Hydroxocobalamin side effects: what 4,118 FDA adverse event reports show

Hydroxocobalamin · 175 reaction terms · 3,748 drug–reaction co-reports · data 2026-09-14

Drug class

Antidote

FDA label (Established Pharmacologic Class) · compare the class

Who reports

4,118 reports · 91% serious · 311 with death outcome · 60% female

openFDA FAERS counts, all years, deduplication not applied

Used for

CYANOKIT is indicated for the treatment of known or suspected cyanide poisoning. CYANOKIT is indicated for the treatment of known or suspected cyanide poisoning. ( 1 )

FDA label, Indications and Usage

What it is

Hydroxocobalamin, the active ingredient in CYANOKIT, is cobinamide dihydroxide dihydrogen phosphate (ester), mono (inner salt), 3'-ester with 5,6-dimethyl-1-α-D-ribofuranosyl-1H-benzimidazole, an antidote.

FDA label, Description section

Boxed warning

None in the current 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 40 strongest signals

Labeled adverse reaction 1Labeled (related wording) 2Reporting / coding artifact 2Not in label — unassessed 35

What the badges mean

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.
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. 135 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
Chromaturia	67	15.1 11.9–19.2ROR 15.4 · χ² 869 / p 2e-191	15.0 EB05 12.2 · IC025 +3.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.9 · ♀ 31% (drug 60%) · 91% clinician	no trial data cached
Orthostatic hypotension (dizziness on standing)	50	14.6 11.1–19.3ROR 14.8 · χ² 620 / p 4e-137	14.4 EB05 11.3 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 10.4 · ♀ 33% (drug 60%)	no trial data cached
Pneumonia aspiration	68	13.9 11.0–17.6ROR 14.1 · χ² 802 / p 1e-176	13.8 EB05 11.2 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 8.8	no trial data cached
Hyponatraemia (low sodium)	137	12.4 10.5–14.7ROR 12.8 · χ² 1,430 / p <1e-300	12.3 EB05 10.7 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 8.0 · 92% clinician	no trial data cached
Inappropriate antidiuretic hormone secretion	22	11.0 7.3–16.7ROR 11.1 · χ² 190 / p 1e-43	10.1 EB05 6.7 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 7.0 · ♀ 95% (drug 60%)	no trial data cached
Liver function test abnormal	52	9.1 6.9–11.9ROR 9.2 · χ² 365 / p 1e-81	8.6 EB05 6.8 · IC025 +2.6 3/3 methods agree	Reporting / coding artifact	serious PRR 7.0	no trial data cached
Lip swelling	59	9.1 7.0–11.7ROR 9.2 · χ² 415 / p 2e-92	8.7 EB05 6.9 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 8.9 · 97% clinician	no trial data cached
Urosepsis	16	8.8 5.4–14.4ROR 8.9 · χ² 104 / p 1e-24	7.6 EB05 4.7 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.6	no trial data cached
Hypomagnesaemia	24	8.8 5.9–13.2ROR 8.9 · χ² 159 / p 1e-36	7.9 EB05 5.5 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 5.7 · ♀ 35% (drug 60%) · 92% clinician	no trial data cached
Upper gastrointestinal haemorrhage	26	7.9 5.4–11.5ROR 7.9 · χ² 149 / p 2e-34	7.1 EB05 5.0 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 4.9 · 92% clinician	no trial data cached
Acute kidney injury (sudden kidney damage)	211	7.1 6.2–8.1ROR 7.4 · χ² 1,099 / p 3e-241	7.0 EB05 6.2 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.4 · 95% clinician	no trial data cached
Lower respiratory tract infection	59	6.6 5.2–8.6ROR 6.7 · χ² 277 / p 2e-62	6.3 EB05 5.1 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Metabolic acidosis	41	6.6 4.9–9.0ROR 6.7 · χ² 189 / p 2e-43	6.2 EB05 4.7 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 4.2 · 92% clinician	no trial data cached
Parkinsonism	12	6.3 3.6–11.0ROR 6.3 · χ² 48 / p 2e-12	5.2 EB05 3.1 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 4.6	no trial data cached
Ileus	15	6.2 3.7–10.3ROR 6.2 · χ² 60 / p 4e-15	5.3 EB05 3.4 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 3.9	no trial data cached
