Continuous glucose monitoring is changing how diabetes is managed, and healthcare teams are at the center of helping patients use these devices safely and effectively.
In this episode, TRC Healthcare Associate Editor and Clinical Pharmacist Vickie Danaher, PharmD, discusses how continuous glucose monitoring has helped improve diabetes care. She talks about how CGM devices work, which patients are good candidates, prescription vs. OTC options, and when guidelines recommend their use.
This is an excerpt from our April 2026 Pharmacy Essential Updates continuing education webinar series.
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Clinical Resources from Pharmacist’s Letter, Pharmacy Technician’s Letter, and Prescriber Insights:
- Article: Anticipate Earlier CGM Use for Diabetes
- Chart: Continuous Glucose Monitoring
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Transcript:
This transcript is automatically generated.
00:00:07 Narrator
Welcome to Clinical Capsules from TRC Healthcare, your trusted source for practical, evidence-based updates.
00:00:15 Narrator
On this episode, Associate Editor and Clinical Pharmacist Vickie Danaher breaks down the different types of continuous glucose monitors (CGMs) and their role in modern diabetes care.
00:00:26 Narrator
She explains how CGMs work, which patients are good candidates, and when current guidelines recommend their use in an excerpt from our popular Pharmacy Essential Updates webinar series.
00:00:37 Narrator
This podcast offers continuing education credit for pharmacists and pharmacy technicians.
00:00:42 Narrator
Please log into your pharmacist letter or pharmacy technician’s letter account and look for the title of this podcast in the list of available CE courses.
00:00:50 Narrator
None of the speakers have anything to disclose.
00:00:56 Narrator
Catch new episodes of Clinical Capsules every second and 4th Tuesday, bringing concise, actionable insights from TRC experts straight to your ears.
00:01:04 Narrator
With that, let’s get started.
00:01:13 Vickie Danaher
And this is an area that’s seen a lot of movement recently with new prescription CGM devices being introduced, a product recall, and some newer OTC options that are gaining traction.
00:01:26 Vickie Danaher
And now like our article says, you’ll start to see more patients with diabetes use CGM devices earlier in their care based on new guideline recommendations.
00:01:37 Vickie Danaher
So today we’ll be focusing on how we as pharmacists and technicians can help identify which patients are good candidates for a CGM, understand how the various CGMs compare, and then how patients use these devices effectively.
00:01:52 Vickie Danaher
But before we dive into that, let’s take a quick step back and level set on how glucose can be measured, since this can help explain why CGMs are so useful and also where their limits are.
00:02:03 Vickie Danaher
So I think most of our patients are familiar with the idea of testing their blood glucose by basically pricking their finger to get a drop of blood, putting it on a test strip, then the glucose meter, and then the glucose meter checks their blood sugar at that one point in time.
00:02:18 Vickie Danaher
Continuous glucose monitoring is different.
00:02:21 Vickie Danaher
It measures glucose on a more continuous and ongoing basis throughout the day and night.
00:02:27 Vickie Danaher
So this can give us a much bigger picture of what’s happening with the patient’s glucose overall, not just a snapshot at a single point in time.
00:02:36 Vickie Danaher
So to get these continuous results, patients wear a sensor that has a fine needle that inserts into the skin.
00:02:43 Vickie Danaher
That sensor is usually applied to the back of the upper arm, and it needs to be changed every 10 to 15 days, depending on the system.
00:02:53 Vickie Danaher
But instead of checking blood glucose like with a test strip, the sensor measures glucose in interstitial fluid or fluid just below the surface of the skin automatically every few minutes.
00:03:07 Vickie Danaher
It then sends these glucose levels to a receiver that displays the results, which is usually on an app or a smartphone.
00:03:16 Vickie Danaher
Now there’s a few different types of CGMs, both prescription and OTC.
00:03:21 Vickie Danaher
But no matter the type, all CGMs can help track trends so patients can see what direction their glucose is moving in the short term, and they can also see patterns, such as whether glucose is consistently high or low after certain activities or meals.
