Anticholinergic effects of phenothiazines include blurred vision, xerostomia, mydriasis, nausea, adynamic ileus, urinary retention, impotence, and constipation. These effects can be enhanced by the concomitant administration of anticholinergic antiparkinsonian drugs, antidepressants, or other anticholinergic agents. Leukopenia including agranulocytosis is the most common hematologic disturbance that has been reported during phenothiazine administration. Agranulocytosis has occurred rarely and has been associated with combination treatment with other agents. Prolonged therapy with phenothiazines can lead to skin hyperpigmentation.
Hyperpigmentation generally is restricted to areas of the body exposed to sunlight.
Withdrawal of the drug can reverse the effects. Contact dermatitis is also possible in predisposed individuals if they come in contact with liquid dosage forms of phenothiazines. Phenothiazines can cause ocular changes. Pigmentary retinopathy can occur with or without pigmentary changes in the skin during therapy with phenothiazines. Symptoms of blurred vision, difficulty with nighttime vision, or defective color vision should be investigated promptly.