Classifications: central nervous system agent; psychotherapeutic; phenothiazine antipsychotic; antiemetic
Prototype: Chlorpromazine
Pregnancy Category: C


2 mg, 4 mg, 6 mg, 8 mg, 16 mg, tablets; 16 mg/5 mL liquid; 5 mg/mL injection


Affects all parts of CNS similar to chlorpromazine, particularly the hypothalamus. Antipsychotic effect: Antagonizes the neurotransmitter dopamine by action on dopamine receptors in the brain. Antiemetic action results from direct blockade of dopamine in the chemoreceptor trigger zone (CTZ) in the medulla.

Therapeutic Effects

Has antipychotic and antiemetic properties. Produces less sedation and hypotension, greater antiemetic effects, higher incidence of extrapyramidal effects, and lower levels of anticholinergic adverse effects than chlorpromazine.


Psychotic disorders, symptomatic control of severe nausea and vomiting, acute conditions such as violent retching during surgery, and intractable hiccups.


Hypersensitivity to perphenazine and other phenothiazines; preexisting liver damage; suspected or established subcortical brain damage, comatose states; bone marrow depression. Safety during pregnancy (category C), lactation, or in children <12 y is not established.

Cautious Use

Previously diagnosed breast cancer; liver or kidney dysfunction; cardiovascular disorders; alcohol withdrawal, epilepsy, psychic depression, patients with suicidal tendency; glaucoma; history of intestinal or GU obstruction; geriatric or debilitated patients; patients who will be exposed to extremes of heat or cold, or to phosphorous insecticides.

Route & Dosage

Psychotic Disorders
Adult: PO 4–16 mg b.i.d. to q.i.d.; 8–32 mg sustained release b.i.d. (max: 64 mg/d) IM 5 mg q6h (max: 15–30 mg/d) IV Dilute to 0.5 mg/mL in NS, administer at not more than 1 mg q1–2min or 5 mg by slow infusion
Child: PO 4 mg b.i.d. to q.i.d.; 8 mg sustained release b.i.d. (max:16 mg/d) IM/IV Same as adult

Dementia Behavior
Geriatric: PO 2–4 mg 1–2 times/d, may increase q4–7d (max: 32 mg/d)

Adult: PO 8–16 mg b.i.d. to q.i.d. IM 5 mg q6h (max:15 mg/d)



PREPARE: Direct: Dilute each 5 mg in 9 mL NS.  

ADMINISTER: Direct: Give at a rate of 0.5 mg (1 mL) over 60 sec.  

INCOMPATIBILITIES Solution/additive: Midazolam, pentobarbital, thiethylperazine. Y-site: Cefoperazone, midazolam, pentobarbital.

Adverse Effects (1%)

CNS: Extrapyramidal effects (dystonic reactions, akathisia, parkinsonian syndrome, tardive dyskinesia), sedation, convulsions. CV: Orthostatic hypotension, tachycardia, bradycardia. Special Senses: Mydriasis, blurred vision, corneal and lenticular deposits. GI: Constipation, dry mouth, increased appetite, adynamic ileus, Abnormal liver function tests, cholestatic jaundice. Urogenital: Urinary retention, gynecomastia, menstrual irregularities, inhibited ejaculation. Hematologic: Agranulocytosis, thrombocytopenic purpura, aplastic or hemolytic anemia. Body as a Whole: Photosensitivity, itching, erythema, urticaria, angioneurotic edema, drug fever, anaphylactoid reaction, pain at injection site, sterile abscess. Nasal congestion, decreased sweating. Metabolic: Hyperprolactinemia, galactorrhea, weight gain.

Diagnostic Test Interference

Perphenazine may cause falsely abnormal thyroid function tests because of elevations of thyroid globulin.


Drug: Alcohol and other cns depressants enhance CNS depression; antacids, antidiarrheals may decrease absorption of phenothiazines; anticholinergic agents add to anticholinergic effects including fecal impaction and paralytic ileus; barbiturates, anesthetics increase hypotension and excitation. Herbal: Kava-kava increased risk and severity of dystonic reactions.


Absorption: Poorly absorbed from GI tract; 20% reaches systemic circulation. Onset: 10 min IM. Peak: 1–2 h IM; 4–8 h PO. Duration: 6–12 h. Distribution: Crosses placenta. Metabolism: Metabolized in liver with some metabolism in GI tract. Elimination: Excreted in urine and feces. Half-Life: 9.5 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug