chlorpromazine THORAZINE

Class: First Generation Antipsychotic/​Phenothiazine
FDA Indications: Psychotic Disorders, Schizophrenia, Nausea And Vomiting, Preoperative Apprehension, Acute Intermittent Porphyria, Adjunct In The Treatment Of Tetanus, Control The Manifestations Of The Manic Type Of Manic-depressive Illness, Intractable Hiccups, Intraoperative Sedation
Off-Label Use: Migraines
Prescribing
Forms: 10, 25, 50, 100, 200mg tablet; 5,20,40mg/ml po soln; 50mg/2ml IM
Dose Range: 25-2000 mg/day
Starting: 25 mg tid; ↑ by 25-50 mg q3-4d; minimal effective dose is roughly 200-400 mg/d; doses of 800 mg/d not uncommon
Stopping: Taper 6-8 weeks, rapid d/c can lead to rebound psychosis
Monitoring:

NAMI drug fact sheet

Precautions
Contraindications: Avoid using in children with suspected Reye syndrome. Use caution in glaucoma, prostatic hypertrophy, stenosing peptic ulcer disease (PUD), history of NMS, Parkinson disease, hypocalcemia, renal or hepatic impairment, history of severe reaction to insulin or electroconvulsive therapy (ECT), history of seizures, asthma, respiratory tract infection, cardiovascular disease, myelosuppression.
Serious Side Effects: , , , Cardiac Arrhythmias, Neutropenia and/or Agranulocytosis (rare), Hyperprolactinemia
Drugs to Avoid in Congenital Long QT
Side Effects: sedation/somnolence, constipation, xerostomia, nausea, urinary retention, restlessness, priapism, jaundice, postural hypotension, pseudoparkinsonism, skin pigmentation
Pharmacodynamics
1° MOA: Dopamine 2 (D2) receptor antagonism in mesolimbic area
Target: D1 (high), D2 (high), 5HT2A (strong), Postsynaptic 5HT1A, 5HT2C, α1 (very high), H1 (high), M1 (high)
Pharmacokinetics
t½: 24 (8-35)° TMAX: 2-4°
Substrate of: 1A2, 2D6, 3A4
Inhibits: ∅ ; Induces:
Active Metabolites: 7-hydroxychlorpromazine
DDIs
  • - 1A2, 2D6 & 3A4 inhibitors can ↑ levels; 1A2, 2D6 & 3A4 inducers can ↓ levels
  • - caution when co-prescribed with other medications that can lower blood pressure
  • - caution when co-prescribed with other CNS depressants
  • - caution when co-prescribed with other medications that can lower seizure threshold
Misc
  • - With acute usage, the most striking effect relates to central H1 (antihistaminic) actions, as chlorpromazine is sedating on first exposure
  • - Persistence of low-grade sedation (as opposed to apathy) is the major reason why chlorpromazine on its own is nowadays of limited use as a long-term maintenance agent
  • - In the words of Edward Shorter, "chlorpromazine initiated a revolution in psychiatry, comparable to the introduction of penicillin in general medicine"
Special Populations

Category C—Although one survey found an increased incidence of defects and a report of ectromelia exists, most studies have found chlorpromazine to be safe for both mother and embryo-fetus if used occasionally in low doses. However, use near term should be avoided due to the danger of maternal hypotension and adverse effects in the newborn.

In 2001, the American Academy of Pediatrics classified chlorpromazine as an agent whose effect on the nursing infant is unknown but may be of concern because of the drowsiness and lethargy observed in one case report

Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death.

No dosage adjustment necessary.


No dosage adjustment necessary.

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Last updated May 19 2018 15:53:20. Disclaimer: This website does not provide medical advice, nor is it a substitute for clinical judgment.