GLP-1 Drug-Interaction Risk Map (263 Pair Analysis, 2026)

Abstract

GLP-1 receptor agonists (semaglutide, tirzepatide, liraglutide) are increasingly co-prescribed alongside diabetes, cardiovascular, anticoagulant, and mental-health medications. Yet the clinical-interaction literature for these combinations is fragmented across FDA labels, drug-class pharmacology, and case reports. We assembled an editorial-grade interaction matrix covering 263 brand × comorbidity-medication pairs, adversarially verified each severity grade against primary FDA sources, and published the result as both a structured dataset (one HTML page per pair) and an open editorial report (this document).

The dominant finding: 53.2% of plausible co-prescribing pairs have no clinically significant interaction documented. Clinical attention should focus on the 51-pair Major/Moderate cluster, which is dominated by additive-hypoglycemia and absorption-timing mechanisms.

Methodology

Per-brand interaction profiles for all six FDA-approved GLP-1 medications (Wegovy, Ozempic, Mounjaro, Zepbound, Saxenda, Rybelsus) were generated against the 49 most-commonly co-prescribed comorbidity medications (sourced from primary-care + endocrinology formulary analysis). Each pair received a 5-field profile: severity grade (Major / Moderate / Minor / None-Known), interaction type (pharmacokinetic / pharmacodynamic / both / none), mechanism narrative, clinical-management guidance, monitoring recommendation, red-flag symptom list, FDA-label citation, and editorial-confidence score (1-10).

Adversarial verification: Every profile was reviewed by an independent skeptic agent prompted to refute severity inflation, fabricated mechanism narratives, or unverified FDA citations. The publishable filter was confidence ≥7 + safeToPublish=true + severityCorrect=true + mechanismCorrect=true. Pairs failing any test were rejected (~14% rejection rate at the ingredient level).

Severity distribution

Mechanism breakdown

Of the 123 pairs with any documented interaction: 101 are pharmacodynamic (additive glucose, blood-pressure, or bleeding effects); 20 are pharmacokinetic (GLP-1- induced delayed gastric emptying altering oral-drug absorption); and 2 involve both mechanisms.

Per-brand interaction profile

Medications most likely to interact with GLP-1s (Major severity)

The medications below received a Major severity grade across multiple GLP-1 brands. These combinations require explicit prescriber discussion before initiation.

• Glimepiride (Amaryl) — Major across 5 brands (Mounjaro, Ozempic, Rybelsus, Wegovy, Zepbound). Mechanism: Like other sulfonylureas, glimepiride causes glucose-independent insulin secretion, which combined with tirzepatide markedly increases hypoglycemia risk. Glimepiride has a longer half-life than glipizide, prolonging the hypoglycemia window.
• Glipizide (Glucotrol) — Major across 5 brands (Mounjaro, Ozempic, Rybelsus, Wegovy, Zepbound). Mechanism: Sulfonylureas stimulate insulin release independent of glucose level, and combining them with tirzepatide's glucose-dependent insulin secretion and slowed gastric emptying substantially increases hypoglycemia risk. This is a well-documented class effect for GLP-1 receptor agonists.
• Insulin Glargine (Lantus) — Major across 5 brands (Mounjaro, Ozempic, Rybelsus, Wegovy, Zepbound). Mechanism: Additive glucose-lowering effects substantially increase the risk of hypoglycemia. Tirzepatide enhances glucose-dependent insulin secretion and reduces glucagon, while basal insulin provides background insulin coverage. The combined effect can drive glucose below physiologic thresholds, particularly during titration or after weight loss reduces insulin requirements.
• Insulin Lispro (Humalog) — Major across 5 brands (Mounjaro, Ozempic, Rybelsus, Wegovy, Zepbound). Mechanism: Mealtime rapid-acting insulin combined with tirzepatide's enhanced glucose-dependent insulin secretion and slowed gastric emptying can cause significant postprandial hypoglycemia. Delayed gastric emptying may also create a mismatch between insulin peak action and carbohydrate absorption, complicating titration.
• Combined Oral Contraceptives — Major across 2 brands (Mounjaro, Zepbound). Mechanism: Tirzepatide-induced delayed gastric emptying reduces the rate and may reduce the extent of oral contraceptive absorption, particularly during dose initiation and escalation. The Mounjaro/Zepbound prescribing information specifically advises that oral contraceptives may be less effective and recommends use of a barrier method or switching to a non-oral contraceptive for 4 weeks after initiation and after each dose escalation.

Implications for clinical practice

Most GLP-1 × comorbidity-medication co-prescribing situations are pharmacologically uneventful. The clinical-attention budget should concentrate on:

1. Insulin and sulfonylurea co-administration — additive hypoglycemia risk; prescriber-initiated dose reduction of the secretagogue at GLP-1 initiation is the standard mitigation.
2. Oral medications with narrow therapeutic windows (warfarin, levothyroxine, oral contraceptives in Mounjaro/Zepbound use) — GLP-1-induced delayed gastric emptying may alter absorption timing. Most labels recommend monitoring rather than avoidance.
3. Use of compounded GLP-1 products — interactions are NOT independently studied for compounded formulations because they are not FDA-reviewed as finished products. Apply the FDA-brand interaction profile conservatively.

Dataset access

The full structured dataset is published as 263 individual interaction pages at glp1zoom.com/drug-interactions. Each pair page carries a Speakable schema block + FAQPage JSON-LD so AI search engines (ChatGPT, Claude, Perplexity, Google AI Overviews) can directly extract the severity grade, mechanism, and clinical-management guidance.

Researchers and journalists wishing to cite this analysis are welcome to do so under the CC BY 4.0 license. Suggested citation block below.

Press contact + media kit

Journalists covering GLP-1 prescribing safety, polypharmacy, or telehealth medication access: editorial sources, on-the-record commentary, and additional data slices are available on request. Visit our /press page for boilerplate, downloadable assets, and contact details. Time-sensitive press inquiries: [email protected].

GLP1Zoom is an affiliate-only comparator — we route to vetted telehealth providers and do not prescribe or sell medications. This study is editorial analysis of FDA-labeled interactions, not patient-specific medical advice. Always verify drug interactions in clinical decision support and with the prescribing clinician. Full disclaimer.