Mounjaro (tirzepatide) is a powerful weekly injection used for type 2 diabetes and weight loss.
It works by slowing down how fast food leaves your stomach and affecting many other drugs.
Because of this, some medicines become dangerous or stop working properly when taken together.
Knowing the interactions is critical for your safety.
Many people combine Mounjaro with other prescriptions without realizing the risk.
This guide covers every major and minor interaction based on official data and real-world reports.
How Mounjaro Changes the Way Other Drugs Work
Mounjaro delays gastric emptying for up to 72 hours or longer after each dose.
This means oral medicines may stay in the stomach longer than normal and absorb slowly or incompletely.
It can also affect insulin release and blood sugar, creating extra risks with diabetes drugs.
What Medicines Can You Not Take With Mounjaro? – Complete List and Explanation
Certain medications have major interactions and should be avoided or used only under close medical supervision.
The list below includes absolute contraindications, high-risk combinations, and drugs that usually need dose changes.
Medicines You Should Almost Never Take With Mounjaro
- Other GLP-1 or GIP agonists (Wegovy, Ozempic, Rybelsus, Trulicity, Saxenda, Zepbound) – risk of overdose effects
- Pramlintide (Symlin) – extreme slowing of stomach emptying
- High-dose or rapid-acting insulin without careful monitoring – severe hypoglycemia possible
High-Risk Medicines That Need Doctor Approval
- Oral contraceptives – reduced effectiveness for at least 4 weeks after starting Mounjaro and after each dose increase
- Warfarin (Coumadin) – changed INR levels, higher bleeding or clotting risk
- Digoxin – altered blood levels
- Thyroxine (levothyroxine) – absorption can drop, leading to hypothyroidism symptoms
Common Medicines That Often Require Dose or Timing Changes
| Medication Class | Examples | Interaction Effect |
|---|---|---|
| Oral birth control pills | Ethinyl estradiol combinations | Lower hormone levels → possible pregnancy risk |
| Antibiotics (some) | Amoxicillin, cephalexin, levofloxacin | Delayed or reduced absorption |
| Pain relievers | Ibuprofen, naproxen, celecoxib | Slightly delayed absorption |
| Statins | Atorvastatin, rosuvastatin | Minor delay, usually no dose change needed |
| Blood pressure meds | Lisinopril, losartan, amlodipine | No major delay, but blood sugar effects add up |
| Antidepressants | Sertraline, duloxetine, bupropion | Generally safe, rare nausea increase |
| Osteoporosis drugs | Alendronate, risedronate (weekly) | Take 60 minutes before food for best absorption |
| Iron supplements | Ferrous sulfate | Take at least 4 hours apart |
Diabetes Medicines – Special Caution Section
- Insulin (all types) – start 20-30% lower dose when adding Mounjaro
- Sulfonylureas (glipizide, glyburide, glimepiride) – high risk of low blood sugar
- SGLT2 inhibitors (Jardiance, Farxiga) – usually safe but watch for dehydration
Safe Over-the-Counter Medicines With Mounjaro
Most people worry about everyday drugs. Here’s what is generally okay:
- Acetaminophen (Tylenol)
- Most allergy medicines (loratadine, cetirizine, fexofenadine)
- Topical creams and patches
- Nasal sprays
- Most vitamins and minerals (except iron – space 4 hours apart)
Herbal Supplements and Mounjaro
Some natural products can cause problems:
- St. John’s Wort – may lower Mounjaro levels
- Ginseng, bitter melon, fenugreek – strong blood-sugar lowering effect
- High-dose berberine – acts like metformin, risk of low sugar
Special Situations Doctors See Often
Women starting Mounjaro while on the pill need backup contraception (condoms or IUD) for the first 4–6 weeks and after every dose increase.
Patients on warfarin usually need INR checks weekly when starting or raising Mounjaro.
Anyone preparing for surgery may need to pause Mounjaro 1–2 weeks before because of slow stomach emptying.
What to Do Before Starting Mounjaro
Give your doctor and pharmacist the full list of everything you take, including supplements.
Ask for a medication review – they can switch you to safer alternatives when possible.
Plan extra blood work if you take warfarin, digoxin, or thyroid medicine.
Summary
The medicines you truly cannot take with Mounjaro are other GLP-1 drugs, pramlintide, and sometimes high-risk combinations like sulfonylureas or large insulin doses without adjustment.
Oral birth control, warfarin, thyroxine, and some antibiotics need special timing or monitoring.
Always tell every provider you see that you are on tirzepatide – it affects far more drugs than older diabetes medications did.
FAQ
Can I take ibuprofen or Tylenol with Mounjaro?
Yes, both are safe. Acetaminophen is usually preferred because it is gentler on the stomach.
Is it safe to take metformin and Mounjaro together?
Yes, they are commonly prescribed together and have no major interaction.
Will Mounjaro make my birth control pill stop working?
Effectiveness can drop for the first 4 weeks and after dose increases. Use backup protection during that time.
Can I drink alcohol while on Mounjaro?
Moderate amounts are usually okay, but alcohol can worsen nausea and affect blood sugar control.
Do I need to stop Mounjaro before surgery?
Yes, most surgeons ask you to stop 1–2 weeks before because of the risk of food staying in the stomach during anesthesia.
Dr. Hamza is a medical content reviewer with over 12+ years of experience in healthcare research and patient education. He specializes in evidence-based health information, medications, and chronic conditions. His reviews are grounded in trusted medical sources and current clinical guidelines to ensure accuracy, transparency, and reliability. Content reviewed by Dr. Hamza is intended for educational purposes and is not a substitute for professional medical advice.