GABA-A Alpha 2/3 but Not Alpha 1 Receptor Subunit Ligand Inhibits Harmaline and Pimozide-Induced Tremor in Rats

Treatment of tremors, such as in essential tremor (ET) and Parkinson's disease (PD) is mostly ineffective. Exact tremor pathomechanisms are unknown and relevant animal models are missing. GABA-A receptor is a target for tremorolytic medications, but current non-selective drugs produce side effects and have safety liabilities. The aim of this study was a search for GABA-A subunit-specific tremorolytics using different tremor-generating mechanisms. Two selective positive allosteric modulators (PAMs) were tested. Zolpidem, targeting GABA-A α1, was not effective in models of harmaline-induced ET, pimozide- or tetrabenazine-induced tremulous jaw movements (TJMs), while the novel GABA-A α2/3 selective MP-III-024 significantly reduced both the harmaline-induced ET tremor and pimozide-induced TJMs. While zolpidem decreased the locomotor activity of the rats, MP-III-024 produced small increases. These results provide important new clues into tremor suppression mechanisms initiated by the enhancement of GABA-driven inhibition in pathways controlled by α2/3 but not α1 containing GABA-A receptors. Tremor suppression by MP-III-024 provides a compelling reason to consider selective PAMs targeting α2/3-containing GABA-A receptors as novel therapeutic drug targets for ET and PD-associated tremor. The possibility of the improved tolerability and safety of this mechanism over non-selective GABA potentiation provides an additional rationale to further pursue the selective α2/3 hypothesis.

STF-62247 and pimozide induce autophagy and autophagic cell death in mouse embryonic fibroblasts

Induction of autophagy can have beneficial effects in several human diseases, e.g. cancer and neurodegenerative diseases (ND). Here, we therefore evaluated the potential of two novel autophagy-inducing compounds, i.e. STF-62247 and pimozide, to stimulate autophagy as well as autophagic cell death (ACD) using mouse embryonic fibroblasts (MEFs) as a cellular model. Importantly, both STF-62247 and pimozide triggered several hallmarks of autophagy in MEFs, i.e. enhanced levels of LC3B-II protein, its accumulation at distinct cytosolic sites and increase of the autophagic flux. Intriguingly, autophagy induction by STF-62247 and pimozide resulted in cell death that was significantly reduced in ATG5- or ATG7-deficient MEFs. Consistent with ACD induction, pharmacological inhibitors of apoptosis, necroptosis or ferroptosis failed to protect MEFs from STF-62247- or pimozide-triggered cell death. Interestingly, at subtoxic concentrations, pimozide stimulated fragmentation of the mitochondrial network, degradation of mitochondrial proteins (i.e. mitofusin-2 and cytochrome c oxidase IV (COXIV)) as well as a decrease of the mitochondrial mass, indicative of autophagic degradation of mitochondria by pimozide. In conclusion, this study provides novel insights into the induction of selective autophagy as well as ACD by STF-62247 and pimozide in MEFs.

Chronic Administration of Pimozide Fails to Attenuate Motor and Pathological Deficits in Two Mouse Models of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease which presently does not have any efficient therapeutic approach. Pimozide, a Food and Drug Administration (FDA)-approved neuroepileptic drug, has been recently proposed as a promising treatment for ALS patients based on apparent stabilization of right hand muscles after a short-time administration. A new clinical trial started at the end of 2017 to recruit patients with a prolonged drug delivery schedule. Here, our aim was to investigate the effects of chronic administration of pimozide on disease progression and pathological events in two mouse models of ALS. Pimozide was administered every 2 days to transgenic mice bearing the ALS-linked A315T mutation on the human TAR DNA-binding protein 43 (TDP-43) gene and to mice carrying the human superoxide dismutase 1 (SOD1) gene with the ALS-linked G93A mutation. Chronic administration of pimozide exacerbated motor performances in both animal models and reduced survival in SOD1G93A mice. In TDP-43A315T, it decreased the percentage of innervated neuromuscular junctions (NMJs) and increased the accumulation of insoluble TDP-43. In SOD1G93A mice, pimozide had no effects on NMJ innervation or motoneuron loss, but it increased the levels of misfolded SOD1. We conclude that a chronic administration of pimozide did not confer beneficial effects on disease progression in two mouse models of ALS. In light of a new clinical trial on ALS patients with a chronic regime of pimozide, these results with mouse models suggest prudence and careful monitoring of ALS patients subjected to pimozide treatment.

