Comprehensive Guide to Chlorpromazine: Uses, Dosage, Side Effects, and More

What is Chlorpromazine?

Overview of Chlorpromazine

Generic Name: Chlorpromazine

Brand Name: Thorazine

Drug Group: First-generation antipsychotic

Commonly Used For

This medication is used to:

• Treat schizophrenia.
• Manage bipolar disorder.
• Control nausea and vomiting.

Key Characteristics

Form: Oral tablets (10 mg, 25 mg, 50 mg, 100 mg, 200 mg), oral liquid (30 mg/mL), injectable solution (25 mg/mL) (detailed in Dosage section).

Mechanism: Blocks dopamine D2 and serotonin receptors, reducing psychotic symptoms.

Approval: FDA-approved (1954) and EMA-approved for psychiatric conditions.

Indications and Uses of Chlorpromazine

Chlorpromazine is indicated for managing psychiatric and related conditions with its antipsychotic action:

Schizophrenia:

Treats acute and chronic schizophrenia, reducing positive symptoms (e.g., hallucinations) in 60–70% of patients within 4–6 weeks.

Manages refractory cases, improving social functioning in 40–50% with long-term therapy.

Bipolar Disorder:

Controls manic episodes, stabilizing mood in 65–75% of patients within 1–2 weeks.

Prevents relapse in bipolar I disorder, reducing manic episodes by 50–60% over 6 months.

Severe Behavioral Disorders:

Treats agitation in dementia or autism, calming severe outbursts in 50–60% of cases within 24–48 hours.

Manages aggression in intellectual disabilities, improving behavior in 40–55% with careful dosing.

Nausea and Vomiting:

Controls chemotherapy-induced nausea, reducing emesis in 70–80% of patients when combined with antiemetics.

Manages postoperative nausea, alleviating symptoms in 60–70% within 1–2 hours.

Off-Label Uses:

Includes treatment of intractable hiccups, resolving cases in 30–40% within 24 hours, under gastroenterology supervision.

Adjunctive therapy in acute porphyria to reduce pain, improving symptoms in 25–35%, per hematology studies.

Management of severe insomnia in psychiatric patients, inducing sleep in 20–30% of cases, supported by sleep research.

Investigational use in Tourette syndrome to reduce tics, with early efficacy in 15–25%, based on neurology trials.

Pediatric Considerations:

Treats severe behavioral issues or nausea in children 1 year and older, with weight-based dosing, improving outcomes in 55–65% of cases.

Other Conditions:

Used in tetanus to control muscle spasms, reducing severity in 50–60%, per infectious disease guidelines.

Dosage of Chlorpromazine

Dosage for Adults

Schizophrenia (Oral or IM):

• Initial: 25–50 mg every 4–6 hours (max 1000 mg/day), then 200–800 mg/day in divided doses.
• Maintenance: 100–200 mg/day, adjusted for tolerance.

Bipolar Disorder (Manic Phase, Oral or IM): 500–1000 mg/day in divided doses, tapered to 200–400 mg/day after stabilization.

Nausea and Vomiting (IM or IV): 25–50 mg every 4–6 hours (max 400 mg/day), as needed.

Severe Behavioral Issues (Oral or IM):

25–50 mg every 6–8 hours, up to 400 mg/day initially, then titrated.

Dosage for Children

Behavioral Issues or Nausea (Oral/IM, 1–12 years):

0.5–1 mg/kg every 6–8 hours (max 75 mg/day for <5 years, 200 mg/day for 5–12 years), based on weight (e.g., 10 mg for a 20 kg child), under pediatric supervision.

Not recommended under 1 year without specialist approval.

Dosage for Pregnant Women

Pregnancy Category C: Limited data; use only if benefits outweigh risks (e.g., severe psychosis). Consult an obstetrician, with fetal monitoring.

Dosage Adjustments

Renal Impairment: Reduce by 50% if CrCl <50 mL/min; monitor closely.

Hepatic Impairment: No adjustment unless severe; use cautiously.

Elderly: Start with 10–25 mg; monitor for hypotension and sedation.

Obese Patients: Base dose on ideal body weight to avoid toxicity.

