Ask about a history of asthma. Many glaucoma drops are beta-blockers, such as timolol. The textbook says beta-blockers should be avoided in patients with obstructive lung disease. Asthma is a disease of that kind. The airways are already twitchy and narrow. A drug that blocks beta receptors can make them tighten further. A drop that looks harmless can therefore cause real trouble with breathing.
Eye drops do not stay in the eye. Some of each drop drains into the nose and throat and is absorbed into the bloodstream. That is why a drop can act on the lungs and the heart. Beta-blockers can also slow the heart rate, so they need care in patients with heart problems. They lower eye pressure by cutting aqueous production, the making of the eye's internal fluid. The drops in this class include timolol (Timoptic, Betimol), betaxolol (Betoptic), levobunolol (Betagan), metipranolol (Optipranolol), and carteolol (Ocupress). Their bottles carry a yellow cap in the standard color code.
Make lung and heart questions part of every glaucoma workup. Ask plainly: do you use an inhaler, and has any doctor treated you for breathing problems? Write the answer in the chart and flag it for the doctor. Taking a drug history that protects the patient is a core part of the COA pharmacology content area.
Incorrect Answers
- A. Migraine is not listed as a caution for any glaucoma drop. It would not change the choice of drop here.
- C. Arthritis is a joint disease. It has no known conflict with glaucoma eye drops.
- D. Kidney stones are a side effect of oral carbonic anhydrase inhibitors, such as Diamox. This patient is being considered for a drop, not a pill.
Testing Pearls
- Beta-blockers should be avoided in obstructive lung disease.
- They can also slow the heart rate, so heart history matters.
- Beta-blockers lower pressure by decreasing aqueous production.
- Timolol, betaxolol, levobunolol, metipranolol, and carteolol are the drops in this class.
- Beta-blocker caps are yellow; beta-blocker combination caps are dark blue.
References
- American Academy of Ophthalmology. Ophthalmic Medical Assisting: An Independent Study Course. Chapter 6, Basics of Ophthalmic Pharmacology.
- American Academy of Ophthalmology. Ophthalmic Medical Assisting: An Independent Study Course. Chapter 8, Comprehensive Medical Eye Examination.