Efficacy of pimozide augmentation for clozapine partial responders with schizophrenia

INTRODUCTION

A substantial number of patients with treatment-resistant schizophrenia respond only partially to clozapine. Therefore, it has been common practice to use augmentation strategies to maximize clozapine's effect. But the efficacy of this strategy remains poorly established. We have conducted a randomized double-blind placebo controlled clinical trial in patients with schizophrenia currently receiving clozapine with partial response, and tested the efficacy of pimozide augmentation on positive and negative symptoms and also on neurocognitive measures.

METHODS

Thirty-two outpatients enrolled in the clinical trial and 28 completed. Patients with adequate blood levels of clozapine were randomized to pimozide vs placebo and participated in the trial for 12 weeks receiving monthly assessments for Brief Psychiatric Rating Scale (BPRS) and Schedule for Assessment of Negative Symptoms (SANS), and weekly assessments for electrocardiogram (EKG), and side effects. Neurocognitive tests measuring verbal fluency, working memory, motor and attention/executive function were obtained at study entry and end of the trial.

RESULTS

We found no significant effect of pimozide on BPRS total, psychosis and depression subscale items, SANS scores or QTc interval. Neurocognitive measures did not show significant improvement either.

DISCUSSION

In this well controlled clinical trial of patients with treatment-resistant schizophrenia currently receiving clozapine, pimozide augmentation was not an effective strategy to maximize the benefit for better control of positive and negative symptoms or improving neurocognitive function.

Aripiprazole as a viable alternative for treating delusions of parasitosis

Delusions of parasitosis (DOP) is a psychiatric disorder characterized by the fixed false belief that one is infested with parasites or other organisms. Historically, pimozide, a first-generation antipsychotic, has been the treatment of choice for DOP, although there is risk for serious adverse effects including extrapyramidal symptoms, QTc prolongation and tardive dyskinesia. Recently, there have been several reports describing the effectiveness of second-generation antipsychotics (SGAs), but these agents have their own unique adverse effects, specifically metabolic changes with olanzapine, sedation with quetiapine and hyperprolactinemia with risperidone. Aripiprazole is a novel, third-generation antipsychotic with comparable efficacy to SGAs, but a more favorable side effect profile. Successful treatment of DOP with aripiprazole has recently been described in the psychiatric and dermatologic literature. The authors present another report to support the use of aripiprazole as an efficacious and safe alternative for treating DOP.

Pimozide for tics in Tourette's syndrome

BACKGROUND

Neuroleptic drugs with potent D-2 receptor blocking properties have been the traditional treatment for tics caused by Tourette Syndrome. Pimozide is the most studied of these. Use of these medications is declining because of concerns about side effects, and new atypical neuroleptics are now available. The true benefit and risks associated with pimozide compared to other drugs is not known.

OBJECTIVES

To evaluate the efficacy and harms of pimozide in comparison to placebo or other medications in the treatment of tics in Tourette Syndrome.

SEARCH STRATEGY

We cross-referenced pimozide and its proprietary names with Tourette Syndrome and its derivations, as MeSH headings and as text words, and searched the Cochrane Movement Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 4), MEDLINE (1950-April 2007), and EMBASE (1980-April 2007). Reference lists of relevant articles were reviewed for additional trials.

SELECTION CRITERIA

All randomized, controlled, double blind studies comparing pimozide to placebo or other medications for the treatment of tics in Tourette Syndrome were considered for inclusion in this review. Both parallel group and crossover studies of children or adults, at any dose and for any duration, were included.

DATA COLLECTION AND ANALYSIS

Data was abstracted independently by two authors onto standardized forms and disagreements were resolved by discussion.

MAIN RESULTS

Six randomized controlled trials were included (total 162 participants, age range 7 to 53 years). Pimozide was compared with: placebo and haloperidol (two trials), placebo (one trial), haloperidol (one trial), and risperidone (two trials). Methodological quality was rated 'fair' for all studies. Studies used different outcome measurement scales for assessing tic severity and adverse effects. Significant clinical heterogeneity made meta-analysis inappropriate. Pimozide was superior to placebo in three studies, though it caused more side effects than placebo in one of these. Pimozide was inferior to haloperidol in one of three studies (the other two showed no significant difference between the drugs), which also showed significantly fewer side effects associated with pimozide. No significant differences between pimozide and risperidone were detected.

