BMA Concise Guide to Medicine & Drugs

Chlorpromazine

Brand names Chloractil, Largactil

Used in the following combined preparations None

QUICK REFERENCE

Drug group Phenothiazine antipsychotic and anti-emetic drug

Overdose danger rating Medium

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Chlorpromazine was the first anti-psychotic drug to be marketed and it is still used today. It has a calming and sedative effect that is useful in the short-term treatment of anxiety, agitation, and aggressive behaviour.

Chlorpromazine is prescribed for the treatment of schizophrenia, psychosis, and mania. Other uses of this drug include the treatment of nausea and vomiting, especially when caused by drug or radiation treatment; and treating severe, prolonged hiccoughs.

Chlorpromazine can produce a number of adverse effects, some of which may be serious. After continuous use of the drug over several years, eye changes and skin discoloration may occur.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, liquid, injection, suppositories (specialist manufacturers only).

Frequency and timing of doses 1–6 x daily.

Adult dosage range Mental illness 75–300mg daily; dose is started low and gradually increased. Some patients may need up to 1g daily. Nausea and vomiting 40–150mg daily.

Onset of effect 30–60 minutes (by mouth); 15–20 minutes (injection); up to 30 minutes (suppository).

Duration of action 8–12 hours (by mouth or injection); 3–4 hours (suppository). Some effects may persist for up to 3 weeks when stopping the drug after regular use.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children. Protect from light. Healthcare professionals should avoid direct contact with the drug because of the risk of contact sensitization; tablets should not be crushed and liquids should be handled carefully.

Missed dose Take as soon as you remember. If your next dose is due within 2 hours, do not take the missed dose. Take your next scheduled dose as usual.

Stopping the drug Do not stop taking the drug without consulting your doctor; symptoms may recur.

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. Larger overdoses may cause unusual drowsiness, fainting, abnormal heart rhythms, muscle rigidity, and agitation. Notify your doctor.

POSSIBLE ADVERSE EFFECTS

Chlorpromazine commonly causes mild drowsiness and has an anticholinergic effect, which can cause various symptoms, such as blurred vision. Other side effects include weight gain, tremor or parkinsonism, dizziness, and fainting. Women may also develop menstrual irregularities. If a light-sensitive rash or jaundice occur, you should stop taking the drug and consult your doctor. Long-term use of the drug may also cause movement problems (see Prolonged use).

INTERACTIONS

Drugs for parkinsonism Chlorpromazine may reduce the effect of these drugs.

Anticholinergic drugs These drugs may intensify the anticholinergic properties of chlorpromazine.

Sedatives All drugs that have a sedative effect on the central nervous system are likely to increase the sedative properties of chlorpromazine.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have long-term liver or kidney problems.

· You have had heart problems.

· You have had epileptic seizures.

· You have any blood disorders.

· You have glaucoma.

· You are taking other medicines.

Pregnancy Occasionally prescribed by specialist centres. Taken near the time of delivery, it may cause drowsiness in the newborn baby. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk and may affect the baby. Discuss with your doctor.

Infants and children Not recommended for infants under 1 year. Reduced dose necessary for older children.

Over 60 Initial dosage is low; it may be increased if there are no adverse reactions, such as abnormal limb movements or low blood pressure.

Driving and hazardous work Avoid such activities until you have learned how chlorpromazine affects you as the drug can cause drowsiness and slowed reactions.

Alcohol Avoid. Alcohol may increase the sedative effects of this drug.

Surgery and general anaesthetics Chlorpromazine treatment may need to be stopped before you have a general anaesthetic. Discuss this with your doctor or dentist before any operation.

PROLONGED USE

If used for many years, chlorpromazine may cause tardive dyskinesia (involuntary movements of the face, jaw, and tongue), which may be irreversible.