Timolol side effects: what 12,011 FDA adverse event reports show

Timolol · Betimol · 1,039 reaction terms · 34,760 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Brand names

Betimol

openFDA label

Who reports

12,011 reports · 47% serious · 575 with death outcome · 59% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Betimol ® is indicated in the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma.

FDA label, Indications and Usage

What it is

DESCRIPTION Betimol ® (timolol ophthalmic solution), 0.25% and 0.5%, is a non-selective beta-adrenergic antagonist for ophthalmic use.

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 (related wording) 5Likely indication confounding 5Reporting / coding artifact 4Lab value / disease marker 3Not in label — unassessed 23

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.
Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
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. 999 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
Total lung capacity increased	26	183.5 122.5–274.8ROR 183.9 · χ² 4,100 / p <1e-300	148.1 EB05 106.2 · IC025 +4.7 3/3 methods agree	Not in label — unassessed	serious n=26 · ♀ 100% (drug 59%) · 100% clinician	no trial data cached
Conjunctival scar	13	168.3 95.2–297.4ROR 168.5 · χ² 1,820 / p <1e-300	125.6 EB05 78.1 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=12	no trial data cached
Treatment failure	3,048	67.3 65.2–69.5ROR 89.9 · χ² 192,330 / p <1e-300	64.8 EB05 62.9 · IC025 +5.9 3/3 methods agree	Reporting / coding artifact	serious PRR 1.6 · 76% consumer	no trial data cached
Hypotony of eye	15	64.9 38.8–108.6ROR 65.0 · χ² 849 / p 7e-187	58.2 EB05 37.4 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious n=15	no trial data cached
Intraocular pressure decreased	19	64.6 40.9–102.2ROR 64.7 · χ² 1,087 / p 1e-238	58.8 EB05 39.8 · IC025 +3.8 3/3 methods agree	Likely indication confounding term in indications	serious n=9	no trial data cached
Floppy iris syndrome	13	63.2 36.4–109.9ROR 63.3 · χ² 709 / p 2e-156	56.3 EB05 35.0 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious n=12	no trial data cached
Peak expiratory flow rate decreased	14	57.1 33.5–97.2ROR 57.2 · χ² 694 / p 3e-153	51.7 EB05 32.7 · IC025 +3.4 3/3 methods agree	Lab value / disease marker	serious n=14	no trial data cached
Product dropper issue	24	54.2 36.1–81.3ROR 54.3 · χ² 1,163 / p 3e-255	50.6 EB05 35.8 · IC025 +4.0 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Lung diffusion test decreased	11	49.8 27.4–90.7ROR 49.9 · χ² 465 / p 2e-103	45.0 EB05 26.8 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious n=11	no trial data cached
Iris adhesions	14	49.7 29.2–84.5ROR 49.8 · χ² 603 / p 2e-133	45.5 EB05 28.8 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious n=13	no trial data cached
Choroidal effusion	19	42.5 27.0–66.9ROR 42.5 · χ² 711 / p 6e-157	40.0 EB05 27.0 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=19	no trial data cached
Intraocular pressure test abnormal	16	40.4 24.6–66.3ROR 40.4 · χ² 563 / p 1e-124	37.9 EB05 24.7 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious n=10	no trial data cached
Intraocular pressure increased (raised eye pressure)	282	39.2 34.9–44.0ROR 40.1 · χ² 10,229 / p <1e-300	38.2 EB05 34.6 · IC025 +5.0 3/3 methods agree	Likely indication confounding term in indications	serious PRR 45.6	no trial data cached
Forced vital capacity decreased	14	38.5 22.7–65.4ROR 38.5 · χ² 464 / p 3e-103	36.0 EB05 22.8 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious n=14	no trial data cached
Haemangioma congenital	10	37.3 19.9–69.7ROR 37.3 · χ² 311 / p 7e-70	34.3 EB05 19.9 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious n=10	no trial data cached
Choroidal detachment	11	35.3 19.5–64.2ROR 35.4 · χ² 327 / p 2e-73	32.8 EB05 19.5 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious n=11	no trial data cached
