Which psychotropic drugs should be avoided in a patient with pigmentary retinopathy?/nBackground: A

Fråga: Which psychotropic drugs should be avoided in a patient with pigmentary retinopathy?

Background: A 25 years old patient with retinitis pigmentosa and impaired vision has been taking chlorpromazine (Hibernal) and orphenadrine (Disipal).

Sammanfattning: Phenothiazines can cause pigmentary retinopathy and impair vision, thioridazine being the compound most often mentioned as the causative agent. If the patient´s condition is related to long term use of chlorpromazine a change to a neuroleptic other than chlorpromazine and thioridazine seems rational although not founded on data showing different properties to cause this side effect. There is no documentation to support the hypothesis that a patient who suffers from a congenital retinitis pigmentosa would be more sensitive to ocular side effects of neuroleptics than other patients.

Svar: Pigmentary retinopathy has been described as a rare side effect of phenothiazine derivatives (1,2). Among the phenothiazines, the condition is more commonly associated with prolonged administration of thioridazine given in excessive dosage of 1200-1800 mg daily (3,4), although one case has been reported with 400 mg daily (5). A phototoxic process has been postulated based on the strong affinity of phenothiazine derivatives for melanin (1,6). No other psychotropic drugs have been associated with pigmentary retinopathy.

Pigmentary deposits in the cornea are reported with chlorpromazine and thioridazine and may occur simultaneously to pigmentary changes in the skin (3,6). Phenothiazines can also cause photosensibility of the conjunctiva (4). 1 Alkemade PPH: Phenothiazine-retinopathy. Ophthalmologica 1968; 155: 70-76

2 Drugline nr 04895 (bifogas)
3 Meyler´s, Side effects of drugs. Ed by MNG Dukes, Elsevier, Amsterdam. 1984; 10th ed: 101-102, 38-39
4 Amerson SR, Ocular side effects of drugs and basic pharmacology. 1972, 37, 144
5 Lam RW: Pigmentary retinopathy associated with low-dose thioridazine treatment. Can Med Assoc J 1985; 132: 737

6 Fraunfelder FT, Drug-induced ocular side effects and drug interactions. 1982; 2nd ed: 97-100