Coma	57	6.1 4.7–7.9ROR 6.2 · χ² 238 / p 6e-54	5.8 EB05 4.7 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 3.8 · ♀ 83% (drug 60%)	no trial data cached
Incorrect route of product administration	20	6.1 3.9–9.4ROR 6.1 · χ² 80 / p 2e-19	5.4 EB05 3.7 · IC025 +1.7 3/3 methods agree	Reporting / coding artifact	serious PRR 6.9	no trial data cached
Swollen tongue	35	5.7 4.1–7.9ROR 5.7 · χ² 131 / p 1e-30	5.3 EB05 4.0 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 5.0	no trial data cached
Erythema multiforme	10	5.5 2.9–10.2ROR 5.5 · χ² 32 / p 7e-9	4.5 EB05 2.6 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious PRR 3.5	no trial data cached
Swelling face	69	5.4 4.3–6.8ROR 5.5 · χ² 244 / p 3e-55	5.2 EB05 4.3 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.5 · 93% clinician	no trial data cached
Hyperkalaemia (high potassium)	37	5.4 3.9–7.4ROR 5.4 · χ² 128 / p 4e-30	5.1 EB05 3.8 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 3.5	no trial data cached
Haematemesis (vomiting blood)	26	5.2 3.6–7.6ROR 5.2 · χ² 84 / p 2e-20	4.8 EB05 3.4 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 3.4 · 92% clinician	no trial data cached
Bradycardia (slow heart rate)	54	5.2 4.0–6.8ROR 5.2 · χ² 178 / p 6e-41	5.0 EB05 4.0 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 3.3 · ♀ 38% (drug 60%) · 96% clinician	no trial data cached
Rash maculo-papular	22	5.1 3.3–7.7ROR 5.1 · χ² 68 / p 1e-16	4.6 EB05 3.2 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 3.4 · 95% clinician	no trial data cached
Liver injury	24	5.1 3.4–7.5ROR 5.1 · χ² 74 / p 4e-18	4.6 EB05 3.3 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 3.3 · 96% clinician	no trial data cached
Paraesthesia oral	14	5.0 2.9–8.4ROR 5.0 · χ² 40 / p 1e-10	4.3 EB05 2.8 · IC025 +1.2 3/3 methods agree	Not in label — unassessed	serious PRR 5.6	no trial data cached
Coagulopathy	16	4.9 3.0–8.0ROR 4.9 · χ² 46 / p 6e-12	4.3 EB05 2.8 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 3.2	no trial data cached
Hypocalcaemia (low calcium)	18	4.9 3.1–7.7ROR 4.9 · χ² 51 / p 4e-13	4.4 EB05 2.9 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 3.2	no trial data cached
Melaena (black stool)	21	4.9 3.2–7.4ROR 4.9 · χ² 60 / p 4e-15	4.4 EB05 3.1 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 3.1 · 90% clinician	no trial data cached
Mouth ulceration	20	4.8 3.1–7.5ROR 4.9 · χ² 57 / p 2e-14	4.4 EB05 3.0 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 4.0	no trial data cached
Hypophagia	24	4.8 3.2–7.2ROR 4.8 · χ² 69 / p 5e-17	4.4 EB05 3.1 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 3.7 · ♀ 19% (drug 60%) · 91% clinician	no trial data cached
Lethargy	51	4.5 3.4–5.9ROR 4.6 · χ² 136 / p 8e-32	4.3 EB05 3.4 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 4.2 · ♀ 87% (drug 60%) · 94% clinician	no trial data cached
Diplopia (double vision)	23	4.5 3.0–6.8ROR 4.5 · χ² 59 / p 6e-15	4.2 EB05 2.9 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 3.9 · 96% clinician	no trial data cached
Circulatory collapse	15	4.5 2.7–7.4ROR 4.5 · χ² 37 / p 6e-10	4.0 EB05 2.6 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious PRR 2.8	no trial data cached
Faeces discoloured	19	4.5 2.9–7.0ROR 4.5 · χ² 48 / p 2e-12	4.1 EB05 2.8 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 4.3	no trial data cached
Paranoia	15	4.4 2.7–7.3ROR 4.4 · χ² 36 / p 9e-10	3.9 EB05 2.5 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious PRR 3.5	no trial data cached
Ataxia	10	4.3 2.3–7.9ROR 4.3 · χ² 22 / p 1e-6	3.7 EB05 2.2 · IC025 +0.8 3/3 methods agree	Not in label — unassessed	serious PRR 2.9	no trial data cached
Hallucination (hallucinations)	61	4.1 3.2–5.3ROR 4.2 · χ² 143 / p 3e-33	4.0 EB05 3.3 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 3.2 · 90% clinician	no trial data cached
Hallucination, visual	17	4.1 2.6–6.6ROR 4.1 · χ² 37 / p 5e-10	3.8 EB05 2.5 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious PRR 3.0	no trial data cached
