fluphenazine decanoate

Action

Unclear. May alter postsynaptic mesolimbic dopamine receptors in brain and reduce release of hypothalamic and hypophyseal hormones thought to depress reticular activating system, thereby preventing psychotic symptoms.

Availability

fluphenazine decanoate

Depot injection: 25 mg/ml

fluphenazine hydrochloride

Elixir: 2.5 mg/5 ml

Injection: 2.5 mg/ml

Oral concentrate: 5 mg/ml

Tablets: 1 mg, 2.5 mg, 5 mg, 10 mg

Indications and dosages

➣ Psychotic disorders

Adults: 2.5 to 10 mg/day (hydrochloride) P.O. in divided doses q 6 to 8 hours or as a single dose at bedtime; typical daily dosage is 1 to 5 mg; give oral doses above 20 mg/day with caution. Or initially, 1.25 mg I.M., divided and given q 6 to 8 hours. Parenteral hydrochloride dosage is one-third to one-half of oral dosage. Or 12.5 to 25 mg I.M. or subcutaneously (decanoate); base subsequent dosage and dosing intervals of 1 to 4 weeks on patient response; don't exceed 100 mg.

Dosage adjustment

• Elderly patients

Contraindications

• Hypersensitivity to drug, sulfites (with injectable form), or benzyl alcohol

• Angle-closure glaucoma

• Bone marrow depression

• Severe hepatic or cardiovascular disease

Precautions

Use cautiously in:

• diabetes, respiratory disease, prostatic hypertrophy, CNS tumors

• elderly patients

• pregnant or breastfeeding patients (safety not established)

• children with acute illnesses, infections, gastroenteritis, or dehydration.

Administration

See Be aware that parenteral form is for I.M. and subcutaneous use only. Don't give I.V.

• Don't give parenteral form to comatose or severely depressed patient.

• Use gloves when handling. To prevent contact dermatitis, keep drug away from clothing and skin.

• Dilute concentrated oral forms in juice, milk, or semisolid food just before administering.

• Give long-acting, oil-based preparations with dry needle of at least 21G.

• Be aware that antacids and adsorbent antidiarrheals may decrease adsorption of fluphenazine. Give 1 hour before or 2 hours after fluphenazine.

Adverse reactions

CNS: drowsiness, sedation, extrapyramidal reactions, tardive dyskinesia, pseudoparkinsonism, neuroleptic malignant syndrome, seizures

CV: hypotension, tachycardia

EENT: blurred vision, dry eyes, lens opacities, nasal congestion

GI: constipation, dry mouth, anorexia, paralytic ileus

GU: urinary retention, menstrual irregularities, inhibited ejaculation, priapism, gynecomastia, lactation

Hematologic: eosinophilia, hemolytic anemia, aplastic anemia, agranulocytosis, leukopenia, thrombocytopenia

Hepatic: jaundice, hepatitis

Metabolic: galactorrhea, hyperthermia

Skin: photosensitivity, rash

Other: allergic reactions, pain at injection site, sterile abscess

Interactions

Drug-drug. Activated charcoal, adsorbent antidiarrheals, antacids: decreased fluphenazine adsorption

Anticholinergics: decreased fluphenazine effects

Antidepressants, antihistamines, general anesthetics, MAO inhibitors, opioid analgesics, sedative-hypnotics: additive CNS depression

Antihistamines, disopyramide, quinidine, tricyclic antidepressants (TCAs): increased risk of anticholinergic effects

Antihypertensives: additive hypotension

Barbiturates: increased fluphenazine metabolism and decreased efficacy

Bromocriptine: decreased bromocriptine efficacy

Guanethidine: inhibition of antihypertensive effects

Lithium: disorientation, unconsciousness, extrapyramidal symptoms

Meperidine: excessive sedation and hypotension

Ofloxacin: increased QTc interval

Phenytoin: increased or decreased phenytoin blood level

Pimozide: increased risk of potentially serious cardiovascular reactions

Propranolol: increased blood levels of both drugs

TCAs: increased blood levels and effects of TCAs

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin: increased levels

Granulocytes, hematocrit, hemoglobin, leukocytes, platelets: decreased values

Pregnancy tests: false-positive or false-negative result

Urine bilirubin: false-positive result

Drug-herbs. Angel's trumpet, jimsonweed, scopolia: increased anticholinergic effects

Chamomile, hops, kava, skullcap: increased CNS depression

St. John's wort: photosensitivity

Yohimbe: fluphenazine toxicity

Drug-behaviors. Alcohol use: increased CNS depression

Sun exposure: increased risk of photosensitivity

Patient monitoring

See Monitor patient for signs and symptoms of neuroleptic malignant syndrome (extrapyramidal symptoms, hyperthermia, autonomic symptoms).

See Stop giving drug and notify prescriber immediately if patient shows signs or symptoms of blood dyscrasias (fever, infection, sore throat, cellulitis, or weakness).

• Observe for tardive dyskinesia.

• Watch for bleeding tendency.

• Monitor CBC, bilirubin level, and liver function test results.

• Assess kidney function and ophthalmic test results in patients on long-term therapy.

Patient teaching

See Tell patient not to stop taking drug suddenly, because serious adverse effects may occur.

• Advise patient to report urinary retention or constipation.

See Instruct patient to immediately report unusual bleeding or bruising.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, alertness, and vision.

• Tell patient to avoid activities that can cause injury. Advise him to use soft toothbrush and electric razor to avoid gum and skin injury.

• Inform patient that he'll undergo regular blood testing during therapy.

• Tell female patient to inform prescriber if she is pregnant or breastfeeding.

• 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.