Glipizide and glimepiride are both sulfonylureas, a class of oral medicines that help lower blood sugar in adults with type 2 diabetes by prompting the pancreas to release more insulin. They work the same way, so the main differences are how often you take them, how long they last in the body, and how their labels handle kidney problems and older age. If you’ve been prescribed one and want to know how it compares with the other, this guide walks through what each FDA label says and what research shows.
Key takeaways
- In a study of more than 11,000 adults starting a sulfonylurea, overall death rates didn’t differ significantly between glipizide and glimepiride.
- Glimepiride is taken once daily, while immediate-release glipizide is taken before meals and may be split into two doses; an extended-release form of glipizide is taken once daily.
- Both can cause low blood sugar, so never switch between them, change your dose, or stop on your own without talking to your prescriber.
What are glipizide and glimepiride?
Both are second-generation sulfonylureas used along with diet and exercise to improve blood sugar control in adults with type 2 diabetes. Neither is used for type 1 diabetes or diabetic ketoacidosis (a dangerous buildup of acids in the blood).
Glipizide is sold as immediate-release tablets and as extended-release tablets (brand name Glucotrol XL). Glimepiride is sold as once-daily tablets (brand name Amaryl). Both are often prescribed alongside metformin, the most common first medicine for type 2 diabetes.
Because they belong to the same class, the comparison comes down to dosing, timing, and a few safety details.
Glipizide vs. glimepiride: side-by-side comparison
The FDA labels for glipizide tablets, glipizide (extended-release), and glimepiride tablets describe these differences:
| Feature | Glipizide (immediate-release) | Glipizide (extended-release) | Glimepiride |
|---|---|---|---|
| Usual starting dose | 5 mg | 5 mg | 1 mg or 2 mg |
| Maximum daily dose | 40 mg | 20 mg | 8 mg |
| How often | Once daily, or split into two doses above 15 mg | Once daily | Once daily |
| When to take | About 30 minutes before a meal | With breakfast or the first main meal | With breakfast or the first main meal |
| Tablet strengths in labels reviewed | 5 mg, 10 mg | Varies by product | 1 mg, 2 mg, 4 mg |
Your prescriber sets your dose based on your blood sugar, other medicines, kidney and liver function, and age. The table reflects label ranges, not a recommendation for you.
How long do glipizide and glimepiride last?
Immediate-release glipizide leaves the body more quickly than glimepiride. The glipizide label lists an elimination half-life (the time for the body to clear half of the drug) of 2 to 4 hours, with peak levels 1 to 3 hours after a dose. The glimepiride label cites a half-life of about 5 hours in adults, with peak levels 2 to 3 hours after a dose.
How the body clears each drug also differs:
- Glipizide is broken down mainly by the liver into inactive substances, and less than 10% leaves the body unchanged in urine.
- Glimepiride is broken down by the liver into two main metabolites. One may have some blood-sugar-lowering activity, and about 60% of the drug’s breakdown products leave through the urine.
- Kidney impairment causes glimepiride’s metabolites to build up, which is why its label recommends starting at 1 mg daily in people with kidney problems.
- Extended-release glipizide releases the drug slowly over the day, so it can be taken once daily.
These differences help explain why prescribers consider kidney function, age, and eating patterns when choosing between them.
Side effects of glipizide and glimepiride
Both medicines share the class’s main risk: low blood sugar (hypoglycemia). Both labels warn that all sulfonylureas can cause severe hypoglycemia, which can lead to unconsciousness, seizures, or, rarely, death.
Other side effects listed in the labels include:
- Glipizide (immediate-release): stomach upset is most common, including nausea, diarrhea, constipation, and stomach pain, while dizziness, drowsiness, and headache occur in about 1 in 50 people.
- Glucotrol XL (extended-release glipizide): dizziness, diarrhea, nervousness, tremor, gas, and low blood sugar were each reported in more than 3% of people.
- Glimepiride: low blood sugar, headache, nausea, and dizziness are the most common.
