The distribution and metabolism of chlorpromazine in rats and the relationship to effects on cerebral monoamine metabolism

Long COVID, neuropsychiatric disorders, psychotropics, present and future

Long COVID refers to the lingering symptoms which persist or appear after the acute illness. The dominant long COVID symptoms in the two years since the pandemic began (2020-2021) have been depression, anxiety, fatigue, concentration and cognitive impairments with few reports of psychosis. Whether other symptoms will appear later on is not yet known. For example, dopamine-dependent movement disorders generally take many years before first symptoms are seen. Post-stroke depression and anxiety may explain many of the early long COVID cases. Hemorrhagic, hypoxic and inflammatory damages of the central nervous system, unresolved systematic inflammation, metabolic impairment, cerebral vascular accidents such as stroke, hypoxia from pulmonary damages and fibrotic changes are among the major causes of long COVID. Glucose metabolic and hypoxic brain issues likely predispose subjects with pre-existing diabetes, cardiovascular or lung problems to long COVID as well. Preliminary data suggest that psychotropic medications may not be a danger but could instead be beneficial in combating COVID-19 infection. The same is true for diabetes medications such as metformin. Thus, a focus on sigma-1 receptor ligands and glucose metabolism is expected to be useful for new drug development as well as the repurposing of current drugs. The reported protective effects of psychotropics and antihistamines against COVID-19, the earlier reports of reduced number of sigma-1 receptors in post-mortem schizophrenic brains, with many antidepressant and antipsychotic drugs being antihistamines with significant affinity for the sigma-1 receptor, support the role of sigma and histamine receptors in neuroinflammation and viral infections. Literature and data in all these areas are accumulating at a fast rate. We reviewed and discussed the relevant and important literature.

Inhibition of the replication of SARS-CoV-2 in human cells by the FDA-approved drug chlorpromazine

INTRODUCTION

Urgent action is needed to fight the ongoing coronavirus disease 2019 (COVID-19) pandemic by reducing the number of infected cases, contagiousness and severity. Chlorpromazine (CPZ), an antipsychotic from the phenothiazine group, is known to inhibit clathrin-mediated endocytosis and has antiviral activity against severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1) and Middle East respiratory syndrome coronavirus. The aim of this in-vitro study was to test CPZ against SARS-CoV-2 in monkey and human cells.

MATERIALS AND METHODS

Monkey VeroE6 cells and human alveolar basal epithelial A549-ACE2 cells were infected with SARS-CoV-2 in the presence of various concentrations of CPZ. Supernatants were harvested at day 2 and analysed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) for the presence of SARS-CoV-2 RNA. Cell viability was assessed in non-infected cells.

RESULTS

CPZ was found to have antiviral activity against SARS-CoV-2 in monkey VeroE6 cells, with a half maximal inhibitory concentration (IC50) of 8.2 µM, half maximal cytotoxic concentration (CC50) of 13.5 µM, and selectivity index (SI) of 1.65. In human A549-ACE2 cells, CPZ was also found to have anti-SARS-CoV-2 activity, with IC50 of 11.3 µM, CC50 of 23.1 µM and SI of 2.04.

DISCUSSION

Although the measured SI values are low, the IC50 values measured in vitro may translate to CPZ dosages used in routine clinical practice because of the high biodistribution of CPZ in lungs and saliva. Also, the distribution of CPZ in brain could be of interest for treating or preventing neurological and psychiatric forms of COVID-19.

CONCLUSIONS

These preclinical findings support clinical investigation of the repurposing of CPZ, a drug with mild side effects, in the treatment of patients with COVID-19.

Repurposing chlorpromazine to treat COVID-19: The reCoVery study

OBJECTIVES

The ongoing COVID-19 pandemic has caused approximately 2,350,000 infections worldwide and killed more than 160,000 individuals. In Sainte-Anne Hospital (GHU PARIS Psychiatrie & Neuroscience, Paris, France) we have observed a lower incidence of symptomatic forms of COVID-19 among patients than among our clinical staff. This observation led us to hypothesize that psychotropic drugs could have a prophylactic action against SARS-CoV-2 and protect patients from the symptomatic and virulent forms of this infection, since several of these psychotropic drugs have documented antiviral properties. Chlorpromazine (CPZ), a phenothiazine derivative, is also known for its antiviral activity via the inhibition of clathrin-mediated endocytosis. Recentin vitro studies have reported that CPZ exhibits anti-MERS-CoV and anti-SARS-CoV-1 activity.

