The question concerns a 50-year-old woman who has been treated since 1958 with different kinds of n

Fråga: The question concerns a 50-year-old woman who has been treated since 1958 with different kinds of neuroleptics. No further details are known about her medication history. Since December 1992 she has been treated with Trilafon decanoate (perphenazine) one ml every three weeks. Within the last two years, she has developed cataract. Could this be a side-effect of the neuroleptics?

Sammanfattning: Phenothiazines, especially chlorpromazine, have been reported to give rise to pigmentary deposits in the lens. This adverse effect is considered to be related to dose and duration of treatment and may in some cases progress to interfere with vision. One retrospective study found an increased risk of cataract extraction in current users of phenothiazines and those exposed 2-5 years prior to extraction. However, the study did not establish a clear relationship with the duration of treatment. Information concerning dosages used and types of cataract developed was lacking, making the results more difficult to interpret. In conclusion, considering that the patient in this case has been treated with neuroleptics for a very long time and developed cataract at a relatively young age, it cannot be excluded that the cataract could be related to the treatment with neuroleptics.

Svar: The most common ocular adverse effect of phenothiazines is blurred vision, due to their anticholinergic properties (1). Following prolonged use, phenothiazines can also cause lens deposits, mainly reported with chlorpromazine and thioridazine, but also probably caused by other phenothiazines (2,3). These deposits are caused by melanin-drug complex deposition and are considered only rarely to cause decreased visual acuity. However, one a case report (4) long-term treatment with chlorpromazine (150-200 mg/day since 1957) was shown to have caused clearly decreased vision in a 71-year-old patient.

One retrospective cohort study was found (5) in which the association between the use of several phenothiazine drugs and haloperidol and the risk of cataract extraction was examined using the data of a health maintenance organization. The antipsychotic phenothiazine drugs included were chlorpromazine, thioridazine, trifluoperazine, perphenazine, fluphenazine hydrochloride and fluphenazine decanoate. All individuals were born 1931 or earlier. It was found that users of phenothiazine drugs showed an association with increased risk of cataract extraction compared with non-users, but there was no clear trend across exposure categories: the use of phenothiazine drugs increased the relative incidence of cataract extraction 3.5 times in current users and 3.3 times in those exposed 2-5 years prior to their extraction. However, there was no association with recent (one year ago), long-term or unknown duration of exposure (relative incidences of 0.92, 0.74 and 0.34 respectively). It was argued that the number of individuals in these latter categories was very small. However, other factors, such as a detection bias due to increased frequency of ophthalmic examinations, could not be excluded as an explanation for the apparent lack of duration-response trend. There was no association between the use of haloperidol and risk for cataract extraction. Unfortunately, the study could not supply any information on cataract subtypes.

Since 1966, the Swedish Adverse Drug Reactions Advisory Committee (SADRAC) has received 22 reports concerning cataract possibly or probably caused by neuroleptics. Most reports concerned phenothiazines such as chlorpromazine, but neuroleptics from other therapeutic groups were also possibly related to the development of cataract.