Ondansetron (Zofran) is Safe in Glaucoma Patients
Ondansetron can be safely used in patients with both open-angle and narrow-angle glaucoma, as it does not affect intraocular pressure and is not associated with angle-closure glaucoma. The FDA label contains no contraindications or warnings regarding glaucoma 1.
Evidence Supporting Safety
No Effect on Intraocular Pressure
A prospective, double-blind, placebo-controlled trial specifically examined ondansetron's effect on IOP during ophthalmic surgery. The study found no significant differences in IOP between ondansetron-treated patients and placebo controls during cataract surgery 2. This directly demonstrates that ondansetron does not elevate intraocular pressure, which is the primary concern in glaucoma management.
Not Implicated in Drug-Induced Glaucoma
Comprehensive reviews of drug-induced glaucoma consistently identify specific medication classes that trigger acute angle-closure glaucoma: sulfonamide derivatives (topiramate, acetazolamide), anticholinergics (atropine, tricyclic antidepressants), adrenergic agents (phenylephrine, ephedrine), cholinergics (pilocarpine), serotonergic antidepressants, and benzodiazepines 3, 4, 5, 6. Ondansetron, as a 5-HT3 receptor antagonist, does not appear in any of these lists and operates through a completely different mechanism than medications known to precipitate angle closure.
FDA Label Confirms No Glaucoma Concerns
The official FDA prescribing information for ondansetron contains no warnings, precautions, or contraindications related to glaucoma 1. The label does mention rare cases of transient blindness (amaurosis), but this is an entirely separate phenomenon unrelated to glaucoma or IOP elevation 1, 7.
Important Distinction: Transient Blindness vs. Glaucoma
While ondansetron has been associated with rare cases of transient blindness (primarily with IV administration), this is not related to glaucoma or IOP changes. A pharmacovigilance study identified 44 cases of blindness-related adverse events with ondansetron, with 72% of patients recovering or having recovered 7. This phenomenon:
- Occurs mainly on the first day of treatment
- Is typically transient (lasting 2-3 minutes)
- Resolves completely without permanent damage
- Has no relationship to glaucoma pathophysiology
Clinical Bottom Line
You can prescribe ondansetron without hesitation in patients with either open-angle or narrow-angle glaucoma. There is no need for:
- Dose adjustments based on glaucoma status
- Additional IOP monitoring
- Avoiding specific routes of administration (oral vs. IV)
- Distinguishing between glaucoma subtypes when prescribing ondansetron
The only caveat is awareness of the rare transient blindness phenomenon, which is unrelated to glaucoma and typically self-resolving.