| Drug Class |
Typical (first‑generation) antipsychotic, but also used for acute agitation, Tourette’s syndrome, and certain forms of nausea/vomiting (rare). |
| Typical Use |
• Schizophrenia (acute or maintenance)
• Acute psychosis or delirium
• Severe agitation or aggression
• Tourette’s syndrome (often as part of combination therapy) |
| Standard Dose Range |
• Adults: 2 – 10 mg/day (usually in divided doses).
• Pediatrics (≥6 yrs): 1 – 8 mg/day (often in divided doses).
• Geriatric: start low (e.g., 0.5 – 1 mg/day) and titrate slowly.
• 0.25 mg is a starter dose (or a maintenance dose for very sensitive patients). |
| How 0.25 mg Tablet Is Typically Used |
• Initial: 0.25 mg PO once or twice a day for a few days, then titrate up.
• Maintenance: Some patients remain on 0.25 mg daily (often when switching to a long‑acting injection or when trying to avoid side effects). |
| Pharmacology |
• Acts as a potent dopamine D₂ receptor antagonist (also blocks D₁, α₁‑adrenergic, H₁‑histamine, and muscarinic receptors).
• Inhibits dopaminergic pathways → reduces positive psychotic symptoms but can cause extrapyramidal symptoms (EPS). |
| Common Adverse Effects |
• EPS: acute dystonia, akathisia, parkinsonism, tardive dyskinesia (especially with long‑term use).
• Metabolic: mild weight gain, hyperlipidemia.
• Cardiac: QTc prolongation → risk of torsades de pointes (especially with other QT‑prolonging drugs).
• Endocrine: hyperprolactinemia → galactorrhea, amenorrhea, gynecomastia.
• Sedation / anticholinergic: dry mouth, constipation, blurred vision. |
| Contraindications / Precautions |
• Known hypersensitivity to haloperidol.
• Severe cardiovascular disease (e.g., long QT syndrome, uncontrolled arrhythmias).
• History of seizures (may lower seizure threshold).
• Severe hepatic or renal impairment (dose adjustments may be needed).
• Elderly patients with dementia‑related psychosis: high risk of mortality – use with extreme caution or avoid. |
| Drug Interactions |
• Other antipsychotics → additive EPS & QT prolongation.
• CNS depressants (benzodiazepines, alcohol) → increased sedation.
• Cardiac drugs that prolong QT (e.g., sotalol, dofetilide, macrolides).
• Metformin → possible reduction of its clearance.
• CYP3A4 inhibitors/inducers: affect plasma levels (e.g., ketoconazole ↑ levels; rifampin ↓ levels). |
| Monitoring |
• Baseline ECG and repeat if dose >4 mg/day or if QT prolongation suspected.
• Periodic assessment of prolactin levels if symptoms develop.
• Periodic assessment of weight, glucose, lipids if long‑term therapy. |
| Patient Counseling Points |
• Take with food to reduce nausea; avoid abrupt stopping to prevent withdrawal or rebound psychosis.
• Report any new or worsening tremor, stiffness, involuntary movements, or changes in sexual function.
• Avoid alcohol and other CNS depressants.
• If you feel dizzy, faint, or develop chest pain, seek medical attention.
• Keep track of any side effects and bring them to your healthcare provider. |
| When to Seek Immediate Care |
• Sudden severe abdominal pain, vomiting, or signs of ileus (especially if you’re on high dose or long‑acting injection).
• Unusual muscle rigidity or seizures.
• Chest pain, palpitations, or shortness of breath (possible cardiac arrhythmia). |
| Key Take‑Away |
Haloperidol 0.25 mg is a very low starting dose that helps reduce the risk of early side effects while allowing gradual titration to the therapeutic range. It’s powerful but requires careful monitoring, especially for cardiac and movement‑related adverse effects. |