Trusopt carries an orange cap. Trusopt is the brand name for dorzolamide. Dorzolamide is a topical carbonic anhydrase inhibitor, often shortened to CAI. Orange is the cap color used for this class of eye drop. The color code lets you sort a patient's bottles by class in a few seconds, even before you read the labels. Every top in a glaucoma patient's bag can be matched to a class this way.
CAIs lower pressure by slowing the making of aqueous humor. Aqueous humor is the clear fluid the eye produces inside the front of the globe. The eye makes aqueous humor all day and drains it all day. A CAI works on the making side of that balance. Less fluid made means less pressure built up. The two topical CAIs are dorzolamide (Trusopt) and brinzolamide (Azopt). The oral forms are acetazolamide (Diamox) and methazolamide (Neptazane). Oral CAIs cause more body-wide side effects. These include tingling in the hands and feet, loss of appetite, a metallic taste, and kidney stones. Dorzolamide is also sold together with timolol, under the brand name Cosopt.
Learn the cap colors as a safety habit. They help you catch a refill error or a mixed-up bottle before a patient uses it. They also help you ask better history questions about each class. Read the label as well, since a color can be misread in poor light. Ask which bottle goes in which eye and how often, then chart the answers. Knowing drug classes, brand names, and cap colors is a core part of the COA pharmacology content area.
Incorrect Answers
- A. Yellow is the code color for beta-blockers, such as timolol. Those drops cut fluid production as well, but they sit in a different class.
- B. Dark blue marks a beta-blocker combination drop, such as Cosopt. Trusopt is a single agent, not a combination. Cosopt pairs dorzolamide with timolol.
- D. Teal is the cap color used for prostaglandin drops, such as Xalatan. Trusopt is a carbonic anhydrase inhibitor, so its cap is orange rather than teal.
Testing Pearls
- Trusopt is dorzolamide; Azopt is brinzolamide.
- CAIs work by decreasing aqueous production.
- Oral CAIs are Diamox and Neptazane.
- Oral CAI side effects include tingling, metallic taste, and kidney stones.
- Yellow caps mean beta-blockers, and dark blue means a beta-blocker combination.
References
- American Academy of Ophthalmology. Ophthalmic Medical Assisting: An Independent Study Course. Chapter 6, Basics of Ophthalmic Pharmacology.
