Succinylcholine side effects: what 1,647 FDA adverse event reports show

Succinylcholine · 57 reaction terms · 1,484 drug–reaction co-reports · data 2026-09-14

Drug class

Depolarizing neuromuscular blocker

FDA label, Indications wording

Who reports

1,647 reports · 94% serious · 140 with death outcome · 52% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Succinylcholine chloride injection is indicated in adults and pediatric patients: as an adjunct to general anesthesia to facilitate tracheal intubation to provide skeletal muscle relaxation during surgery or mechanical ventilation. Succinylcholine chlo.

FDA label, Indications and Usage

What it is

Succinylcholine Chloride Injection, USP is a sterile, nonpyrogenic solution to be used as a short-acting, depolarizing neuromuscular blocker for intravenous or intramuscular use. Succinylcholine chloride injection contains succinylcholine chloride as the active pharmaceutical ingredient.

FDA label, Description section

Boxed warning

VENTRICULAR DYSRHYTHMIAS, CARDIAC ARREST, AND DEATH FROM HYPERKALEMIC RHABDOMYOLYSIS IN PEDIATRIC PATIENTS Acute rhabdomyolysis with hyperkalemia followed by ventricular dysrhythmias, cardiac arrest, and death has oc.

FDA label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 39 strongest signals

Labeled — boxed warning 5Labeled adverse reaction 7Labeled (related wording) 2Reporting / coding artifact 5Lab value / disease marker 1Not in label — unassessed 19

What the badges mean

Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 18 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Serotonin syndrome	68	45.4 36.0–57.3ROR 47.3 · χ² 2,902 / p <1e-300	44.7 EB05 36.5 · IC025 +4.7 3/3 methods agree	Not in label — unassessed	serious PRR 28.1 · ♀ 26% (drug 52%) · 98% clinician	no trial data cached
Anaphylactic shock	76	37.9 30.4–47.2ROR 39.6 · χ² 2,686 / p <1e-300	37.4 EB05 30.9 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	serious PRR 23.3 · 100% clinician	no trial data cached
Status epilepticus	30	33.8 23.7–48.3ROR 34.4 · χ² 921 / p 1e-202	33.1 EB05 24.3 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 20.8 · ♀ 90% (drug 52%) · 90% clinician	no trial data cached
Respiratory depression	22	22.9 15.1–34.7ROR 23.2 · χ² 438 / p 1e-97	22.4 EB05 15.6 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 14.5 · 95% clinician	no trial data cached
Ventricular fibrillation	18	20.6 13.0–32.6ROR 20.8 · χ² 316 / p 5e-71	20.1 EB05 13.3 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 12.7	no trial data cached
Premature delivery	25	19.9 13.5–29.4ROR 20.2 · χ² 430 / p 7e-96	19.6 EB05 13.9 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 12.0 · ♀ 100% (drug 52%) · 100% clinician	no trial data cached
Paralysis	22	19.5 12.9–29.6ROR 19.8 · χ² 368 / p 3e-82	19.1 EB05 13.2 · IC025 +3.1 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 10.8	no trial data cached
Ventricular tachycardia	24	18.5 12.4–27.5ROR 18.7 · χ² 379 / p 1e-84	18.1 EB05 12.7 · IC025 +3.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 11.5 · 91% clinician	no trial data cached
Muscle rigidity	17	18.1 11.3–29.1ROR 18.3 · χ² 258 / p 2e-58	17.6 EB05 11.3 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.5	no trial data cached
Anaphylactic reaction (severe allergic reaction)	72	16.7 13.3–20.9ROR 17.4 · χ² 1,049 / p 2e-230	16.6 EB05 13.6 · IC025 +3.5 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 10.3 · 100% clinician	no trial data cached
Generalised tonic-clonic seizure	21	16.4 10.7–25.0ROR 16.6 · χ² 287 / p 9e-65	15.9 EB05 10.7 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 10.2 · 95% clinician	no trial data cached
Rhabdomyolysis (muscle breakdown)	49	15.0 11.4–19.8ROR 15.4 · χ² 627 / p 1e-138	14.8 EB05 11.6 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 9.1 · 94% clinician	no trial data cached
Cardiac arrest (heart stopping)	94	14.5 11.9–17.6ROR 15.3 · χ² 1,167 / p 4e-256	14.4 EB05 12.1 · IC025 +3.4 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 8.9 · 100% clinician	no trial data cached
Bronchospasm (airway tightening)	16	14.2 8.7–23.2ROR 14.4 · χ² 184 / p 3e-42	13.3 EB05 8.1 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 8.5	no trial data cached
Premature baby	33	13.9 9.9–19.5ROR 14.2 · χ² 383 / p 1e-85	13.6 EB05 9.9 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.2 · 100% clinician	no trial data cached
Blood calcium decreased	12	13.6 7.7–23.8ROR 13.6 · χ² 127 / p 8e-30	12.1 EB05 6.5 · IC025 +2.2 3/3 methods agree	Lab value / disease marker	serious PRR 10.4	no trial data cached
Bradycardia (slow heart rate)	54	13.0 10.0–16.8ROR 13.4 · χ² 585 / p 2e-129	12.7 EB05 10.0 · IC025 +3.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.2 · 98% clinician	no trial data cached
Sinus tachycardia	14	12.6 7.5–21.2ROR 12.7 · χ² 138 / p 4e-32	11.3 EB05 6.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 7.9	no trial data cached
Hypoxia (low oxygen)	34	12.4 8.9–17.2ROR 12.6 · χ² 344 / p 5e-77	11.9 EB05 8.7 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.7 · 94% clinician	no trial data cached
Hyperkalaemia (high potassium)	33	12.0 8.6–16.9ROR 12.3 · χ² 324 / p 1e-72	11.6 EB05 8.4 · IC025 +2.8 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 7.6 · 100% clinician	no trial data cached
Neuroleptic malignant syndrome	11	11.8 6.5–21.2ROR 11.9 · χ² 98 / p 2e-23	9.9 EB05 5.3 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 7.3	no trial data cached
Metabolic acidosis	27	10.9 7.5–15.8ROR 11.0 · χ² 232 / p 9e-53	10.2 EB05 7.1 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 6.7 · ♀ 28% (drug 52%) · 96% clinician	no trial data cached
Foetal exposure during pregnancy	69	10.8 8.6–13.6ROR 11.3 · χ² 607 / p 2e-134	10.6 EB05 8.6 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious PRR 6.6 · 94% clinician	no trial data cached
Exposure during pregnancy	50	10.2 7.8–13.5ROR 10.5 · χ² 409 / p 3e-91	9.9 EB05 7.7 · IC025 +2.8 3/3 methods agree	Reporting / coding artifact	serious PRR 9.1 · ♀ 100% (drug 52%) · 100% clinician	no trial data cached
Circulatory collapse	13	9.7 5.6–16.6ROR 9.8 · χ² 93 / p 3e-22	8.1 EB05 4.7 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.0	no trial data cached
Pneumothorax	12	9.6 5.5–17.0ROR 9.7 · χ² 85 / p 2e-20	7.9 EB05 4.5 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.0	no trial data cached
Encephalopathy	18	9.4 5.9–14.8ROR 9.5 · χ² 126 / p 1e-29	8.2 EB05 5.3 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 5.8	no trial data cached
Hypotension (low blood pressure)	138	8.8 7.5–10.3ROR 9.5 · χ² 952 / p 3e-209	8.6 EB05 7.5 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.2 · 96% clinician	no trial data cached
Tachycardia (fast heart rate)	59	8.5 6.6–10.9ROR 8.7 · χ² 382 / p 2e-85	8.1 EB05 6.5 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.4 · ♀ 24% (drug 52%) · 96% clinician	no trial data cached
Drug interaction	102	8.2 6.8–9.9ROR 8.7 · χ² 641 / p 1e-141	8.0 EB05 6.7 · IC025 +2.7 3/3 methods agree	Reporting / coding artifact	serious PRR 5.7 · 99% clinician	no trial data cached