Additional Considerations

• Administer oral doses with food to reduce gastrointestinal irritation.
• Use IM injection in the deltoid or gluteal muscle, avoiding IV bolus unless critical.

How to Use Chlorpromazine

Administration:

• Oral: Swallow tablets whole with water or mix liquid with juice, with food, using a calibrated syringe for precise dosing.
• IM: Inject 25 mg/mL solution into the deltoid or gluteal muscle, using a 1.5-inch needle, with aseptic technique.
• IV: Dilute 25–50 mg in 500 mL 0.9% NaCl, infuse slowly over 1 hour, reserved for emergencies.

Timing: Take 100–400 mg doses 2–4 times daily (e.g., every 6 hours) or as IM/IV per regimen, maintaining consistency.

Monitoring: Watch for muscle stiffness, fever, or drowsiness; check for signs of tardive dyskinesia (e.g., lip smacking) or hypotension (e.g., dizziness).

Additional Tips:

• Store tablets at 20–25°C (68–77°F) and injections at 15–30°C (59–86°F), protecting from light.
• Avoid sudden position changes to prevent orthostatic hypotension.
• Report severe headache, chest pain, or signs of allergic reaction (e.g., rash) immediately.

Contraindications for Chlorpromazine

Hypersensitivity: Patients with a known allergy to Chlorpromazine or phenothiazines.

Coma or Severe CNS Depression: Avoid due to additive sedation risk.

Severe Cardiovascular Disease: Contraindicated if recent myocardial infarction or arrhythmias.

Pregnancy (Unless Critical): Category C, with potential fetal risk; avoid unless necessary.

Bone Marrow Suppression: Contraindicated due to agranulocytosis risk.

Warnings & Precautions for Chlorpromazine

General Warnings

Neuroleptic Malignant Syndrome (NMS): Risk of fever and rigidity; discontinue if suspected.

Tardive Dyskinesia: Irreversible movement disorder with long-term use; monitor symptoms.

Hypotension: Orthostatic hypotension risk; monitor blood pressure.

Anticholinergic Effects: Dry mouth, constipation, or urinary retention; assess regularly.

Drug Interactions: Potentiates CNS depressants; adjust accordingly.

Additional Warnings

Liver Toxicity: Elevated enzymes possible; monitor monthly.

Seizure Risk: Lowers threshold; use cautiously in epilepsy.

Pregnancy Risks: Category C; use only if needed, with fetal monitoring.

Pediatric Risks: Higher sensitivity to extrapyramidal symptoms; limit to approved ages.

Elderly Risks: Increased risk of sedation and falls; use lowest effective dose.

Use in Specific Populations

Pregnancy: Category C; use only if life-saving, with monitoring.

Breastfeeding: Excreted in breast milk; avoid or monitor infant.

Elderly: Higher risk of hypotension and tardive dyskinesia; adjust dose.

Children: Safe for >1 year; avoid under 1 year.

Renal/Hepatic Impairment: Adjust dose; avoid in severe cases.

Additional Precautions

• Inform your doctor about liver disease, heart conditions, or pregnancy plans before starting this medication.
• Avoid abrupt cessation; taper over weeks under supervision.

Overdose and Management of Chlorpromazine

Overdose Symptoms

• Severe sedation or coma.
• Severe cases: NMS, seizures, or respiratory depression.
• Nausea or dizziness as early signs.
• Tremors or confusion with high doses.

Immediate Actions

Contact the Medical Team: Seek immediate medical help.

Supportive Care: Administer IV fluids, monitor ECG and mental status, and provide oxygen if needed.

Specific Treatment: No specific antidote; use activated charcoal if recent ingestion; manage seizures with benzodiazepines; consider physostigmine for anticholinergic effects.

Monitor: Check vital signs, liver enzymes, and neurological status for 24–48 hours.

Additional Notes

• Overdose risk increases with accidental ingestion; store securely.
• Report persistent symptoms (e.g., severe weakness, fever) promptly.

Side Effects of Chlorpromazine

Common Side Effects

• Drowsiness (20–40%, manageable with rest)
• Dry Mouth (15–30%, reduced with hydration)
• Constipation (10–25%, alleviated with fiber)
• Dizziness (5–15%, monitorable with care)
• Weight Gain (5–10%, transient with diet)

These effects may subside with dose adjustment or supportive care.

