Glaucoma drops at a glance
Every glaucoma class by mechanism, side effects and the one contraindication Part II loves to hide in the history.
Part II loves to give you a glaucoma patient with one complicating detail, such as asthma, a heart block or a sulfa allergy, and ask what to prescribe. Know each class by mechanism, typical effect and the contraindication that rules it out.
The classes side by side
| Class | Examples | Main mechanism | Watch for |
|---|---|---|---|
| Prostaglandin analogs | Latanoprost, travoprost, bimatoprost, tafluprost | Increase uveoscleral outflow | Redness, lash growth, darker iris and lid skin, periorbital fat atrophy; caution with active uveitis or herpetic keratitis |
| Beta-blockers | Timolol, levobunolol, carteolol, betaxolol | Reduce aqueous production | Bronchospasm with nonselective agents, bradycardia, heart block, fatigue; betaxolol is beta-1 selective |
| Alpha-2 agonists | Brimonidine, apraclonidine | Reduce production; brimonidine also adds uveoscleral outflow | Allergic follicular conjunctivitis, dry mouth, fatigue; avoid brimonidine in infants and young children and with MAO inhibitors |
| Carbonic anhydrase inhibitors | Dorzolamide, brinzolamide; oral acetazolamide and methazolamide | Reduce production | Stinging or blur as drops; tingling, fatigue, kidney stones and metabolic acidosis when oral; caution with sulfonamide allergy |
| Rho kinase inhibitor | Netarsudil | Increases trabecular outflow and lowers episcleral venous pressure | Conjunctival redness, corneal verticillata, small subconjunctival hemorrhages |
| Miotics | Pilocarpine | Ciliary muscle contraction opens the trabecular meshwork | Brow ache, myopic shift, dim vision, retinal detachment risk |
Typical pressure lowering
Numbers vary with the study and the starting pressure, but prostaglandin analogs lower IOP the most of the single drugs, by roughly a quarter to a third. Beta-blockers and alpha-2 agonists sit in the middle, and topical carbonic anhydrase inhibitors lower it somewhat less. Netarsudil performed similarly to timolol in trials of patients with starting pressures below 25 mmHg. Strong effect, once-nightly dosing and few systemic effects are why prostaglandin analogs are the usual first choice.
Matching the drug to the patient
- Asthma or COPD: avoid nonselective beta-blockers.
- Bradycardia, heart block or uncompensated heart failure: avoid beta-blockers.
- Sulfonamide allergy: use carbonic anhydrase inhibitors with caution.
- Infants and young children: avoid brimonidine.
- Uveitis or herpes simplex keratitis in the history: use prostaglandin analogs with caution.
- Acute angle closure: pilocarpine helps once the pressure starts to fall; the definitive treatment is laser peripheral iridotomy.
Combination drops
Fixed combinations cut the number of bottles and the preservative load: dorzolamide with timolol, brimonidine with timolol, brinzolamide with brimonidine, and netarsudil with latanoprost. Each carries the contraindications of both of its parts.
Exam habit: before you choose a drop, scan the history for lungs, heart, allergies and age.