Corneal oedema	37	29.2 21.1–40.5ROR 29.3 · χ² 965 / p 4e-212	28.4 EB05 21.5 · IC025 +3.8 3/3 methods agree	Labeled (related wording) related wording	serious n=27	no trial data cached
Reaction to preservatives	12	26.0 14.7–46.0ROR 26.0 · χ² 260 / p 7e-59	24.7 EB05 14.8 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious n=6	no trial data cached
Growth of eyelashes	11	24.4 13.5–44.3ROR 24.5 · χ² 221 / p 2e-50	23.1 EB05 13.4 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Punctate keratitis	11	22.0 12.2–39.9ROR 22.0 · χ² 198 / p 3e-45	20.8 EB05 11.8 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious n=11	no trial data cached
Cystoid macular oedema	23	21.8 14.5–32.9ROR 21.9 · χ² 431 / p 5e-96	21.2 EB05 14.8 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious n=23	no trial data cached
Glaucoma	235	21.5 19.0–24.5ROR 22.0 · χ² 4,530 / p <1e-300	21.3 EB05 19.1 · IC025 +4.1 3/3 methods agree	Likely indication confounding term in indications	serious PRR 25.7	no trial data cached
Optic nerve injury	13	19.9 11.5–34.4ROR 19.9 · χ² 213 / p 2e-48	18.9 EB05 11.3 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious n=12	no trial data cached
Vitamin b12 decreased	32	19.6 13.9–27.8ROR 19.7 · χ² 541 / p 5e-120	19.2 EB05 14.2 · IC025 +3.3 3/3 methods agree	Lab value / disease marker	serious n=32 · ♀ 100% (drug 59%)	no trial data cached
Ocular hypertension	21	19.3 12.6–29.7ROR 19.4 · χ² 343 / p 7e-77	18.7 EB05 12.8 · IC025 +3.0 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious n=18	no trial data cached
Conjunctival hyperaemia	39	19.3 14.1–26.4ROR 19.3 · χ² 651 / p 7e-144	18.9 EB05 14.4 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious n=16	no trial data cached
Angle closure glaucoma	27	18.6 12.7–27.1ROR 18.6 · χ² 427 / p 3e-95	18.1 EB05 13.0 · IC025 +3.2 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious n=26	no trial data cached
Eyelid margin crusting	29	18.1 12.6–26.1ROR 18.2 · χ² 448 / p 1e-99	17.7 EB05 12.8 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious n=6	no trial data cached
Forced expiratory volume decreased	28	17.4 12.0–25.2ROR 17.4 · χ² 412 / p 6e-92	17.0 EB05 12.2 · IC025 +3.1 3/3 methods agree	Lab value / disease marker	serious n=28 · ♀ 100% (drug 59%) · 100% clinician	no trial data cached
Iridocyclitis	29	16.3 11.3–23.5ROR 16.4 · χ² 398 / p 6e-89	15.9 EB05 11.4 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious n=28	no trial data cached
Corneal disorder	20	16.2 10.4–25.2ROR 16.2 · χ² 268 / p 1e-60	15.6 EB05 10.3 · IC025 +2.8 3/3 methods agree	Labeled (related wording) related wording	serious n=16	no trial data cached
Eye allergy	14	16.0 9.5–27.1ROR 16.0 · χ² 181 / p 2e-41	15.0 EB05 8.8 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Foreign body sensation in eyes	46	13.0 9.7–17.3ROR 13.0 · χ² 492 / p 3e-109	12.6 EB05 9.7 · IC025 +3.0 3/3 methods agree	Labeled (related wording) related wording	serious n=7	no trial data cached
Corneal opacity	10	12.9 6.9–24.1ROR 12.9 · χ² 98 / p 2e-23	10.9 EB05 5.5 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious n=8	no trial data cached
Retinal disorder	19	12.8 8.2–20.1ROR 12.8 · χ² 194 / p 2e-44	11.9 EB05 7.5 · IC025 +2.5 3/3 methods agree	Labeled (related wording) related wording	serious n=17	no trial data cached
Eyelid pain	14	12.7 7.5–21.4ROR 12.7 · χ² 138 / p 3e-32	11.3 EB05 6.5 · IC025 +2.3 3/3 methods agree	Labeled (related wording) related wording	–	no trial data cached
Ulcerative keratitis	19	12.2 7.8–19.2ROR 12.2 · χ² 184 / p 4e-42	11.2 EB05 7.1 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious n=19	no trial data cached
Product container issue	55	11.5 8.8–14.9ROR 11.5 · χ² 511 / p 2e-113	11.1 EB05 8.7 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious n=11	no trial data cached
Vitreous haemorrhage	18	11.4 7.2–18.1ROR 11.4 · χ² 159 / p 8e-37	10.3 EB05 6.4 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious n=18	no trial data cached
