THERAPEUTIC FORUM

A Continuing Role For Topical Beta Blockers

by Christopher J. Quinn, O.D.

Topically applied beta blockers continue to be the most common initial therapy in our management of open angle and secondary glaucoma. Despite the emergence of a variety of new drugs to reduce the intraocular pressure, beta blockers continue to hold on to their number one position because of their excellent efficacy, low risk of side effects and good patient tolerability.

Most non-selective beta blockers are effective on a once-daily dosing regimen and generally provide up to a 30 percent reduction in IOP. The selective beta blockers, although not as effective in reducing IOP as non-selective beta blockers, remain an excellent choice in patients for whom non-selective beta blockers may be contraindicated.

Most practitioners screen their patients carefully for specific contraindications to the use of a non-selective beta blocker. The most widely recognized contraindications include congestive heart failure, sinus bradycardia, chronic obstructive pulmonary disease (COPD) or asthma. If possible, you should avoid beta blockers in these patients to reduce the potential to exacerbate these conditions.

The use of the selective beta blockers may be appropriate in patients with asthma or COPD, although these patients may still experience exacerbation of their conditions since the selective nature of the beta blockade is not complete. These potential contraindications are generally easy to recognize, so clinicians are able to avoid using beta blockers in these situations.

Equally important, however, is to make sure during follow-up examinations that you carefully question patients regarding symptoms related to the possible complications of the use of topical beta blockers. Because these medications are easily absorbed from the eye into the blood stream, systemic side effects can occur. It is not unusual to find that patients under chronic therapy develop conditions that were not apparent or diagnosed at the time you had initiated therapy. For example, difficulty with breathing can develop as a result of progressive obstructive pulmonary disease when none was present at the time you prescribed the medication.

Likewise, patients may develop congestive heart failure or a slowed heart rate that is only clinically apparent with the use of the topically applied beta blocker. Patients, as well as other health-care professionals involved in the care of your patient, may not readily recognize the potential complications that the topically applied eye drops either cause or exacerbate.

Perhaps equally important is your ability to recognize the less common side effects associated with the use of topically applied beta blockers. Once again, patients and their other health care practitioners do not always relate these conditions to the patient's eye drops. Two of the most commonly unrecognized side effects from the use of the topical beta blocker include clinical depression and impotence.

When you follow up with glaucoma patients who are using systemic beta blockers, you should carefully question them about these areas of function. By asking patients how they are feeling and assessing their mental status, you can often identify patients for whom a change in glaucoma medications may benefit their mental health. Likewise, the patient may experience erectile dysfunction as a result of the systemic effect of topically applied beta blockers. Identifying these patients and substituting an alternative glaucoma medication may improve their condition and reduce their need to use other medications designed to treat impotence.

Because we have good alternatives to the topical beta blockers to control intraocular pressure today, investigating whether patients are experiencing these less common side effects is important for their general well-being. We can also increase compliance by reducing these side effects and keeping the patient healthy and happy.