systemic medications

How To Manage Patients When Systemic Medications Affect Vision

Use these strategies to minimize drug-related adverse events, and build a loyal patient base.

APRIL JASPER, O.D., F.A.A.O., West Palm Beach, Fla.

From analgesics to tetracyclines, many systemic medications may produce ocular adverse effects. (Click here for table.) As our patients' gatekeeper for their eye care needs, it's our responsibility to detect and treat these adverse effects as well as educate patients about how these drugs may affect ocular health and vision.

This is no small task: Reports reveal that 75% of all visits to the doctor result in at least one prescription. Seventy-five percent of the population over the age of 12 take one or more medications, while 30% take three or more. Eighty three percent of those over the age of 85 take three or more medications. Of those individuals who take six or more medications, half receive them from three or more doctors.

In the face of these daunting statistics, my practice has taken steps to ensure that we minimize drug-related adverse events. In this article, I will share these strategies with you.

Determine who is taking systemic medications

It's impossible to determine the adverse effects of medications if we do not know what medications our patients are taking. Therefore, our offices face the initial challenge of identifying those patients who take systemic medications. A 2008 survey, The Adult Consumer Eye Exam Experience (Jobson Optical Research), reported that only 78% of patients remembered being asked at any time during their eye exam about what medications they were taking. Let me simply say: We will not know if we do not ask.

I am certain that most optometrists give patients a patient information form when they arrive at the office. This form typically includes an area for patients to write all the medications that they take. An informal study that I completed confirmed that less than 50% of patients fill this out correctly — if at all. The most common reason given for leaving this information blank: "I didn't think you really needed that information, as it has nothing to do with my eyes."

To make the patient form more valuable, in terms of acquiring accurate drug information, tell your patients why this information is important to your practice. To do this, consider adding the following sentence to your practice's patient information form: "Because many systemic medications can have ocular side effects, please list all your medications here for the doctor to review."

In my same informal survey, I found that upon further questioning by office staff and the doctor, only 75% of patients knew the names of all of their medications. A step that can be taken to enable doctors to obtain a more complete list of medications from our patients is to request (when confirming appointments) that patients bring a written list or a printed list from their pharmacy of all the medications that they take. Add this instruction to automated phone messages — if your office uses an automated system to confirm appointments for the next day.

I recommend that all of us provide patients with a medication card, which provides details of the patient's prescriptions as well as emergency information. Dr. Jon Jacobs, a VisionSource administrator, developed such a card, which I adopted for my practice (see below for an image of the card). This card can be very important not only for us but also for emergency medical personnel who know to look for this card in the wallet of a person whom they are treating. The card has the potential to save our patients lives in an emergency situation. Contact me if you require information on printing a medication card.

Determine which patients are at risk:

Once you have determined what systemic medications your patient takes, the next challenge is to assess the patient's risk level for developing specific ocular adverse events. This information enhances our ability to manage these patients, as we will be better prepared for any drug-related adverse events.

Some of the factors that increase the probability of an adverse event include:

► dosage (the higher the dosage, the greater the probability of an adverse event). Of all these risk factors, drug dosage is most closely associated with the prevalence of adverse reactions, so be certain to collect information not just on drug usage, but also drug dosage.
► length of time the medication has been taken,
► pre-existing eye disease,
► age (young children are at greater risk because their capacity to metabolize drugs is not fully developed; older patients are less able to metabolize drugs as their liver ages),
► pre-existing liver or kidney disease, which also influences the body's ability to metabolize and excrete the drug,
► the use of multiple medications,
► those with difficulty understanding and following directions,
► alcoholism,
► body fat
► low body weight.

Most optometrists are not pharmacists, so it can be difficult to remember all of the possible ocular adverse events associated with each medication and at what dosage they are more likely to occur. Fortunately, many resources can aid us in finding this information, including numerous websites. Use sources that provide information on safe dosage and frequency and seriousness of ocular adverse events, which can vary significantly among patients, depending on the risk factors cited above. Also note that many sources report only the adverse events as determined by pre-release studies, yet adverse events can occur after pre-release studies are published.

Two resources I have found useful in clinical practice are Clinical Ocular Toxicology: Drug Induced Ocular Side Effects (Saunders 2008) by Fraunfelder, Fraunfelder and Chambers and Clinical Ocular Pharmacology (Butterworth-Heinemann 2007) by Bartlett and Jaanus. The Fraunfelder book lists each medication that has the probability of an ocular adverse event, its safe dosage and the appropriate testing and management of a patient taking that specific medication. In selecting a resource, choose those that are complete and updated frequently.

It is also important to report any drug-induced ocular adverse events that are as of yet undocumented. Report these to the National Registry of Drug-Induced Ocular Side Effects at www.eyedrugregistry.com.

Determine whether symptoms are related to medications

The following scenario describes how to determine whether a systemic drug is affecting a patient's vision and if so, how to diagnose and treat it.

During a visit, a patient complains that she has had this "terrible dryness" and is almost unable to open her eyes because of the "burning and pain" she experiences when doing so. First, make certain you take the complaint seriously. When we ignore or make light of a patient's complaints, we risk destroying the doctor-patient relationship and exposing our practices to medico-legal problems.

