Every FDA-approved GLP-1 and GIP/GLP-1 label opens with a contraindications section and, for the weight-loss and most diabetes products, a boxed warning for medullary thyroid carcinoma. Those sections live deep in the prescribing information and rarely make it onto patient handouts. This card pulls the absolute do-not-prescribe list, the cautions, and the interaction notes onto one page.
Absolute contraindications
| Condition | Why | Source |
|---|---|---|
| Personal or family history of medullary thyroid carcinoma (MTC) | Boxed warning. Rodent studies showed dose- and duration-dependent thyroid C-cell tumors with semaglutide, tirzepatide, and liraglutide. Human relevance is undetermined; the label rules these patients out entirely. | DailyMed Wegovy, Ozempic, Zepbound, Mounjaro, Saxenda labels (boxed warning + Section 4) |
| Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) | Boxed warning. MEN 2 carries near-universal MTC risk and is listed alongside personal/family MTC history as an absolute contraindication. | DailyMed Wegovy, Zepbound, Saxenda labels (boxed warning + Section 4) |
| Prior serious hypersensitivity to the drug or any excipient | Anaphylaxis and angioedema have been reported. Cross-reactivity within the class is plausible and should be assessed by an allergist before any switch. | DailyMed all GLP-1 labels (Sections 4 and 5) |
| Type 1 diabetes mellitus | FDA indications for Ozempic, Mounjaro, and Trulicity are limited to type 2. GLP-1s do not replace insulin and have caused DKA when used as monotherapy in insulin-dependent disease. | DailyMed Ozempic, Mounjaro, Trulicity labels (Section 1) |
| Pregnancy — and planning to conceive within the washout window | Animal studies showed fetal harm. The Wegovy label directs discontinuation at least 2 months before a planned pregnancy because of the ~1-week half-life; other GLP-1s direct discontinuation when pregnancy is recognized. | DailyMed Wegovy, Zepbound, Mounjaro, Saxenda, Foundayo Section 8.1 |
Counsel patients on thyroid-tumor symptoms — a neck mass, dysphagia, dyspnea, or persistent hoarseness — before starting and at every visit.
Extreme caution — relative contraindications
- Prior acute or chronic pancreatitis. A label warning, not a contraindication, but most prescribers avoid GLP-1s after any documented episode. Discontinue immediately for persistent severe abdominal pain and rule out pancreatitis before re-initiation.
- Severe gastroparesis or pre-existing severe GI disease. GLP-1s slow gastric emptying by design; layering that on established delayed emptying produces intolerable symptoms and aspiration risk at anesthesia. The ASA 2023 guidance flags GLP-1 use on the day of surgery.
- Known cholelithiasis or active gallbladder disease. Rapid weight loss increases gallstone formation; the Wegovy and Zepbound labels carry explicit gallbladder warnings. New right-upper-quadrant pain warrants imaging.
- Diabetic retinopathy on insulin or sulfonylureas. SUSTAIN-6 flagged a transient worsening of retinopathy with semaglutide that tracked the magnitude of A1C drop. The Ozempic label carries a retinopathy warning; a baseline dilated exam is reasonable.
- History of restrictive eating disorder. No label contraindication, but the appetite-suppressing mechanism overlaps directly with the pathology. Clinical-society consensus recommends against initiation in active or recent restrictive eating disorder.
- Active suicidality or recent attempt. The FDA concluded in January 2024 that evidence does not support a causal link between GLP-1s and suicidality, but the Wegovy label retains a precaution to monitor depression, suicidal thoughts, and unusual mood changes.
- Stage 4 or 5 CKD (eGFR <30). Not contraindicated by eGFR, but data below 30 are sparse. Volume depletion from nausea, vomiting, or diarrhea is the dominant renal risk and most consequential in advanced CKD.
- History of bariatric surgery. Post-surgical anatomy can blunt or amplify GLP-1 effects; safety data are limited. ASMBS 2023 endorses use for post-bariatric weight regain with careful titration.
Drug interactions
- Oral contraceptives. Slowed gastric emptying can reduce absorption. The Zepbound label recommends a non-oral method or barrier backup for 4 weeks after starting and after each titration step.
- Insulin and sulfonylureas. Reduce doses by 20–50% at GLP-1 start to avoid hypoglycemia. Sulfonylureas are often discontinued entirely.
- DPP-4 inhibitors (Januvia, Tradjenta, Onglyza, Nesina). Do not combine. The labels state these products have not been studied with other incretin-pathway drugs and DPP-4s offer no additive efficacy when a GLP-1 is on board.
