Pharmacology and Biochemistry of HaloperidolHaldol, Haldol Decanoate, more Haloperidol Hxloperidol, Peridol Classes: Lower initial doses and more gradual adjustments recommended; 0. Lower adult doses and longer dosing intervals recommended compared with typical adult doses. Lower initial doses pharmacology of haloperidol more gradual adjustments recommended; monthly dose times daily PO dose.
Haloperidol , marketed under the trade name Haldol among others, is a typical antipsychotic medication. Haloperidol may result in a movement disorder known as tardive dyskinesia which may be permanent. Haloperidol was discovered in by Paul Janssen.
Haloperidol was considered indispensable for treating psychiatric emergency situations,   although the newer atypical drugs have gained greater role in a number of situations as outlined in a series of consensus reviews published between and In a comparison of 15 antipsychotics in schizophrenia, haloperidol demonstrated standard effectiveness.
Data from animal experiments indicate haloperidol is not teratogenic , but is embryotoxic in high doses. In humans, no controlled studies exist. Reports in pregnant women revealed possible damage to the fetus, although most of the women were exposed to multiple drugs during pregnancy. Following accepted general principles, haloperidol should be given during pregnancy only if the benefit to the mother clearly outweighs the potential fetal risk.
Haloperidol, when given to lactating women, is found in significant amounts in their milk. Breastfed children sometimes show extrapyramidal symptoms. If the use of haloperidol during lactation seems indicated, the benefit for the mother should clearly outweigh the risk for the child, or breastfeeding should be stopped.
During long-term treatment of chronic psychiatric disorders, the daily dose should be reduced to the lowest level needed for maintenance of remission. Sometimes, it may be indicated to terminate haloperidol treatment gradually.
The decanoate ester of haloperidol haloperidol decanoate, trade names Haldol decanoate, Halomonth, Neoperidole has a much longer duration of action, so is often used in people known to be noncompliant with oral medication. A dose is given by intramuscular injection once every two to four weeks. Topical formulations of haloperidol should not be used as treatment for nausea because research does not indicate this therapy is more effective than alternatives.
Sources for the following lists of adverse effects    . As haloperidol is a high-potency typical antipsychotic, it tends to produce significant extrapyramidal side effects. According to a meta-analysis of the comparative efficacy and tolerability of 15 antipsychotic drugs it was the most prone of the 15 for causing extrapyramidal side effects.
Treatment is merely symptomatic and involves intensive care with stabilization of vital functions. In early detected cases of oral overdose, induction of emesis , gastric lavage , and the use of activated charcoal can all be tried. Epinephrine is avoided for treatment of hypotension and shock, because its action might be reversed. In the case of a severe overdose, antidotes such as bromocriptine or ropinirole may be used to treat the extrapyramidal effects caused by haloperidol, acting as dopamine receptor agonists.
In general, the prognosis of overdose is good, provided the person has survived the initial phase. An overdose of haloperidol can be fatal. Haloperidol is a typical butyrophenone type antipsychotic that exhibits high affinity dopamine D 2 receptor antagonism and slow receptor dissociation kinetics.
Given that antagonism of D 2 receptors is more beneficial on the positive symptoms of schizophrenia and antagonism of 5-HT 2 receptors on the negative symptoms, this characteristic underlies haloperidol's greater effect on delusions, hallucinations and other manifestations of psychosis.
Haloperidol acts on these receptors: The drug is well and rapidly absorbed with a high bioavailability when injected intramuscularly.
The T max is 20 minutes in healthy individuals and The plasma concentrations of haloperidol decanoate reach a peak at about six days after the injection, falling thereafter, with an approximate half-life of three weeks.
The apparent volume of distribution is between 9. If haloperidol is given as a slow IV infusion, the onset of action is slowed, and the duration of action is prolonged. Plasma levels of four to 25 micrograms per liter are required for therapeutic action. The determination of plasma levels can be used to calculate dose adjustments and to check compliance, particularly in long-term patients.
Plasma levels in excess of the therapeutic range may lead to a higher incidence of side effects or even pose the risk of haloperidol intoxication. The concentration of haloperidol in brain tissue is about fold higher compared to blood levels. It is slowly eliminated from brain tissue,  which may explain the slow disappearance of side effects when the medication is stopped.
Haloperidol is heavily protein bound in human plasma, with a free fraction of only 7. The greatest proportion of the hepatic clearance is by glucuronidation, followed by reduction and CYP-mediated oxidation, primarily by CYP3A4.
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Fluspirilene Penfluridol Pimozide Phenothiazines: Chlorprothixene Clopenthixol Flupentixol Tiotixene thiothixene Zuclopenthixol. Azacyclonol Cannabidiol Oxypertine Reserpine Tetrabenazine. Dronabinol Nabilone Tetrahydrocannabinol cannabis. Atropine Diphenhydramine Hydroxyzine very mild Hyoscyamine Scopolamine.