From the patient's drug card or medical record, you see that the patient takes a drug that, according to your resource guide, lists dry eye as an adverse effect. The next step is to determine the timing of the complaint to see whether there's a connection between the drug and the adverse effect. Did this symptom occur after beginning a new medication? (Keep in mind that some medications can take many months to produce ocular adverse events.) Understand that the patient's complaint may create another challenge: If the patient is bothered enough to complain, then there's also a possibility that the patient will stop taking any perceived causative medication on her own as well. Counsel the patient on the importance of adhering to prescribed dosages of medications. Assure her that you will treat her complaints.

Third, after ruling out causes other than the medication in question, the best course of action is to start treatment for her dry eyes. Fourth, write a letter to the internist outlining the patient's complaint, your diagnosis, your course of treatment and any concerns. If appropriate, request a challenge-dechallenge-rechallenge, in which the drug is administered, withdrawn, then administered again, all while the patient is monitored for adverse effects. It is very important that we inform the patient that this must be done with the approval of — and under the supervision of — the internist.

Guidelines for patients using high-risk medications

If the drug in question is one that has reported serious risks — such as retinal or optic nerve toxicity (not just dry eye) — you must perform further tests. In addition to a normal complete exam with refraction, perform the following baseline tests at each visit to rule out ocular toxicity: Farnsworth color vision testing, Humphrey 24-2 visual field testing or equivalent, Amsler grid, retinal photos and of course, a thorough dilated fundus evaluation. Remember that dilation can affect the results of many tests, so do not to dilate until you complete all other tests.

If you detect abnormalities when performing any of the above tests, report them to the internist immediately to determine the appropriate course of action. When defects are found, repeat the visual field test to eliminate false positives and ensure the defect is reproducible. To determine a connection between the drug and a serious adverse condition, it's important to review baseline data in the patient record that show whether the patient had defects prior to taking the drug(s) in question.

With medications that list optic neuritis or even macular changes as adverse events, you can detect changes early by testing the patient's color vision and visual fields. The advantage of the Farnsworth color vision test is that it can detect red-green anomalies as well as yellow-blue. Drug-induced color vision defects can cause either or both types of color vision defect. (For information on evaluating results of Farnsworth testing, visit http://colorvision.belatorok. com/dir_for_use.htm.)

In screening for early macular toxicity of certain medications, such as hydroxychloroquine, recent studies have found optical coherence tomography (OCT) to be helpful.

When patients take the recommended safe dosage of a medication, they should visit your office typically once a year. However, it's important to consult with a medication reference for specifics on each drug, as you may want to more closely monitor those patients at high risk for adverse affects.

Also keep in mind that there are a few medications that may cause severe ocular adverse events, such as isotretinoin, a treatment for severe cystic acne that may be associated with sight- and life-threatening adverse events. I recommend that you provide patients who are on these medications with an "Informed Consent Form" that educates them of the risk of adverse effects, who to contact if any occur and how often they should see you for care related to this high-risk medication.

When you prescribe

As research has found, good communication, which involves both our listening to and educating our patients, is key to reducing or eliminating medication errors and adverse events. Before you write any prescriptions, make certain to document prominently in the record whether the patient has any allergies. In addition to reviewing the record for allergy information, ask the patient verbally whether she has any allergies.

Always document what you prescribe, why you prescribe it and the expected outcome of the treatment.

Be aware of potential drug interactions when you prescribe medications. For example, the carbonic anhydrase inhibitor acetazolamide may cause a major hemorrhage when given to a person who takes warfarin sodium, an anticoagulant.

The extra effort benefits both you and your patients

If you use the appropriate resources, perform the proper tests and take an extra two minutes to communicate with patients, you can eliminate most errors that can lead to adverse drug events.

This isn't a one-way street — discuss with patients their responsibilities. They need to know the brand name and generic name of each medication they are taking. They need to know what the medications look like (shape, size color, etc.), and they need to use only one pharmacy — if at all possible — so that the pharmacist can help prevent unintended drug interactions, as well as prevent overdosing that may occur when the patient accidentally takes the same drug (with two different names) at twice the recommended dosage.

Let patients know that they should call you and their internist if they experience any decreased vision or eye pain. Always document this conversation in the patients' chart and include notes on any related brochures or written information that you provide to patients. (By having this conversation with your patients, you can detect problems early and potentially change their lives for the better.)

As you implement these strategies you will be amazed at the response you receive from your patients. The time you take to "go the extra mile" will build patient relationships and increase patient loyalty.

Patients will be extremely grateful for your concern and will be "wowed" with the care you give and the difference in your exam from the doctors they have seen in the past. You will not only improve both of your lives, but also help your patients see that "gatekeeper" is more than a metaphor, at least as far as this doctor is concerned. OM

Dr. Jasper is in private practice in West Palm Beach, Fl. She graduated from Nova Southeastern University and completed a residency in ocular disease at the Brockton/West Roxbury VA Medical Center. She is a fellow of the American Academy of Optometry, trustee for the Florida Optometric Association and a VisionSource administrator. E-mail Dr. Jasper at drjasper@aeswpb.com