HALOPERIDOL

  • Be able to compare the PD of haloperidol with the other anti-psychotics.
Structure/class
  1. Typical anti-psychotic of the Butyrophenone class.
Pharmacodynamics
  1. D2 receptor antagonist.
  2. Also has α-blockade, serotonergic blockade, histaminergic blockade and muscarinic blockade (see previous page for side effect details)
  3. Haloperidol has the highest chance of causing extra-pyramidal SES.
Administration
  1. PO, IM, IV
Distribution
  1. Readily (but incompletely) absorbed
  2. Highly lipid soluble, strong protein binding and large Vd – means that it has a longer clinical duration of action than can be predicted from T ½
Metabolism
  1. Hepatic. Note that haloperidol has the least first-pass metabolism with bioavailability 65%.
Excretion
  1. Urine
Indications
  1. Psychosis
  2. Mania
  3. Agitation/Tourette
  4. Droperidol (a butyrophenone) is used together with fentanyl as neurolepanaesthesia.
Contraindications
Special precautions
  1. Elderly – oversedation
  2. Liver disease
  3. CVS disease
Interactions
  1. Haloperidol may potentiate the effects of other CNS depressants, especially if used in conjunction with benzodiazepines
  2. Reduced effect of Levodopa
  3. Worsens Parkinson’s disease
Adverse events
  1. As with previous page
Dosing/administration
Toxicology
Withdrawal syndrome
Special notes