Symptoms of withdrawal commonly include nausea, vomiting, and loss of appetite. Other symptoms may include restlessness, increased sweating, and trouble sleeping. Less commonly, there may be a feeling of the world spinning, numbness, or muscle pains. Symptoms generally resolve after a short period of time.There is tentative evidence that discontinuation of antipsychotics can result in psychosis. It may also result in reoccurrence of the condition that is being treated. Rarely, tardive dyskinesia can occur when the medication is stopped. Pharmacology
Chlorpromazine is classified as a low-potency typical antipsychotic. Low-potency antipsychotics have more anticholinergic side effects, such as dry mouth, sedation, and constipation, and lower rates of extrapyramidal side effects, while high-potency antipsychotics (such as haloperidol) have the reverse profile. Pharmacokinetics
Pharmacodynamics
Chlorpromazine is a very effective antagonist of D2 dopamine receptors and similar receptors, such as D3 and D5. Unlike most other drugs of this genre, it also has a high affinity for D1 receptors. Blocking these receptors causes diminished neurotransmitter binding in the forebrain, resulting in many different effects. Dopamine, unable to bind with a receptor, causes a feedback loop that causes dopaminergic neurons to release more dopamine. Therefore, upon first taking the drug, patients will experience an increase in dopaminergic neural activity. Eventually, dopamine production of the neurons will drop substantially and dopamine will be removed from the synaptic cleft.
The effect of this drug in emptying psychiatric hospitals has been compared to that of penicillin and infectious diseases. But the popularity of the drug fell from the late 1960s as newer drugs came on the scene. From chlorpromazine a number of other similar antipsychotics were developed. It also led to the discovery of antidepressants.Chlorpromazine largely replaced electroconvulsive therapy, hydrotherapy, psychosurgery, and insulin shock therapy. By 1964, about 50 million people worldwide had taken it. Chlorpromazine, in widespread use for 50 years, remains a "benchmark" drug in the treatment of schizophrenia, an effective drug although not a perfect one. The relative strengths or potencies of other antipsychotics are often ranked or measured against chlorpromazine in aliquots of 100 mg, termed chlorpromazine equivalents or CPZE.In the movie: "Shutter Island", chlorpromazine is presented as being the new medicament for psychosis treatment however with adverse effects like tremors or abstinence syndrome. Society and culture
Names
Brand names include Thorazine, Largactil, Hibernal, and Megaphen (sold by Bayer in West-Germany since July 1953).) Research
Chlorpromazine has tentative benefit in animals infected with Naegleria fowleri, and shows antifungal and antibacterial activity in vitro. Veterinary use
The veterinary use of chlorpromazine has generally been superseded by use of acepromazine.Chlorpromazine may be used as an antiemetic in dogs and cats, or, less often, as sedative before anesthesia. In horses, it often causes ataxia and lethargy, and is therefore seldom used.It is commonly used to decrease nausea in animals that are too young for other common anti-emetics.