What is the recommended approach to combining medications from different classes in glaucoma management?

• A. Always combine two PGAs with BB, CAI, and AA for the maximum reduction
• B. Avoid mixing two PGAs with BB, CAI, and AA at the same time
• C. Use all available classes simultaneously for any patient
• D. Only monotherapy should be used

Answer: (B)

In POAG management, the goal is to lower intraocular pressure effectively with the simplest, safest regimen. Prostaglandin analogs are a powerful first-line option and are usually given once daily. However, adding a second prostaglandin yields only a small extra drop in pressure because both drugs act through the same mechanism, and it increases the chance of local side effects (like conjunctival redness and irritation) and cost without much additional benefit. Therefore, when more IOP lowering is needed, the better approach is to add a medication from a different class—such as a beta-blocker, a carbonic anhydrase inhibitor, or an alpha-2 agonist—or switch to a fixed-dose combination that pairs a different mechanism with the prostaglandin, rather than mixing two prostaglandin analogs with other classes all at once. This helps maximize efficacy while limiting side effects and treatment burden.