AUTHORS' CONCLUSIONS

Pimozide is an effective treatment for tics in Tourette Syndrome, though the number of trials comparing its effect to placebo and other drugs is limited. Trials of longer duration (minimum six months) are needed to investigate the longer-term effects of pimozide compared to atypical neuroleptics. Future trials should use the Yale Global Tic Severity Scale to assess the main outcome measure, and quantify adverse events with the Extrapyramidal Symptoms Rating Scale.

Coadministration of scrtraline with cisapride or pimozide: an open-label, nonrandomized examination of pharmacokinetics and corrected qt intervals in healthy adult volunteers

BACKGROUND

Sertraline hydrochloride is a selective serotonin reuptake inhibitor with demonstrated efficacy and safety for the treatment of the following disorders: major depressive, obsessive-compulsive, panic, premenstrual dysphoric, social anxiety, and posttraumatic stress. Although sertraline is unlikely to cause clinically significant inhibition of cytochrome P450 (CYP) 3A4 substrates, even modest concentration increases for narrow therapeutic index drugs, such as pimozide or cisapride, are potentially important.

OBJECTIVE

The goal of this study was to determine whether there is a pharmacokinetic interaction, as shown by plasma concentrations and electrocardiographic evidence of QTc intervals, between sertraline 200 mg QD and cisapride 10 mg QID, and between sertraline 200 mg QD and pimozide (single 2-mg dose).

METHODS

Patients in group A were administered cisapride on days 1 and 2 (10 mg QID), day 3 (10 mg/d), days 25 through 29 (10 mg QID), and day 30 (10 mg/d). Sertraline was administered on days 4 through 29 at a starting dose of 50 mg/d, which was titrated upward in 50-mg increments every third day to a maximum of 200 mg/d. Patients in group B were treated with 2 mg of pimozide on days 1 and 39. Sertraline was administered on days 18 through 46 at a starting dose of 50 mg/d, which was titrated upward in 50-mg increments every third day to a maximum of 200 mg/d.

RESULTS

There were 9 males and 6 females in group A (sertraline + cisapride) (mean age, 34.4 years for males, 41.7 years for females; mean weight, 78.7 kg for males, 66.6 kg for females; 14 Hispanic, 1 white), and 8 males and 7 females in group B (sertraline + pimozide) (mean age, 26.1 years for males, 33.4 years for females; mean weight, 70.8 kg for males, 61.4 kg for females; 15 Hispanic). Coadministration of sertraline and cisapride resulted in statistically significant reductions of 29% and 36% in cisapride C(max) and AUC from time 0 to 6 hours, respectively, compared with cisapride alone. Coadministration of sertraline and pimozide resulted in statistically significant increases of 35% and 37% in pimozide Cmax and AUC(0-infinity), respectively, compared with pimozide alone. No subject exhibited a prolongation of the QTc interval > or =15% with coadministration of sertraline and cisapride, or sertraline and pimozide.

CONCLUSIONS

This study found that coadministration of sertraline with cisapride resulted in decreases in cisapride concentrations, and no significant effects on QTc intervals. Coadministration of sertraline 200 mg/d and a single dose of pimozide 2 mg produced significant increases in pimozide concentrations but no prolongation of the QTc interval > or =15%. This opposite effect for pimozide compared with cisapride, as well as other previously tested CYP3A4 substrates, suggests that there are mechanisms other than CYP3A4 involved in the sertraline-pimozide interaction.

Drug interactions of clinical significance for the dermatologist: recognition and avoidance

While it would be impossible for any dermatologist to remember all potential drug interactions, knowledge of the mechanisms of drug interactions can help reduce the risk of serious adverse outcomes. Most drugs are associated with interactions but the majority do not produce significant outcomes. Dealing with drug interactions is a challenge in all clinical practice, including dermatology. New information continues to appear, and dermatologists need to know about the drugs they use.This article focuses on the mechanisms of drug interactions. In particular, the life of a drug in terms of absorption, distribution, metabolism and excretion are reviewed with the focus on points of importance and relevance to drug interactions. The most clinically important drug interactions in dermatological practice are caused by alterations in drug metabolism. The contributions of P-glycoprotein, pharmacogenetic variation and genetic polymorphisms to drug interactions are highlighted, and the best evidence for drug interactions involving drug classes relevant to the dermatologist is presented. Since the initial evidence for clinically relevant drug interactions comes from case reports, prescribing physicians can have a major role in collating information on interactions. By understanding the mechanisms behind drug interactions and staying alert for toxicities, we can help make drug therapy safer and reduce the fear of drug interactions.

