GLP-1 Contraindications: Safety Checklist & Risk Assessment
Review the complete list of conditions that make GLP-1 medications unsafe or higher-risk. Understand which are absolute contraindications versus which require careful monitoring.
Disclaimer
This information is for educational purposes only. GLP-1 safety is complex and individualized. Always discuss your complete medical history with your prescriber before starting any GLP-1 medication. Only your doctor can determine whether GLP-1 therapy is safe for you specifically.
Absolute Contraindications: DO NOT USE GLP-1
These conditions make GLP-1 medications unsafe. GLP-1s should never be used if you have any of these:
Personal History of Medullary Thyroid Carcinoma (MTC)
Absolute Contraindication
GLP-1 medications increase calcitonin (a marker of MTC). Patients with MTC cannot use any GLP-1 medication due to risk of cancer growth. This is an FDA black-box warning.
Family History of Medullary Thyroid Cancer or MEN 2 Syndrome
Absolute Contraindication
If multiple family members (parent, sibling, child) have had MTC, or if your family carries the RET gene mutation (MEN 2 syndrome), you cannot use GLP-1 medications. You have increased genetic risk of developing MTC, and GLP-1s could accelerate this.
What to do: If you have family history of MTC or MEN 2, ask your doctor about genetic testing. If positive, GLP-1s are not an option.
Pregnancy
Absolute Contraindication
GLP-1 medications cause fetal abnormalities in animal studies. They are contraindicated in pregnancy. If you become pregnant while on GLP-1, stop immediately and contact your doctor.
Pre-conception planning: If you plan to become pregnant:
- Stop semaglutide at least 2 months before attempting conception (it has a long half-life)
- Stop tirzepatide at least 2 months before attempting conception
- Use effective contraception while on GLP-1s if you don't plan pregnancy
- Discuss alternative weight loss/diabetes strategies with your doctor for use during pregnancy
Breastfeeding
Absolute Contraindication
It is unknown whether GLP-1 medications pass into breast milk or what effects they could have on nursing infants. Therefore, breastfeeding is contraindicated.
Relative Contraindications: Use With Caution & Monitoring
These conditions make GLP-1 medications higher-risk, but they may still be used if your doctor determines benefits outweigh risks and if you're carefully monitored. You MUST discuss these with your prescriber:
Type 1 Diabetes
Relative Contraindication
GLP-1s are NOT approved for type 1 diabetes. They don\'t provide adequate glucose control. Using GLP-1 as monotherapy in type 1 diabetes delays necessary insulin therapy and increases risk of diabetic ketoacidosis (DKA)—a life-threatening emergency.
Plain language: If you have type 1 diabetes, do not use GLP-1s without insulin therapy. Type 1 requires insulin always.
Personal History of Acute Pancreatitis
Relative Contraindication
GLP-1s increase risk of pancreatitis recurrence. If you\'ve had pancreatitis before, GLP-1s may trigger it again. Risk is higher if your previous pancreatitis had ongoing triggers (gallstones, high triglycerides).
What to do: If you have history of pancreatitis, tell your doctor. They may decide the benefits still outweigh risk, but only under close monitoring. If you develop severe upper abdominal pain during GLP-1 therapy, seek emergency care immediately.
History of Gallbladder Disease or Gallstones
Relative Contraindication
Rapid weight loss from GLP-1s can precipitate gallstone formation or gallbladder inflammation. If you have existing gallstones or gallbladder disease, risk may increase.
What to do: Discuss with your doctor. If you proceed with GLP-1, monitor for gallbladder symptoms (upper right abdominal pain, nausea after fatty meals). Get ultrasound imaging if symptoms develop.
Chronic Kidney Disease
Relative Contraindication (Risk Increases With Severity)
Mild-moderate kidney disease (eGFR >30): Generally safe; minimal need for dose adjustment
Severe kidney disease (eGFR <30): Higher risk; requires careful monitoring; may need dose reduction or avoidance
End-stage renal disease (on dialysis): Contraindicated or requires specialist oversight; limited data available
What to do: Have your kidney function checked before starting GLP-1 (eGFR, creatinine). If eGFR <30, discuss specifically with your prescriber or nephrologist whether GLP-1 is appropriate.
Diabetic Retinopathy (Vision-Threatening)
Relative Contraindication
Rapid improvement of blood sugar (from GLP-1 therapy) can worsen certain types of diabetic retinopathy temporarily. If you have vision-threatening retinopathy, your doctor must carefully assess whether the benefits of improved glucose control outweigh the short-term worsening risk.
