Introduction to Haloperidol

Haloperidol (Haldol) is the first of the butyrophenone series of major antipsychotics. The chemical designation is 4-[4-(p-chlorophenyl)-4-hydroxypiperidino] 4’-fluorobutyrophenone. [1]
It comes as tablets, oral liquid, fast-acting injection, and long-acting injection (deconate).

Using Haloperidol

Haloperidol dosage

Moderate disease: 0.5 mg to 2 mg every 8 to 12 hours
Severe disease: 3 mg to 5 mg every 8 to 12 hours initially; not to exceed 30 mg per day.

Haloperidol pharmacology

Antagonizes dopamine D1 and D2 receptors in the brain; depresses reticular activating system and inhibits release of hypothalamic and hypophyseal hormones.[2]

Haloperidol metabolism

Metabolized by hepatic enzyme CYP3A4 into hydroxyhaloperidol. Inhibits CYP2D6 enzyme.
Half-life: 18 hours.

Dangers of Haloperidol

Haloperidol side effects

Extrapyramidal symptoms, including akathisia, muscle stiffness, parkinsonism, and tardive dyskinesia (which may be permanent) are common. Other side effects include sedation and weight gain.

General warnings about Haloperidol

Haloperidol and recreational drugs

Haloperidol and fenanyl increase the effect of one another by effecting CYP3A4 metabolism, which may lead to respiratory depression, profound sedation, and coma or death. Other central nervous system depressants (such as skeletal muscle relaxants or benzodiazepines) can also be dangerous when combined with haloperidol.
Because of it's fast action, relatively short duration of action, lack of lingering side effects, and general availability, haloperidol would be a good trip-ender.
When combining drugs which may be psychotomimetic, including cannabis, with antipsychotics like haloperidol, reactions may be unpredictable.

References

1. ^Haldol [package insert]. Raritan, NJ: Ortho-McNeil Pharmaceutical, Inc.; Revised June 2009.
2. ^Medscape app, "haloperidol pharmacology" accessed 8/22/20.