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Monitor patients for ocular effects of systemic treatments
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Millions of patients whose chronic diseases and conditions are treated with systemic drugs can experience mild vision disturbances and even sight-threatening adverse events in response to the medications. The cranial nerves affecting the optic nerve may be impaired and extraocular and eyelid muscles, accommodation, visual clarity and vision functioning may be affected. Some agents may even contribute to the progression of cataracts and cause glaucoma.
The Food and Drug Administration’s Prescription Drug User Fee Act has “allowed for drug makers to bring out many more new drugs and be more competitive,” according to newly appointed FDA Deputy Commissioner, Lester M. Crawford, DVM. This Health and Human Services (HHS) agency reviews side effects from drugs currently on the market, and it is anticipated that there will be a doubling in the post-marketing reviewers’ staffing. As of December 2000 legislation, the FDA can now require pharmaceutical companies to perform pediatric studies on drugs currently on the market to identify potential safety hazards. Post-marketing labeling guidance and changes are issued by the FDA. Pharmaceutical companies can be required to send a letter to health care practitioners stating changes and citing potential adverse events.
Allergy/asthma
Clarinex (desloratadine, Schering) tablets taken once daily for the treatment of seasonal and perennial allergic rhinitis and chronic idiopathic urticaria gained FDA approval in February. Clinical trials revealed that 14% of patients taking this drug suffered headaches. “Allergy and sleep medications typically can cause patients to suffer from headaches, dry eyes and blurred vision,” according to Sal Musumeci, OD, who lectures on ocular side effects from systemic medications.
Singulair (montelukast sodium, Schein) inhibits the cystein/leukotriene CysLT receptor and is indicated for the prevention and chronic treatment of asthma in adults and children older than 2. A once-daily tablet, Singulair is nonsteroidal and did not cause any significant side effects, according to Dr. Musumeci. The FDA did, however, require a safety-related drug labeling change in October 2000 because Singulair caused ocular stinging, burning and irritation.
Headaches occurred in 18.4% of users, according to a February 2001 package insert. Mydriasis is among the most frequent adverse effects with overdosage of Singulair.
About 40 million Americans suffer from allergies, and the most popular systemic allergy medication, Claritin (loratadine, Schering), is about to gain FDA over-the-counter (OTC) approval. Some physician groups are urging that allergies are a serious illness, requiring medical supervision.
Claritin patients may experience blurred vision, ocular pain, blepharospasms, paresthesia and conjunctivitis. The 12-hour version additionally may cause abnormal lacrimation, mydriasis and photophobia. Claritin-D extended release tablets, which can be taken once daily for up to 2 weeks, also can cause abnormal vision, facial edema, alopecia, dermatitis, photosensitive reaction and rashes. It is indicated for patients 12 years of age and older.
Flonase (fluticasone, Glaxo Wellcome), a steroidal nasal spray indicated for seasonal and perennial allergic rhinitis in patients older than 12, may cause increased intraocular pressure, glaucoma, cataracts, conjunctivitis, dryness, ocular irritation and blurred vision. An additional side effect is headache.
Arthritis
Nonsteroidal capsules or the oral suspension of Indocin (indomethacin, Merck Sharp & Dohme) has anti-inflammatory and analgesic properties for rheumatoid and osteoarthritis. Corneal deposits and retinal disturbances, including those of the macula, have been reported with long-term therapy. The FDA’s Center for Drug Evaluation and Research (CDER) recommended guidance and cited corneal deposits as a more serious side effect of this systemic medication. Blurred vision and diplopia also have been reported.
Cardiovascular diseases
The cardiac arrhythmia medication Cordarone (amiodarone, Wyeth-Ayerst) can cause optic neuropathy or optic neuritis, usually resulting in visual impairment. Regular ophthalmic examinations, including funduscopy and slit lamp examination, are recommended during administration of this medication. Corneal micro deposits can be reduced in the majority of patients when the dose is reduced or the medication is discontinued.
According to Dr. Musumeci, amiodarone tablets “have had a rebirth in side effects with a whorl or vortex opacity in the corneal epithelium.” On June 6, 2001, the FDA posted on its Web site a practitioner and patient notice about adverse events from intravenous administration of Cordarone. This was followed by a practitioner letter from the pharmaceutical manufacturer about adverse events from intravenous administration.
It causes “gasping syndrome,” which may be fatal in neonates following administration of the benzyl alcohol preservative. It also causes cardiovascular collapse, which follows bradycardia. Cordarone IV can leach out plasticizers from intravenous tubing.
The National Institutes of Health’s National Heart Lung and Blood Institute, in its updated treatment guidelines of May 15, 2001, suggested 36 million Americans could benefit from taking statin drugs. Currently, the estimated 12 million who do have had the option of taking a generic version of Mevacor (lovastatin, Merck) since January 2002. As the first statin, it was introduced 15 years ago, and at the highest recommended daily dose of 80 mg it reduces low-density lipoproteins by 35%. The most potent new statin, Lipitor (atorvastatin calcium, Pfizer) reduces those lipoproteins by an additional 25%, while other statins can reduce them by more than 35%.
Adverse ophthalmic reactions to Mevacor include the progression of cataracts and ophthalmoplegia. Neurological adverse events can cause a dysfunction of certain cranial nerves, including impairment of extraocular movement, facial paresis and Stevens-Johnson syndrome. Lovastatin has produced optic nerve degeneration (Wallerian degeneration of retinogeniculate fibers) at a 60-mg daily dose and retinal ganglion cell chromatolysis at a 180-mg daily dose after 14 weeks. Generic drugs are required by the FDA to have the same safety and efficacy as the brand-name version.
Depression
On Feb. 27, 2001, the FDA approved Prozac (fluoxetine HCl, Eli Lilly) weekly, making it the first once-a-week anti-depressant. While the FDA did not require the pharmaceutical company to prove that Prozac’s weekly is equivalent to its daily tablet version, a slightly higher risk of diarrhea may occur with the weekly dose.
Since the Sept. 11 terrorist attacks, followed by the biological warfare attacks with anthrax, an increasing number of patients have been prescribed systemic treatments for depression. Prozac’s ocular adverse events include conjunctivitis, dry eye, mydriasis, photophobia, blepharitis, diplopia, strabismus, glaucoma, iritis, scleritis and visual field defects.
Seizures
“A syndrome consisting of acute myopia associated with secondary angle closure glaucoma” was the Sept. 26, 2001, FDA warning for Topamax (topiramate, R.W. Johnson). This drug, which entered the market in 1996, is an anti-epileptic indicated as adjunctive therapy for treating adults with partial onset seizures.
Symptoms typically occur within 1 month of initiating treatment and consist of acute onset of reduced visual acuity and/or ocular pain, anterior chamber shallowing, hyperemia and increased intraocular pressure. Narrow-angle glaucoma was seen in some patients younger than 40 years, and secondary angle closure occurred in pediatric and adult patients.
Previously listed vision disorders were conjunctivitis, abnormal accommodation, photophobia, abnormal lacrimation, strabismus, color blindness, myopia and mydriasis, cataracts, corneal opacities and iritis.
For Your Information:
- Sal Musumeci, OD, FAAO, is in private practice in Tampa, Fla. He can be reached at 3667 W. Waters Ave., Tampa, FL 33614; (813) 931-1892; fax: (813) 936-8187.
- Serious adverse events should be reported to the FDA at the MEDWATCH Program, Web site: www.fda.gov/medwatch; (800) FDA-1088; fax: (800) FDA-0178. The Web site has almost daily posting of safety summaries for biologics, dietary supplements and drugs. More than 300,000 adverse events were reported to the FDA in 2001.