METHODS

In this context, the ReCoVery study aims to repurpose CPZ, a molecule with an excellent tolerance profile and a very high biodistribution in the saliva, lungs and brain. We hypothesize that CPZ could reduce the unfavorable course of COVID-19 infection among patients requiring respiratory support without the need for ICU care, and that it could also reduce the contagiousness of SARS-CoV-2. For this purpose, we plan a pilot, multicenter, randomized, single blind, controlled, phase III therapeutic trial (standard treatment vs. CPZ+standard treatment).

CONCLUSION

This repurposing of CPZ for its anti-SARS-CoV-2 activity could offer an alternative, rapid strategy to alleviate infection severity. This repurposing strategy also avoids numerous developmental and experimental steps, and could save precious time to rapidly establish an anti-COVID-19 therapy with well-known, limited and easily managed side effects.

[Repurposing of chlorpromazine in COVID-19 treatment: the reCoVery study]

OBJECTIVES

The ongoing COVID-19 pandemic comprises a total of more than 2,350,000 cases and 160,000 deaths. The interest in anti-coronavirus drug development has been limited so far and effective methods to prevent or treat coronavirus infections in humans are still lacking. Urgent action is needed to fight this fatal coronavirus infection by reducing the number of infected people along with the infection contagiousness and severity. Since the beginning of the COVID-19 outbreak several weeks ago, we observe in GHU PARIS Psychiatrie & Neurosciences (Sainte-Anne hospital, Paris, France) a lower prevalence of symptomatic and severe forms of COVID-19 infections in psychiatric patients (∼4%) compared to health care professionals (∼14%). Similar observations have been noted in other psychiatric units in France and abroad. Our hypothesis is that psychiatric patients could be protected from severe forms of COVID-19 by their psychotropic treatments. Chlorpromazine (CPZ) is a phenothiazine derivative widely used in clinical routine in the treatment of acute and chronic psychoses. This first antipsychotic medication has been discovered in 1952 by Jean Delay and Pierre Deniker at Sainte-Anne hospital. In addition, to its antipsychotic effects, several in vitro studies have also demonstrated a CPZ antiviral activity via the inhibition of clathrin-mediated endocytosis. Recently, independent studies revealed that CPZ is an anti-MERS-CoV and an anti-SARS-CoV-1 drug. In comparison to other antiviral drugs, the main advantages of CPZ lie in its biodistribution: (i) preclinical and clinical studies have reported a high CPZ concentration in the lungs (20-200 times higher than in plasma), which is critical because of the respiratory tropism of SARS-CoV-2; (ii) CPZ is highly concentrated in saliva (30-100 times higher than in plasma) and could therefore reduce the contagiousness of COVID-19; (iii) CPZ can cross the blood-brain barrier and could therefore prevent the neurological forms of COVID-19.

METHODS

Our hypothesis is that CPZ could decrease the unfavorable evolution of COVID-19 infection in oxygen-requiring patients without the need for intensive care, but also reduce the contagiousness of SARS-CoV-2. At this end, we designed a pilot, phase III, multicenter, single blind, randomized controlled clinical trial. Efficacy of CPZ will be assessed according to clinical, biological and radiological criteria. The main objective is to demonstrate a shorter time to response (TTR) to treatment in the CPZ+standard-of-care (CPZ+SOC) group, compared to the SOC group. Response to treatment is defined by a reduction of at least one level of severity on the WHO-Ordinal Scale for Clinical Improvement (WHO-OSCI). The secondary objectives are to demonstrate in the CPZ+SOC group, compared to the SOC group: (A) superior clinical improvement; (B) a greater decrease in the biological markers of viral attack by SARS-CoV-2 (PCR, viral load); (C) a greater decrease in inflammatory markers (e.g. CRP and lymphopenia); (D) a greater decrease in parenchymal involvement (chest CT) on the seventh day post-randomization; (E) to define the optimal dosage of CPZ and its tolerance; (F) to evaluate the biological parameters of response to treatment, in particular the involvement of inflammatory cytokines. Patient recruitment along with the main and secondary objectives are in line with WHO 2020 COVID-19 guidelines.