Pimozide injections into the Nucleus accumbens disrupt maternal behaviour in lactating rats

In rodents ongoing maternal behaviour requires activation of dopamine receptors. Therefore, it is possible that some motor components of maternal behaviour might be mediated by concurrent dopaminergic stimulation. It has been previously demonstrated that peripheral injections of some antipsychotic drugs such as pimozide have disruptive effects on maternal behaviour. The present experiments were designed to verify the effects of pharmacological blockade of limbic dopamine receptors on ongoing maternal behaviour in lactating rats. The hypothesis that central injections of the drug pimozide would have an effect on maternal behaviour was tested. We investigated the effects of central bilateral intra-accumbens microinjections of the dopamine D2 receptor antagonist pimozide (1.5 and 3.0 microg) on maternal behaviour. Animals treated with 3.0 microg of pimozide showed significantly longer latencies for all parameters of maternal behaviour compared to controls. These results suggest that dopamine receptors in the nucleus accumbens play a role in ongoing maternal behaviour.

Pimozide: use in dermatology

Pimozide is widely used in psychiatry for chronic psychoses, schizophrenia, the syndrome of Gilles de la Tourette and to a certain extent, also in dermatology. The only dermatological indication is for delusions of parasitosis. Though there is a good rationale for using pimozide in this disease, the majority of the studies on pimozide in dermatology are uncontrolled trials and case reports.

Delusions of parasitosis. A dermatologist's guide to diagnosis and treatment

Delusions of parasitosis is a rare psychiatric disorder in which the patient has a fixed, false belief that he or she is infested by parasites. Even though it is a psychiatric disorder, these patients usually present to a dermatologist because they are convinced that they have a dermatological problem. Patients with delusions of parasitosis generally reject psychiatric referral. The diagnosis of delusions of parasitosis can often be made on the basis of the history alone, but it is important to make sure that the patient does not have a organic skin disorder, and the delusion is not secondary to another mental or physical illness. The current treatment of choice is the antipsychotic medication pimozide. The principal difficulty in management is convincing patients to take the drug. This results from the obvious discrepancy between the patients' belief system and the clinician's understanding of the situation. The most common adverse effects of pimozide are extrapyramidal symptoms such as stiffness and, less frequently, a special inner sense of restlessness called akathisia. Effective treatment of such extrapyramidal reactions includes benztropine 1 to 2 mg up to 4 times daily as needed, or diphenhydramine 25 mg 3 times daily as needed. Pimozide can have cardiotoxic effects at high dosages. Traditionally, it has been recommended to check pretreatment and post-treatment electrocardiograms even for patients who have no history or cardiac conduction abnormalities or arrhythmia. However, a more recent publication questions the need for this if the patient takes < 10 mg/day, is not elderly, and has no history of cardiac arrhythmia. Effective dosages of pimozide for delusions of parasitosis have ranged from 1 to 10 mg/day. The lowest effective dosage of pimozide should be used for the shortest possible duration to minimize the risk of tardive dyskinesia developing in these patients. Significant improvements in quality of life have been achieved with successful treatment with pimozide. Atypical antipsychotics such as risperidone with a much safer adverse effect profile may prove to be effective for the treatment of delusions of parasitosis in the future.

Olanzapine in severe Gilles de la Tourette syndrome: a 52-week double-blind cross-over study vs. low-dose pimozide

We selected four patients with severe Gilles de la Tourette syndrome, high frequency of tics (two to ten per minute), vocalizations, and lack of comorbidity. These patients (aged 19-40 years) underwent a 52-week double-blind cross-over study with olanzapine (5 and 10 mg daily) vs. low-dose pimozide (2 and 4 mg daily). The reduction in rating scale scores for the syndrome was highly significant with 10 mg olanzapine vs. basal and vs. 2 mg pimozide, and was significant for 5 mg olanzapine vs. 4 mg pimozide. Only moderate sedation was reported by one patient during olanzapine treatment while three complained of minor motor side effects and sedation during pimozide treatment. At the end of the study all patients opted for olanzapine treatment.

