Conventional Antipsychotics

• What are conventional antipsychotics?
• What are they used for?
• How do they work?
• Precautions
• Side effects

What are conventional antipsychotics?

Conventional antipsychotics (also called neuroleptics) are a class of drug mainly used in the treatment of psychotic disorders. They are generally used to relieve symptoms such as hallucinations, delusions or abnormal behaviour/thought, and also for sedative tranquillising effects in very disturbed or aggressive patients.

Members of this class include:

• Droperidol
• Fluphenazine
• Fluphenthixol
• Haloperidol
• Pericyazine
• Pimozide
• Thioridazine
• Thiothixene
• Trifluoperazine
• Zuclophenthixol

What are they used for?

Conventional antipsychotics are used for:

• Treatment of acute and chronic psychoses (eg schizophrenia)
• Acute mania
• Organic psychoses (eg dementia-associated agitation)
• Severe behavioural disorders in children
• Together with other treatments for psychotic depression
• Together with other treatments for alcoholic hallucination
• Tourette’s syndrome
• Persistent nausea and vomiting (haloperidol, droperidol)
• Persistent hiccups (chlorpromazine)

How do they work?

The exact basis is not fully understood, but it is widely believed that the conventional antipsychotics work by blocking certain receptors of chemical messengers called dopamine and thus help to relieve the symptoms of psychotic disorders.

Precautions

Hepatic impairment (liver disease)

The doctor may use a lower starting dose in patients who have liver impairment. Please inform your doctor if you have had any history of liver disease.

Elderly

The doctor may use a lower dose of an antipsychotic and more gradual increase because of greater risk of adverse effects in older patients.

Pregnancy

The doctor may choose to avoid prescribing antipsychotics for pregnant women or will prescribe the lowest possible dose. The doctor may consider lowering the dose of the antipsychotics under supervision or stop its use for 7-10 days prior to delivery. Speak to your doctor if you have any concerns.

Breastfeeding

The use of antipsychotics during breastfeeding should be avoided when possible. Speak to your doctor if you have any concerns.

Side effects

The side effects for each type of medication vary but listed below are the common and infrequent adverse effects of conventional antipsychotics.

Common (occur in more than 1% of patients):

• Sedation
• Orthostatic hypotension (a sudden fall in blood pressure)
• Tachycardia (rapid beating of the heart)
• Dry mouth
• Blurred vision
• Constipation
• Urinary retention (difficulty urinating)
• Sexual adverse effects
• Weight gain

Infrequent (occur in less than 1% of patients):

• Allergic reactions, including allergic skin reactions
• Photosensitivity (chlorpromazine)
• Pigmentary changes of skin or eye (particularly thioridazine)
• Corneal and lens opacities
• Heat stroke or sun stroke
• Hypothermia (a condition in which the body’s temperature drops below that which is required for normal body function)

All medicines have side effects. Most commonly the side effects are minor, however some can be more serious. Usually the benefits of taking a medication outweigh the associated side effects. Your doctor would have considered these side effects before prescribing the medication.

For information on related treatments and other relevant topics:

• Treatment – Atypical Antipsychotics
• Anatomy – Central Nervous System

References

1. Australian Medicines Handbook 2006, Adelaide, Pharmaceutical society of Australia, 2006.
2. Keks NA, Hope J. Long-term management of people with psychotic disorders in the community. Australian prescriber. 2007; 30(2):44-46.
3. Lazo J, Gilman A, Brunton L, Parker K. Goodman and Gilman’s the pharmacological basis of therapeutics. 11th ed. New York: McGraw-Hill; 2005
4. Sadock BJ and Sadock VA Kaplan & Sadock’s Comprehensive Textbook of Psychiatry USA Lippincott Williams & Wilkins 2005
5. Warrell DA, Cox TA et al. Oxford Textbook of Medicine UK 2003

This treatment is used for the following diseases:

• Bipolar Affective Disorder (Manic Depression)
• Schizophrenia
• Tourette’s Syndrome (Gilles de la Tourette Syndrome; Tics)