A dark blue cap is most commonly associated with which product type?

• A. Cholinergic agonist
• B. Fixed combination without beta-blocker
• C. Fixed combination with beta-blocker
• D. Prostaglandin analog

Answer: (C)

Color cues on glaucoma eye-drop bottles help you quickly identify the type of medication. A dark blue cap is most often associated with fixed combinations that include a beta-blocker (timolol). This packaging convention is used because many fixed-combination products pair timolol with another agent, and blue caps have been used to signal the presence of the beta-blocker component. By contrast, prostaglandin analogs and cholinergic agonists typically use different cap colors, and fixed combinations without a beta-blocker have their own distinct packaging cues. So when you see a dark blue cap, think of a fixed combination that includes timolol rather than a single-agent cholinergic or prostaglandin product. If in doubt, always verify the exact composition on the label.