CONCLUSION

This repositioning of CPZ as an anti-SARS-CoV-2 drug offers an alternative and rapid strategy to alleviate the virus propagation and the infection severity and lethality. This CPZ repositioning strategy also avoids numerous developmental and experimental steps and can save precious time to rapidly establish an anti-COVID-19 therapy with well-known, limited and easy to manage side effects. Indeed, CPZ is an FDA-approved drug with an excellent tolerance profile, prescribed for around 70 years in psychiatry but also in clinical routine in nausea and vomiting of pregnancy, in advanced cancer and also to treat headaches in various neurological conditions. The broad spectrum of CPZ treatment - including antipsychotic, anxiolytic, antiemetic, antiviral, immunomodulatory effects along with inhibition of clathrin-mediated endocytosis and modulation of blood-brain barrier - is in line with the historical French commercial name for CPZ, i.e. LARGACTIL, chosen as a reference to its "LARGe ACTion" properties. The discovery of those CPZ properties, as for many other molecules in psychiatry, is both the result of serendipity and careful clinical observations. Using this approach, the field of mental illness could provide innovative therapeutic approaches to fight SARS-CoV-2.

Time-related changes in serum perphenazine, striatal 3H-spiperone binding and regional brain acid metabolites of dopamine and 5-hydroxy-tryptamine after a single dose of perphenazine

A single dose of perphenazine (5.0 mg/kg) was administered intraperitoneally to male Wistar rats. The time-related alterations in serum levels of perphenazine, striatal 3H-spiperone binding ex vivo and the regional brain metabolism of dopamine and 5-hydroxy-tryptamine were studied. Low serum levels of perphenazine were observed together with increased Kd of 3H-spiperone. No significant changes in Bmax were observed. Since Kd of 3H-spiperone binding peaked several hours after the maximal serum levels of perphenazine, perphenazine in serum appeared not to directly reflect the events at the receptor level. The concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxy, 4-hydroxyphenylacetic acid (HVA) in the striatum were increased after perphenazine. They were maximal 1-3 h after the drug administration and showed positive correlations (correlation coefficient 0.93 and 0.80, respectively) with the serum levels of perphenazine. Increased levels of HVA were also observed both in the olfactory tubercle and in the frontal cortex. However, in the olfactory tubercle, administration of perphenazine did not significantly increase the DOPAC concentrations. In the olfactory tubercle 5-hydroxyindoleacetic acid (5-HIAA) was decreased 1-24 h after administration of perphenazine. In the striatum and in the frontal cortex only slight changes in 5-HIAA were seen. Thus, in the olfactory tubercle 5-hydroxytryptaminergic mechanisms could modulate the dopaminergic neurotransmission.

Joint cholinergic-serotonergic control of neocortical and hippocampal electrical activity in relation to behavior: effects of scopolamine, ditran, trifluoperazine and amphetamine

Previous research has indicated that low voltage fast activity (LVFA) in the neocortex and rhythmical slow activity (RSA) in the hippocampus can result from activity in either (or both) the cholinergic corticipetal projections from the basal forebrain and the serotonergic corticipetal projections from the brainstem raphe. These inputs appear to give rise, respectively, to atropine-sensitive LVFA and RSA and atropine-resistant LVFA and RSA. The atropine-sensitive and atropine-resistant waveforms have been shown to have distinctive behavioral correlates. The present experiments extend these findings by providing dose-response data on the effects of scopolamine and Ditran on neocortical activity in relation to behavior in the rat. In addition, new evidence is presented which indicates that neuroleptic drugs reduce activity in the atropine-resistant (presumably serotonergic) inputs to the hippocampus and neocortex by an indirect action involving dopamine receptors. A single dose of d-amphetamine or apomorphine appears to increase activity in the same pathway by a similar indirect action. These findings may be relevant to the psychiatric effects of neuroleptic drugs.

Time course for effects of sulpiride and chlorpromazine on monoamine metabolite and prolactin levels in cerebrospinal fluid from schizophrenic patients

Schizophrenic patients were treated with the dopamine (DA)-2 receptor blocking drug sulpiride (800 mg daily) or the non-selective DA receptor blocking compound chlorpromazine (400 mg daily). Samples of lumbar cerebrospinal fluid (CSF) and blood were drawn before and after 1, 2, 4 and 8 weeks of treatment. Concentrations of the monoamine metabolites HVA, MOPEG and 5-HIAA in CSF and of prolactin (PRL) in CSF and serum were determined. In both treatment groups there were significant and similar elevations of HVA concentrations. HVA levels reached peaks after 1 to 2 weeks treatment and subsequently declined almost to the pretreatment level after 8 weeks. CSF and serum levels of PRL reached maximal levels within 2 weeks and remained stable at that level in both treatment groups. There were significantly higher PRL levels in sulpiride- than in chlorpromazine-treated patients. Women had higher PRL elevations in CSF in both treatment groups. The HVA/PRL ratio in CSF was significantly reduced in the sulpiride but not in the chlorpromazine group. After 1 week there was a significantly elevated 5-HIAA level in the chlorpromazine but not in the sulpiride group. In both groups, the MOPEG concentrations were significantly reduced in relation to pretreatment levels. The reduction was significantly more pronounced in the chlorpromazine group. The results indicate that sulpiride affects central DA metabolism in a similar way as chlorpromazine when administered in doses that induce antipsychotic effects. After both drugs evidence was obtained for the development of tolerance to the effect on the receptors that regulate HVA levels in the CSF but not to receptors regulating PRL release. The different effects of the drugs on PRL, 5-HIAA and MOPEG levels indicate that sulpiride has a more specific effect than chlorpromazine on dopaminergic mechanisms.