Post procedural complication	11	7.3 4.0–13.1ROR 7.3 · χ² 54 / p 1e-13	5.8 EB05 3.4 · IC025 +1.5 3/3 methods agree	Reporting / coding artifact	serious PRR 4.9	no trial data cached
Maternal exposure during pregnancy	49	7.1 5.4–9.3ROR 7.3 · χ² 251 / p 1e-56	6.7 EB05 5.2 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious PRR 5.0 · ♀ 100% (drug 52%) · 96% clinician	no trial data cached
Unresponsive to stimuli	14	6.9 4.1–11.7ROR 7.0 · χ² 65 / p 3e-16	5.8 EB05 3.6 · IC025 +1.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 3.7	no trial data cached
Cardio-respiratory arrest	21	6.4 4.2–9.7ROR 6.4 · χ² 90 / p 1e-21	5.6 EB05 3.9 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 3.9	no trial data cached
Rash maculo-papular	11	6.3 3.5–11.4ROR 6.4 · χ² 44 / p 2e-11	5.1 EB05 3.0 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 4.3	no trial data cached
Shock	10	5.6 3.0–10.4ROR 5.6 · χ² 33 / p 4e-9	4.5 EB05 2.7 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious PRR 3.5	no trial data cached
Lactic acidosis	13	5.2 3.0–8.9ROR 5.2 · χ² 40 / p 2e-10	4.4 EB05 2.8 · IC025 +1.2 3/3 methods agree	Not in label — unassessed	serious PRR 3.2	no trial data cached
Sedation	10	4.9 2.6–9.1ROR 4.9 · χ² 27 / p 9e-8	4.1 EB05 2.4 · IC025 +1.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.1	no trial data cached
Aggression	12	3.0 1.7–5.4ROR 3.1 · χ² 15 / p 7e-5	2.8 EB05 1.7 · IC025 +0.5	Not in label — unassessed	serious PRR 2.1	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Hypotension (low blood pressure)	138	8.8 7.5–10.3ROR 9.5 · χ² 952 / p 3e-209	8.6 EB05 7.5 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.2 · 96% clinician	no trial data cached
Drug interaction	102	8.2 6.8–9.9ROR 8.7 · χ² 641 / p 1e-141	8.0 EB05 6.7 · IC025 +2.7 3/3 methods agree	Reporting / coding artifact	serious PRR 5.7 · 99% clinician	no trial data cached
Cardiac arrest (heart stopping)	94	14.5 11.9–17.6ROR 15.3 · χ² 1,167 / p 4e-256	14.4 EB05 12.1 · IC025 +3.4 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 8.9 · 100% clinician	no trial data cached
Anaphylactic shock	76	37.9 30.4–47.2ROR 39.6 · χ² 2,686 / p <1e-300	37.4 EB05 30.9 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	serious PRR 23.3 · 100% clinician	no trial data cached
Anaphylactic reaction (severe allergic reaction)	72	16.7 13.3–20.9ROR 17.4 · χ² 1,049 / p 2e-230	16.6 EB05 13.6 · IC025 +3.5 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 10.3 · 100% clinician	no trial data cached
Foetal exposure during pregnancy	69	10.8 8.6–13.6ROR 11.3 · χ² 607 / p 2e-134	10.6 EB05 8.6 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious PRR 6.6 · 94% clinician	no trial data cached
Serotonin syndrome	68	45.4 36.0–57.3ROR 47.3 · χ² 2,902 / p <1e-300	44.7 EB05 36.5 · IC025 +4.7 3/3 methods agree	Not in label — unassessed	serious PRR 28.1 · ♀ 26% (drug 52%) · 98% clinician	no trial data cached
Tachycardia (fast heart rate)	59	8.5 6.6–10.9ROR 8.7 · χ² 382 / p 2e-85	8.1 EB05 6.5 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.4 · ♀ 24% (drug 52%) · 96% clinician	no trial data cached
Bradycardia (slow heart rate)	54	13.0 10.0–16.8ROR 13.4 · χ² 585 / p 2e-129	12.7 EB05 10.0 · IC025 +3.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.2 · 98% clinician	no trial data cached
Exposure during pregnancy	50	10.2 7.8–13.5ROR 10.5 · χ² 409 / p 3e-91	9.9 EB05 7.7 · IC025 +2.8 3/3 methods agree	Reporting / coding artifact	serious PRR 9.1 · ♀ 100% (drug 52%) · 100% clinician	no trial data cached
Maternal exposure during pregnancy	49	7.1 5.4–9.3ROR 7.3 · χ² 251 / p 1e-56	6.7 EB05 5.2 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious PRR 5.0 · ♀ 100% (drug 52%) · 96% clinician	no trial data cached
Rhabdomyolysis (muscle breakdown)	49	15.0 11.4–19.8ROR 15.4 · χ² 627 / p 1e-138	14.8 EB05 11.6 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 9.1 · 94% clinician	no trial data cached
Hypoxia (low oxygen)	34	12.4 8.9–17.2ROR 12.6 · χ² 344 / p 5e-77	11.9 EB05 8.7 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.7 · 94% clinician	no trial data cached
Hyperkalaemia (high potassium)	33	12.0 8.6–16.9ROR 12.3 · χ² 324 / p 1e-72	11.6 EB05 8.4 · IC025 +2.8 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 7.6 · 100% clinician	no trial data cached
Premature baby	33	13.9 9.9–19.5ROR 14.2 · χ² 383 / p 1e-85	13.6 EB05 9.9 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.2 · 100% clinician	no trial data cached

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Serotonin syndrome — n=68, PRR 45.4
Anaphylactic shock — n=76, PRR 37.9
Status epilepticus — n=30, PRR 33.8
Premature delivery — n=25, PRR 19.9
Generalised tonic-clonic seizure — n=21, PRR 16.4
Premature baby — n=33, PRR 13.9
Metabolic acidosis — n=27, PRR 10.9
Cardio-respiratory arrest — n=21, PRR 6.4

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Succinylcholine?

In FDA FAERS, the most frequently co-reported reaction terms for Succinylcholine are hypotension, cardiac arrest, anaphylactic shock, anaphylactic reaction, serotonin syndrome, tachycardia. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Succinylcholine have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: VENTRICULAR DYSRHYTHMIAS, CARDIAC ARREST, AND DEATH FROM HYPERKALEMIC RHABDOMYOLYSIS IN PEDIATRIC PATIENTS Acute rhabdomyolysis with hyperkalemia followed by ventricular dysrhythmias, cardiac arrest, and death has oc.

Do FAERS signals prove that Succinylcholine causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID f55dd1c0-c259-219a-5bca-f139e9515d07, effective 20240225; matched on openfda.generic_name.exact:"SUCCINYLCHOLINE")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 57 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.