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Pharmacologic class: Phenothiazine, dopaminergic antagonist
Therapeutic class: Antipsychotic, antiemetic
Pregnancy risk category NR
Unknown. Thought to antagonize dopamine and serotonin type 2 in CNS. Also antagonizes muscarinic receptors in respiratory tract, causing cholinergic activation.
Tablets: 2 mg, 4 mg, 8 mg, 16 mg
Indications and dosages
➣ Schizophrenia in nonhospitalized patients
Adults and children older than age 12: Initially, 4 to 8 mg P.O. t.i.d.
➣ Schizophrenia in hospitalized patients
Adults and children older than age 12: Initially, 8 to 16 mg P.O. two to four times daily, increased p.r.n.; avoid dosages greater than 64 mg daily.
➣ Severe nausea and vomiting
Adults: 8 to 16 mg P.O. daily in divided doses, to a maximum of 24 mg.
• Intractable hiccups
• Hypersensitivity to drug, its components, or related compounds
• Blood dyscrasias
• Bone marrow depression
• Hepatic damage
• Subcortical damage
• Concurrent use of high-dose CNS depressants
Use cautiously in:
• respiratory disorders, hepatic or renal dysfunction, breast cancer, alcohol withdrawal symptoms, suicidal tendency, surgery
• patients taking CNS depressants or anticholinergics
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 12.
• Give with food to avoid GI upset.
CNS: drowsiness, dizziness, insomnia, vertigo, headache, hyperactivity, nocturnal confusion, bizarre dreams, tremor, ataxia, slurring, exacerbation of psychotic symptoms, paranoid reactions, parkin-sonism, dystonias, akathisia, tardive dyskinesia, hyperreflexia, cerebrospinal fluid abnormality, catatonic-like state, paradoxical stimulation, seizures, neuroleptic malignant syndrome
CV: hypotension, orthostatic hypotension, hypertension, peripheral edema, ECG changes, tachycardia, bradycardia, cardiac arrest, heart failure
EENT: glaucoma, blurred vision, miosis, mydriasis, corneal and lens deposits, pigmentary retinopathy, oculogyric crisis, photophobia, nasal congestion, dysphagia
GI: nausea, vomiting, diarrhea, constipation, obstipation, abnormal tongue color or movement, dry mouth, anorexia, adynamic ileus
GU: dark urine, urinary retention, urinary frequency, urinary incontinence, bladder paralysis, galactorrhea, lactation, breast enlargement, menstrual irregularities, inhibited ejaculation, libido changes
Hematologic: hemolytic anemia, leukopenia, agranulocytosis, thrombocytopenic purpura
Hepatic: jaundice, biliary stasis
Metabolic: hyponatremia, glycosuria, hyperglycemia, hypoglycemia, syndrome of inappropriate antidiuretic hormone secretion, pituitary tumor
Musculoskeletal: numbness and aching of arms and legs
Respiratory: dyspnea, suppressed cough reflex, asthma, bronchospasm, laryngospasm, laryngeal edema
Skin: urticaria, pallor, erythema, eczema, pruritus, perspiration, pigmentation changes, photosensitivity, angioedema, exfoliative dermatitis
Other: increased appetite, weight gain, fever, systemic lupus erythematosuslike syndrome, hypersensitivity reactions including anaphylactoid reaction
Drug-drug. Anticholinergics: increased risk of adverse anticholinergic reactions
CNS depressants: increased perphenazine effects, increased adverse CNS reactions
Tricyclic antidepressants: increased perphenazine blood level, greater risk of adverse reactions
Drug-diagnostic tests. Eosinophils, liver function tests: increased values Glucose: increased or decreased level Granulocytes, hemoglobin, platelets, sodium, white blood cells: decreased levels
Pregnancy test: false-positive result
Drug-herbs. Kava: dystonic reactions
St. John's wort: photosensitivity
Yohimbe: yohimbe toxicity
Drug-behaviors. Alcohol use: increased CNS depression
Sun exposure: increased risk of photosensitivity reaction
☞ Watch for anaphylactoid reaction and angioedema. Monitor neurologic status; stay alert for signs and symptoms of neuroleptic malignant syndrome (high fever, unstable blood pressure, stupor, muscle rigidity, autonomic dysfunction), parkinsonian symptoms, and catatonic-like state.
• Monitor cardiovascular status and vital signs periodically.
☞ Evaluate respiratory status, especially for dyspnea and airway spasm.
☞ Monitor CBC, glucose level, and liver function tests. Watch for evidence of blood dyscrasias.
• Explain importance of combining drug therapy with psychotherapy.
• Tell patient to take exactly as prescribed and to report adverse reactions promptly.
• Instruct patient to avoid sun exposure and to wear sunscreen outdoors to prevent photosensitivity reaction.
• Advise patient to consult prescriber before taking other prescription drugs or over-the-counter preparations.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects him.
• Instruct patient to avoid alcohol, smoking, caffeine, and herbs.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.