Studies on the mechanism of a fatal clarithromycin-pimozide interaction in a patient with Tourette syndrome

The authors report in detail the case of a 27-year-old man who experienced sudden cardiac death 2 days after coprescription of the neuroleptic pimozide and the macrolide antibiotic clarithromycin after the documentation of a prolonged QT interval. To determine the prevalence of this interaction, the authors referred to the Spontaneous Reporting System of the Food and Drug Administration and identified one similar case in which clarithromycin was coprescribed with pimozide and sudden cardiac death occurred shortly thereafter. In addition, the search identified 39 cases of cardiac arrhythmia associated with pimozide, 11 with pimozide alone, and 6 with clarithromycin alone, 1 of which had a positive rechallenge. The mechanism of the interaction between clarithromycin and pimozide seems to involve the inhibition of the hepatic metabolism of pimozide by the macrolide. The authors demonstrated that clarithromycin is able to inhibit the metabolism of pimozide in human liver microsomal preparations (K(i) = 7.65 +/- 1.18 microM) and that pimozide, but not clarithromycin or its primary metabolite, is able to prolong the electrocardiac QT interval in a dose-dependent manner in the isolated perfused rabbit heart. The increase was 9.6 +/- 1.1% in male hearts (N = 5) and 13.4 +/- 1.2% in female hearts (N = 4) (p < 0.05).

Does a four-week delay in the introduction of medication alter the course of functional psychosis?

This study is an analysis of findings of a follow-up study of 105 patients with functional psychotic illness who had participated in a random and blind 4-week trial of pimozide, lithium, both and placebo. The intention was to examine the question of whether a 4-week delay in initiating antipsychotic treatment has a detrimental effect 2.5 years later. Detailed follow-up measures included need for care over the 2.5 years, treatments required, occupational decline, police contact, substance misuse, psychopathology and cognitive function. There was no evidence at all that those initially randomized to placebo had a poorer outcome in terms of any of these variables. It is concluded that a 4-week delay in initiating active treatment in patients with functional psychosis has no long-term adverse effects.

Pimozide-induced depression in men who stutter

BACKGROUND

Neuroleptic-related dysphoric reactions are well recognized in the context of psychiatric disorders, especially in association with extrapyramidal side effects. Very few controlled data exist regarding the effects of neuroleptics on the mood of psychiatrically "normal" subjects. In this study, the depressogenic effect of the neuroleptic drug pimozide was assessed in men without psychiatric disorders.

METHOD

Eight men with developmental stuttering but no past or present psychiatric illness participated in a double-blind, placebo-controlled study assessing the effect of 6 weeks of pimozide treatment on speech fluency and mood.

RESULTS

Four of the seven subjects who were compliant with the treatment developed marked depressive symptoms. No clear association was found between these reactions and pimozide dose, blood level, or degree of neurologic side effects. Symptoms abated soon after drug discontinuation.

CONCLUSION

Pimozide induced significant depressive symptoms in this group of psychiatrically normal men who stutter. Neuroleptic drugs may have a causal effect in the induction of depression in psychiatrically normal subjects, ostensibly independent of dose or severity of neurologic side effects.

Relative efficacy of haloperidol and pimozide in children and adolescents with Tourette's disorder

OBJECTIVE

The authors evaluated the relative efficacy and safety of pimozide and haloperidol in the treatment of Gilles de la Tourette's syndrome in children and adolescents.

METHOD

A double-blind, 24-week, placebo-controlled double crossover study of equivalent dose formulations of haloperidol and pimozide was conducted with 22 subjects, aged 7-16 years, with Tourette's disorder who were randomly assigned to first one active drug treatment and then the other. Biweekly assessment and flexible dose titration mimicked clinical practice. The primary outcome variable was total score on the Tourette Syndrome Global Scale. Final outcome was determined after 6 weeks of each treatment (placebo, pimozide, haloperidol), with a 2-week placebo baseline period and intervening 2-week placebo washout periods between treatments.

RESULTS

Pimozide proved significantly different from placebo in affecting the primary outcome variable, whereas haloperidol failed to have a significant effect. Haloperidol exhibited a threefold higher frequency of serious side effects and significantly greater extrapyramidal symptoms relative to pimozide. Haloperidol-associated treatment-limiting adverse events were experienced by 41% of the patients. The therapeutic doses of pimozide and haloperidol were equivalent (mean = 3.4 mg/day, SD = 1.6, and mean = 3.5 mg/day, SD = 2.2, respectively).