What to do: Have an eye exam before starting GLP-1. Tell your eye doctor you\'re considering GLP-1 therapy. If you have active vision-threatening retinopathy, discuss with both your eye doctor and prescriber before starting.
Diabetic Nephropathy (Kidney Damage from Diabetes)
Relative Contraindication
GLP-1s actually improve kidney outcomes in most cases. However, in advanced nephropathy with severely reduced kidney function, careful monitoring is needed.
What to do: Get baseline kidney function tests before starting. Monitor kidney function at regular intervals. GLP-1 is usually beneficial for kidney health, but your specific situation should be discussed with your doctor.
History of Other Thyroid Cancer (Non-MTC)
Relative Contraindication
Papillary, follicular, or anaplastic thyroid cancer is not an absolute contraindication, but requires careful consideration and possibly specialist input.
What to do: Tell your prescriber and oncologist about GLP-1 consideration. They can jointly assess safety.
Personal or Family History of C-Cell Hyperplasia
Relative Contraindication
C-cell hyperplasia (precancerous thyroid changes) is not common but means increased thyroid cancer risk. GLP-1s can stimulate C-cell growth, so this is a relative contraindication.
Severe Gastroparesis (Severe Gastric Emptying Delay)
Relative Contraindication
GLP-1s slow gastric emptying. If you already have severe gastroparesis (mechanical stomach dysfunction), GLP-1 could make it worse and worsen nausea/vomiting.
What to do: If you have documented gastroparesis, discuss with your gastroenterologist before using GLP-1. Mild gastroparesis symptoms may be tolerable, but severe cases likely contraindicate GLP-1.
History of Severe Nausea or Vomiting Disorders
Relative Contraindication
GLP-1s cause nausea in 20-50% of users, especially during dose escalation. If you have history of severe vomiting disorders or extreme sensitivity to nausea, GLP-1s may be poorly tolerated.
Inflammatory Bowel Disease (IBD: Crohn's or Ulcerative Colitis)
Relative Contraindication
GLP-1s affect GI motility, which could potentially worsen IBD symptoms. However, limited data exists on safety specifically. This is considered a relative contraindication requiring careful discussion with both your gastroenterologist and prescriber.
High Risk for Dehydration
Relative Contraindication
GLP-1s can cause diarrhea or vomiting, leading to dehydration. If you have conditions making you prone to dehydration (excessive sweating from work, living in hot climate, limited water access, severe exercise routine), GLP-1s carry increased risk.
What to do: Ensure you can maintain high hydration (100+ ounces of water daily) while on GLP-1. If this isn\'t feasible for your situation, discuss with your prescriber.
Significant Drug Interactions
GLP-1s slow gastric emptying, which can reduce absorption of oral medications. Key interactions include:
| Medication/Class | Interaction Concern | What to Do |
|---|---|---|
| Oral contraceptives (birth control pills) | Delayed absorption; may reduce effectiveness | Discuss timing with your doctor; may take pill 1 hour before GLP-1 injection |
| Antibiotics (orally taken) | Delayed absorption; may reduce effectiveness | Take antibiotics at different time from meals; discuss with doctor/pharmacist |
| Diabetes medications (metformin, insulin) | Enhanced hypoglycemia risk (low blood sugar) | Your doctor may reduce insulin or metformin doses; monitor blood sugar closely |
| Blood pressure medications (especially ACE inhibitors) | GLP-1 can lower blood pressure; risk of hypotension | Monitor blood pressure; your doctor may adjust medication doses |
| Digoxin (heart medication) | Delayed absorption; reduced effectiveness | Space doses apart; discuss with prescriber |
Key action: Always tell your prescriber about ALL medications you take, including over-the-counter drugs and supplements. Ask specifically whether GLP-1 will affect the absorption of any of your medications.
Age Considerations
Adolescents (12-17): Tirzepatide (Mounjaro/Zepbound) is FDA-approved for type 2 diabetes and weight management in ages 12+. Semaglutide (Wegovy) is approved for weight management in ages 12+. These should be prescribed by pediatric specialists experienced with GLP-1s.
Elderly adults (>65): No specific age cutoff for GLP-1 use. However, older patients should have baseline kidney function and cardiovascular assessment. GLP-1s are often beneficial in elderly patients with type 2 diabetes and heart disease. Dosing may need adjustment if kidney function is reduced.