Delirium	28	4.1 2.9–6.0ROR 4.1 · χ² 63 / p 9e-16	3.9 EB05 2.8 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 2.6 · 93% clinician	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
Acute kidney injury (sudden kidney damage)	211	7.1 6.2–8.1ROR 7.4 · χ² 1,099 / p 3e-241	7.0 EB05 6.2 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.4 · 95% clinician	no trial data cached
Hyponatraemia (low sodium)	137	12.4 10.5–14.7ROR 12.8 · χ² 1,430 / p <1e-300	12.3 EB05 10.7 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 8.0 · 92% clinician	no trial data cached
Confusional state (confusion)	119	3.7 3.1–4.5ROR 3.8 · χ² 238 / p 5e-54	3.7 EB05 3.2 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 3.0	no trial data cached
Somnolence (drowsiness)	113	2.9 2.4–3.4ROR 2.9 · χ² 136 / p 8e-32	2.8 EB05 2.4 · IC025 +1.2 3/3 methods agree	Not in label — unassessed	serious PRR 3.0 · ♀ 81% (drug 60%)	no trial data cached
Peripheral swelling	73	2.4 1.9–3.0ROR 2.4 · χ² 60 / p 5e-15	2.4 EB05 2.0 · IC025 +0.9	Labeled (related wording) related wording	serious PRR 2.5	no trial data cached
Myalgia (muscle pain)	69	2.1 1.6–2.6ROR 2.1 · χ² 37 / p 5e-10	2.1 EB05 1.7 · IC025 +0.6	Not in label — unassessed	serious PRR 2.1	no trial data cached
Swelling face	69	5.4 4.3–6.8ROR 5.5 · χ² 244 / p 3e-55	5.2 EB05 4.3 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.5 · 93% clinician	no trial data cached
Pneumonia aspiration	68	13.9 11.0–17.6ROR 14.1 · χ² 802 / p 1e-176	13.8 EB05 11.2 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 8.8	no trial data cached
Chromaturia	67	15.1 11.9–19.2ROR 15.4 · χ² 869 / p 2e-191	15.0 EB05 12.2 · IC025 +3.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.9 · ♀ 31% (drug 60%) · 91% clinician	no trial data cached
Hallucination (hallucinations)	61	4.1 3.2–5.3ROR 4.2 · χ² 143 / p 3e-33	4.0 EB05 3.3 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 3.2 · 90% clinician	no trial data cached
Lower respiratory tract infection	59	6.6 5.2–8.6ROR 6.7 · χ² 277 / p 2e-62	6.3 EB05 5.1 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Lip swelling	59	9.1 7.0–11.7ROR 9.2 · χ² 415 / p 2e-92	8.7 EB05 6.9 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 8.9 · 97% clinician	no trial data cached
Coma	57	6.1 4.7–7.9ROR 6.2 · χ² 238 / p 6e-54	5.8 EB05 4.7 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 3.8 · ♀ 83% (drug 60%)	no trial data cached
Gastrooesophageal reflux disease (acid reflux)	56	3.6 2.7–4.6ROR 3.6 · χ² 101 / p 5e-24	3.5 EB05 2.8 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 3.5 · ♀ 93% (drug 60%)	no trial data cached
Palpitations (pounding heartbeat)	54	2.4 1.8–3.1ROR 2.4 · χ² 41 / p 9e-11	2.3 EB05 1.8 · IC025 +0.8	Not in label — unassessed	serious PRR 2.2	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.

Orthostatic hypotension — n=50, PRR 14.6
Pneumonia aspiration — n=68, PRR 13.9
Hyponatraemia — n=137, PRR 12.4
Inappropriate antidiuretic hormone secretion — n=22, PRR 11.0
Hypomagnesaemia — n=24, PRR 8.8
Upper gastrointestinal haemorrhage — n=26, PRR 7.9
Lower respiratory tract infection — n=59, PRR 6.6
Metabolic acidosis — n=41, PRR 6.6
Coma — n=57, PRR 6.1
Swollen tongue — n=35, PRR 5.7

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 Hydroxocobalamin?

In FDA FAERS, the most frequently co-reported reaction terms for Hydroxocobalamin are acute kidney injury, hyponatraemia, confusional state, somnolence, peripheral swelling, myalgia. 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 Hydroxocobalamin have an FDA boxed warning?

No. The FDA label retrieved for Hydroxocobalamin has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Hydroxocobalamin 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 d56fcc8d-bd64-46ab-b0c0-2124bd745a6b, effective 20230427; matched on openfda.generic_name.exact:"HYDROXOCOBALAMIN")
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, 175 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.