CONCLUSIONS

At equivalent doses, pimozide is superior to haloperidol for controlling symptoms of Tourette's disorder in children and adolescents.

[Diagnosis and treatment of the patient with trigeminal neuralgia]

Neuralgia of the trigeminus (NT) is the most common of cranial nerve neuralgias. Its diagnosis is entirely clinical and its most common form of presentation is well understood. Questions of differential diagnosis can emerge with certain entities such as atypical trigeminal neuralgia, short-duration unilateral neuralgiform cephalea of the trigeminus (SUNCT) arising from injection to the conjunctival, lacrimal or other glands, cluster headache, chronic paroxymal hemicrania, pain arising in the teeth and myofacial pain syndrome. The three main causative factors of NT are compression of the nerve root by an artery in the prepontine space, thereby creating an area of demyelinization, compression of the nerve by a tumor, and multiple sclerosis. The first is the most common of the three. NT can be classified as essential in 10 to 30% of patients. Recent advances in magnetic resonance (MR), and its advantages over other imaging systems, have made MR the diagnostic method of choice. The first treatment is medical and the basic drugs involved can be considered classic. Other therapies have been suggested in recent years, however, and should probably be studied further. Two substances stand out among those proposed: tocainide, an antiarrhythmic drug, and pimozide, an antipsychotic. Surgical treatment of NT can address either the cause (tumor or vascular compression) or symptoms, the latter being indicated when medical treatment fails. Surgery can be performed on peripheral nerves, on the gasserian ganglion and on the posterior fossa. The indications, outcomes and possible complications are quite different for each approach, making choice controversial.

Prolactin monitoring of haloperidol and pimozide treatment in children with Tourette's syndrome

Neuroleptic therapy of children and adolescents with Tourette's syndrome (GTS) is associated with unpredictable outcome and adverse drug responses (i.e., extrapyramidal symptoms). Assessing the potential outcomes in GTS from a physiologic marker such as plasma prolactin concentration is important in limiting exposure and optimizing therapy. In a double-blind, placebo-controlled, double crossover comparison of pimozide and haloperidol therapy, prolactin, tic severity, and extrapyramidal symptoms were assessed at a 6-week end point. Twenty-six GTS patients (10.5 +/- 2.6 years), experienced clinical response rates of 69% on 3.4 +/- 1.6 mg pimozide and 65% on 3.5 +/- 2.2 mg/day haloperidol. Pimozide responders demonstrate elevated prolactin (26.1 +/- 11.8 ng/mL) versus pimozide nonresponders (10.5 +/- 3.8 ng/mL) (p = .05) and haloperidol treated patients (p = .05). Prolactin may be a marker for tic response to pimozide, and conversely, a potential marker for haloperidol-related incidence of extrapyramidal symptoms during haloperidol therapy.

The successful treatment of a gender dysphoric patient with pimozide

OBJECTIVE

The case is reported of a gender dysphoric patient who responded successfully to pharmacotherapy with pimozide.

CLINICAL PICTURE

An adult male patient with a borderline learning disability presented with cross-dressing and a strong wish to undergo a sex change.

TREATMENT

Supportive psychotherapy and pharmacotherapy with pimozide was tried.

OUTCOME

There was an excellent response to pimozide 2 mg daily, with a cessation of both cross-dressing and the wish for sex reassignment. When, after 1 year, the dose was reduced to 1 mg daily, there was a rapid return of the cross-dressing and the wish for sex reassignment. An increase in the dose again led to a remission which has been maintained since then.

CONCLUSION

Pharmacotherapy with pimozide should be considered in cases of doubtful gender dysphoria.

Differences between haloperidol- and pimozide-induced withdrawal syndrome: a role for Ca2+ channels

We investigated the behavioral and biochemical events appearing in rats after withdrawal for 24 h or 8-12 days from two classical neuroleptics, haloperidol and pimozide. The neuroleptics were given for 14 days alone or shortly after injection of the Ca2+ channel blocker nifedipine. We have found that withdrawal effects after haloperidol and pimozide were different. After haloperidol treatment we observed an increase in cortical Ca2+ channel and limbic dopamine D1 receptor density and an increase in spontaneous motor activity and apomorphine-induced hyperactivity and stereotypy. In contrast no biochemical changes were observed during pimozide withdrawal, and locomotor activity and responses to apomorphine were depressed. Co-administration of nifedipine with haloperidol prevented the observed biochemical and behavioral symptoms of withdrawal. Nifedipine administration did not change the depressant effects of pimozide. Our results suggest that the voltage-dependent Ca2+ channel is involved in the observed withdrawal syndrome of neuroleptics, and that the absence of this syndrome after pimozide may be related to its considerable Ca2+ channel-blocking properties.