Eye irritation	343	10.8 9.7–12.0ROR 11.1 · χ² 3,030 / p <1e-300	10.7 EB05 9.8 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 15.1	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
Treatment failure	3,048	67.3 65.2–69.5ROR 89.9 · χ² 192,330 / p <1e-300	64.8 EB05 62.9 · IC025 +5.9 3/3 methods agree	Reporting / coding artifact	serious PRR 1.6 · 76% consumer	no trial data cached
Drug ineffective (drug did not work)	806	1.1 1.0–1.1ROR 1.1 · χ² 4 / p 0.027	1.1 EB05 1.0 · IC025 -0.0 PRR-only: not supported by EBGM or IC	Reporting / coding artifact	serious PRR 1.7	no trial data cached
Fatigue (tiredness)	487	1.1 1.0–1.2ROR 1.1 · χ² 4 / p 0.022	1.1 EB05 1.0 · IC025 -0.0 PRR-only: not supported by EBGM or IC	Labeled (related wording) related wording	serious PRR 1.6	no trial data cached
Hypersensitivity (allergic reaction)	461	4.4 4.0–4.8ROR 4.5 · χ² 1,194 / p 7e-262	4.3 EB05 4.0 · IC025 +2.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 1.8	no trial data cached
Dizziness	411	1.4 1.3–1.6ROR 1.5 · χ² 56 / p 3e-14	1.4 EB05 1.3 · IC025 +0.4	Labeled adverse reaction exact term	serious PRR 2.1	no trial data cached
Off label use (used outside approved label)	409	0.8 0.7–0.9ROR 0.8 · χ² 16 / p 3e-5	0.8 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC	Reporting / coding artifact	serious PRR 1.1	no trial data cached
Diarrhoea (diarrhea)	400	1.1 1.0–1.2ROR 1.1 · χ² 3 / p 0.050	1.1 EB05 1.0 · IC025 -0.0 PRR-only: not supported by EBGM or IC	Labeled adverse reaction exact term	serious PRR 1.6	no trial data cached
Dyspnoea (shortness of breath)	366	1.1 1.0–1.2ROR 1.1 · χ² 5 / p 0.010	1.1 EB05 1.0 · IC025 +0.0	Labeled adverse reaction exact term	serious PRR 1.5	no trial data cached
Nausea	360	0.8 0.7–0.9ROR 0.8 · χ² 19 / p 6e-6	0.8 EB05 0.7 · IC025 -0.5 PRR-only: not supported by EBGM or IC	Labeled adverse reaction exact term	serious PRR 1.2	no trial data cached
Eye irritation	343	10.8 9.7–12.0ROR 11.1 · χ² 3,030 / p <1e-300	10.7 EB05 9.8 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 15.1	no trial data cached
Fall	325	1.7 1.5–1.9ROR 1.7 · χ² 96 / p 6e-23	1.7 EB05 1.6 · IC025 +0.6	Not in label — unassessed	serious PRR 2.2	no trial data cached
Headache	312	0.9 0.8–1.0ROR 0.9 · χ² 6 / p 0.007	0.9 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC	Labeled adverse reaction exact term	serious PRR 1.2	no trial data cached
Eye pain	294	9.3 8.3–10.5ROR 9.5 · χ² 2,174 / p <1e-300	9.2 EB05 8.4 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.1	no trial data cached
Vision blurred (blurred vision)	285	3.6 3.3–4.1ROR 3.7 · χ² 547 / p 2e-121	3.6 EB05 3.3 · IC025 +1.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.3	no trial data cached
Intraocular pressure increased (raised eye pressure)	282	39.2 34.9–44.0ROR 40.1 · χ² 10,229 / p <1e-300	38.2 EB05 34.6 · IC025 +5.0 3/3 methods agree	Likely indication confounding term in indications	serious PRR 45.6	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.

Total lung capacity increased — n=26, PRR 183.5
Cystoid macular oedema — n=23, PRR 21.8
Conjunctival hyperaemia — n=39, PRR 19.3
Eyelid margin crusting — n=29, PRR 18.1
Iridocyclitis — n=29, PRR 16.3
Eye irritation — n=343, PRR 10.8

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 Timolol?

In FDA FAERS, the most frequently co-reported reaction terms for Timolol are fatigue, hypersensitivity, dizziness, diarrhoea, 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 Timolol have an FDA boxed warning?

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

Do FAERS signals prove that Timolol 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 3ae775f4-340c-4bf4-aa49-8a31daba0f8b, effective 20250627; matched on openfda.generic_name.exact:"TIMOLOL")
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, 1,039 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.