Haloperidol Mercury Pharmaceuticals (Ireland)

Haloperidol, supplied by Mercury Pharmaceuticals in Ireland, is an intramuscular injection containing the antipsychotic active ingredient haloperidol. It is a butyrophenone derivative classified under ATC code N05AD01 and is marketed within the European Union. The product is prescription‑only (Rx) and is intended for use under medical supervision for conditions such as schizophrenia and acute psychosis. Its mechanism involves dopamine D2 receptor antagonism and may be administered in clinical settings.

Haloperidol intramuscular injection is indicated for the short‑term management of several psychiatric conditions where rapid control of symptoms is required.

- Schizophrenia, particularly during acute exacerbations or when oral therapy is not feasible. - Acute psychotic episodes associated with mood disorders or substance‑induced states. - Severe agitation or aggression that requires prompt calming in emergency or inpatient settings. - Management of tics, including those related to Tourette syndrome, when other treatments are insufficient. - Pre‑operative sedation in patients with known psychotic disorders.

Side effects of haloperidol injection vary in frequency and severity; they reflect its dopamine antagonism and can affect multiple organ systems.

Common: - Drowsiness, fatigue, or sedation. - Extrapyramidal symptoms such as tremor, rigidity, or akathisia. - Dry mouth, constipation, or blurred vision. - Orthostatic hypotension leading to dizziness on standing.

Serious: - Neuroleptic malignant syndrome, characterized by fever, muscle rigidity, and autonomic instability. - Torsades de pointes or other significant cardiac arrhythmias. - Severe depression or suicidal thoughts, especially during early treatment.

When prescribing haloperidol injection, clinicians should evaluate patient history and monitor for conditions that may increase risk of adverse outcomes.

- History of cardiovascular disease, prolonged QT interval, or electrolyte disturbances. - Current or past diagnosis of Parkinson’s disease or other movement disorders. - Pregnancy (Category C) and breastfeeding; benefits must outweigh potential fetal risks. - Elderly patients, especially those with dementia‑related psychosis, due to higher sensitivity to sedation and falls. - Severe hepatic or renal impairment that may alter drug clearance. - Concomitant use of other dopamine‑blocking agents, which can amplify extrapyramidal effects. - Known hypersensitivity to haloperidol or any component of the formulation.

Haloperidol can interact with several medications, affecting its plasma concentration or enhancing adverse effects; awareness of these interactions supports safe use.

Avoid: - Other antipsychotics or dopamine antagonists that increase risk of extrapyramidal symptoms. - Medications that prolong the QT interval, such as certain antiarrhythmics, macrolide antibiotics, or fluoroquinolones. - Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) that may raise haloperidol levels.

Use with caution: - CYP3A4 inducers like carbamazepine or rifampin, which can reduce therapeutic effect. - CNS depressants, including benzodiazepines or opioids, that may enhance sedation and respiratory depression. - Anticholinergic agents, which can mask early signs of extrapyramidal side effects.