Which cap color is common to carbonic anhydrase inhibitor eye drops such as Dorzolamide or Brinzolamide?

• A. White
• B. Yellow
• C. Purple
• D. Orange

Answer: (D)

Color coding of eye-drop bottles helps clinicians quickly identify the drug class. For topical carbonic anhydrase inhibitors like dorzolamide and brinzolamide, orange caps are common. This orange cue distinguishes them from other glaucoma medications and aids safe selection and dispensing. These drugs work by inhibiting carbonic anhydrase in the eye, reducing aqueous humor production and lowering intraocular pressure. The orange color is a packaging convention tied to this drug class, not a pharmacologic property, which is why it’s the best match. Other colors aren’t consistently associated with carbonic anhydrase inhibitors, so they don’t fit as well.