Do alfuzosin, amitriptyline, diphenhydramine (Benadryl), apixaban (Eliquis), losartan, levothyroxine, meclizine, tamsulosin, and torsemide affect glaucoma?

Medication Effects on Glaucoma

Among your medications, amitriptyline, diphenhydramine (Benadryl), and meclizine pose the highest risk for acute angle-closure glaucoma and should be avoided or used with extreme caution, particularly if you have narrow angles or are at risk for angle closure.

High-Risk Medications

Anticholinergic Agents (Amitriptyline, Benadryl, Meclizine)

These three medications share potent anticholinergic properties that can precipitate acute angle-closure glaucoma:

• Amitriptyline (tricyclic antidepressant): The FDA label explicitly warns about "exacerbation of narrow-angle glaucoma" as a peripheral anticholinergic effect, particularly in elderly patients 1. This medication can cause pupillary dilation and lens-iris structural changes that block aqueous outflow 2, 3.

• Diphenhydramine (Benadryl): As an antihistamine with strong anticholinergic activity, it carries similar angle-closure risk through parasympaticolytic effects 4, 3.

• Meclizine: This antihistamine/antiemetic also has anticholinergic properties that can trigger angle closure through the same mechanism 2.

Critical caveat: These medications are particularly dangerous if you have:

• Narrow iridocorneal angles (more common in hypermetropia, older age, Asian ancestry)
• Undiagnosed anatomically narrow angles
• History of angle-closure glaucoma

3 recommends ophthalmological evaluation with gonioscopy prior to starting these medications in high-risk patients, with consideration of prophylactic laser peripheral iridotomy.

Alpha-Blockers (Alfuzosin, Tamsulosin)

These medications do NOT increase glaucoma risk but require special surgical consideration:

• Neither alfuzosin nor tamsulosin affects intraocular pressure or causes glaucoma 5
• However, they are associated with Intraoperative Floppy Iris Syndrome (IFIS) during cataract surgery
• Inform your ophthalmologist about these medications before any eye surgery
• The study found alfuzosin caused more pupil constriction than tamsulosin, but neither affected choroidal thickness significantly 5

Low-Risk Medications

Losartan

• No glaucoma risk identified in FDA labeling 6
• No ocular adverse effects related to glaucoma documented
• Safe to continue

Apixaban (Eliquis)

• No glaucoma risk 7
• Primary concern is bleeding risk during glaucoma surgery or procedures
• Inform ophthalmologist before any eye procedures

Levothyroxine

• No direct glaucoma effects
• Safe to continue

Torsemide

• No significant glaucoma risk
• Loop diuretics do not have the sulfonamide structure that triggers angle closure (unlike acetazolamide)

Clinical Action Plan

1. Immediate assessment needed: If you have not had gonioscopy (angle assessment), request this before continuing amitriptyline, Benadryl, or meclizine

2. If you have narrow angles:

   • Discuss laser peripheral iridotomy with your ophthalmologist
   • Consider alternative medications without anticholinergic effects

3. If you have open angles: Risk from anticholinergics is substantially lower but not zero

4. Before any eye surgery: Disclose alfuzosin and tamsulosin use to prevent IFIS complications

5. Warning signs of acute angle closure (seek emergency care):

   • Severe eye pain
   • Sudden vision loss
   • Halos around lights
   • Nausea/vomiting with eye pain
   • Red eye with fixed, mid-dilated pupil

The evidence strongly supports that anticholinergic medications (amitriptyline, Benadryl, meclizine) represent your primary glaucoma risk, while your other medications are safe from a glaucoma perspective 1, 2, 8, 4, 3.