"First do no harm” is the dictum by which all physicians should try to live when treating patients with glaucoma. The ideal medication is one that maximally lowers IOP, requires infrequent dosing, and has no local or systemic side effects. Obviously, there is no such medication, but wouldn't it be nice? Choosing the best IOP-lowering drug for your patients is a two-step process. First, you try to select the best medication for each individual. Second, after he or she is using the medication, you must confirm that it is indeed the best choice. Adverse events, even minor ones such as itching or burning, may prompt your patient to discontinue therapy.
PICKING THE BEST MEDICATION
History
Obtain a complete and accurate medical history,
including a review of systems. Part of this process
includes observing the patient. If he or she exhibits strenuous
breathing, wheezing, or obvious pedal edema, avoid
systemic β-blockers. Perform simple tests. If you are
about to prescribe a &deta;-blocker or a fixed-combination
medication containing a ß-blocker, checking the patient's
heart rate can help you avoid a serious blunder.
When taking a history, look for contraindications to β-blockers or systemic carbonic anhydrase inhibitors. Does the patient have chronic obstructive pulmonary disease or asthma? Does he or she have diabetes that is not controlled? Is there a history of depression or somnolence? Is the patient taking systemic medications that may have cross-reactivity? Is he or she allergic to specific classes of medications? Systemic sulfa allergies seem to be a specific case.1,2 There is little documentation that an allergy to a systemic sulfa drug can induce allergies to a topical sulfa medication. The former is usually indicative of a person's tendency to be sensitive to other medications.3,4
Communication
Selecting a medication is not a simple algorithm but is
instead based upon effective doctor-patient communication
(as well as clear discussion by your entire staff). Ask patients
about their social and business schedules. Is the dosing schedule
of the medication you are considering conducive to adherence?
If the patient takes most of his or her other medications
in the morning, remembering to take a prostaglandin
analogue in the evening may be difficult. Perhaps prescribing
the prostaglandin analogue for the morning would work better.
Could increased pigmentation of the eyelids or conjunctival
hyperemia negatively affect the patient's livelihood (eg, a
career in sales)? If so, you might want to avoid α-agonists and
prostaglandins as initial therapies.
In today's economy, the cost of medical therapy is a significant factor. The individuals who ask for samples are not always the poorest in your population. Patients may be embarrassed to tell you that they cannot afford a drug. Ask patients if they can afford the brand name or a specific class of medication. Bear in mind that generic equivalents are not always less expensive than their branded counterparts. Some glaucoma medications (eg, timolol maleate), however, are on the $4/month supply list at some large pharmaceutical retailers.
Simplified Dosing
Simplicity is key! When prescribing an initial medication
(or when adding a medication), the simplest dosing schedule
has the best chance of success.5,6 Medications dosed once
daily are generally a better choice than those administered
two or three times daily, and patients' adherence is higher
with a single drug than with two or more.7-9 If appropriate,
start patients on a once-daily medication (prostaglandin analogue
or nonselective β-blocker).
Capability
Someone with crippling arthritis will find it difficult or
impossible to instill a drop. Never forget to ask patients if
they are capable of administering their drops before you
begin the prescribing process.
Evaluate each patient's ability to self-administer a medication. If he or she is forgetful or is taking a plethora of other medications for diabetes, systemic hypertension, chronic obstructive pulmonary disease, and hormonal replacement therapy, adding multiple ophthalmic medications may not be a wise choice. Even patients who appear relatively healthy may use multiple medications that have complex dosing patterns.10 Do not forget to inquire about over-the-counter medications. Patients' use of vitamins, fish oils, and multiple nutraceuticals probably affects whether they will able to administer a topical glaucoma drop consistently.
ASSESSING THE MEDICATION AT FOLLOW-UP
Communication
If you or your staff members do not ask about problems
with adherence, patients may never admit to difficulties
in this area. Do not assume that a fear of blindness
alone will keep a patient on his or her prescribed therapy.
Side Effects
Because many patients do not consider their eye drops to
be “real” medications, they may not associate adverse events
they are experiencing with these drugs. Ask them about
their ocular comfort and inquire about any typical side
effects. If they are using a prostaglandin analogue, ask about
hyperemia and changes to their eyelids and eyelashes. For a
ß-blocker, measure their heart rate and inquire about their
breathing, signs of congestive heart failure, fatigue, depression,
and impotence. For an α-agonist, question patients
about fatigue, allergic symptoms, and hyperemia. Finally, for
a topical carbonic anhydrase inhibitor, ask about blurred
vision, stinging, a bad taste in their mouth, and allergy.
Storage
Find out how patients are storing their medications.
This is most important when they are using topical drops
not preserved with benzalkonium chloride because of
potential contamination.
Supply
Again, ask patients if they can afford their medication so
that you can prescribe an alternative, if need be. Inquire
how many bottles of the drug they required and whether
they ran out before they could refill their prescription. It is
not unusual for patients to run through a month's supply of
medication in 2 weeks due to unintentional waste or the
accidental administration of more than one drop at a time.
The pharmacy will tell these individuals that their insurance
company will not permit refills except at full price, so these
patients may discontinue therapy until the refill is covered.
Instillation
Ask your patients if they can administer their drops and
how often they do so. Request that they bring their medication
to their follow-up appointments. In addition to verifying
the drug they are using, ask patients to demonstrate
their administration of the medication. A surprising number
will have great difficulty opening the bottle and will be
unable to get the drop onto their eye. In these cases, you
may want to ask a family member to help the patient, or
you may want to try to teach the patient how to administer
the drop.11-13 These approaches, however, may not succeed.
CONCLUSION
By asking questions, you will get to know your patients, what will help each of them to adhere to prescribed glaucoma medical therapy, and what may be compromising their efforts. Observation is the best way to know if patients are capable of instilling their drops, and it may offer an important explanation of why therapy has failed to achieve the target IOP.
A video reflecting some of Dr. Robin's observations of experienced patients placing drops on their eyes is available at http://eyetube.net/?v=sewam.
Alan L. Robin, MD, is an associate professor of ophthalmology at the Wilmer Eye Institute and an associate professor of international health at the Bloomberg School of Public Health, both at Johns Hopkins University in Baltimore. Dr. Robin may be reached at (410) 377-2422; arobin@glaucomaexpert.com.
