Lantus Drug Interactions You Should Know About

Lantus (Insulin Glargine) interacts with a surprisingly large number of medications — from blood pressure pills to over-the-counter pain relievers. Some make Lantus work too well, increasing your risk of dangerously low blood sugar. Others work against it, making your blood sugar harder to control.

This guide breaks down the most important Lantus drug interactions, explains what to watch for, and tells you exactly what to share with your doctor.

How Drug Interactions Work with Insulin

Drug interactions with Lantus fall into two main categories:

1. Drugs that increase the blood-sugar-lowering effect — These make hypoglycemia (low blood sugar) more likely. When combined with Lantus, your blood sugar could drop lower than expected.
2. Drugs that decrease the blood-sugar-lowering effect — These raise blood sugar, working against Lantus. You may need a higher Lantus dose to maintain control.

Some medications do both depending on the dose or situation. And a few don't change your blood sugar but mask the symptoms of hypoglycemia — which can be just as dangerous.

Medications That Interact with Lantus

Major Interactions (Increased Hypoglycemia Risk)

These medications can increase the blood-sugar-lowering effect of Lantus, raising the risk of hypoglycemia:

• Other diabetes medications and insulins — Taking Lantus with other glucose-lowering drugs (Metformin, sulfonylureas like Glipizide or Glimepiride, GLP-1 agonists like Ozempic or Mounjaro) increases the risk of hypoglycemia. Your doctor will account for this when dosing.
• Thiazolidinediones (TZDs) — Pioglitazone (Actos) and Rosiglitazone (Avandia) can cause fluid retention and increase the risk of heart failure when combined with insulin. This is a particularly important interaction.
• ACE inhibitors — Common blood pressure medications like Lisinopril, Enalapril, and Ramipril may enhance insulin's blood-sugar-lowering effect.
• Angiotensin II receptor blockers (ARBs) — Losartan, Valsartan, and similar medications may also increase hypoglycemia risk.
• High-dose Salicylates — High doses of Aspirin (not typical low-dose daily Aspirin) can enhance insulin's effect.
• Sulfonamide antibiotics — Antibiotics like Sulfamethoxazole (found in Bactrim) may enhance insulin's blood-sugar-lowering effect.
• MAO inhibitors — Medications like Phenelzine (Nardil) and Tranylcypromine (Parnate) used for depression may increase hypoglycemia risk.

Moderate Interactions (May Raise Blood Sugar)

These medications can work against Lantus by raising blood sugar, potentially requiring dose adjustments:

• Corticosteroids — Prednisone, Dexamethasone, Methylprednisolone, and other steroids commonly raise blood sugar, sometimes significantly. If you're prescribed a course of steroids, your Lantus dose may need to be temporarily increased.
• Diuretics (thiazides) — Hydrochlorothiazide (HCTZ) and Chlorthalidone can raise blood sugar levels.
• Estrogens and oral contraceptives — Birth control pills and hormone replacement therapy may increase blood sugar.
• Atypical antipsychotics — Olanzapine (Zyprexa), Quetiapine (Seroquel), and similar medications are known to raise blood sugar and increase diabetes risk.
• Protease inhibitors — HIV medications like Ritonavir can raise blood sugar.
• Thyroid hormones — Levothyroxine (Synthroid) and other thyroid medications may increase blood sugar.
• Sympathomimetics — Albuterol (used in asthma inhalers), Epinephrine, and Pseudoephedrine can raise blood sugar.
• Niacin (Vitamin B3) — High-dose Niacin, sometimes used for cholesterol, can increase blood sugar.
• Danazol — Used for endometriosis, can raise blood sugar.
• Isoniazid — Used for tuberculosis treatment, may raise blood sugar.
• Phenothiazines — Older antipsychotic medications that can increase blood sugar.

Medications That Mask Hypoglycemia Symptoms

This category is especially important to know about:

• Beta-blockers — Metoprolol (Lopressor), Atenolol (Tenormin), Propranolol (Inderal), and others can mask the warning signs of low blood sugar, particularly rapid heartbeat and tremor. You may not feel the typical shakiness or racing heart that alerts you to hypoglycemia. If you take a beta-blocker with Lantus, rely on blood sugar monitoring rather than symptoms alone.
• Clonidine — A blood pressure medication that can also mask hypoglycemia symptoms.

Supplements and OTC Medications to Watch

Over-the-counter products and supplements can also interact with Lantus:

• High-dose Aspirin — Can enhance insulin's blood-sugar-lowering effect (low-dose daily Aspirin is generally fine)
• Decongestants containing Pseudoephedrine — Found in many cold and sinus medications (Sudafed, many "-D" formulations), can raise blood sugar
• Niacin supplements — Can raise blood sugar at high doses
• Chromium supplements — May enhance insulin sensitivity and increase hypoglycemia risk
• Alpha-lipoic acid — May lower blood sugar when combined with insulin
• Bitter melon, fenugreek, and cinnamon supplements — Marketed for blood sugar support, these can have additive effects with insulin

Always tell your doctor and pharmacist about all supplements you take — even "natural" ones.

Food and Drink Interactions

Alcohol

Alcohol is the most important food/drink interaction with Lantus. It can:

• Increase hypoglycemia risk — Alcohol inhibits your liver's ability to release glucose, which can cause blood sugar to drop, especially if you drink on an empty stomach
• Cause delayed hypoglycemia — Blood sugar may drop hours after drinking, sometimes overnight
• Mask hypoglycemia symptoms — The effects of alcohol can mimic or hide symptoms of low blood sugar

If you drink alcohol, do so in moderation, always with food, and monitor your blood sugar more frequently. Talk to your doctor about how much is safe for you.

Meal Timing

While Lantus itself doesn't need to be taken with food (it's a basal insulin, not a mealtime insulin), skipping meals or eating significantly less than usual while on Lantus increases hypoglycemia risk.

What to Tell Your Doctor

Before starting Lantus — and at every follow-up visit — make sure your doctor knows about:

• All prescription medications you take, including those prescribed by other doctors
• All over-the-counter medications, including pain relievers, cold medicines, and allergy pills
• All supplements, vitamins, and herbal products
• Alcohol use — be honest about how much and how often
• Any recent medication changes — starting, stopping, or changing doses of any medication
• Any episodes of hypoglycemia — even mild ones

Your pharmacist is also an excellent resource for checking drug interactions. When filling a new prescription, ask your pharmacist to review it against your current medications, including Lantus.

Final Thoughts

Lantus interacts with many commonly prescribed medications, but that doesn't mean you can't take them together. In most cases, your doctor can adjust your Lantus dose or monitoring schedule to account for the interaction. The key is making sure your healthcare team knows everything you're taking.

Never stop or change a medication without talking to your doctor first — including Lantus. If you're concerned about interactions or side effects, bring it up at your next appointment.

For more information about Lantus, including uses and dosage, savings options, and how to find it in stock, explore our other guides on Medfinder.