OpenPV Signal Explorer
FAERS disproportionality dashboard
← All causality assessments
Causality assessment · Causality: well established

Morphine (opioids) and Overdose / respiratory depression: is the FAERS signal real?

n=23,522 co-reports · PRR 21.1 · ROR 26.0
Morphine (opioids) side-effect profileAll assessmentsSee in the full list
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Causality: well established

Morphine (opioids) ↔ Overdose / respiratory depression

n=23,522 co-reports · PRR 21.1 · ROR 26.0

Reporting over time (stimulated-reporting check)

2004: 49 reports (2.96% of the drug's reports)2005: 45 reports (2.95% of the drug's reports)2006: 22 reports (1.77% of the drug's reports)2007: 10 reports (1.26% of the drug's reports)2008: 21 reports (2.37% of the drug's reports)2009: 15 reports (1.57% of the drug's reports)2010: 8 reports (0.62% of the drug's reports)2011: 16 reports (1.02% of the drug's reports)2012: 26 reports (1.10% of the drug's reports)2013: 10 reports (0.53% of the drug's reports)2014: 11 reports (0.47% of the drug's reports)2015: 10 reports (0.33% of the drug's reports)2016: 15 reports (0.41% of the drug's reports)2017: 9 reports (0.18% of the drug's reports)2018: 19 reports (0.07% of the drug's reports)2019: 33 reports (0.68% of the drug's reports)2020: 29 reports (0.33% of the drug's reports)2021: 31 reports (0.15% of the drug's reports)2022: 48 reports (0.33% of the drug's reports)2023: 41 reports (0.48% of the drug's reports)2024: 33 reports (0.89% of the drug's reports)2025: 67 reports (1.93% of the drug's reports)05081114172023

Reporting spiked in 2025 — 18% of all 568 reports arrived in two years (2024–2025). A burst like this usually follows a regulatory communication, media coverage or litigation advertising rather than a change in the drug's effect; it inflates disproportionality for those years.

Bars: reports per year as a share of all FAERS reports for this drug, 2004–2025; amber = spike year (>3× the median share, ≥50 reports). Source: openFDA count=receivedate, retrieved 2026-10-09.

Morphine is a full mu-opioid receptor agonist, and the dose-related triad of respiratory depression, sedation, and death in overdose is the defining, mechanistically direct hazard of the opioid class. The opioid-overdose epidemic is a public-health emergency addressed by the CDC clinical practice guideline, opioid REMS, and naloxone access. The FAERS term "overdose" here spans intentional and unintentional excess and reflects a well-established, dose-dependent risk rather than a statistical artifact — though it also aggregates suicides, misuse, and medication errors, so it is not a pure "adverse reaction."

Regulatory basis: opioid analgesic REMS; CDC Clinical Practice Guideline for Prescribing Opioids (2016, updated 2022); morphine prescribing information (boxed warning for respiratory depression and addiction).

Bradford Hill viewpointStatusNote
Temporality (necessary)metRespiratory depression follows dosing and rises with dose
StrengthmetPRR 21 on a very large base; the leading cause of drug-overdose death
ConsistencymetReproduced across the whole opioid class and decades of data
SpecificitypartialA class effect; the FAERS term also captures misuse and error
Biological gradientmetCentral hypoventilation is classically dose-dependent
PlausibilitymetMu-opioid receptor agonism directly suppresses brainstem respiratory drive
CoherencemetCoheres with the entire opioid pharmacology and toxicology literature
ExperimentmetNaloxone reverses opioid-induced respiratory depression — a clean pharmacologic antagonist experiment
AnalogymetShared by every mu-opioid agonist

This page's own qualitative read, not an automated/citation-gated assessment.

✗ Searched, nothing relevant found. The trial that surfaced (NCT02145468) was a cardiovascular trial in acute coronary syndrome, not a morphine trial; its "overdose"/"respiratory depression" entries were single events. Overdose is a dosing/behavioral outcome that short, titrated trials are not designed to capture — the hazard is established from pharmacology, poison-center, and mortality data.