A patient with chronic open-angle glaucoma started on topical beta-blocker reports fatigue, dizziness, and generalized weakness. What is the most likely cause?

• A. The eye drops
• B. Depression
• C. Glaucoma
• D. Advanced age

Answer: (A)

The key idea is that topical medicines for glaucoma can cause effects throughout the body. Nonselective beta-blockers used in eye drops, like timolol, can be absorbed through the conjunctiva and nasal passages into the bloodstream. Once in circulation, they block beta receptors systemically, which can slow the heart rate and lower blood pressure. That can lead to fatigue, dizziness, and a general sense of weakness—precisely the symptoms described after starting the eye drops. This makes the eye drops the most likely cause.

Other possibilities don’t fit as well with the new symptoms appearing after initiating treatment. Glaucoma itself doesn’t suddenly cause fatigue or dizziness, and while depression or advanced age can contribute to weakness, they wouldn’t typically explain a temporal link to a new medication.