Glycopyrrolate and Amitriptyline: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amitriptyline
Glycopyrrolate
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Both amitriptyline and glycopyrrolate have what we call anticholinergic effects. That means they can both cause dry mouth, blurred vision, constipation, and trouble emptying your bladder. When you take them together, these effects can stack up and become stronger.
For most people the bigger concerns are severe constipation or being unable to urinate, and in people with narrow-angle glaucoma it can raise eye pressure. The good news is this is very manageable. Keep taking both exactly as prescribed, and let your pharmacist or doctor know so they can watch for these effects and adjust things if needed.
Mechanism: Additive antimuscarinic (anticholinergic) effects. Amitriptyline is a tertiary tricyclic with strong anticholinergic activity; glycopyrrolate is a quaternary antimuscarinic. This is a pharmacodynamic interaction, not a PK/metabolic one. Neither drug is a prodrug here.
Direction/effect: Additive anticholinergic burden.
- Risks: worsening narrow-angle glaucoma, urinary retention, delayed gastric emptying, constipation, paralytic ileus, and toxic megacolon.
- Evidence: theoretical; severity: major; onset unspecified.
- Management: combination generally not recommended; if used, monitor bowel/bladder function, hydration, and IOP; individualize dosing and consider alternatives.
What happens
An increased risk of anticholinergic side effects
Interaction Deep Dive
It is advised against combining glycopyrrolate with other anticholinergic agents or drugs that slow GI peristalsis1, because doing so may heighten the potential for cumulative anticholinergic effects2. Such effects include the worsening of narrow-angle glaucoma, urinary retention3, slowed gastric emptying, constipation, and intestinal pseudo-obstruction. Additionally, paralytic ileus and toxic megacolon may be exacerbated1.
Why it happens (mechanism)
Additive anticholinergic effects
How to manage this interaction
Your care team can manage this by watching you more closely and tailoring your doses if needed.
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Watch for and report severe constipation, trouble urinating, belly pain or bloating, or vision changes/eye pain.
- Stay well hydrated and keep moving to help your bowels.
- Tell your team if you have glaucoma, prostate issues, or a history of bowel problems, since the combination is generally not recommended in those situations.
- Your team may adjust doses or choose an alternative to reduce the combined anticholinergic load.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Glycopyrrolate and Amitriptyline together?
Taking amitriptyline and glycopyrrolate together can stack up anticholinergic side effects like constipation, urinary retention, and worsening glaucoma. Keep taking both as prescribed and tell your pharmacist or doctor so they can monitor you and adjust if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Glycopyrrolate and Amitriptyline interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Glycopyrrolate and Amitriptyline interaction managed?
Your care team can manage this by watching you more closely and tailoring your doses if needed. Keep taking both as prescribed unless your prescriber tells you otherwise. Watch for and report severe constipation, trouble urinating, belly pain or bloating, or vision changes/eye pain. Stay well hydrated and keep moving to help your bowels. Tell your team if you have glaucoma, prostate issues, or a h… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Glycopyrrolate or Amitriptyline need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: DARTISLA ODT orally disintegrating tablets, glycopyrrolate orally disintegrating tablets. Edenbridge Pharmaceuticals LLC (per FDA), Parsippany, NJ, 2021.
- Product Information: PREVDUO intravenous injection, neostigmine methylsulfate glycopyrrolate intravenous injection. Slayback Pharma LLC (per FDA), Princeton, NJ, 2023. DailyMed
- Product Information: LONHALA(TM) MAGNAIR(TM) oral inhalation solution, glycopyrrolate oral inhalation solution. Sunovion Respiratory Development Inc (per manufacturer), Marlborough, MA, 2017. DailyMed
Keep reading about Amitriptyline
Keep reading about Glycopyrrolate
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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