- Shared warnings: both labels warn about hemolytic anemia (breakdown of red blood cells) in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency, and both carry a class warning about cardiovascular risk based on an older study of a different sulfonylurea.
MedlinePlus advises calling your doctor right away for yellowing of the skin or eyes, dark urine, light-colored stools, unusual bruising or bleeding, fever, or sore throat while taking glipizide, and lists similar warning signs for glimepiride. Alcohol can make side effects of either medicine worse.
Which has a higher risk of low blood sugar?
Both can cause low blood sugar, and research doesn’t clearly show that one is safer than the other in this respect. A network meta-analysis of 27 trials of sulfonylureas added to metformin found that hypoglycemia risk varied across the class, but differences in how studies defined low blood sugar limited the comparisons.
What’s clearer is that sulfonylureas may cause low blood sugar more often than some newer diabetes medicines. In the CAROLINA trial of 6,033 adults, 37.7% of people taking glimepiride had at least one episode of low blood sugar over about 6 years, compared with 10.6% of those taking linagliptin, while rates of major heart events were similar.
Older adults are at higher risk. Both labels note that older people are especially sensitive to these medicines and that low blood sugar can be harder to recognize, so prescribers often start at a lower dose. Learn the signs of low blood sugar, which the CDC lists as shakiness, sweating, a fast heartbeat, dizziness, hunger, irritability, or confusion.
Is one safer for the heart?
Neither medicine has been shown to be clearly safer for the heart than the other. In a cohort study of 11,141 adults starting sulfonylurea monotherapy, overall death rates didn’t differ significantly among glipizide, glyburide, and glimepiride. In people with coronary artery disease, there was a trend toward lower mortality with glimepiride, but it didn’t reach statistical significance.
The CAROLINA trial also showed that glimepiride and linagliptin had similar rates of major heart events, which supports glimepiride’s heart safety compared with that newer medicine. These findings can help guide a conversation with your prescriber, but they don’t replace advice based on your own heart health.
Can you switch between glipizide and glimepiride?
Only your prescriber should make that decision. The doses aren’t interchangeable, the timing differs, and a change can raise or lower your blood sugar unexpectedly.
Talk with your prescriber about whether a different medicine or dose makes sense if you have:
- Frequent low blood sugar, especially overnight or when you skip meals.
- Trouble with timing, such as difficulty taking immediate-release glipizide before meals.
- Changes in kidney function, which can affect how glimepiride is cleared.
- New medicines or illnesses, which can change how your blood sugar responds.
Don’t stop either medicine suddenly without a plan, since blood sugar can rise. The guide to what happens if you stop taking metformin explains why staying consistent with diabetes treatment matters.
Refilling glipizide or glimepiride online
If you’re stable on glipizide or glimepiride and about to run out before you can see your regular provider, an online refill may help you avoid a gap. A board-certified physician can review your refill request without an appointment and, if appropriate, send it to your pharmacy, typically within a few hours.
A refill service continues a medicine that’s already working for you. It doesn’t start new medicines, switch you from one sulfonylurea to another, or change your dose. If your blood sugar has been running high or low, or you’re thinking about switching, a virtual primary care visit is the better route. Keep up with regular follow-up care and lab work with your own provider, too.
When to seek medical attention
Treat low blood sugar right away. The CDC recommends the 15-15 rule: have 15 grams of fast-acting carbohydrate, such as half a cup of juice or regular soda, wait 15 minutes, and recheck. Repeat if your blood sugar is still below 70 mg/dL.
Get emergency help if someone has severe low blood sugar and can’t eat or drink safely, has a seizure, or passes out. Contact your provider if lows keep happening or if your blood sugar stays higher than your target. This is not an emergency service. In an emergency, call 911 or go to the nearest emergency room.
Frequently asked questions
Is glimepiride stronger than glipizide?
Not in a way that helps you choose between them. Glimepiride is given in smaller milligram doses, but milligram amounts can’t be compared directly between different medicines. Your prescriber adjusts either one until it controls your blood sugar.
