Perphenazine Side Effects

ADVERSE REACTIONS Not all of the following adverse reactions have been reported with this specific drug;

however, pharmacological similarities among various phenothiazine derivatives require that each be considered.

With the piperazine group (of which perphenazine is an example), the extrapyramidal symptoms are more common, and others (e.g., sedative effects, jaundice, and blood dyscrasias) are less frequently seen.

CNS Effects Extrapyramidal Reactions opisthotonus, trismus, torticollis, retrocollis, aching and numbness of the limbs, motor restlessness, oculogyric crisis, hyperreflexia, dystonia, including protrusion, discoloration, aching and rounding of the tongue, tonic spasm of the masticatory muscles, tight feeling in the throat, slurred speech, dysphagia, akathisia, dyskinesia, parkinsonism, and ataxia.

Their incidence and severity usually increase with an increase in dosage, but there is considerable individual variation in the tendency to develop such symptoms.

Extrapyramidal symptoms can usually be controlled by the concomitant use of effective antiparkinsonian drugs, such as benztropine mesylate, and/or by reduction in dosage.

In some instances, however, these extrapyramidal reactions may persist after discontinuation of treatment with perphenazine.

Dystonia Class effect: Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment.

Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue.

While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first generation antipsychotic drugs.