Topical ocular application of neomycin has been reported to cause allergic conjunctival or lid reactions in 4% of patients using this drug. If neomycin is used topically for longer than 7–10 days on inflammatory dermatosis, the incidence of allergic reaction is increased 13-fold over matched controls. Neomycin preparations for minor infections should rarely be used over 7–10 days. Also, if the patient has been previously exposed to neomycin there is a significantly higher chance of an allergic response. In one study neomycin was found to be one of the three most common drugs causing periocular allergic contact dermatitis. Rarely will neomycin be given alone in topical ocular medication. Often a steroid is added, which may mask the incidence of hypersensitivity reactions. Additional antibiotics are frequently added to increase the antimicrobial spectrum. Some feel that, of the more commonly used antibiotics, topical neomycin has the greatest toxicity to the corneal epithelium. It probably produces plasma membrane injury and cell death primarily of the superficial cell layers with chronic topical exposure. Dohlman (1966) describes tiny snowflakes on the corneal epithelial surface, along with superficial punctate keratitis persisting for weeks after topical ocular neomycin use. After long-term ocular exposure to neomycin, fungi superinfections have been reported. Nystagmus has been reported in a 9-year-old child following topical treatment of the skin with 1% neomycin in 11% dimethyl sulfoxide ointment­ .

References and Further Reading

Baldinger J, Weiter JJ. Diffuse cutaneous hypersensitivity reaction after dexamethasone/polymyxin B/neomycin combination eyedrops. Ann Ophthalmol 18: 95, 1986.

Dohlman CH. (Reply to Query). Arch Ophthalmol 76: 902, 1966.

Fisher AA, Adams RM. Alternative for sensitizing neomycin topical medications. Cutis 28: 491, 1981.

Fisher AA. Topical medications which are common sensitizers. Ann Allergy 49: 97, 1982.

Kaeser HE. Drug-induced myasthenic syndromes. Acta Neurol Scand 70(Suppl 100): 39, 1984.

Kaufman HE. Chemical blepharitis following drug treatment. Am J Ophthalmol 95: 703, 1983.

Kruyswijk MRJ, et al. Contact allergy following administration of eyedrops and eye ointments. Doc Ophthalmol 48: 251, 1979.

Wilson FM II. Adverse external ocular effects of topical ophthalmic medications. Surv Ophthalmol 24: 57, 1979.

2. Decreased vision

3. Eyelids or conjunctiva

a.Allergic reactions

b.Photosensitivity

c.Angioedema

d.Urticaria

e.Loss of eyelashes or eyebrows 4. Problems with color vision

a.Color vision defect

b.Objects have yellow tinge

Probable

1. Papilledema secondary to intracranial hypertension

2. Myasthenia gravis (aggravates)

a.Diplopia

b.Ptosis – unilateral or bilateral

c.Paresis of extraocular muscle

Possible

1. Subconjunctival or retinal hemorrhages secondary to drug-induced anemia

2. Retinal – crystalline retinopathy

3. Eyelids or conjunctiva

a.Lupoid syndrome

b.Erythema multiforme

c.Lyell’s syndrome

d.Stevens-Johnson syndrome

Clinical significance

A unique ocular side effect secondary to nitrofurantoin is a ­severe itching, burning and tearing reaction, which may persist long after discontinuing the drug. Aggravating or causing an ocular myasthenia has been well documented with nitrofurantoin. This is probably due to interference in the transmission of the neuro impulse pharmacologically to the resting muscle (Wittbrodt 1997). In addition, various degrees of polyneuropathies with demyelination and degeneration of sensory and motor nerves have occurred with long-term use of nitrofurantoin, probably on a toxic basis. Intracranial hypertension associated with nitrofurantoin therapy has been reported (Mushet 1980). A report by Ibanez et al (1994) suggests an intraretinal crystalline deposit in both eyes of a 69-year-old male who for 19 years received nitrofurantoin daily for a chronic urinary tract infection.

Generic name: Nitrofurantoin.

Proprietary names: Furadantin, Macrodantin, Macrobid.

Primary use

This bactericidal furan derivative is effective against specific ­organisms that cause urinary tract infections, especially E. coli, enterococci and S. aureus.

Ocular side effects

Systemic administration

Certain

1. Non-specific ocular irritation

a.Lacrimation

b.Burning sensation

c.Epiphoria

References and Further Reading

Ibanez HE, Williams DF, Boniuk I. Crystalline retinopathy associated with long-term nitrofurantoin therapy. Case report. Arch Ophthalmol 112: 304–305, 1994.

Mesaros MP, Seymour J, Sadjadpour K. Lateral rectus muscle palsy associated with nitrofurantoin (Macrodantoin). Am J Ophthalmol 94: 816, 1982.

Mushet GR. Pseudotumor and nitrofurantoin therapy. Arch Neurol 34: 257, 1977.

Nitrofurantoin. Med Lett Drugs Ther 22: 36, 1980.

Penn RG, Griffin JP. Adverse reactions to nitrofurantoin in the United Kingdom, Sweden. Holland. BMJ 284: 1440, 1982.

Sharma DB, James A. Benign intracranial hypertension associated with nitrofurantoin therapy. BMJ 4: 771, 1974.

Toole JF, Parrish MD. Nitrofurantoin polyneuropathy. Neurology 23: 554–559, 1973.

Wasserman BN, Chronister TE, Stark BI, Saran BR. Ocular myasthenia and nitrofurantoin. Am J Ophthalmol 130: 531–533, 2000.

Wittbrodt ET. Drugs and myasthenia gravis: an update. Arch Intern Med 157(4): 399–408, 1997.