Medication Toxicity

High Risk Medications
Plaquenil is used for the treatment of systemic lupus erythematosus, rheumatoid arthritis, and other inflammatory and dermatologic conditions. Retinal toxicity from Plaquenil is of serious concern because even after cessation of the drug there is little if any visual recovery, and sometimes a progression of visual loss over several years after the drug has been stopped. No medical therapy has proven effective in Plaquenil toxicity other than cessation of the drug. There may be a stage of very early functional loss where cessation of the drug will allow a reversal of the toxicity. However significant clinical recovery does not occur after bull’s eye maculopathy becomes evident.

There appears to be minimal risk of toxicity for individuals using less than 6.5 mg/kg of hydroxychloroquine or 3 mg/kg of chloroquine for less than 5 years. Hydroxychloroquine has been prescribed typically at a dosage of either 200 or 400 mg/day, because of the tablet size, rather than on a per weight basis. A 200 mg daily dose will be relatively safe for all but extremely small individuals (less than 68 pounds or 31 kg, if of average build), but a daily dosage of 400 mg puts anyone under 135 pounds (62 kg) in the higher-risk category.

The baseline and subsequent eye examination includes Amsler Grid examination, Humphrey 10-2 visual field test, color vision tests and color photographs of the retina. If a baseline examination is normal and dosages are at the relatively safe levels, screening during the next 5 years can be at the frequency of regular ophthalmic examinations (every 6 months to annually). Annual screening during the first 5 years of usage is highly recommended for individuals who are at higher risk because of their higher dosage, duration of use (more than 5 years), or other complicating factors (kidney or liver disease, obesity).

Tamoxifen is a drug used in the treatment of breast cancer. Ocular side effects consist of crystalline retinopathy, corneal deposits, and optic neuritis. Ocular side effects to tamoxifen are relatively rare, with the reported incidence in the literature varying between 0.9% and 12%. There is evidence of retinal nerve fiber degeneration. Cessation of treatment usually prevents further deterioration but may not result in visual recovery.

Antihistamines are found as prescription and non-prescription pills, capsules, liquids, and effervescent tablets (like alka-seltzer). They may be sold as an individual medication or in combination with other medications such as decongestants, pain medications, etc. Often listed as a warning in package information sheets for antihistamines is that the drug should not be used if one has glaucoma. However, for most people with glaucoma, antihistamines can be used safely. The most common type of glaucoma is termed “open angle glaucoma”. Antihistamines generally should have no effect with this type of glaucoma. With a more rare type of glaucoma termed “angle closure glaucoma” or “narrow angle glaucoma”, the use of antihistamines may trigger an attack of angle closure glaucoma. Basically, the part of the eye that drains fluid becomes blocked and the pressure within the eye will skyrocket. This is usually accompanied by pain, blurred vision, eye redness, seeing rainbows around lights, and even nausea or vomiting. Angle closure glaucoma is an emergency, and vision can be permanently lost. Many people may be at risk for angle closure glaucoma unknowingly. Consult with Phoenix Ophthalmologists who can determine if it is safe to use antihistamines.

Accutane is commonly used to treat acne, and is known to cause dryness of mucous membranes, and the eye is included. Symptoms of dry eye include the sensation that something is in the eye, redness, burning, and even blurred vision. Artificial tears and ointments may help. Accutane may also lead to temporary visual disturbances and trouble with night vision.

Tricyclic antidepressants are associated with eye pathology in rare instances. This class of medication including amitriptyline can have several ocular side effects. They can cause a decrease in tearing, which can lead to dry eye problems. They also can lead to a decrease in focusing ability (accommodation). This temporary effect may cause difficulty with reading or even distance vision. Finally, these medications may have a risk for causing acute angle closure glaucoma, in those persons at risk for this type of glaucoma. Most people with glaucoma have “open angle” glaucoma, and would have no problem with taking these medication. Consult with Doctors Mackman and Van Buren if you are unsure.

Amiodarone is a potent cardiac medication with a common ocular side effect which rarely gives any symptoms. A person taking this medication will develop a whorl-like pattern on the surface of the cornea over a period of time. Rarely this may interfere with vision or cause glare symptoms. The condition is reversible.
Recently, an association between amiodarone and optic neuritis or optic neuropathy has been made. Optic neuritis and/or optic neuropathy have been reported in patients receiving this drug, and that the problem could develop at any time during the use of the drug. It has NOT been clearly established that the drug causes the optic nerve problem, but if there are any changes in vision or peripheral vision then a prompt ophthalmic examination should be performed. Regular ophthalmic examination is recommended for patients receiving amiodarone.

Cimetidine is an anti-ulcer medication can rarely lead to angle closure glaucoma in people susceptible to this type of glaucoma. Most people with glaucoma have “open angle” glaucoma, and would not be at risk with taking these medication. Consult with Phoenix Ophthalmologists if you are unsure.

Oral or intravenous steroids are commonly used especially during attacks of asthma or emphysema, and as an anti-inflammatory agent with arthritis. It is also used after organ transplantation. Short term use of steroids normally does not cause eye problems, but long term chronic use may lead to two possible complications. One complication is glaucoma. Certain predisposed individuals exhibit a rise in eye pressure with the use of steroids, usually after 3 to 4 weeks. This includes oral and IV steroids as well as eye drop steroids. The glaucoma is treatable using medication or rarely surgery, and the pressure usually returns to normal if steroids can be stopped.

Cataract is another complication. The typical steroid induced cataract develops on the back surface of the lens in the eye, and is called a “posterior subcapsular cataract”. This can be a rapidly forming and very visually significant type of cataract, often causing glare disability. Once a cataract forms, it cannot be reversed, although surgery can remove the cataract and restore the vision.

Oral contraceptives, or birth control pills, can lead to numerous ocular problems and headaches. Also, increased pressure of the fluid around the brain (pseudotumor cerebri) can occur, leading to headache, visual changes, and a swollen optic nerve. Finally, certain retinal vascular problems may be caused or worsened by oral contraceptives.

Minocycline, which is a drug similar to tetracycline, is commonly used orally in the treatment of acne and rosacea. Recently reported is a pigmentation of the white of the eye (sclera) which can occur with the use of this drug. It is typically a blue-gray discoloration, but may also be black or brownish. It may be worse in areas exposed to sunlight. This is also true with the similar skin pigmentation which can occur with the drug, as well as fingernail and tooth discoloration. If the abnormal pigmentation is recognized quickly, discontinuation of the drug may allow the skin, eye, etc. to return to their normal appearance.