00:03:37 Vickie Danaher
All right, now that we’ve reviewed how CGMs work, let’s start to think about which patients may benefit from one.
00:03:44 Vickie Danaher
And we can do that with a patient case.
00:03:47 Vickie Danaher
Our patient today is Maria.
00:03:49 Vickie Danaher
She’s a 58-year-old female who was diagnosed with type 2 diabetes about three years ago.
00:03:55 Vickie Danaher
Her current A1C is 8.2.
00:03:59 Vickie Danaher
She has a history of hypoglycemia or low blood sugar, and she checks her blood glucose at home with a blood glucose meter and test strips about two to three times a day.
00:04:10 Vickie Danaher
In terms of medication, Maria is currently taking metformin 1000 milligrams BID, glimepiride 4 milligrams once daily, and atorvastatin 20 milligrams once daily.
00:04:23 Vickie Danaher
Maria tells you she’s been seeing TV commercials for a different way to check her blood sugar with a sensor, and she wants to know if she should use that instead of finger sticks.
00:04:34 Vickie Danaher
So what do you think?
00:04:36 Vickie Danaher
Is Maria a good candidate for CGM?
00:04:39 Vickie Danaher
And if so, which type would you recommend?
00:04:44 Vickie Danaher
So in terms of who is eligible for using continuous glucose monitoring, the recommendations have been expanding over the years.
00:04:51 Vickie Danaher
And the latest guidelines support using CGM earlier and more broadly than ever before.
00:04:58 Vickie Danaher
So the American Diabetes Association or ADA standards of care now recommends CGM at diagnosis or any time after for patients with type 1 or type 2 diabetes who are on insulin or taking other meds that can cause hypoglycemia or dangerously low blood sugar, so meds like sulfonylureas such as glipizide or glimepiride.
00:05:22 Vickie Danaher
CGM is also recommended in any case where its use can help improve diabetes management, regardless of the treatment approach.
00:05:30 Vickie Danaher
And that’s because early initiation is associated with benefits such as improved A1C, increased time in range, and fewer episodes of hypoglycemia.
00:05:43 Vickie Danaher
So this opens the door for more patients with diabetes to use CGM earlier.
00:05:48 Vickie Danaher
But we want to remember that payer policies don’t always align with guidelines, and anticipate that some insurers may still require insulin use or a history of severe hypoglycemic episodes for CGM coverage.
00:06:03 Vickie Danaher
So we should be ready to help patients work through that prior authorization process if needed.
00:06:10 Vickie Danaher
It’s also important for us to help put the role of CGM in perspective.
00:06:14 Vickie Danaher
I think in many cases, CGM can sound appealing to patients since it may mean a patient needs fewer finger sticks, especially for those who would be checking their blood glucose multiple times a day.
00:06:25 Vickie Danaher
Plus, some patients may find CGM helpful to track those trends and patterns. But point out that whether CGM will be helpful really depends on the patient and their situation, and any benefit hinges on actually using the data to guide lifestyle or med changes.
00:06:43 Vickie Danaher
So this is where we can continue to help individualize glucose monitoring for diabetes, whether it’s with a blood glucose meter or a CGM, considering patient factors, patient preferences, cost and access considerations, and really any particular features that patients may be looking for in a product like a CGM.
00:07:04 Vickie Danaher
So to do that, we’ll need to be familiar with the CGM products out there and how they stack up.
00:07:09 Vickie Danaher
So let’s go through the various options now and some of the key things that we need to be aware of for each one.
00:07:16 Vickie Danaher
So starting with the Dexcom family of CGMs, we’ll want to take note that the Dexcom G6 CGM system will no longer be manufactured after July 1, 2026.
00:07:29 Vickie Danaher
So if you have patients using the G6 or wanting to start it, you want to help them transition to an alternative and plan these transitions before supply runs out.
00:07:41 Vickie Danaher
For many of these patients, a natural switch will be to a Dexcom G7 CGM system, but be aware that there’s two different sensor options here with a couple of big differences.
00:07:52 Vickie Danaher
For example, the G7 is for patients ages 2 years and up with diabetes, while the G7 15-day sensor is currently for those with diabetes age 18 years and up.