Pharmacologic treatment of delusions

Delusions usually respond to antipsychotic medications. When delusions are present within certain diagnostic categories, however, pharmacotherapy other than or in addition to antipsychotic agents is indicated. Many delusional disorders have been found to respond to pimozide even after failing to respond to other antipsychotic agents. Delusions accompanied by affective symptomatology should be treated with both antipsychotic medications and antidepressants or mood stabilizers. When delusions are the result of a medical condition, treatment of the medical condition may lead to resolution of the delusion.

Withdrawal akathisia: case reports and a proposed classification of chronic akathisia

Two patients with akathisia developing only after neuroleptic dosage reduction or withdrawal are described. The literature dealing with tardive or chronic akathisia is reviewed with an emphasis on the existence of variants including the occurrence of symptoms upon withdrawal of the causative drug. A classification of tardive or chronic akathisia syndrome is proposed.

Delusional parasitosis: a dermatologic, psychiatric, and pharmacologic approach

Delusional parasitosis is a syndrome in which the patient has the false belief that he is infested by parasites. Although this is a psychiatric disorder, patients usually seek care from dermatologists. DP has various causes. It may occur as the sole psychologic disturbance, or it may be associated with an underlying psychiatric disorder or physical illness. A dermatology-psychiatry liaison is advocated for establishing a viable differential diagnosis and selecting appropriate therapy. The antipsychotic agent pimozide is currently the most effective treatment when DP occurs as an encapsulated delusion. Pimozide therapy requires careful monitoring because this drug has several potentially serious adverse effects, and relapse often occurs on discontinuation of the drug.

Acute dystonic reaction with low-dose pimozide

It is essential to recognize individual susceptibility to neuroleptic-induced side effects for treatment guidelines. This paper reports on a 6.9-year-old autistic male who developed repeated episodes of acute dystonic reactions associated with pimozide administration at the doses of 0.096 mg/kg/day and 0.032 mg/kg/day and 32 hours following pimozide withdrawal, as well as during subsequent thioridazine administration. It draws the clinician's attention to unusual susceptibility to extrapyramidal side effects and suggests that if a child shows this type of susceptibility to one neuroleptic, he/she may react similarly to other neuroleptics as well.

Clinical uses of pimozide

One of the more difficult psychopharmacologic aspects of current clinical psychiatry is finding a neuroleptic drug that adequately treats delusional states. Furthermore, many chronic schizophrenics remain resistant to standard antipsychotic medication, and clozapine is effective in only 30% to 50% of refractory cases. In addition, clozapine has several serious side effects and is expensive. We have determined that pimozide is clearly effective in Tourette's syndrome, maintenance schizophrenia, and some delusional disorders. We further demonstrate that the drug is likely to be effective in the treatment of the negative symptoms of schizophrenia and other delusional states. In addition, we suggest that a trial of pimozide may be indicated before giving clozapine to treatment-resistant schizophrenic patients. The side effect that probably most limits pimozide's current use is the possible production of ECG abnormalities. This side effect does not seem to be a realistic clinical concern, however, if the patients are properly screened and the pimozide dose is maintained at or below 20 mg/day.

Possible interaction between fluoxetine and pimozide causing sinus bradycardia

Fluoxetine has been reported to have interactions with antipsychotics and other antidepressants with symptoms of toxicity of these drugs. We report a case of a possible interaction with pimozide which led to a potentially life threatening bradycardia. Careful monitoring should be done when these two drugs are prescribed at the same time, especially in the elderly and in patients with cardiac disease.

The Scottish first episode schizophrenia study. VIII. Five-year follow-up: clinical and psychosocial findings. The Scottish Schizophrenia Research Group

Forty-four schizophrenic patients were followed up for five years after their first admission to hospital for a first episode of illness. Thirteen (30%) of 43 patients had not relapsed; 28 of the 30 patients who did relapse did so within the first 42 months. The relapses occurred despite antipsychotic drug therapy. Also, 24% of patients had at least one course of ECT. Only 19% of the patients at five years were in open employment; unemployment was strongly associated with relapse. Eighteen per cent had neither relapses nor schizophrenic symptoms at follow-up. Poor outcome at five years was associated with greater psychological distress among relatives at first admission. At five years 43% of relatives continued to show case level psychological stress.

