SKIN AND EYE COMPLICATIONS
Most phenothiazines increase sensitivity of the skin to sunlight and may therefore cause severe sunburn with only limited brief exposure to the sun.
This photosensitization is far more common with chlorpromazine than with other phenothiazines. Since metabolites of this drug persist for many months after its administration has been discontinued, the photosensitivity may continue long after the drug has been discontinued. Patients receiving chlorpromazine or other phenothiazines should use carefully applied sunscreens containing para-aminobenzoic acid prior to any sun exposure. Photosensitization does not occur with haloperidol or other nonphenothiazine neuroleptic drugs. Many believe that tricyclic antidepressants can produce photosensitivity reactions. There is no clear evidence that this is true although these agents may at times produce a patchy erythematous skin rash.
High-dosage phenothiazine treatment may give rise to pigmentary changes in the skin or conjunctive. These changes are most likely to occur with chlorpromazine, particularly when administered in high doses. Phenothiazine-induced skin changes generally begin with a tan or brownish coloration, progressing to slate-gray, metallic blue, or purple discoloration of exposed skin surfaces. Biopsy of the involved skin reveals pigmentary granules similar in appearance to melanin. Longterm high-dose chlorpromazine administration produces whitish-brown granular deposits in the anterior subcapsular area of the eye or in the anterior cortex of the lens. These changes may also involve the endothelium and be associated with corneal opacities and in some cases brownish discoloration of the conjunctive. Avoidance of long-term, high-dose administration of chlorpromazine is the best way to avoid these pigmentary changes. Thioridazine may produce pigmentary retinopathy, although in most instances this complication does not occur in daily dosages of less than 800 mg. Since questions have arisen regarding these retinal changes occurring in association with smaller doses of thioridazine, I do not feel comfortable recommending long-term maintenance with this medication at dosages exceeding 400 mg/day. The loss of visual acuity in association with phenothiazine induced changes in the lens or retina has been reported, although this effect appears to be quite rare. There is no evidence that tricyclic antidepressants produce corneal, lenticular, or retinal changes. On the other hand, the association between these drugs and the occurrence of blurred vision and excessive sensitivity to light is well-known. These effects are undoubtedly due to the pupillary dilatation and relaxation of muscles of accommodation produced by the anticholinergic actions of these drugs. Patients with open-angle glaucoma may generally be treated with various psychotropic agents without the fear of worsening this condition, although periodic tonometry may be a useful means of following the patient. Individuals with narrow-angle glaucoma should be treated with caution when tricyclic drugs or neuroleptics must be administered. These patients should receive medications possessing the least possible anticholinergic potency, and antiparkinsonian drugs should generally be avoided. Periodic tonometry in patients with narrow-angle glaucoma being treated with psychotropic medication is of greater necessity than in individuals with open-angle glaucoma. Tinnitus is a rare side effect that has been reported with cyclic antidepressants which may also occur with MAOls. Frequently tinnitus disappears spontaneously or with dosage reduction.