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ODs must take the time to ask patients about current medication use because adverse reactions are more likely in patients who previously had allergic reactions, says Blair Lonsberry, OD, MS, MEd, FAAO, at the American Optometric Association’s Optometry’s Meeting in Washington, DC.
Washington, DC- ODs must take the time to ask patients about current medication use because adverse reactions are more likely in patients who previously had allergic reactions, says Blair Lonsberry, OD, MS, MEd, FAAO, at the American Optometric Association’s Optometry’s Meeting in Washington, DC.
“The amount of drug administered is a factor that increases risk,” says Dr. Lonsberry.
The variables that increase the risk of ocular side effects (OSE):
• The amount of the drug administered
• Nature of the drug given
• Route the drug is administered
“All medications have potential for toxicity if given in excessive amounts,” says Dr. Lonsberry.
Long-term use of therapeutic medications can also cause toxicity and increase the risk of OSE in patients.
Because each patient you see is different, it’s important to monitor each patient individually.
“You want to monitor pathophysiologic variables such as a patients’ liver and kidney function,” says Dr. Lonsberry. “You also want to examine a patients’ individual idiosyncrasy such as enzymatic differences and muscle mass”
Age and sex are also factors as OSE is more common in the very young and very old and more in women than men.
According to Dr. Lonsberry, drug interaction is one of the main factors in a patient’s risk of developing OSE.
“Incidence of alternative dispute resolutions (ADR) is directly related to the number of drugs administered,” says Dr. Lonsberry. “It is important to specifically ask about a patient’s social habits and supplements taken.”
A common antimalarial medication prescribed to patients who are suffering from rheumatoid arthritis is hydroxychloroquine (Plaquenil, Concordia Pharmaceuticals Inc.).
“Plaquenil is primarily used to help manage pain and increase mobility,” says Dr. Lonsberry. “It has a mild effect on slowing down joint destruction.”
Common OSE from antimalarial medications:
• Affinity for pigmented structures such as iris, choroid, and retinal pigment epithelium (RPE)
• Toxic effect on the RPE and photoreceptors leading to rod and cone loss
• Slow excretion rate out of body with toxicity and functional loss continuing to occur despite drug discontinuation
“Hydroxychloroquine is a safe medication for patients; we have to monitor that they are not running into issues,” says Dr. Lonsberry.
Monitoring each patient is crucial to avoiding further ocular complications. Medication toxicity can also lead to
• Whorl keratopathy
• “Bulls eye” maculopathy
• Retinal vessel attenuation
• Optic disc pallor
“Early stages of maculopathy are seen as mild stippling or mottling and reversible loss of foveal light reflex,” says Dr. Lonsberry. “Classic maculopathy is in form of a ‘bulls eye’ and is seen in later stages of toxicity.”
Disorders such as whorl keratopathy can cause Fabry disease, a rare genetic lysosomal storage disease. It’s important to identify whorl early, or patients will worsen quickly, says Dr. Lonsberry.
Tetracyclines are the drug of choice for treating Lyme disease, Rocky Mountain fever, cholera, mycoplasma pneumonia, and chlamydial infections. Its side effects include gastric discomfort, effects on calcified tissues, and vestibular problems.
Children under age eight should not use tetracyclines because they can cause discoloration of their teeth.
Of the prescribed tetracycline, doxycycline is the most prescribed, says Dr. Lonsberry.
When taking doxycycline, patients should not:
• Take with calcium
• Take antacids
• Take with dairy
• Take with food
• Take before bed
“Systemic use of tetracyclines rarely causes serious side effects,” says Dr. Lonsberry. “The most commonly reported side effect is pseudotumor cerebri associated primarily with tetracycline and minocycline.”
Amiodarone is a common anti-anginal medication used to treat atrial and ventricular tachcardias. According to Dr. Lonsberry, after long-term use, more than 50 percent of patients have to discontinue use due to toxic responses.
Systemic adverse side effects include:
• Interstitial pulmonary fibrosis
• GI intolerance
• Liver toxicity
• Muscle weakness
“Corneal microdeposits occur in nearly all patients who are using the drug long-term,” says Dr. Lonsberry. “Generally visible keratopathy develops in most patients within six weeks of initial drug initiation and reaches its peak within three to six months.”
Patients will see regression approximately three to seven months after dicontinuation of amiodarone, says Dr. Lonsberry.
Other complications include:
• Decreased vision acuity
• Color vision defects
• Dry eyes
• Decreased corneal sensation
• Optic neuropathy
When prescribing antidepressants, doctors tend to ask a variety of questions in order to determine which is safest for each patient.
Selective serotonin reuptake inhibitors (SSRIs) have largely replaced tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) as the drugs of choice in treating depression.
SSRI side effects:
• Sexual dysfunction
• Adverse drug interaction
“Most of the side effects are transient, reversible, and cause little clinical significance,” says Dr. Lonsberry.
Ocular side effects can include:
• Blurred vision
• Mydriasis in patients with narrow angles or narrow-angle glaucoma (NAG)
• Increased symptoms of dry eye
Corticosteroids or glucocorticoids promote normal metabolism, increase resistance to stress, alter blood cell levels, and has anti-inflammatory action.
Systemic use can result in:
• PSC cataracts
• Increased IOP
• Delayed wound healing
• Visual hallucinations
• Subconjunctival/retinal hemes and edema
“Race plays a role as steroid-induced glaucoma is more prevalent in whites than blacks,” says Dr. Lonsberry. “Steroids also affect all ocular structures, resulting in development of steroid-induced glaucoma.”
Tamoxifen is commonly used in the treatment of breast cancer. It works by stimulating normal breast tissue to grow by estrogens.
Common adverse side effects are:
• Hot flashes
• Menstrual irregularities; vaginal bleeding can also occur
“Significant visual loss can occur with tamoxifen,” says Dr. Lonsberry, “Stopping tamoxifen usually prevents further deterioration but may not result in visual recovery.”
“Evidence shows antihistamine use demonstrates a decrease in tear production, making patients symptomatic for dry eyes and contact lens intolerance,” says Lonsberry.
With chronic use of antihistamines, anisocoria, decreased accommodation, and blurred vision can also occur in patients.
Tamsulosin (Flomax, Boehringer Ingelheim Pharmaceuticals) is used to treat prostate enlargement and improve urinary flow in men and is now being used to treat women as well. Intraoperative floppy iris syndrome is commonly associated with the use of tamsulosin and used to only occur in men, but now it’s a concern for women for are using it.
“Even if tamsulosin is discontinued, the patient is at a lifetime risk of more complicated cataract surgery,” says Dr. Lonsberry. “The patient becomes a risk of more complicated cataract surgery with even one dose.”