Information concerning optic neuropathy as a side-effect of amiodarone treatment is requested as tw

Fråga: Information concerning optic neuropathy as a side-effect of amiodarone treatment is requested as two cases have recently been reported to the Swedish Adverse Drug Reactions Advisory Committee (SADRAC).

Sammanfattning: Optic neuropathy has been reported in connection with amiodarone treatment. The frequency of this side-effect is difficult to determine, as the underlying illness in the amiodarone-treated population also increases the risk of ischemic optic neuropathy.

Svar: Optic neuropathy is listed as a rare (occurring in a frequency of less than 1/1000) side-effect of amiodarone treatment in FASS (1). A total of three cases has been reported to SADRAC. The WHO side-effect registry contains 31 reports labelled optic neuritis and another 91 reports of abnormal vision. Corneal deposits are the most frequently reported adverse events involving the eye, with 171 reports to WHO and 14 reports to SADRAC.

A literature search including Medline and Embase has revealed about 20 cases of amiodarone-associated optic neuropathy (2-9), 13 of which are reported in the same article (2). From 1981 to 1986, 447 patients were treated with amiodarone in one clinic. All were followed with an ophtalmic examination, at least yearly. Seven patients experienced sudden visual disturbances (including decreased visual acuity and/or visual field) and another two patients had edema of the optical disc on routine examination. One of these patients was diagnosed with temporal arteritis, but none of the others had any signs suggesting arteritis. All patients had pallid swelling of the optic disc unilaterally (6 cases) or bilaterally (2 cases). Another similar five cases, collected by two physicans outside the clinic are described. Three patients improved after drug withdrawal. The incidence of optic neuropathy reported in this article was 1.8 per cent, as compared to 0.3 per cent in an age-matched untreated population. The authors conclude that optic neuropathy can possibly be connected to amiodarone treatment. If so, the clinical severity of this drug-related neuropathy seems to be milder than that characteristically described in anterior ischemic optic neuropathy. They add, however, that it cannot be excluded that the underlying illness (cardiovascular disease, diabetes mellitus) in the amiodarone treated patients contributes to the higher frequency in this group, as no comparison has been made with age-matched patients with similar disease. Therefore, they consider the occurrence of optic neuritis in an amiodarone-treated patient a relative indication to stop the treatment (2).

In one case-report the possible mechanism of amiodarone induced optic neuropathy is discussed. A 57-year-old amiodarone treated man underwent enucleation of the right eye due to a melanoma. Multiple lamellated inclusion bodies were seen in several large axons of the optic nerve. The authors conclude that primary lipidosis is a likely mechanism of optic nerve damage in amiodarone treatment (3). 1 FASS 2 Feiner LA, Younge BR, Kazmier FJ, Stricker BHC, Fraunfelder FT: Optic neuropathy and amiodarone therapy. Mayo Clin Proc 1987; 62: 702-717 3 Mansour AM, Puklin JE, O´Grady R: Optic nerve ultrastructure following amiodarone therapy. J Clin Neuro-ophthalmol 1988; 8: 231-237 4 Gittinger JW Jr, Asdourian GK: Amiodarone-related optic neuropathy. Mayo Clin Proc 1988; 63: 210 5 Nazarian SM, Jay WM: Bilateral optic neuropathy associated with amiodarone therapy. J Clin Neuro-ophthalmol 1988; 8: 25-28 6 Dewachter A, Lievens H: Amiodarone and optic neuropathy. Bull Soc Belge Ophtalmol 1988; 227: 47-50 7 Belec L, Davila G, Bleibel JM, Azoulay A, Laloun L, Poisson M: Neuropathie optique bilaterale au cours d´un traitement prolonge par l´amiodarone. Ann Med Interne (Paris) 1992; 143: 349-350 8 Krieg P, Schipper I: Bilaterale Optikusneuropathie nach Amiodarone-Therapie. Klin Mbl Augenheilk 1992; 200: 128-132 9 Hedges TR III, Newman NJ: Getting to the heart of visual loss: when cardiac medication may be dangerous to the optic nerves. Surv Ophthalmol 1992; 36: 366-372