Pimozide: Effects, Uses & Risks

The drug pimozide is an active substance that belongs to the category of so-called antipsychotics. The drug is primarily available on the pharmaceutical market under the trade name Orap. In the majority of cases, the drug pimozide is used orally in the form of tablets. In this context, the drug is used primarily for the treatment of psychoses with a chronic course, which belong to the schizophrenias.

What is pimozide?

The drug pimozide is characterized by its antipsychotic properties. For this reason, it is primarily used as part of the drug treatment of mental illness. In most cases, it is used to treat various forms of schizophrenia. The active ingredient pimozide is often used as an adjunct to psychotherapeutic treatment. Basically, the drug belongs to the so-called diphenylbutylpiperidines. In addition, it is a neuroleptic or a depot neuroleptic, which is suitable for the long-term therapy of certain mental diseases and complaints. In this context, the active ingredient pimozide is classified as highly potent.

Pharmacologic Action

The antipsychotic pimozide is characterized by a specific mechanism of action. It is used in the majority of cases for the treatment of schizophrenic disorders, because pimozide is a neuroleptic that has sedative and antipsychotic effects. In principle, neuroleptics are divided into different generations and categorized in terms of their neuroleptic potency. First-generation neuroleptics include low-, medium- and high-potency agents, such as promethazine, perazine, perphenazine, melpero and fluphenazine. The second generation includes the so-called atypical neuroleptics, such as olanzapine, risperidone or quetiapine. Psychoses are associated with an altered mode of action of the neurotransmitters serotonin and dopamine. In order to treat such disorders with medication, it is necessary to influence and block the respective receptors in the central nervous system. Various active substances are available for this purpose, including the drug pimozide. The drug acts as a so-called dopamine antagonist in the central nervous system. The substance inhibits the receptors for the neurotransmitter dopamine, resulting in its antipsychotic and sedative effects. The blockade of the receptors for dopamine occurs through postsynaptic capture, as a result of which increased dopamine is released presynaptically. As a result, postsynaptic receptors are stimulated and activated. In addition, the active ingredient pimozide also functions as an inhibitor of acid sphingomyelinase. Thus, the active ingredient pimozide can also be used against hallucinations and delusions without clouding the mind. While taking the drug, it should be noted that pimozide may exhibit toxicological effects. These are primarily related to the central nervous system as well as the cardiovascular system.

Medical application and use

Pimozide is suitable for the treatment of various mental diseases and disorders. Primarily, it is used for the drug therapy of schizophrenia. These include, for example, delusions and hallucinations, as well as psychosis and personality disorders. In principle, it is possible to use the drug pimozide as part of a long-term treatment. In the majority of cases, the drug Orap is used. This is available on the market in various dosages. At the beginning of treatment, low doses are usually used, which are gradually increased to the so-called maintenance dose. This is done under strict medical supervision. When treating adults, two to twelve milligrams daily are usually prescribed.

Risks and side effects

While pimozide is taken, a number of discomforts and side effects are possible. All undesirable side effects are listed in the drug’s prescribing information. The frequencies with which the side effects occur are also noted there. Basically, the complaints during the intake vary from patient to patient. Potential side effects caused by the active ingredient pimozide include headaches, anxiety disorders, and sleep problems. Some people also experience increased sleepiness.In addition, antipsychotics are capable of affecting the cardiovascular system. For example, prolonged intervals of QT time, torsade de pointes tachycardia, ventricular tachycardia, and ventricular arrhythmias with ventricular fibrillation and even cardiac death have been observed. In addition, sudden deaths with unclear causes occurred. Specifically related to the active ingredient pimozide, fatigue states, erectile dysfunction, and an increase in body weight have been observed. Pollakiuria, nocturia, and excessive production of sebum may also occur. Hyperhidrosis also occurs in some patients. The drug pimozide is contraindicated in the presence of specific diseases of the heart, disturbed electrolyte balance, as well as a subdued central nervous system. Increased mortality of elderly patients with dementia has been shown in connection with the use of pimozide. For this reason, pimozide is not allowed to be used in dementia patients. It should also be noted that serotonin reuptake inhibitors should not be taken concurrently with pimozide. These include, for example, paroxetine, sertraline, and escitalopram. During pregnancy, the use of pimozide must be thoroughly weighed up by the treating physician, because the effect on the unborn child is mostly unknown. In addition, the active ingredient passes into breast milk, which is why it should not be administered during breastfeeding. Renal impairment is also a contraindication.