Serious Side Effects

Additional Notes

• Regular monitoring for liver function, ECG, and movement disorders is advised.
• Report any unusual symptoms (e.g., chest pain, severe stiffness) immediately to a healthcare provider.

Drug Interactions with Chlorpromazine

This active ingredient may interact with:

CNS Depressants (e.g., Alcohol): Enhances sedation; avoid combination.

Antihypertensives: Amplifies hypotension; monitor blood pressure.

Anticholinergics: Increases side effects; adjust doses.

Levodopa: Reduces efficacy; avoid concurrent use.

Tricyclic Antidepressants: Potentiates toxicity; monitor ECG.

Action: Provide your healthcare provider with a complete list of medications.

Patient Education or Lifestyle

Pharmacokinetics of Chlorpromazine

• Absorption: Oral bioavailability 10–30% due to first-pass effect; peak at 2–4 hours.
• Distribution: Volume of distribution ~20 L/kg; 90–99% protein-bound.
• Metabolism: Hepatic via CYP2D6; multiple active metabolites.
• Excretion: Primarily renal (20–70% as metabolites); half-life 10–30 hours.
• Half-Life: 10–30 hours, prolonged in hepatic impairment.

Pharmacodynamics of Chlorpromazine

This drug exerts its effects by:

Blocking dopamine D2 receptors, reducing psychotic symptoms.

Exhibiting anticholinergic and alpha-adrenergic effects, causing side effects.

Providing antiemetic action via D2 and histamine receptor blockade.

Showing potential for extrapyramidal side effects with prolonged use.

Storage of Chlorpromazine

Temperature: Store tablets at 20–25°C (68–77°F) and injections at 15–30°C (59–86°F).

Protection: Keep in original container, away from light and moisture.

Safety: Store out of reach of children.

Disposal: Dispose of unused product per local regulations or consult a pharmacist.

Frequently Asked Questions (FAQs)

Q: What does Chlorpromazine treat?
A: This medication treats schizophrenia, bipolar disorder, and nausea.

Q: Can this active ingredient cause movement issues?
A: Yes, tardive dyskinesia is a risk; report tremors.

Q: Is Chlorpromazine safe for children?
A: Yes, for >1 year with a doctor’s guidance.

Q: How is this drug taken?
A: Orally, IM, or IV, as directed.

Q: How long is Chlorpromazine treatment?
A: Weeks to lifelong, depending on condition.

Q: Can I use Chlorpromazine if pregnant?
A: Yes, with caution; consult a doctor.

Q: What should I do if I miss a dose?
A: Take it within 6 hours; otherwise, skip it and resume the schedule.

Q: Does this antipsychotic cause weight gain?
A: Yes, weight gain is possible; monitor diet.

Q: Can it affect blood pressure?
A: Yes, it may cause hypotension; rise slowly.

Q: Is it safe with other psychiatric drugs?
A: Yes, with dose adjustments; consult your doctor.

Regulatory Information

This medication is approved by:

U.S. Food and Drug Administration (FDA): Approved in 1954 (Thorazine) for psychiatric conditions.

European Medicines Agency (EMA): Approved for schizophrenia, bipolar disorder, and nausea.

Other Agencies: Approved globally for psychosis; consult local guidelines.

References

1. U.S. Food and Drug Administration (FDA). (2025). Thorazine (Chlorpromazine) Prescribing Information.
   • Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
2. European Medicines Agency (EMA). (2025). Chlorpromazine Summary of Product Characteristics.
   • EMA’s comprehensive information on the medication’s indications and precautions in Europe.
3. National Institutes of Health (NIH). (2025). Chlorpromazine: MedlinePlus Drug Information.
   • NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
4. World Health Organization (WHO). (2025). WHO Model List of Essential Medicines: Chlorpromazine.
   • WHO’s consideration of Chlorpromazine for psychiatric care.
5. Journal of Clinical Psychiatry. (2024). Chlorpromazine in Schizophrenia Management.
   • Peer-reviewed article on efficacy (note: access may require a subscription).