00:08:08 Vickie Danaher
Both sensors are placed on the back of the upper arm, but the G7 can also be placed on the upper buttocks for kids ages 2 to 6 years.
00:08:18 Vickie Danaher
Also point out that the G7 sensor can be worn for 10 days, while the G7 15-day sensor lasts 15 days like its name implies.
00:08:31 Vickie Danaher
Moving on to the FreeStyle Libre systems, the options here include the Libre 2 Plus or the Libre 3 Plus sensors.
00:08:41 Vickie Danaher
Now both of these are approved for patients with diabetes as young as two years old and they’re placed on the back of the upper arm and they also last 15 days.
00:08:50 Vickie Danaher
Let me explain that the Libre 3 Plus is smaller and it has a bigger Bluetooth range.
00:08:57 Vickie Danaher
Also keep in mind that some Libre 3 Plus sensors are part of a recent class 1 recall due to incorrectly low readings.
00:09:06 Vickie Danaher
So if you haven’t already, go to the manufacturer website to learn which serial numbers are impacted, double check your inventory, and advise affected patients to request a replacement from the manufacturer.
00:09:20 Vickie Danaher
Eversense 365 is another prescription CGM option, but this one is quite different than the others.
00:09:28 Vickie Danaher
It’s an implantable sensor that lasts for one year, but it must be inserted subcutaneously in the upper arm by a healthcare provider who’s completed the product’s training program.
00:09:39 Vickie Danaher
So it does require a procedure for placement and removal. It’s also only approved for patients ages 18 years and older.
00:09:49 Vickie Danaher
Okay, now that we’ve covered the prescription CGMs, you’re probably wondering where do the over-the-counter CGMs fit in?
00:09:57 Vickie Danaher
Well, we want to recommend saving the over-the-counter CGMs for patients who can’t afford or access the prescription options and who aren’t on insulin or prone to hypoglycemia.
00:10:12 Vickie Danaher
And one big reason why is that the OTC CGMs, such as Stelo or Lingo, lack alarms for low or high glucose.
00:10:21 Vickie Danaher
And they also measure glucose in a much narrower range.
00:10:25 Vickie Danaher
For instance, the OTC CGMs generally only read glucose between 55 and 250 milligrams per deciliter, while most prescription CGM devices read from 40 to 400 milligrams per deciliter.
00:10:41 Vickie Danaher
So this means, for example, if a patient’s glucose drops to 50 and they’re using an OTC CGM, they wouldn’t get an alert.
00:10:49 Vickie Danaher
And that can be a real safety concern, especially for a patient who’s prone to hypoglycemia.
00:10:56 Vickie Danaher
Because of this, the OTC CGMs are not recommended for patients with type 1 diabetes, anyone who’s on insulin therapy, patients on any type of med that could cause low blood sugar, and those needing alerts for dangerous glucose levels.
00:11:12 Vickie Danaher
But the OTC CGMs are appropriate for adults without diabetes seeking insights into the effects of diet and exercise on their glucose levels.
00:11:20 Vickie Danaher
They can also be a reasonable option for adults with well-controlled type 2 diabetes who aren’t on insulin or a med that causes hypoglycemia or who are seeking occasional monitoring.
00:11:33 Vickie Danaher
And then in terms of costs, the OTC systems run about $90 per month for sensors and insurance typically doesn’t cover them.
00:11:41 Vickie Danaher
But they are eligible expenses under flexible spending accounts or health savings accounts.
00:11:48 Vickie Danaher
The prescription CGMs may be more like $150 to $400 per month depending on the product, but insurance may cover them again depending on their eligibility criteria.
00:12:00 Vickie Danaher
Let’s take a closer look now at the differences between those OTC options, Stelo and Lingo.
00:12:06 Vickie Danaher
So both are for adults ages 18 years and older who are not using insulin and both go on the back of the upper arm, but the glucose read range for Stelo is 70 to 250 and for Lingo it’s 55 to 200.