- Other GLP-1 receptor agonists. Do not combine. Discontinue one before starting another — GLP-1 RAs have not been studied with another GLP-1 RA.
- Drugs requiring stable absorption. Levothyroxine, warfarin, anti-epileptics, and digoxin have narrow therapeutic windows. Monitor INR, thyroid function, and serum drug levels more frequently during the first 8–12 weeks and after each dose escalation.
Special populations
- Pediatrics. Wegovy and Saxenda are approved in patients 12 and older; Trulicity in patients 10 and older for type 2 diabetes. Ozempic, Mounjaro, Zepbound, Rybelsus, and Foundayo remain adult-only. Compounded products have no pediatric data.
- Older adults (65+). No dose adjustment by age alone, but the labels note older patients are more sensitive to volume depletion and to hypoglycemia when GLP-1s are layered on insulin or sulfonylureas. Start at the lowest dose and titrate slowly; screen for falls risk if orthostatic hypotension develops.
- Athletes and very lean BMI (under 25). Efficacy and risk balance are not established outside the indicated BMI thresholds (27 with comorbidity or 30 without). Performance or aesthetic use is off-label.
- Underweight or recent unintentional weight loss (BMI under 18.5). Do not initiate. Further appetite suppression risks malnutrition, sarcopenia, and worsening of any underlying cause of the weight loss.
What this cheat sheet does not cover
Each FDA-approved GLP-1 has product-specific warnings beyond the class-level list above — read the individual DailyMed label for the prescribed drug. Compounded GLP-1 products carry additional sterility, identity, and dosing-error concerns not addressed in any FDA label and out of scope here. Surgery hold protocols live on the GLP-1 Sick-Day Guide; pregnancy washout windows have their own page.
Related on Weight Loss Rankings
- All cheat sheets — the full one-page reference library.
- GLP-1 + Pregnancy, Fertility & Contraception — the washout numbers and the inadvertent-exposure protocol.
- GLP-1 + Diabetes Medication Interactions — the insulin and sulfonylurea adjustment table.
- Top GLP-1 + Cancer-History Questions (Reddit, Answered) — the boxed-warning conversation in plain English.
Sources
- DailyMed. WEGOVY (semaglutide) injection prescribing information. SetID ee06186f-2aa3-4990-a760-757579d8f77b. Boxed Warning (thyroid C-cell tumors); Section 4 (personal/family MTC, MEN 2, prior serious hypersensitivity); Section 5 (pancreatitis, gallbladder, suicidality monitoring); Section 8.1 (discontinue at least 2 months before planned pregnancy).
- DailyMed. OZEMPIC (semaglutide) injection prescribing information. SetID adec4fd2-6858-4c99-91d4-531f5f2a2d79. Boxed Warning; Section 4 Contraindications; Section 5.5 Diabetic Retinopathy Complications; Section 1 Indications and Usage (type 2 diabetes only).
- DailyMed. ZEPBOUND (tirzepatide) injection prescribing information. SetID 487cd7e7-434c-4925-99fa-aa80b1cc776b. Boxed Warning; Section 4; Section 5 (acute gallbladder disease, pancreatitis); Section 7.1 (oral hormonal contraceptives — barrier method or non-oral contraceptive for 4 weeks after initiation and each dose escalation).
- DailyMed. MOUNJARO (tirzepatide) injection prescribing information. SetID d2d7da5d-ad07-4228-955f-cf7e355c8cc0. Boxed Warning; Section 4 Contraindications; Section 5 Warnings; Section 1 Indications and Usage (type 2 diabetes only).
- DailyMed. SAXENDA (liraglutide) injection prescribing information. Boxed Warning (thyroid C-cell tumors); Section 4 Contraindications (personal/family MTC, MEN 2, pregnancy, prior serious hypersensitivity); Section 5 Warnings (pancreatitis, gallbladder, suicidal behavior and ideation monitoring); Section 8.4 Pediatric Use (approved in patients 12 and older).
- U.S. Food and Drug Administration. Update on FDA’s ongoing evaluation of reports of suicidal thoughts or actions in patients taking a certain type of medicines approved for type 2 diabetes and obesity. Drug Safety Communication, January 2024. FDA found no evidence that GLP-1 receptor agonist use causes suicidal thoughts or actions; monitoring is still recommended.
- Joshi GP, Abdelmalak BB, Weigel WA, et al. American Society of Anesthesiologists Consensus-Based Guidance on Preoperative Management of Patients on Glucagon-Like Peptide-1 Receptor Agonists. 2023. Hold daily-dosed GLP-1s on the day of surgery and weekly-dosed GLP-1s for one week before elective procedures to reduce aspiration risk from delayed gastric emptying.