OpenPV Signal Explorer
FAERS disproportionality dashboard
← All drug classes
Drug class · FAERS comparison

Antidote side effects compared: 3 drugs, 13,672 FDA adverse event reports

Class as assigned in the FDA label (Established Pharmacologic Class) · data 2026-09-14
How to read this page. Report counts are not incidence rates: a drug with more reports is usually older, more widely used or more publicised, not more dangerous. Signals are screened against each product's FDA label on its own page; a term flagged across most of a class usually reflects the shared mechanism or the shared patient population.

Members

DrugFAERS reportsSeriousDeath outcomeBoxed warningTop labeled signalsUnlabeled (unassessed)
Acetylcysteine9,36589%1,754––Bronchiectasis; Toxic epidermal necrolysis
Hydroxocobalamin4,11891%311–Acute kidney injury; Chromaturia; Lip swellingHyponatraemia; Swelling face
Fomepizole18998%69––Toxicity to various agents; Metabolic acidosis

Class-wide signals (flagged in at least 2 of 3 members)

ReactionMembers flaggedMedian PRRReports (sum)In label
Metabolic acidosis2/343.6640/2 members' labels
Coagulopathy2/335.9260/2 members' labels

Member-specific signals (flagged in exactly one drug)

No strong single-member signals (n ≥ 50) in this class.

Common questions

Which antidote has the most FDA adverse event reports?

Acetylcysteine has the most FAERS co-reports in this class (9,365), followed by Hydroxocobalamin (4,118). Report volume tracks how widely and how long a drug has been used, and how much attention it has had, far more than its risk.

Which side effects are shared across antidote drugs?

Reaction terms flagged in at least half of the 3 members include metabolic acidosis, coagulopathy. A term shared across a class usually reflects the shared mechanism (or the shared patient population) rather than one product.

Does a FAERS signal mean the drug causes the reaction?

No. These are disproportionality signals from voluntary reports with no denominator. Each is screened against the FDA label (known vs unlabeled) on the drug pages; causality needs temporality, dose-response, plausibility and trial or cohort evidence.

Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, seriousness and death counts from openFDA count queries. Generated 2026-10-08. Not medical advice.