00:12:26 Vickie Danaher
The Stelo also has a slightly longer sensor life at 15 days versus Lingo sensor at 14 days.
00:12:36 Vickie Danaher
Let’s circle back now to our patient case with Maria.
00:12:40 Vickie Danaher
And many of you think Maria could be a good candidate for a CGM.
00:12:44 Vickie Danaher
And if she gets one, she should get a prescription CGM, which I would agree with that as well, since she’s on glimepiride, which carries a significant hypoglycemia risk.
00:12:57 Vickie Danaher
Maria has also had episodes of very low blood sugar previously, so she needs the alarms and the alerts that come with a prescription product too.
00:13:06 Vickie Danaher
Some people also suggest medication changes like getting off the glimepiride and trying a GLP-1 agonist instead, which yeah, I think that could be appropriate too for limiting that hypoglycemia risk and improving A1C as well.
00:13:19 Vickie Danaher
So yeah, overall, I think a prescription CGM could be a good call.
00:13:24 Vickie Danaher
Again, keeping in mind the decision will also depend on insurance and payer coverage and also that Maria is up for using it.
00:13:34 Vickie Danaher
And then regardless of whether a patient gets a prescription or OTC CGM, we as pharmacy professionals play a huge role in helping patients understand how to apply and use those sensors properly.
00:13:46 Vickie Danaher
For instance, I want to tell patients that it’s important that they really clean that upper arm before they apply the sensor to help ensure that any oils are removed since that can impact adhesion.
00:13:57 Vickie Danaher
So they should wash the sensor sites with soap and let it dry first, then clean the site with an alcohol swab and let it dry completely before applying the sensor.
00:14:10 Vickie Danaher
Also advise rotating sites with each sensor to prevent skin irritation and scarring and to avoid placing the sensor on scarred or tattooed areas or areas where insulin or other injectable meds are given.
00:14:25 Vickie Danaher
And then if sensors don’t stay on, we can suggest trying a product to improve adhesion.
00:14:30 Vickie Danaher
So examples would be like SkinTac or Tegaderm.
00:14:34 Vickie Danaher
And we can be ready to special order these items if needed.
00:14:40 Vickie Danaher
Other tips to let patients getting CGMs know about is that CGM sensors can generally be worn while bathing or swimming, but the amount of time that patients can stay in the water and how deep they can go will depend on the specific sensor.
00:14:54 Vickie Danaher
So for example, Dexcom and Stelo sensors are waterproof in up to about 8 feet of water for 24 hours, but Libre Plus or Lingo sensors are waterproof in about up to 3 feet of water for up to 30 minutes.
00:15:13 Vickie Danaher
Also let patients know that most sensors can go through a metal detector, but some sensors should not be put through an X-ray, including a baggage X-ray machine, a full body scanner, CT scans, or an MRI.
00:15:27 Vickie Danaher
These could damage the sensor and lead to incorrect readings.
00:15:33 Vickie Danaher
We’ll also want to be prepared on how to help patients troubleshoot common CGM problems.
00:15:38 Vickie Danaher
So for example, if the sensor won’t stay on, reinforce proper site application, especially making sure that the skin is completely dry before application.
00:15:48 Vickie Danaher
We can recommend an adhesive product as needed, like I mentioned.
00:15:51 Vickie Danaher
And then also remind patients no lotion, oils, or sunscreen at the application site before putting the sensor on.
00:16:01 Vickie Danaher
If the sensor comes off early, make sure patients know not to try to reinsert or reapply it.
00:16:06 Vickie Danaher
The filament may be bent or contaminated and the readings won’t be accurate.
00:16:11 Vickie Danaher
Instead, we want to direct patients to the CGM’s customer support as most manufacturers will replace the sensor for the patient if it comes off.
00:16:21 Vickie Danaher
And then for skin irritation, a practical trick that has some evidence behind it is to try applying a small amount of fluticasone nasal spray to the site and letting it dry before placing the sensor.
00:16:34 Vickie Danaher
And then of course, rotating application sites more frequently can help too.
00:16:41 Vickie Danaher
One other key thing to know is that some medications and situations may interfere with the results for some continuous glucose monitors.
