Pyridostigmine Bromide side effects: what 7,410 FDA adverse event reports show
Drug class
Cholinesterase inhibitor
Label matched
Pyridostigmine Bromide (Pyridostigmine Bromide)
Who reports
7,410 reports · 71% serious · 516 with death outcome · 61% female
Used for
Pyridostigmine bromide is indicated for pretreatment against the lethal effects of soman nerve agent poisoning in adults. Pyridostigmine bromide is intended for use in conjunction with protective garments, including a mask. At the first sign of nerve agent poisoning, pyridostigmine bromide should be stopped, and atropine and pralidoxime therapy started immediately.
What it is
Pyridostigmine bromide is an orally active, reversible cholinesterase inhibitor. Pyridostigmine bromide is a white or almost white, crystalline, deliquescent powder, very soluble in water and alcohol, and practically insoluble in ether. CAS registration number is 101-26-8.
Boxed warning
RISKS WITH IMPROPER USE OF PYRIDOSTIGMINE BROMIDE After Exposure to Soman, Use Atropine and Pralidoxime Pyridostigmine bromide is for use as a pretreatment for exposure to soman nerve agent. Pyridostigmine bromide alone will not protect against exposure to soman.
Causality screen of the 40 strongest signals
What the badges mean
- 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. 581 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Eyelid ptosis | 185 | 52.4 45.4–60.5ROR 53.7 · χ² 9,111 / p <1e-300 | 51.2 EB05 45.3 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=137 | no trial data cached |
| Diplopia (double vision) | 290 | 31.9 28.5–35.8ROR 33.2 · χ² 8,572 / p <1e-300 | 31.5 EB05 28.6 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 26.3 | no trial data cached |
| Paraesthesia oral | 98 | 19.4 15.9–23.7ROR 19.7 · χ² 1,683 / p <1e-300 | 19.2 EB05 16.2 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 13.2 · 97% consumer | no trial data cached |
| Insurance issue | 70 | 13.4 10.6–16.9ROR 13.5 · χ² 787 / p 2e-173 | 13.2 EB05 10.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 18.3 · ♀ 86% (drug 61%) · 84% consumer | no trial data cached |
| Salivary hypersecretion | 38 | 10.8 7.9–14.8ROR 10.8 · χ² 327 / p 2e-73 | 10.3 EB05 7.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 10.0 | no trial data cached |
| Muscular weakness | 394 | 9.8 8.9–10.8ROR 10.3 · χ² 3,126 / p <1e-300 | 9.8 EB05 9.0 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 | no trial data cached |
| Poor venous access | 34 | 9.3 6.7–13.1ROR 9.4 · χ² 244 / p 2e-55 | 8.7 EB05 6.4 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=28 · ♀ 89% (drug 61%) | no trial data cached |
| Therapeutic response shortened | 100 | 8.9 7.3–10.8ROR 9.0 · χ² 694 / p 4e-153 | 8.7 EB05 7.3 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 12.1 · 78% consumer | no trial data cached |
| Hypoaesthesia oral | 44 | 8.3 6.2–11.1ROR 8.3 · χ² 274 / p 7e-62 | 7.8 EB05 6.0 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 · 81% consumer | no trial data cached |
| Dysphagia (difficulty swallowing) | 275 | 8.2 7.3–9.3ROR 8.5 · χ² 1,745 / p <1e-300 | 8.1 EB05 7.4 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 | no trial data cached |
| Dysarthria (slurred speech) | 105 | 7.9 6.5–9.6ROR 8.0 · χ² 627 / p 1e-138 | 7.7 EB05 6.5 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 | no trial data cached |
| Choking | 53 | 7.7 5.9–10.1ROR 7.8 · χ² 304 / p 2e-68 | 7.3 EB05 5.8 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 6.8 | no trial data cached |
| Therapy change | 22 | 6.5 4.3–9.8ROR 6.5 · χ² 96 / p 5e-23 | 5.8 EB05 4.0 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious n=20 | no trial data cached |
| Drug effect less than expected | 30 | 6.0 4.2–8.6ROR 6.1 · χ² 121 / p 2e-28 | 5.5 EB05 4.1 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | serious n=20 · 83% consumer | no trial data cached |
