What the label lists and what reports show

Cromolyn side effects

Cromolyn's FDA label: “The most frequently reported adverse reaction attributed to the use of cromolyn sodium ophthalmic solution, on the basis of reoccurrence following readministration, is transient ocular stinging or burning upon instillation.” FAERS holds 3,585 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (226 reports).

Generic listed

Check it at the source: the cromolyn FDA label on DailyMed (effective February 20, 2025, Sandoz Inc); the FDA FAERS public dashboard.

What does the label list?

From the label: adverse reactions
The most frequently reported adverse reaction attributed to the use of cromolyn sodium ophthalmic solution, on the basis of reoccurrence following readministration, is transient ocular stinging or burning upon instillation.

From the label: adverse reactions, continued
The most frequently reported adverse reaction attributed to the use of cromolyn sodium ophthalmic solution, on the basis of reoccurrence following readministration, is transient ocular stinging or burning upon instillation. The following adverse reactions have been reported as infrequent events. It is unclear whether they are attributable to the drug: Conjunctival injection; watery eyes; itchy eyes; dryness around the eye; puffy eyes; eye irritation; and styes. Immediate hypersensitivity reactions have been reported rarely and include dyspnea, edema and rash.

Source: FDA drug label, Sandoz Inc, effective February 20, 2025 (SPL set b32851c3-cd97-4be4-a09c-1deab1d6966b), via openFDA; the full label on DailyMed

What do FAERS reports show?

3,585 reports list cromolyn among the medicines taken, each a report of something that happened, not proof the medicine caused it; 48 are coded as a death and 433 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Reports rose sharply in 2020 (1,119, against a median of 165 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 19 reactions below, 3 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.

Reports received each year

The 25 most reported reactions

Treatment Failure (a use or a product term, not a reaction)1,005
Drug Ineffective (a use or a product term, not a reaction)324
Fatigue226
Nausea197
Headache189
Off Label Use (a use or a product term, not a reaction)168
Diarrhoea163
Dyspnoea (named in the label)158
Urticaria146
Hypersensitivity (named in the label)135
Dizziness134
Pruritus132
Pain127
Anaphylactic Reaction123
Condition Aggravated (a use or a product term, not a reaction)117
Malaise117
Product Dose Omission Issue (a use or a product term, not a reaction)105
Asthma (a use or a product term, not a reaction)102
Rash (named in the label)97
Vomiting93
Feeling Abnormal87
Arthralgia86
Cough86
Insomnia81
Migraine74

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms

What next?

Cromolyn: the full record: label, generics, price, shortages, recalls
Report a side effect to the FDA: MedWatch
Side effects hub: the most reported medicines and reactions