of Medicine at Dartmouth.

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