Dear Dr. Roach:. I am a healthy 67-year-old female being treated with Eylea for wet age-related macular degeneration (AMD). I have just had my second round of Eyelea, and with the pollen starting up, my eyes are beginning to itch. Is it safe to use over-the-counter eye drops? I also take Zyrtec nightly for my interstitial cystitis. — C.H.

Answer: Eylea is used to treat several cancers as well as the “wet” form of AMD. Eylea works by preventing the formation of new blood vessels and blocking a compound called the vascular endothelial growth factor (VEGF).

In the eye, AMD causes damage by creating new blood vessels, which tend to leak. This causes blood and proteins to develop under the retina, leading to distortions in vision and affecting sight. VEGF inhibitors like Eylea can be directly injected into the vitreous humor of the eye, providing high levels of the medicine around the blood vessels and stopping new blood vessels from forming.

Because Eylea is injected directly into the vitreous humor, regular eye drops that go in the front of the eye should not interfere with its action. I did look up interactions between Eylea, Zyrtec, and several over-the-counter eye drops, and I couldn’t find any evidence of harmful interactions.

Your pharmacist also has access to the data I have and lots of experience with looking up drug interactions.

Dear Dr. Roach: I am a 94-year-old female who takes one 0.75-mg pill of levothyroxine per day since 1970. It was prescribed because of low energy. My doctor thinks the usual blood test is all that is required for proper diagnostics. Would I benefit from a more thorough test, and if so, what would you recommend, as my energy level is now very low? — S.H.

Answer: For most people with low thyroid levels, a simple test of the thyroid level and/or the TSH (thyroid stimulating hormone) level is all that is needed to be sure that the dose of the replacement thyroid hormone, levothyroxine, is adequate. However, there are many causes for low energy. A low blood count and abnormalities of any critical organ can all cause fatigue.

The diagnosis starts with a careful history review and exam. Lab tests are important, but nothing is as likely to give the correct diagnosis as listening to the patient will.

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