Which is better for older adults?
Both labels advise starting low and adjusting slowly in older adults because they’re more sensitive to low blood sugar. Your prescriber will weigh your kidney function, eating habits, and other medicines when choosing one.
Can you take glipizide or glimepiride with metformin?
Yes. Both are commonly combined with metformin. The combination can lower blood sugar more, so watch for signs of low blood sugar, especially when a dose changes.
Do glipizide and glimepiride cause weight gain?
They can for some people. The National Institute of Diabetes and Digestive and Kidney Diseases notes that some diabetes medicines can cause side effects such as weight gain. Ask your prescriber how your medicine may affect your weight and what to watch for.
Can you get glipizide or glimepiride refilled online?
Often, yes, if you’re already stable on the medicine and have been taking it as prescribed. A physician reviews each request and decides whether a refill is appropriate. The diabetes refill page explains how online refills work for diabetes medicines.
Get your prescription refill
If you’re stable on glipizide or glimepiride and can’t reach your regular provider before you run out, My Med Refills can help. A board-certified physician will review your request, typically within a few hours, and send an approved prescription to your pharmacy. Get your prescription refill; current pricing is shown on the booking page.
Sources
- U.S. National Library of Medicine, DailyMed. Revised May 2017. Glipizide tablets (Apotex Corp.): prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=dcf426b8-bcdc-8214-a1b6-6388bd3399a0
- U.S. National Library of Medicine, DailyMed. Revised August 2023. Glucotrol XL (glipizide) extended-release tablets: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=eed99b60-d043-4249-9b2a-f05e46fb588d
- U.S. National Library of Medicine, DailyMed. Revised May 2024. Glimepiride tablets (Accord Healthcare): prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9b74fbac-9e04-4927-9981-1e3dace89c6d
- MedlinePlus. Revised October 15, 2017. Glipizide. https://medlineplus.gov/druginfo/meds/a684060.html
- MedlinePlus. Revised May 15, 2020. Glimepiride. https://medlineplus.gov/druginfo/meds/a696016.html
- Andersen SE, Christensen M. Hypoglycaemia when adding sulphonylurea to metformin: a systematic review and network meta-analysis. Br J Clin Pharmacol. 2016;82(5):1291-1302. doi:10.1111/bcp.13059. https://pubmed.ncbi.nlm.nih.gov/27426428/
- Rosenstock J, Kahn SE, Johansen OE, et al. Effect of linagliptin vs glimepiride on major adverse cardiovascular outcomes in patients with type 2 diabetes: the CAROLINA randomized clinical trial. JAMA. 2019;322(12):1155-1166. doi:10.1001/jama.2019.13772. https://pubmed.ncbi.nlm.nih.gov/31536101/
- Pantalone KM, Kattan MW, Yu C, et al. The risk of overall mortality in patients with type 2 diabetes receiving glipizide, glyburide, or glimepiride monotherapy. Diabetes Care. 2010;33(6):1224-1229. doi:10.2337/dc10-0017. https://pubmed.ncbi.nlm.nih.gov/20215447/
- Centers for Disease Control and Prevention. Published May 16, 2024. Low Blood Sugar (Hypoglycemia). https://www.cdc.gov/diabetes/about/low-blood-sugar-hypoglycemia.html
- Centers for Disease Control and Prevention. Published May 15, 2024. Treatment of Low Blood Sugar (Hypoglycemia). https://www.cdc.gov/diabetes/treatment/treatment-low-blood-sugar-hypoglycemia.html
- National Institute of Diabetes and Digestive and Kidney Diseases. Last reviewed March 2022. Insulin, Medicines, & Other Diabetes Treatments. https://www.niddk.nih.gov/health-information/diabetes/overview/insulin-medicines-treatments
This article is for informational purposes only and is not a substitute for professional medical advice.
This is not an emergency service. In an emergency, call 911 or go to the nearest emergency room.