What medications are used to treat angle closure glaucoma?

Medications for Angle Closure Glaucoma

The primary medications used to treat angle closure glaucoma include topical beta-adrenergic antagonists, alpha2-adrenergic agonists, carbonic anhydrase inhibitors (topical, oral, or intravenous), parasympathomimetics (miotics), and oral or intravenous hyperosmotic agents. 1

Acute Angle Closure Crisis (AACC) Management

In acute angle closure, the immediate goal is to lower intraocular pressure (IOP) to relieve symptoms and prevent optic nerve damage:

• First-line medical therapy (used to lower IOP before definitive treatment with laser iridotomy):
  • Topical beta-adrenergic antagonists (e.g., timolol) 1
  • Topical alpha2-adrenergic agonists (e.g., brimonidine) 1
  • Carbonic anhydrase inhibitors - both topical and systemic forms 1
    • Oral acetazolamide (250-500 mg) is commonly used 2
  • Topical parasympathomimetics (e.g., pilocarpine) - may help open the angle by constricting the pupil 1
  • Hyperosmotic agents (e.g., oral glycerol, IV mannitol) - for rapid IOP reduction in severe cases 1

Important note: Agents that suppress aqueous humor formation (beta-blockers, carbonic anhydrase inhibitors) may be initially ineffective if the ciliary body is ischemic. Similarly, miotics may be ineffective when IOP is markedly elevated due to pressure-induced ischemia of the pupillary sphincter. 1

Chronic Angle Closure Glaucoma Management

After laser iridotomy has addressed pupillary block, ongoing IOP management follows similar principles to open-angle glaucoma: 1

• Topical medications:

  • Prostaglandin analogs - often first-line due to efficacy 1, 3
  • Beta-adrenergic antagonists 1
  • Alpha2-adrenergic agonists 1
  • Topical carbonic anhydrase inhibitors (e.g., dorzolamide, brinzolamide) 4, 3
  • Parasympathomimetics - less commonly used in chronic management 1, 3

• Systemic medications:

  • Oral carbonic anhydrase inhibitors (e.g., acetazolamide 250-1000 mg/day) - for cases not controlled with topical therapy 2, 3

Special Considerations

• Mydriatics may be more effective than miotics in cases of secondary pupillary block due to intraocular gas, oil, vitreous, or lens-related pupillary block 1

• Target IOP should typically be set at approximately 20% lower than baseline measurements 4

• Medication limitations:

  • Oral carbonic anhydrase inhibitors like acetazolamide can cause serious side effects including Stevens-Johnson syndrome, electrolyte disturbances, and kidney stones 4
  • Recent research suggests brinzolamide may not significantly improve outcomes in the initial management of acute primary angle closure 5

Definitive Treatment

While medications are crucial for initial management, definitive treatment typically requires:

• Laser iridotomy - the preferred surgical treatment with favorable risk-benefit ratio 1, 6
• Lens extraction - growing evidence supports cataract extraction for substantial IOP lowering in some patients 1

Treatment Algorithm

1. For acute angle closure crisis:

   • Initiate multiple medications simultaneously to rapidly lower IOP 1
   • Perform laser iridotomy as soon as corneal clarity permits 1
   • Consider anterior chamber paracentesis for immediate pressure relief if medications fail 7

2. For chronic angle closure after iridotomy:

   • Start with prostaglandin analogs or beta-blockers 1, 3
   • Add or switch medications if target IOP not achieved 1
   • Consider lens extraction if significant cataract present 1

Remember that while medications are important for managing IOP, they do not address the underlying anatomical problem in angle closure glaucoma, which typically requires laser iridotomy or other surgical interventions for definitive treatment. 1, 6