We sometimes get questions about when to take medicines. Does it matter whether you take them all at once, or do they need to be separated? (The correct answer to this question, unfortunately, depends on the specific pills.) Should you take them with food or on an empty stomach? And, of course, must you take them first thing in the morning, or can you take them at night. People are sometimes surprised to learn that it’s okay to take thyroid hormone (levothyroxine) before bed. Some blood pressure pills also work as well or even better when taken in the evening. But, as an alert reader warned us, you should check with ALL your health care providers when making this decision. Glaucoma patients should be wary of nighttime blood pressure medications.
Advice on Blood Pressure Pills Not Good for Glaucoma Patients:
Q. You wrote recently about the proper time of day to take medication for hypertension. The idea of medicating at bedtime is correct in most cases. This timing minimizes the risk of orthostatic hypotension [dizziness on standing].
However, there is a notable exception to that advice. One should avoid taking anti-hypertensive medications at bedtime if being treated for glaucoma, particularly low-tension glaucoma. Perfusion pressure to the optic nerve is normally greatly reduced at night. Reducing it further with blood pressure medicine dramatically increases the risk of optic nerve damage.
As a recently retired optometrist who treated many patients for glaucoma, I always consulted with the patient’s general physician. One would not want to increase the risk of advancing glaucoma by taking antihypertension medications at night. Such patients should take their medicines in the morning.
A. Thank you for alerting us to this complication. When blood pressure drops too low overnight, it may indeed pose a risk for glaucoma patients (Expert Opinion on Pharmacotherapy, Dec. 2020).
In glaucoma, pressure within the eye (intra-ocular pressure) damages the optic nerve. Usually this is due to a build-up of fluid in the eyeball. However, some people may suffer optic nerve damage even if the intra-ocular pressure is not very high. Because they risk vision loss if their hypertension is over-treated or if their overnight blood pressure is too low, they must get all their healthcare providers to work together for optimal results (Clinical Ophthalmology, Feb. 9, 2021).