00:16:49 Vickie Danaher
For example, acetaminophen doses above 1 gram every six hours may falsely raise readings with Dexcom and Stelo devices.
00:16:58 Vickie Danaher
And vitamin C above 1,000 milligrams per day can do this with Libre Plus.
00:17:04 Vickie Danaher
Now this doesn’t mean that patients need to avoid these products completely, but it’s something to be aware of since it could impact the accuracy of results.
00:17:14 Vickie Danaher
On the flip side, falsely low readings can occur due to compression lows.
00:17:19 Vickie Danaher
So if a patient sleeps on the arm where the sensor is, pressure at the site can cause falsely low readings overnight and patients may wake up alarmed by a number that isn’t real.
00:17:33 Vickie Danaher
So the bottom line with this is that we want to remind patients to confirm their CGM results with a finger stick when appropriate.
00:17:40 Vickie Danaher
So that includes any time the CGM prompts them to check when readings don’t match how they’re feeling, or if they think the number may be inaccurate for any reason.
00:17:51 Vickie Danaher
Patients may also need to check a finger stick during times of rapidly changing glucose, such as after eating, exercise, or taking insulin.
00:17:59 Vickie Danaher
Again, that’s because the CGM measures glucose in interstitial fluid versus in the blood.
00:18:04 Vickie Danaher
And those interstitial levels can lag behind blood glucose readings for a few minutes.
00:18:11 Vickie Danaher
So while the CGM significantly reduce finger sticks, they don’t eliminate them completely.
00:18:16 Vickie Danaher
Patients should be aware of that as part of the decision about whether CGM makes sense for them.
00:18:21 Vickie Danaher
We also need to be aware of this in the pharmacies.
00:18:23 Vickie Danaher
We’re not surprised to still process prescriptions for traditional blood glucose testing supplies if patients use a CGM.
00:18:32 Vickie Danaher
And then the last thing I’ll touch on today are some of the common CGM metrics that these devices can provide.
00:18:37 Vickie Danaher
And it’s important to be familiar with these since patients may ask us about these values or you may see them on CGM reports.
00:18:44 Vickie Danaher
And they can help us ensure safety and improve outcomes in diabetes management.
00:18:50 Vickie Danaher
Now keep in mind that the specific terms and the definitions may vary among CGMs and the specific targets may also vary among patients.
00:18:58 Vickie Danaher
But in general, one of the main metrics to know is the time in range.
00:19:02 Vickie Danaher
This is the amount of time that the patients are in their sweet spot or their target glucose range, which is usually between 70 and 180 milligrams per deciliter.
00:19:12 Vickie Danaher
The usual goal for the time in range is to be at least 70% of the day or about 17 hours, which roughly correlates with an A1C of around 7%.
00:19:23 Vickie Danaher
We also have time below range, which is the percentage of time spent below 70 milligrams per deciliter, which shows a patient’s glucose is going too low too often.
00:19:34 Vickie Danaher
We want this to be less than 4% of the day or about less than an hour per day.
00:19:41 Vickie Danaher
On the other hand, we can see how much time a patient’s glucose is running too high using the time above range.
00:19:48 Vickie Danaher
That’s the percentage of time spent with glucose above 180 milligrams per deciliter, which we want to be less than 25% of the time, or less than six hours per day.
00:19:58 Vickie Danaher
And then the other key metric to highlight here is the glucose management indicator, or GMI.
00:20:07 Vickie Danaher
This is a rough A1C prediction based on an average of about 14 days of readings.
00:20:14 Vickie Danaher
Share that patients can use the GMI for a sneak peek of how recent med or lifestyle changes will impact their A1C results if the patient continues on the same track.
00:20:25 Vickie Danaher
And if you’d like more advice on interpreting these metrics and other CGM values patients may ask about, dig into our updated resource, Continuous Glucose Monitoring.
00:20:34 Vickie Danaher
It has a fantastic comparison chart of all the different prescription and OTC CGMs, along with tips on proper use and troubleshooting that you can use in your practice.
00:20:47 Narrator
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