Ocular and cutaneous effects of chronic phenothiazine therapy

Abstract

The pathogenesis and treatment of the ocular and cutaneous effects of chronic phenothiazine therapy are reviewed. Lenticular and corneal lesions, including epithelial keratopathy, have been associated primarily with several years of high-dose chlorpromazine therapy; in most cases the lesions do not significantly affect the patient's vision. Pigmentary retinopathy is the most serious phenothiazine- induced ocular effect, thioridazine being the most common offender. Critical factors in the development of thioridazine-induced retinopathy are the dosage and duration of therapy Permanent visual impairment can be prevented by dosage limitation and early detection. Chronic high-dose phenothiazine therapy also can produce abnormal pigmentation, of the skin. Chlorpromazine is the phenothiazine most commonly implicated. Phenothiazine-induced melanin infiltration of the myocardium may be associated with irregular cardiac rhythm and toxic cardiomyopathy. Melanosis and blue-gray coloration can be treated by avoiding or limiting sunlight exposure and, rarely, with penicillamine. To minimize ocular and cutaneous effects, phenothiazine dosage and duration of therapy should be limited and drug holidays should be considered. If a patient develops potentially serious effects while receiving a prolonged high dosage of phenothiazine, the clinician should consider temporarily discontinuing phenothiazine therapy or prescribing other nonphenothiazine neuroleptics (e.g., haloperidol) or phenothiazines that are effective at low doses (e.g., piperazme derivatives). If the patient's overall condition warrants a continued high dosage of phenothiazine, frequent and careful examinations of the patient are needed.