Regional aspects of the delay of acquisition conditioned avoidance responding by chlorpromazine

Chlorpromazine injected into the amygdala, septum, or caudate delayed the acquisition of a one-way active avoidance response. Injections into nine other brain areas were inactive. Following a standard dose of chlorpromazine at its ED50 for delaying avoidance acquisition, tissue levels of chlorpromazine from those animals displaying reduced acquisition were significantly higher in the caudate and amygdala than from animals not demonstrating a drug effect.

The in vivo distribution of an antidepressant drug (DMI) in male and female rats

The accumulation of IP injected 3H-desipramine (DMI) in the brain and in the liver has been studied in both male and female rats. The total amount of DMI in the brains of females is 2 to 4 times that found in the brains of males. In females the amount of DMI is highest on the day of estrus and lowest on proestrus. This sex difference was not found following the injections of another psychoactive drug, 3H-chlorpromazine. In both males and females the level of DMI in the cortex and caudate is slightyl higher than in the hippocampus, septum and hypothalamus. The pharmaco-kinetics and dose dependence of the accumulation of DMI are also similar in males and females. Maximal levels are reached in the liver in less than 15 min, whereas in the brain it takes 30 min. The decline of radioactivity in the liver is faster than in brain. There is no saturation in the amount of DMI taken in brain. There is no saturation in the amount of DMI taken up in brain or liver in the dose range up to 40 mg/kg. The sex difference in the amount of 3H-DMI in brain, which may be the result of sex-dependent metabolism in liver microsomes, may explain the male-female differences in reaction to antidepressants.

Clozapine concentrations in brain regions: relationship to dopamine metabolite increase

Levels of clozapine in rat striatum and tuberculum olfactorium were quantitated by a gas chromatographic technique. The relationship of the increase in 3,4-dihydroxyphenylacetic acid (DOPAC) in these regions produced by clozapine to the concentration of clozapine was explored. One hour after 10, 20 or 40 mg/kg clozapine i.p. the concentration of drug increased in proportion to the dose and at each dose was similar in striatum and T.O. The percent increase in DOPAC in both areas was related to the clozapine concentration in a typical dose--response manner and was greater in the striatum than the T.O. A relatively high concentration of clozapine (40 micron) was required to produce a half-maximal elevation of DOPAC. Striatal clozapine levels were similar in acutely and chronically treated animals. The concentrations of clozapine in striatum and T.O. reflect the dose injected and do not account for its atypical properties.

Effect of chlorpromazine treatment on monoamine metabolite levels in cerebrospinal fluid of psychotic patients

Levels of HVA, MOPEG and 5-HIAA in cerebrospinal fluid (CSF) from psychotic men and women with a schizophrenic symptomatology were measured by mass fragmentography. Measurements were made before, 2 and 4 weeks after treatment with chlorpromazine (CPZ) which was given randomly in doses of 200, 400 or 600 mg per day. Before treatment there were positive correlations between the levels of HVA and 5-HIAA in both sexes. During CPZ treatment HVA was significantly elevated, whereas MOPEG and 5-HIAA were reduced. There was a tendency towards tolerance to CPZ's effect on HVA during treatment but a significant effect persisted after 4 weeks. No indication of tolerance to the effects on MOPEG or 5-hiaa was found. There were the same tendencies for the elevations of the HVA/MOPEG and HVA/5-HIAA ratios. The changes in HVA, MOPEG, 5-HIAA, HVA/MOPEG and HVA/5-HIAA were related to dose of CPZ in men but not in women. The bidirectional change of the different metabolites in CSF during CPZ treatment excluses a general and non-specific mechanism for the metabolite changes. The HVA elevation is in accordance with previous results in animals and man, and is presumably related to blockade of central dopamine receptors. Possible mechanisms for the effects on MOPEG and 5-HIAA are discussed.