Acetophenazine

Pronunciation

(a set oh FEN a zeen)

Synonyms

Acetophenazine Maleate

Generic Available

Use

Management of manifestations of psychotic disorders

Restrictions

Not available in U.S.

Pregnancy Risk Factor

Contraindications

Hypersensitivity to acetophenazine or any component of the formulation; blood dyscrasias and bone marrow suppression; patients in coma or brain damage

Adverse Reactions

>10%:

Cardiovascular: Hypotension, orthostatic hypotension

Central nervous system: Pseudoparkinsonism, akathisia, dystonias, tardive dyskinesia, dizziness

Gastrointestinal: Constipation

Ocular: Pigmentary retinopathy

Respiratory: Nasal congestion

Miscellaneous: Diaphoresis (decreased)

1% to 10%:

Dermatologic: Increased sensitivity to sun, rash

Endocrine & metabolic: Changes in menstrual cycle, breast pain, libido (changes in)

Gastrointestinal: Weight gain, nausea, vomiting, stomach pain

Genitourinary: Difficulty in urination, ejaculatory disturbances

Neuromuscular & skeletal: Trembling fingers

<1%: Agranulocytosis, cholestatic jaundice, cornea and lens changes, discoloration of skin (blue-gray), galactorrhea, hepatotoxicity, impairment of temperature regulation, leukopenia, lowering of seizure threshold, neuroleptic malignant syndrome (NMS), pigmentary retinopathy, priapism

Drug Interactions

Aluminum salts: May decrease the absorption of phenothiazines; monitor

Amphetamines: Efficacy may be diminished by antipsychotics. In addition, amphetamines may increase psychotic symptoms; avoid concurrent use.

Anticholinergics: May inhibit the therapeutic response to phenothiazines and excess anticholinergic effects may occur; includes benztropine, trihexyphenidyl, biperiden, and drugs with significant anticholinergic activity (TCAs, antihistamines, disopyramide)

Antihypertensives: Concurrent use of phenothiazines with an antihypertensive may produce additive hypotensive effects (particularly orthostasis)

Bromocriptine: Phenothiazines inhibit the ability of bromocriptine to lower serum prolactin concentrations

CNS depressants: Sedative effects may be additive with phenothiazines; monitor for increased effect; includes barbiturates, benzodiazepines, narcotic analgesics, ethanol, and other sedative agents

Epinephrine: Chlorpromazine (and possibly other low potency antipsychotics) may diminish the pressor effects of epinephrine

Guanethidine and guanadrel: Antihypertensive effects may be inhibited by chlorpromazine

Levodopa: Chlorpromazine may inhibit the antiparkinsonian effect of levodopa; avoid this combination

Lithium: Chlorpromazine may produce neurotoxicity with lithium; this is a rare effect

Metoclopramide: May increase extrapyramidal symptoms (EPS) or risk.

Phenytoin: May reduce serum levels of phenothiazines; phenothiazines may increase phenytoin serum levels

Propranolol: Serum concentrations of phenothiazines may be increased; propranolol also increases phenothiazine concentrations

Polypeptide antibiotics: Rare cases of respiratory paralysis have been reported with concurrent use of phenothiazines

QTc-prolonging agents: Effects on QTc interval may be additive with phenothiazines, increasing the risk of malignant arrhythmias; includes type Ia antiarrhythmics, TCAs, and some quinolone antibiotics (sparfloxacin, moxifloxacin and gatifloxacin)

Sulfadoxine-pyrimethamine: May increase phenothiazine concentrations

Tricyclic antidepressants: Concurrent use may produce increased toxicity or altered therapeutic response

Trazodone: Phenothiazines and trazodone may produce additive hypotensive effects

Valproic acid: Serum levels may be increased by phenothiazines

Ethanol/Nutrition/Herb Interactions

Ethanol: Avoid ethanol (may increased sedation)

Stability

Protect from light; dispense in amber or opaque vials

Mechanism of Action

Acetophenazine is a piperazine phenothiazine antipsychotic which antagonizes the effects of dopamine in the basal ganglia and limbic areas of the forebrain; this activity appears responsible for the antipsychotic efficacy, as well as the production of extrapyramidal symptoms; increases the secretion of prolactin and has a marked suppressive effect on the chemoreceptor trigger zone; also produces peripheral blockade of cholinergic neurons

Pharmacodynamics/Kinetics

Onset of action: 2-4 hours

Duration: ~24 hours

Absorption: Tissue saturation, particularly in high lipid tissues (eg, CNS)

Half-life elimination: 20-40 hours

Dosage

Adults: Oral: 20 mg 3 times/day up to 60-120 mg/day

Hospitalized schizophrenic patients may require doses as high as 400-600 mg/day

Hemodialysis: Not dialyzable (0% to 5%)

Monitoring Parameters

Vital signs; lipid profile, fasting blood glucose/Hgb A1c; BMI; mental status, abnormal involuntary movement scale (AIMS), extrapyramidal symptoms (EPS)

Patient Education

Do not take antacid within 1 hour of taking drug; may cause drowsiness, avoid alcohol; avoid excess sun exposure (use sunblock); rise slowly from recumbent position; use of supportive stockings may help prevent orthostatic hypotension

Nursing Implications

Observe for tremor and abnormal movement or posturing (extrapyramidal symptoms), increased confusion or psychotic behavior, constipation, urinary retention, abnormal gait

Additional Information

Not available in U.S.

Dental Health: Effects on Dental Treatment

No significant effects or complications reported

Dental Health: Vasoconstrictor/Local Anesthetic Precautions

No information available to require special precautions

Dosage Forms

Tablet, as maleate: 20 mg

References

Peabody CA, Warner MD, Whiteford HA, et al, "Neuroleptics and the Elderly," J Am Geriatr Soc , 1987, 35(3):233-8.

Risse SC and Barnes R, "Pharmacologic Treatment of Agitation Associated With Dementia," J Am Geriatr Soc , 1986, 34(5):368-76.

Saltz BL, Woerner MG, Kane JM, et al, "Prospective Study of Tardive Dyskinesia Incidence in the Elderly," JAMA , 1991, 266(17):2402-6.

Seifert RD, "Therapeutic Drug Monitoring: Psychotropic Drugs," J Pharm Pract , 1984, 6:403-16.

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