The drug prochlorperazine is used in human medicine primarily as a medication for nausea, vomiting, and migraine. Occasionally, the dopamine antagonist is also prescribed to treat psychiatric or mental illness. Accordingly, prochlorperazine is both an antiemetic and a neuroleptic.
What is prochlorperazine?
The active medical ingredient prochlorperazine belongs to the group of antiemetics. This term covers substances or preparations that – like prochlorperazine – are administered to treat nausea and vomiting. Since prochlorperazine binds to the dopamine receptors of the human brain, the substance also exerts psychoactive effects. It is therefore occasionally used as a neuroleptic to treat mental or psychiatric disorders such as schizophrenia or anxiety disorder in the short, medium or long term. Compared to antiemetic treatment, however, the dose administered in these cases is increased many times over. In addition, prochlorperazine is also used to treat severe migraine attacks. The white to whitish-yellow substance is described in chemistry and pharmacology by the molecular formula C 20 – H 24 – C – I – N 3 – S, which corresponds to a moral mass of 373.943 g/mol. There is currently no approval in Germany, Austria, and Switzerland.
Pharmacological action
Based on its pharmacological properties as well as its effects, prochlorperazine belongs to the group of dopamine antagonists. Antagonists are those chemical substances that cancel, reduce, or cause an opposite effect of a reference substance similar to them, called an agonist. Prochlorperazine, like the reference substance dopamine, binds to the D2 receptors of the human brain. As a result of the binding, the receptors are blocked. A drive-reducing, antipsychotic effect is produced, with mild sedative effects as well. The pharmacological action of prochlorperazine thus largely corresponds to the action of the other phenothiazines such as perphenazine, thioridazine, fluphenazine or thiethylperazine. Therefore, the literature also reports that prochlorperazine has a slight affinity at the serotonin receptors (5HT2 receptors). Consequently, the substance also blocks these receptors, which may enhance the effect.
Medical application and use
Prochlorperazine has a relatively broad range of uses. This is due to the fact that it has neuroleptic or sedative effects as well as antiemetic effects. The treatment or suppression of massive nausea and severe vomiting represents one of the main uses of prochlorperazine. It is also prescribed to treat migraine. In addition to this antiemetic use, prochlorperazine is also used as a neuroleptic to treat various mental disorders. These include psychoses caused by schizophrenia and various anxiety and obsessive-compulsive disorders. It is taken only orally in film-coated tablet form. However, the prescribed dose for the treatment of psychiatric disorders is many times higher than the amount of the active substance administered for antiemetic treatment. Prochlorperazine is subject to pharmacy and prescription requirements in every country where it is licensed. Thus, the substance cannot be purchased without a doctor’s prescription. It is dispensed exclusively through licensed pharmacies. The best-known preparation, which is based exclusively on prochlorperazine as the active ingredient, is sold in the USA under the trade name Compazine. Prochlorperazine is not currently approved for use in Germany, Austria or Switzerland. The substance may not be used in any preparation in these countries. However, other drugs are available that have similar effects.
Risks and side effects
As with all medications, before taking prochlorperazine for the first time, it is necessary to check whether there is an allergy or other intolerance. If this is the case, treatment must not be given. This is because in these cases there is a contraindication. This describes that a medical contraindication prohibits an application. Prochlorperazine is also contraindicated if severe diseases of the liver or kidneys have been diagnosed, as these organs are significantly involved in the breakdown of the substance.Also, prochlorperazine must not be taken together with cisapride, terfenadine, or astemizole. In addition, attention should be paid to interactions with other drugs. For example, prochlorperazine enhances the effects of alcohol and other narcotics, which is typical for representatives of its class of active ingredients. Accordingly, before performing an operation and administering anesthetics, the patient should be advised to take prochlorperazine. Consumption of alcohol should be refrained from during the period of treatment. In addition, prochlorperazine may cause undesirable side effects after ingestion, although this is not necessarily the case. The most common side effects of prochlorperazine include extrapyramidal motor system (EPMS) disorders, a noticeable drop in blood pressure (hypotension), an excess heart rate (tachycardia), and headache, general malaise, and dry mouth. Medical advice should be sought immediately if side effects occur.