[Gilles-de-la-Tourette syndrome]

Gilles de la Tourette's syndrome, a combination of multiple chronic tics and vocalizations, usually first occurring during childhood, is described in its history, symptomatology, genetics, etiology and therapy. Traditionally TS has been viewed either as an organic or as a psychogenic disorder. We propose an integrative concept combining both aspects. During a vulnerable phase in childhood a hypersensitivity of dopamine 2-receptors, induced by gene defects or perinatal trauma, leads to a lack of suppression of subcortical programs which discharge as tics. Tics are modified by multiple psychological contents (aggressive or sexual impulses, imitation of others) which tend to become independent of their origin. Severity of tics in the course of the illness is often dependent on the emotional status of the patient. Recent research focuses on the search for a major gene locus and the relationship between dopamine-receptor hypersensibility and the disturbances of other neurotransmitter systems (norepinephrine, serotonin, endorphin).

[Three cases of hyponatremia during administration of pimozide]

Three patients with hyponatremia were found at an residential home of mental developmental delay. Because pimozide had been administered to all of them, it was suggested that pimozide might have induced compulsive water drinking resulting in hyponatremia. To my knowledge, there has been no previous report that pimozide may induce hyponatremia. As children with mental developmental delay and/or autism frequently develop epilepsy, hyponatremia should be included in the differential diagnosis of convulsive seizures. Particularly when antipsychotic drugs such as pimozide have been given, we should pay attention to polydipsia, polyuria and/or general malaise and prevent hyponatremia.

The role of pimozide in clinical psychiatry: a review

Pimozide, a diphenylbutylpiperidine neuroleptic which is FDA-approved as a backup treatment for Gilles de la Tourette's syndrome, has been used abroad for many years as a treatment of schizophrenia and has been recently reported to be particularly effective in treating monosymptomatic hypochondriacal psychosis and delusional jealousy. Pimozide may also have a role in the treatment of negative schizophrenic symptoms, pain syndromes, and obsessive compulsive disorder. After reviewing the relevant clinical literature supporting these indications, the authors review preclinical studies that provide points of departure regarding biochemical mechanisms underlying this unique therapeutic profile.

Three thousand days of pregnancy. A case of monosymptomatic delusional pseudocyesis responding to pimozide

An unusual case of pseudocyesis of almost ten-year duration, characterised by a monosymptomatic hypochondriacal delusion and a selective response to pimozide is reported. The nosological status of the diagnosis, delusional (paranoid) disorder, is suggested to be a variety of the Kraepelinian concept of paranoia. The therapeutic pitfalls of relying on a phenomenological distinction between overvalued ideas and delusional beliefs are discussed.

Tourette syndrome: a follow-up study

We describe a long-term follow-up study (1-15 years) of 33 patients with Tourette syndrome who were treated with pimozide (2-18 mg), haloperidol (2-15 mg), or no drugs. Both drugs produced comparable relief of symptoms at follow up; however, significantly more patients on haloperidol (eight of 17), compared with those on pimozide (one of 13), discontinued treatment (p less than or equal to 0.05). Haloperidol produced significantly more acute dyskinesias/dystonias than pimozide (p less than or equal to 0.03); otherwise, the adverse effect profile was similar for the two drugs. In particular, we found no increased incidence of ECG abnormalities in patients treated with pimozide. A prospective, randomized, double-blind crossover trial is required to determine whether there are significant differences in efficacy between pimozide and haloperidol in treatment of Tourette's disorder.

Pimozide therapy for trigeminal neuralgia

Pimozide was compared with carbamazepine in a double-blind crossover trial in 48 patients with trigeminal neuralgia who were refractory to medical therapy. Pimozide treatment produced greater reduction in trigeminal neuralgia symptoms than carbamazepine treatment. All of the pimozide-treated patients improved, while only 56% of carbamazepine-treated patients were relieved of their pain. Although both drugs provoked some adverse effects, it was not necessary to interrupt the trial in any case. After this 24-week trial, all patients began receiving pimozide and were followed up according to an open-label study design. In all cases, the pimozide dosage was progressively reduced until the minimal effective dose was reached. Central and peripheral mechanisms that may underlie pimozide-induced improvement are discussed.