Effects of concurrent use of topical, oral beta blockers

Recently, I received a progress note from a glaucoma surgeon concerning a patient whom he and I share. The patient is a 58-year-old African-American female with a longstanding history of primary open-angle glaucoma. She has mild cataracts and is under the care of a primary-care physician for hypertension and hypercholesterolemia.

The patient’s systemic medications are atenolol (Tenormin, AstraZeneca) and simvastatin (Zocor, Merck). The atenolol was a recent change from hydrochlorothiazide (Microzide, Actavis plc) for reasons not readily apparent, and it can be assumed that the hydrochlorothiazide was not yielding a proper efficacy. She is a former crack cocaine user and has been sober for almost 10 years. She has no other known systemic illnesses or medication allergies.

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Her intraocular pressures (IOP) were well controlled for years by a prostaglandin at bedtime and a beta blocker-containing combination drop in the morning and afternoon. Recently, progression was detected, and the decision to have a consultation for selective laser trabeculoplasty (SLT) was made after a discussion with the patient regarding a laser procedure vs. the possible addition of a third drop.

She did great and has consistently remained at or below target (12 to 14 mm Hg) since then. The most recent consultation note stated that we should change her combination drop because it contained a beta blocker and she is now taking a systemic beta blocker. Using the topical beta blocker would be a contraindication.

Beta blocker usage

This situation prompted me to revisit the question regarding concurrent use of topical beta blockers and oral beta blockers. Admittedly, I haven’t given this as much thought as I probably should. Common sense tells me that the effect of topical beta blocker use on IOPs will be diminished in the presence of oral beta blocker use, namely due to the fact that beta blocker molecules ingested orally will find their way to the vascularized tissues of the eye.

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This does not mean an absolute contraindication exists, but topical beta blockers do have detectable levels in the bloodstream and will likely have effects on cardiovascular metrics, specifically systolic and diastolic blood pressure and heart rate.¹ I am reminded of a court case from my Legal Aspects of Optometry course in which a patient’s cause of death was ultimately linked to topical timolol (Timoptic, Merck) use.

With that said, most patients who use topical beta blocker-containing medications do so with no apparent adverse effects. It is advised to check a patient’s heart rate and blood pressure before and after starting a beta blocker-containing medication. As well, a thorough medical history should be obtained to include confirmation of routine physical examinations.

Direct contraindication not found

Beta blockers have numerous contraindications and precautions related to pulmonary and cardiovascular diseases, including severe chronic obstructive pulmonary disease (COPD), bronchial asthma, and bradycardia.²   However, no direct contraindication exists for concurrent use of topical and oral beta blockers; I don’t think the glaucoma surgeon meant to imply direct contraindication in his letter.

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It is generally thought that much of systemic hypotension is caused by use (or overuse) of medications that lower blood pressure with an emphasis on those specifically used to treat hypertension. The next time I see this patient for a follow-up examination, I will check her pulse and blood pressure, and we are already in good communication with her primary-care physician. However, although I think it’s a valid point, I currently remain unconvinced that her topical beta blocker use concurrent with her oral beta blocker use is a true contraindication.

I think it is prudent, however, that this be discussed. I also remain unconvinced that she truly needs a topical beta blocker in her current glaucoma medication regimen. Her cup-to-disc ratios are not 0.9 x 0.9, and her visual field studies do not show advanced functional loss-although recent progression was detected, thus prompting the consultation for SLT.

Treatment moving forward

In short, she doesn’t have severe glaucoma, and I believe we are at a point where, in light of her recent success with SLT, we can start to let some specificity into our treatment regimen. Therefore, I am going to call her glaucoma surgeon who performed the SLT and discuss the possibility that she remain at our new target without so many medications. (She has two bottles with a total of three medications on top of a recent successful bilateral SLT.)

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Very little, if anything, in the world of glaucoma treatment is truly cookie-cutter, and some patients truly need the kitchen sink thrown at them. If this patient’s glaucoma was worse, I don’t think I’d be taking anything away from her treatment. But at this point, the question surrounding the efficacy and potential adverse effects of beta blocker use in her particular care has done well to serve as an impetus for the broader question of just how much is enough.

References

1. Schuman JS. Effects of systemic beta-blocker therapy on the efficacy and safety of topical brimonidine and timolol. Brimonidine Study Groups 1 and 2. Ophthalmology. 2000 Jun;107(6):1171-7.

2. Houde M, Castilloux AM, Tingey D, Assalian A, LeLorier J. Prescription of topical antiglaucoma agents for patients with contraindications to beta-blockers. Can J Ophthalmol. 2003 Oct;38(6):469-75.