Pre-Start Safety Checklist: Before Beginning GLP-1
Complete This Checklist With Your Doctor
- Do I have any personal history of medullary thyroid cancer, or family history of MTC/MEN 2?
If yes: GLP-1 is absolutely contraindicated. Do not use. - Am I pregnant, trying to become pregnant, or breastfeeding?
If yes: Wait or discuss alternative options. - Do I have type 1 diabetes (or am I unsure of my diabetes type)?
If yes: GLP-1 is not approved; insulin is necessary. - Have I had pancreatitis? If so, when and what caused it?
If yes: Discuss risk vs. benefit carefully. - Do I have chronic kidney disease? What is my eGFR (kidney function)?
If yes: Get baseline kidney function tested before starting. - Have I had thyroid cancer of any type, or do I have family history of thyroid cancer?
If yes: Discuss type specifically with doctor. - Do I have gastroparesis or severe nausea/vomiting history?
If yes: Discuss whether GLP-1 is tolerable. - Do I have inflammatory bowel disease, gallbladder disease, or severe diabetic complications (retinopathy, nephropathy)?
If yes: Each requires specific discussion. - What medications do I take? (List all, including supplements)
Have your doctor review for interactions. - Am I able to stay well-hydrated (100+ ounces water daily) while on GLP-1?
If unsure: Discuss realistic hydration plans.
Related Resources
Explore specific Ozempic side effects and management. Learn about GLP-1 insurance coverage. Understand tirzepatide side effects in detail.
Frequently Asked Questions
A contraindication is a condition or situation that makes a treatment unsafe or inadvisable. Absolute contraindications mean the treatment is dangerous and should not be used. Relative contraindications mean the treatment carries increased risk, but may still be used if benefits outweigh risks and the patient is carefully monitored.
Yes. Personal history of medullary thyroid carcinoma and family history of MEN 2 are absolute contraindications—GLP-1s are never appropriate in these cases. Pregnancy is also an absolute contraindication. Most other contraindications are relative, meaning they require careful consideration and monitoring but aren't automatic disqualifiers.
No. GLP-1s are approved and effective only for type 2 diabetes and weight management. They do not provide sufficient glucose control in type 1 diabetes. In fact, using GLP-1s in type 1 diabetes could delay necessary insulin therapy and increase risk of diabetic ketoacidosis.
No. GLP-1 medications are contraindicated in pregnancy. Animal studies show potential fetal harm. You must stop GLP-1 at least 2 months before trying to conceive (for semaglutide and tirzepatide, which have long half-lives). Breastfeeding is also contraindicated due to unknown risks to infants.
It depends. Mild-to-moderate complications (retinopathy, nephropathy, neuropathy) are relative contraindications but don't necessarily exclude GLP-1 use—your doctor must carefully assess. Advanced complications (severe kidney disease, vision-threatening retinopathy, end-stage renal disease) require cautious consideration. Discuss your specific situation with your doctor.
Personal history of pancreatitis is a relative contraindication. GLP-1s increase risk of pancreatitis recurrence. However, some patients with previous pancreatitis successfully use GLP-1s under close monitoring. Your doctor must weigh the risk: is your previous pancreatitis stable? Do you have ongoing risk factors? Your individual risk assessment is crucial.
It depends on severity. Mild-to-moderate kidney disease (eGFR >30) doesn't contraindicate GLP-1 use. Severe kidney disease (eGFR <30) requires careful assessment and likely dose adjustment or avoiding use. End-stage renal disease (dialysis patients) is a contraindication or requires specialist oversight. Ask your doctor about your specific kidney function.
Depends on type. Personal history of medullary thyroid cancer (MTC) is an ABSOLUTE contraindication—never use GLP-1s. History of other thyroid cancers (papillary, follicular) is a relative contraindication requiring doctor discretion. Family history of MTC or MEN 2 syndrome is an absolute contraindication even if you haven't had cancer.
GLP-1s slow gastric emptying, potentially reducing absorption of oral medications. This matters most for diabetes medications, oral contraceptives, and some antibiotics. Metformin can be taken with GLP-1s. Always tell your doctor all medications you take so they can assess for interactions and adjust timing if needed.
No specific age cutoff exists. GLP-1s are approved for adults 18+. In adolescents (12-17), tirzepatide is FDA-approved for type 2 diabetes and weight management, and semaglutide is approved for weight management. Elderly patients can use GLP-1s if they have no contraindications, though kidney function should be checked.