Haloperidol Decanoate is a long-acting, esterified injectable formulation of the typical antipsychotic haloperidol. It is a decanoate ester prodrug, designed for deep intramuscular administration to provide sustained release over several weeks. It is primarily used for the maintenance treatment of chronic psychotic disorders, particularly schizophrenia, in patients who are stabilized on oral antipsychotics and require long-term depot therapy to ensure adherence. Its use is a cornerstone of long-term management in the Indian psychiatric setting.
Adult: Initial dose: 10-15 times the stabilized daily oral haloperidol dose, up to a maximum initial dose of 100 mg. Usual maintenance range: 50-200 mg every 4 weeks. The 5mg strength is typically used for dose titration, very low maintenance doses, or in elderly/debilitated patients.
Note: For DEEP INTRAMUSCULAR injection ONLY. Use a 21-gauge needle or larger. Administer by Z-track technique into a large muscle mass (gluteus maximus preferred). Do not massage the injection site. Rotate injection sites. Aspirate before injection to avoid intravascular administration. Use immediately after drawing into syringe. Do not mix with other medications.
Haloperidol exerts its antipsychotic effect primarily through potent and central dopamine D2 receptor antagonism in the mesolimbic pathway. It also has significant antagonistic activity at alpha-1 adrenergic receptors and weak antagonism at histamine H1 and muscarinic receptors.
Pregnancy: Category C: Risk cannot be ruled out. Use only if potential benefit justifies potential fetal risk. Neonates exposed in the 3rd trimester are at risk for EPS and withdrawal symptoms. Not recommended during pregnancy unless absolutely necessary.
Driving: Patients should be warned that haloperidol can cause drowsiness, dizziness, and blurred vision. They should not drive or operate machinery until their individual response is known.
| Other CNS Depressants (Alcohol, Opioids, Benzodiazepines) | Additive CNS and respiratory depression | Major |
| Enzyme Inducers (Carbamazepine, Phenytoin, Rifampicin) | Reduced plasma levels of haloperidol, leading to therapeutic failure | Major |
| Enzyme Inhibitors (Fluoxetine, Paroxetine, Ketoconazole, Cimetidine) | Increased plasma levels of haloperidol, leading to toxicity and increased EPS | Major |
| QT-prolonging drugs (Class IA & III antiarrhythmics, Macrolides, Fluoroquinolones, TCAs) | Additive risk of QTc prolongation and Torsades de Pointes | Major |
| Anticholinergic drugs (Trihexyphenidyl, Benztropine) | May reduce EPS but can worsen constipation, glaucoma, and cognitive effects | Moderate |
| Levodopa and Dopamine Agonists | Mutual antagonism of therapeutic effects | Major |
Same composition (Haloperidol Decanoate (5mg)), different brands: