Drug Interaction Report

Lasmiditan and Hydromorphone Injection: Interaction Details

Name: Lasmiditan and Hydromorphone Injection Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Lasmiditan and Hydromorphone Injection interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Lasmiditan

Reyvow

Hydromorphone Injection

Dilaudid Dilaudid-HP® Dilaudid®

Medically reviewed by

Dr. Brian Staiger, PharmD, BCPS

Updated Aug 8, 2026

Editorial policy · Data sources

Interaction severity

Major

Potentially serious — often needs a change or close monitoring.

Minor

Moderate

Major

Contraindicated

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.

Of 27 documented Lasmiditan interactions, 26 are rated major — including this one.

Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.

Onset

unspecified

Evidence

theoretical

Severity

Major

What happens

Increased risk of serotonin syndrome (hypertension, hyperthermia, myoclonus, mental status changes)

Interaction Deep Dive

Lasmiditan is a serotonin agonist and coadministration with another serotonergic agent may increase the risk of serotonin syndrome. Use lasmiditan with caution in patients taking drugs that increase serotonin and discontinue lasmiditan if serotonin syndrome is suspected¹.

Why it happens (mechanism)

Additive serotonergic effects

Common questions

Can I take Lasmiditan and Hydromorphone Injection together?

Increased risk of serotonin syndrome (hypertension, hyperthermia, myoclonus, mental status changes) Always confirm with your pharmacist or prescriber before making any change.

How serious is the Lasmiditan and Hydromorphone Injection 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 strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

Does my dose of Lasmiditan or Hydromorphone Injection 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 (1)

Product Information: REYVOW(TM) oral tablets, lasmiditan oral tablets. Lilly USA LLC (per manufacturer), Indianapolis, IN, 2019. DailyMed

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Lasmiditan

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All Lasmiditan interactions (27)

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Hydromorphone Injection

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All Hydromorphone Injection interactions (344) Hydromorphone Injection drug information

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HelloPharmacist doesn't license one of the big commercial interaction databases, so what you'll find here is not a complete list of every known drug interaction. Instead, each entry is researched, analyzed, and written up individually — documented from the published literature, reviewed by a pharmacist, and cited so you can check every source yourself.

If a combination isn't listed here, it means we haven't documented it yet — never that it's safe. For screening a full medication list, we recommend pairing this site with a comprehensive tool like the Drugs.com Interaction Checker and, most importantly, a review by your own pharmacist. For a deep, plain-English, fully sourced explanation of a specific documented interaction — that's exactly what we built this for.

This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.