| Skin laceration | 22 | 5.8 3.8–8.8ROR 5.8 · χ² 82 / p 7e-20 | 5.2 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 · 71% consumer | no trial data cached |
| Peripheral coldness | 27 | 5.6 3.8–8.1ROR 5.6 · χ² 96 / p 5e-23 | 5.1 EB05 3.7 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 · 85% consumer | no trial data cached |
| Blood pressure fluctuation | 47 | 5.5 4.2–7.4ROR 5.6 · χ² 170 / p 4e-39 | 5.3 EB05 4.1 · IC025 +1.9 3/3 methods agree | Lab value / disease marker | serious PRR 4.6 | no trial data cached |
| Blood iron decreased | 23 | 5.5 3.7–8.3ROR 5.5 · χ² 81 / p 1e-19 | 5.0 EB05 3.5 · IC025 +1.6 3/3 methods agree | Lab value / disease marker | serious PRR 4.5 · 78% consumer | no trial data cached |
| Speech disorder | 102 | 5.5 4.5–6.7ROR 5.6 · χ² 373 / p 2e-83 | 5.4 EB05 4.6 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Pneumonia aspiration | 48 | 5.5 4.1–7.2ROR 5.5 · χ² 170 / p 3e-39 | 5.2 EB05 4.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 · ♀ 33% (drug 61%) | no trial data cached |
| Pulmonary mass | 28 | 5.3 3.7–7.7ROR 5.4 · χ² 94 / p 1e-22 | 4.9 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Decreased activity | 20 | 5.3 3.4–8.2ROR 5.3 · χ² 65 / p 3e-16 | 4.7 EB05 3.2 · IC025 +1.5 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.5 | no trial data cached |
| Dermatitis contact | 21 | 5.2 3.4–8.0ROR 5.3 · χ² 68 / p 9e-17 | 4.7 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious n=16 · 81% consumer | no trial data cached |
| Urosepsis | 17 | 5.2 3.2–8.4ROR 5.2 · χ² 54 / p 1e-13 | 4.6 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Blood pressure systolic increased | 35 | 5.1 3.6–7.0ROR 5.1 · χ² 110 / p 5e-26 | 4.8 EB05 3.6 · IC025 +1.7 3/3 methods agree | Lab value / disease marker | serious PRR 4.1 · ♀ 86% (drug 61%) | no trial data cached |
| Dyspnoea exertional | 67 | 5.1 4.0–6.4ROR 5.1 · χ² 214 / p 9e-49 | 4.9 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Brain fog | 26 | 5.0 3.4–7.4ROR 5.1 · χ² 80 / p 2e-19 | 4.7 EB05 3.3 · IC025 +1.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.2 · 77% consumer | no trial data cached |
| Sleep apnoea syndrome | 34 | 5.0 3.6–7.0ROR 5.1 · χ² 106 / p 4e-25 | 4.7 EB05 3.5 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Autoimmune disorder | 17 | 5.0 3.1–8.1ROR 5.0 · χ² 51 / p 5e-13 | 4.5 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Pharyngeal swelling | 17 | 5.0 3.1–8.1ROR 5.0 · χ² 51 / p 5e-13 | 4.5 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Atelectasis | 17 | 5.0 3.1–8.0ROR 5.0 · χ² 50 / p 8e-13 | 4.4 EB05 2.9 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 | no trial data cached |
| Intentional product use issue | 153 | 4.9 4.2–5.8ROR 5.0 · χ² 476 / p 6e-106 | 4.9 EB05 4.2 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious PRR 4.1 | no trial data cached |
| Aspiration | 18 | 4.7 3.0–7.5ROR 4.7 · χ² 49 / p 1e-12 | 4.2 EB05 2.8 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Bursitis | 20 | 4.7 3.0–7.3ROR 4.7 · χ² 54 / p 8e-14 | 4.3 EB05 2.9 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 · ♀ 85% (drug 61%) | no trial data cached |
| Infusion site pain | 21 | 4.7 3.0–7.1ROR 4.7 · χ² 57 / p 3e-14 | 4.3 EB05 2.9 · IC025 +1.4 3/3 methods agree | Labeled (related wording) related wording | serious n=10 | no trial data cached |
| Seasonal allergy | 23 | 4.6 3.1–6.9ROR 4.6 · χ² 62 / p 2e-15 | 4.2 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious n=18 · 87% consumer | no trial data cached |
| Sensory disturbance | 26 | 4.6 3.1–6.7ROR 4.6 · χ² 69 / p 5e-17 | 4.2 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Viral infection | 53 | 4.5 3.5–5.9ROR 4.5 · χ² 142 / p 6e-33 | 4.3 EB05 3.5 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Micturition urgency | 18 | 4.5 2.8–7.1ROR 4.5 · χ² 45 / p 8e-12 | 4.1 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 | no trial data cached |
