Toujeo Drug Interactions You Need to Know About

When you're taking Toujeo (Insulin Glargine U-300), other medications, supplements, and even certain foods can change how it works. Some interactions can make your blood sugar drop dangerously low. Others can make Toujeo less effective, leaving your blood sugar too high.

This guide covers the most important Toujeo drug interactions so you know what to watch for and what to tell your doctor.

How Drug Interactions Work with Insulin

Toujeo lowers blood sugar by helping your cells absorb glucose and by telling your liver to release less sugar. Any medication that also lowers blood sugar — or changes how your body processes insulin — can interact with Toujeo.

Interactions generally fall into two categories:

• Medications that increase hypoglycemia risk — They lower blood sugar on their own, so combining them with Toujeo amplifies the effect.
• Medications that raise blood sugar — They work against Toujeo's effect, potentially requiring a dose increase.

Medications That Interact with Toujeo

Major Interactions (Increased Hypoglycemia Risk)

These medications can significantly increase your risk of low blood sugar when taken with Toujeo:

• Sulfonylureas — Glipizide (Glucotrol), Glimepiride (Amaryl), Glyburide (Diabeta). These oral diabetes medications stimulate your pancreas to produce more insulin, stacking on top of Toujeo's effect.
• Meglitinides — Repaglinide (Prandin), Nateglinide (Starlix). Similar to sulfonylureas, they increase insulin secretion.
• GLP-1 receptor agonists — Semaglutide (Ozempic, Rybelsus), Liraglutide (Victoza), Dulaglutide (Trulicity), Tirzepatide (Mounjaro). These lower blood sugar through multiple mechanisms and are commonly used alongside basal insulin, but your doctor may need to reduce your Toujeo dose when starting one.
• ACE inhibitors and ARBs — Lisinopril (Zestril), Enalapril (Vasotec), Losartan (Cozaar), Valsartan (Diovan). These blood pressure medications can increase insulin sensitivity and lower blood sugar.
• MAO inhibitors — Phenelzine (Nardil), Tranylcypromine (Parnate). These antidepressants can enhance insulin's blood sugar-lowering effect.

Medications That May Mask Hypoglycemia Symptoms

• Beta-blockers — Metoprolol (Lopressor), Atenolol (Tenormin), Propranolol (Inderal). Beta-blockers don't necessarily cause low blood sugar, but they can hide the warning signs — like rapid heartbeat and shakiness — making it harder to detect and treat lows. If you take a beta-blocker with Toujeo, monitor your blood sugar more frequently.

Medications That Increase Heart Failure Risk

• Thiazolidinediones (TZDs) — Pioglitazone (Actos), Rosiglitazone (Avandia). When used with insulin like Toujeo, TZDs increase the risk of heart failure and fluid retention. Watch for sudden weight gain, swelling in legs or feet, and shortness of breath. Report these symptoms immediately.

Medications That May Reduce Toujeo's Effectiveness

These medications can raise blood sugar, potentially requiring a higher Toujeo dose:

• Corticosteroids — Prednisone, Dexamethasone, Methylprednisolone. Even short courses of steroids can significantly raise blood sugar. If you need steroids for another condition, your doctor may temporarily increase your Toujeo dose.
• Sympathomimetic agents — Albuterol (ProAir, Ventolin), Epinephrine, Pseudoephedrine (Sudafed). These stimulate glucose release from the liver.
• Thiazide diuretics — Hydrochlorothiazide (HCTZ), Chlorthalidone. Water pills used for blood pressure can raise blood sugar.
• Thyroid hormones — Levothyroxine (Synthroid). Thyroid replacement can increase blood sugar levels.
• Oral contraceptives and estrogens — Birth control pills and hormone replacement therapy may reduce insulin sensitivity.
• Atypical antipsychotics — Olanzapine (Zyprexa), Clozapine (Clozaril), Quetiapine (Seroquel). These medications are known to increase blood sugar and may worsen diabetes control.

Moderate Interactions: Medications That May Enhance Toujeo's Effect

These can increase hypoglycemia risk to a lesser degree:

• SSRIs — Fluoxetine (Prozac) and other selective serotonin reuptake inhibitors may enhance insulin's blood sugar-lowering effect.
• Fibrates — Fenofibrate (Tricor), Gemfibrozil (Lopid). Used for cholesterol, they may increase hypoglycemia risk.
• Pentoxifylline (Trental) — Used for circulation problems, may enhance hypoglycemic effect.
• High-dose salicylates — Taking high doses of Aspirin (more than the standard 81 mg daily) can lower blood sugar.

Supplements and OTC Medications to Watch

Several over-the-counter products can affect blood sugar when used with Toujeo:

• High-dose Aspirin — As noted above, high doses (not standard low-dose) can increase hypoglycemia risk.
• Cold and flu medications — Many contain Pseudoephedrine or other decongestants that can raise blood sugar. Check labels carefully or ask your pharmacist.
• Cinnamon supplements — Some evidence suggests cinnamon may modestly lower blood sugar. While this is usually minor, it's worth mentioning to your doctor.
• Chromium — This mineral supplement is marketed for blood sugar support and may add to hypoglycemia risk.
• Alpha-lipoic acid — An antioxidant supplement that may lower blood sugar.

Always tell your doctor and pharmacist about any supplements you take, even if they seem harmless.

Food and Drink Interactions

Alcohol

Alcohol is the most important food interaction with Toujeo. Drinking can lower blood sugar unpredictably — sometimes hours after your last drink. This happens because alcohol interferes with your liver's ability to release stored glucose.

Guidelines for drinking with Toujeo:

• Never drink on an empty stomach.
• Limit alcohol to moderate amounts (1 drink/day for women, 2 for men).
• Monitor your blood sugar before, during, and after drinking.
• Be especially careful at bedtime — alcohol-related hypoglycemia can happen overnight.
• Wear a medical ID bracelet so others know you're on insulin if you experience severe low blood sugar.

Meals and Carbohydrates

While not a "drug interaction," your carbohydrate intake directly affects how Toujeo performs. Skipping meals or eating significantly fewer carbs than usual while on Toujeo increases hypoglycemia risk. If you're changing your diet, talk to your doctor about adjusting your dose.

What to Tell Your Doctor

Before starting Toujeo — or whenever your medications change — make sure your doctor knows about:

• All prescription medications, including those from other doctors
• Over-the-counter drugs, especially cold medicines, pain relievers, and allergy medications
• Supplements and vitamins, including herbal products
• Alcohol use, including how often and how much
• Any recent changes to your medication list

Keep a complete, up-to-date medication list and bring it to every appointment. Your pharmacist can also run an interaction check each time you fill a new prescription.

Final Thoughts

Toujeo is safe and effective for millions of people, but like any insulin, it interacts with a long list of medications. The biggest risks involve drugs that increase hypoglycemia (sulfonylureas, ACE inhibitors, MAOIs) and drugs that raise blood sugar (corticosteroids, atypical antipsychotics). Beta-blockers don't cause lows but can hide the symptoms.

The most important thing you can do is keep your healthcare team informed about everything you take. For more about Toujeo, see our guides on what Toujeo is, side effects, and how to save money on it.

Need help finding Toujeo at a pharmacy? Medfinder can help you check availability near you.