Information on Risk for Non-Steroidal Drug-Induced Secondary Glaucoma Critical During Patient Counseling
January is National Glaucoma Awareness Month, which makes it the perfect time to reach out to high-risk patients and offer counseling about non-steroidal medications that can trigger glaucoma. You should also consider using this month to raise awareness about glaucoma and to alert customers about the value of early screening to catch the problem before it damages the optic nerve. Your efforts don’t have to consume much time, but the payoff is significant—you can promote overall eye health and help prevent drug-induced secondary glaucoma while letting your pharmaceutical expertise shine.
Why Pharmacists Should Educate Patients About Glaucoma
Glaucoma can be confusing for patients because they don’t realize they have the condition until their vision changes. Then when they finally get an eye exam, they learn that intraocular pressure was building for years and now the optic nerve is damaged. At that point, the damage is irreversible (at least until innovative treatments are developed) and all they can do is use medications to lower eye pressure and avoid additional damage.
Pharmacists need to be prepared to explain glaucoma because they’re in the best position to alert people long before they have symptoms. Most don’t get regular eye exams to screen for glaucoma, but if they know it is a silent disease, they might be more diligent about taking care of their eyes. The following patients have the highest risk for developing glaucoma:
- People over 60 – After the age of 60, they’re six times more likely to develop glaucoma1
- Family history of glaucoma – The most common form of glaucoma—primary open-angle glaucoma—is inherited; a family history means a 4- to 9-times higher risk.
- African Americans – Glaucoma is six to eight times more common in African Americans compared to Caucasians.
- Asians – Have a higher risk for angle-closure glaucoma and normal-tension glaucoma.
- Hispanics – Over the age of 60, Hispanics have a higher risk than people from European ancestry.
- Eye injury – Common cause of secondary glaucoma. Any blunt trauma to the eye can lead to glaucoma, but it’s often due to a sports injury.
- Steroid users – Drug-induced secondary glaucoma is often caused by steroid use, most often due to topical treatments, but it also occurs with inhaled, oral, intravenous, periocular or intravitreal delivery.
Non-Steroidal Medications That Cause Drug-Induced Secondary Glaucoma
A large number of drugs can elevate intraocular eye pressure (IOP) through open-angle or closed-angle mechanisms. Steroids are well known for causing open-angle glaucoma as they produce morphological and biochemical changes in the trabecular meshwork, a structure that regulates eye pressure by draining aqueous humor.2 The patient’s IOP increases within the first few weeks of starting steroids, but pressure should return to normal when the drugs are discontinued. One-third of normal eyes and 90 percent of patients diagnosed with open-angle glaucoma experience more than 6 mm Hg of IOP elevation after a 4-week course of topical dexamethasone.3
Many classes of non-steroidal medications induce angle-closure glaucoma, which is also called narrow angle or closed-angle glaucoma. Angle-closure is often acute and can quickly turn into a medical emergency due to a rapid rise in IOP, which causes sudden pain, red eyes and blurred or reduced vision. However, it can also develop chronically either following an acute case or as the chamber angle gradually closes, resulting in a slow increase in pressure.
Medications that can cause angle-closure glaucoma include:
- Tricyclic antidepressants
- Monoamine oxidase inhibitors
- Antihistamines – H1- and H2-blockers
- Antiparkinsonian drugs
- Antipsychotic medications
- Antispasmolytic agents
- Topical anticholinergic or sympathomimetic dilating drops
- Sulfonamides – May induce angle-closure glaucoma by causing anterior rotation of the ciliary body, but this is a rare reaction.
Unlike sulfa drugs, most medications cause angle-closure glaucoma by triggering pupil dilation, which pushes the lens against the iris and blocks the flow of aqueous humor.
A literature review published in the February 2016 issue of the Journal of Glaucoma suggests that you should be on the watch for these specific drugs that may present a higher risk for bilateral acute angle-closure glaucoma:4
- Mefenamic acid
Raise Awareness During January and Year Round
If you want to take advantage of National Glaucoma Awareness Month, you can keep it as simple as putting up colorful posters reminding customers that glaucoma sneaks up and can affect vision before they have symptoms. Another good idea is a poster alerting patients who know they have glaucoma to consult the pharmacist before using any supplements or medications, including OTC products.
In the meantime, be sure to ask patients if they have hypertension, glaucoma or a family history of glaucoma before dispensing medications that could exacerbate or trigger the condition. Remember that most patients don’t get preventive testing for glaucoma—you may be the one health professional who can educate about glaucoma and nudge them toward a vision-saving eye exam.
Pharmaceutica North America provides prescription drug products including diclofenac sodium and lidocaine ointment, a diverse line of high-quality active pharmaceutical ingredients, and OTC supplements. Contact us today to talk about how we can support your pharmaceutical needs
- “Are You at Risk for Glaucoma?” January 2011, http://www.glaucoma.org/glaucoma/are-you-at-risk-for-glaucoma.php ↩
- “Meds That Don’t Mix With Glaucoma Patients,” October 2012, https://www.reviewofoptometry.com/ce/meds-that-dont-mix-with-glaucoma-patients ↩
- “Drug-Induced Glaucoma,” July 2014, http://emedicine.medscape.com/article/1205298-overview ↩
- “Drug-Induced Bilateral Secondary Angle-Closure Glaucoma: A Literature Synthesis,” February 2016, https://www.ncbi.nlm.nih.gov/pubmed/25943730 ↩