Haloperidol

by Abbas Jahangir · June 14, 2024

Haloperidol is a typical antipsychotic drug , neuroleptic, which is part of the butyrophenones . It is one of the first medications used in the 20th century for the treatment of mental illness, particularly schizophrenia .

It is a non-selective blocker of dopamine receptors in the brain. In addition to its increased activity in psychotic disorders, dopamine involves the extrapyramidal motor pathway; Lately, hypersensitivity can develop due to the constant blockade of these receptors, which explains tardive dyskinesia in long-term treatments.

Summary

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1 Composition.
2 Pharmacology.
3 Description.
4 Indications.
5 Precautions.
6 Contraindications.
7 Warnings.
8 Adverse reactions.
9 Dosage
10 Presentation.
11 Sources.
12 External links.

Composition.

Each tablet contains 1.5mg of haloperidol excipients.

Pharmacology.

Its bioavailability is 60% (oral). It undergoes first pass metabolism. Absorption is rapid (time taken to reach maximum concentration (Tmax) = 2-6 h, oral; 10-20 min, im). The degree of binding to plasma proteins is 92%. It is metabolized in the liver, giving rise, among others, to hydroxyhaloperidol with pharmacological activity. It is eliminated with feces and urine, 1% in unchanged form. Its elimination half-life is 13-40 hours.

Description.

On the basis of its limbic activity, haloperidol possesses neuroleptic sedative activity and has been shown to be useful as an adjuvant in the treatment of chronic pain. Activity in the basal ganglia is probably the reason for the undesirable extrapyramidal motor effects (dystonia, akathisia and parkinsonism). The more peripheral antidopaminergic effects explain its action on nausea and vomiting (via the chemoreceptor trigger zone), the relaxation of the gastro-intestinal sphincters and the increase in prolactin release (through an inhibition of the activity of the inhibition factor of the prolactin, PIF).

Indications.

– Anxiety: adjuvant symptomatic treatment of severe anxiety in case of ineffectiveness of the usual therapies. – Psychomotor agitation: manic states, delirium tremens, delirious waves, etc. – Psychoses: acute and chronic. Chronic delusion, paranoid and schizophrenic delusions. – Abnormal movements: motor tics, stuttering and symptoms of Gilles de la Tourette syndrome and related choreas. – Vomiting: of central or peripheral origin (due to antimitotics, post-radiotherapy). – Persistent hiccups. – Anesthesia: in premedication and anesthetic mixtures. For 10 mg tablets: – Schizophrenia: chronic schizophrenia that does not respond to normal antipsychotic medication, preferably in those under 40 years of age. – Acute psychoses: attack treatment.

Precautions.

Serious cardiovascular disorders (heart or coronary failure due to the hemodynamic changes they can produce, in particular hypotension. Diabetes: can cause an alteration in blood glucose levels. Respiratory diseases (chronic asthma, chronic obstructive pulmonary disease): can have effects depressants on respiratory function. Epilepsy: neuroleptics can lower the seizure threshold, with the risk of seizures, especially in high-risk patients: due to their depressant effect on the central nervous system.

Contraindications.

– Allergy to haloperidol or butyrophenones. – Severe depression of the central nervous system or coma. – Parkinson’s: due to the enhancement of extrapyramidal symptoms.

Warnings.

Inform the doctor if tremors, jaundice, altered vision or involuntary muscle movements appear. Gradual discontinuation of long-term treatments is advised to avoid the risk of withdrawal syndrome or rapid relapse of the disease. During chronic treatments, blood counts should be performed.

Adverse reactions.

The adverse effects of haloperidol are, in general, frequent, although moderately important. The toxicological profile of this drug is similar to that of the rest of the antipsychotic butyrophenones. In most cases, adverse effects are a prolongation of the pharmacological action and mainly affect the central nervous system. The most characteristic adverse reactions are: – Frequently (10-25%): drowsiness, sedation, dry mouth, blurred vision, urinary retention and constipation; at the start of treatment: extrapyramidal symptoms such as parkinsonism, akathisia and dystonia that are dose-related.

Posology

– Adults: initial dose, 0.5-2 mg/8-12 h. Maintenance dose, 1-15 mg daily (higher doses in severe or resistant cases) divided into 2-3 times a day. 10 mg tablets (chronic schizophrenia, treatment of acute psychoses): recommended initial dose, 15 mg/day, increasing it by 50% each week until symptoms disappear (in resistant cases up to 60-100 mg daily), in doses divided into 2-3 daily doses. – Children: generally 0.05 mg/kg/day. Over 5 years: 0.5 mg/12 h. Children under 5 years: 0.25 mg/12 h. If necessary, adapt children’s doses progressively, as in adults, until reaching half the adult dose. Parenteral route: – Adults: Slow im or iv route: the usual dose is 5-10 mg/12-24 h, however, in severe cases, doses of 5 mg can be administered even every hour, although an interval is sufficient. 4-8 hours (the IV route is reserved for major emergencies). In cases of agitation, it is advisable to start parenterally.