| Gastroenteritis | 23 | 4.5 3.0–6.7ROR 4.5 · χ² 58 / p 1e-14 | 4.1 EB05 2.9 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
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 |
|---|---|---|---|---|---|---|
| Fatigue (tiredness) | 745 | 2.7 2.5–2.9ROR 2.9 · χ² 836 / p 5e-184 | 2.7 EB05 2.6 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 2.9 | no trial data cached |
| Drug ineffective (drug did not work) | 612 | 1.3 1.2–1.4ROR 1.3 · χ² 49 / p 1e-12 | 1.3 EB05 1.2 · IC025 +0.3 | Reporting / coding artifact | serious PRR 2.0 | no trial data cached |
| Asthenia (weakness) | 582 | 4.4 4.1–4.7ROR 4.7 · χ² 1,542 / p <1e-300 | 4.4 EB05 4.1 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Off label use (used outside approved label) | 572 | 1.9 1.7–2.0ROR 1.9 · χ² 239 / p 4e-54 | 1.9 EB05 1.7 · IC025 +0.8 | Reporting / coding artifact | serious PRR 2.2 | no trial data cached |
| Diarrhoea (diarrhea) | 541 | 2.4 2.2–2.6ROR 2.5 · χ² 445 / p 4e-99 | 2.4 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.3 | no trial data cached |
| Headache | 513 | 2.3 2.1–2.5ROR 2.4 · χ² 395 / p 3e-88 | 2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.6 | no trial data cached |
| Dyspnoea (shortness of breath) | 512 | 2.6 2.4–2.8ROR 2.7 · χ² 499 / p 6e-111 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
| Nausea | 461 | 1.7 1.5–1.8ROR 1.7 · χ² 123 / p 7e-29 | 1.7 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.8 | no trial data cached |
| Muscular weakness | 394 | 9.8 8.9–10.8ROR 10.3 · χ² 3,126 / p <1e-300 | 9.8 EB05 9.0 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 | no trial data cached |
| Fall | 376 | 3.2 2.9–3.5ROR 3.3 · χ² 576 / p 2e-127 | 3.2 EB05 2.9 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 | no trial data cached |
| Dizziness | 335 | 1.9 1.7–2.1ROR 1.9 · χ² 146 / p 5e-34 | 1.9 EB05 1.7 · IC025 +0.7 | Labeled adverse reaction exact term | serious PRR 1.9 | no trial data cached |
| Malaise (feeling unwell) | 307 | 2.0 1.8–2.2ROR 2.0 · χ² 150 / p 8e-35 | 2.0 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 2.0 | no trial data cached |
| Pain | 300 | 1.4 1.2–1.5ROR 1.4 · χ² 32 / p 8e-9 | 1.4 EB05 1.3 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.4 | no trial data cached |
| Diplopia (double vision) | 290 | 31.9 28.5–35.8ROR 33.2 · χ² 8,572 / p <1e-300 | 31.5 EB05 28.6 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 26.3 | no trial data cached |
| Dysphagia (difficulty swallowing) | 275 | 8.2 7.3–9.3ROR 8.5 · χ² 1,745 / p <1e-300 | 8.1 EB05 7.4 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 | 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.
- Eyelid ptosis — n=185, PRR 52.4
- Diplopia — n=290, PRR 31.9
- Paraesthesia oral — n=98, PRR 19.4
- Insurance issue — n=70, PRR 13.4
- Salivary hypersecretion — n=38, PRR 10.8
- Muscular weakness — n=394, PRR 9.8
- Poor venous access — n=34, PRR 9.3
- Hypoaesthesia oral — n=44, PRR 8.3
- Dysphagia — n=275, PRR 8.2
- Dysarthria — n=105, PRR 7.9
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 Pyridostigmine?
In FDA FAERS, the most frequently co-reported reaction terms for Pyridostigmine are fatigue, asthenia, diarrhoea, headache, dyspnoea, nausea. 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 Pyridostigmine have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: RISKS WITH IMPROPER USE OF PYRIDOSTIGMINE BROMIDE After Exposure to Soman, Use Atropine and Pralidoxime Pyridostigmine bromide is for use as a pretreatment for exposure to soman nerve agent. Pyridostigmine bromide alone will not protect against exposure to soman.
Do FAERS signals prove that Pyridostigmine 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 0b296555-c32f-42db-b5f3-ea981a3dd2f8, effective 20251223; matched on
openfda.generic_name.exact:"PYRIDOSTIGMINE BROMIDE") - 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, fieldpatient.drug.openfda.generic_name.exact, 621 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.