Side effects of atypical antipsychotics: a brief overview

This paper reviews the available evidence concerning the side effects of atypical antipsychotics, including weight gain, type II diabetes mellitus, hyperlipidemia, QTc interval prolongation, myocarditis, sexual side effects, extrapyramidal side effects and cataract. Some recommendations about how to prevent and manage these side effects are also provided. It is concluded that atypical antipsychotics do not represent a homogeneous class, and that differences in side effects should be taken into account by clinicians when choosing an antipsychotic for an individual patient.     

Discovery of tetrahydropyridopyrimidine phosphodiesterase 10A inhibitors for the treatment of schizophrenia

We describe the discovery of potent and orally bioavailable tetrahydropyridopyrimidine inhibitors of phosphodiesterase 10A by systematic optimization of a novel HTS lead. Lead compound THPP-1 exhibits nanomolar potencies, excellent pharmacokinetic properties, and a clean off-target profile. It displays in vivo target engagement as measured by increased rat striatal cGMP levels upon oral dosing. It shows dose-dependent efficacy in a key pharmacodynamic assay predictive of antipsychotic activity, the psychostimulant-induced rat hyperlocomotion assay. Further, THPP-1 displays significantly fewer preclinical adverse events in assays measuring prolactin secretion, catalepsy, and weight gain, in contrast to the typical and atypical antipsychotics haloperidol and olanzapine.     

The HSP co-inducer BGP-15 can prevent the metabolic side effects of the atypical antipsychotics

Weight gain and dysfunction of glucose and lipid metabolism are well-known side effects of atypical antipsychotic drugs (AAPD). Here, we address the question whether a heat-shock protein (HSP) co-inducer, insulin sensitizer drug candidate, BGP-15, can prevent AAPD-induced glucose, lipid, and weight changes. We also examined how an AAPD alters HSP expression and whether BGP-15 alters that expression. Four different experiments are reported on the AAPD BGP-15 interventions in a human trial of healthy men, a rodent animal model, and an in vitro adipocyte cell culture system. Olanzapine caused rapid insulin resistance in healthy volunteers and was associated with decreased level of HSP72 in peripheral mononuclear blood cells. Both changes were restored by the administration of BGP-15. In Wistar rats, weight gain and insulin resistance induced by clozapine were abolished by BGP-15. In 3T3L1 adipocytes, clozapine increased intracellular fat accumulation, and BGP-15 inhibited this process. Taken together, our results indicate that BGP-15 inhibits multiple metabolic side effects of atypical antipsychotics, and this effect is likely to be related to its HSP co-inducing ability.     

Metabolic outcomes of bergamot polyphenolic fraction administration in patients treated with second-generation antipsychotics: a pilot study

Second-generation antipsychotics (SGAs) are notoriously associated with a marked increase in body weight and with a wide range of metabolic adverse effects, and their chronic use is related with an increased risk for the development of metabolic syndrome (MS). Different adjunctive treatments have been proposed to reduce SGAs-induced weight gain and/or metabolic abnormalities with inconsistent or too limited evidence to support their regular clinical use, thus suggesting the need to find new possible treatments. Bergamot polyphenolic fraction (BPF) has been proven effective in patients with MS, as demonstrated by a concomitant improvement in lipemic and glycemic profiles. The present study was aimed to explore the efficacy and safety of BPF treatment on metabolic parameters in a sample of subjects receiving atypical antipsychotics. Fifteen outpatients treated with SGAs assumed BPF at the oral daily dose of 1000 mg/day for 30 days. Fasting levels of glucose, glycated hemoglobin, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglycerides were determined. BPF administration resulted in a statistically significant reduction of body weight (P=.004) and in a trend for body mass index decrease (P=.005). No significant differences in other and metabolic parameters were observed. Our findings suggest that BPF, at the daily dose of 1000 mg for 30 days, could be an effective and safe agent to prevent weight gain associated with atypical antipsychotic use. However, further clinical trials with adequately powered and well-designed methodology are needed to better explore the BPF effectiveness on the SGAs-induced weight gain and metabolic side effects.     

Metabolic side effects in persons with schizophrenia during mid- to long-term treatment with antipsychotics: a network meta-analysis of randomized controlled trials

Metabolic side effects of antipsychotic drugs can have serious health consequences and may increase mortality. Although persons with schizophrenia often take these drugs for a long time, their mid- to long-term metabolic effects have been studied little so far. This study aimed to evaluate the mid- to long-term metabolic side effects of 31 antipsychotics in persons with schizophrenia by applying a random-effects Bayesian network meta-analysis. We searched the Cochrane Schizophrenia Group's Study-Based Register of Trials (up to April 27, 2020) and PubMed (up to June 14, 2021). We included published and unpublished, open and blinded randomized controlled trials with a study duration >13 weeks which compared any antipsychotic in any form of administration with another antipsychotic or with placebo in participants diagnosed with schizophrenia. The primary outcome was weight gain measured in kilograms. Secondary outcomes included “number of participants with weight gain”, fasting glucose, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. We identified 137 eligible trials (with 35,007 participants) on 31 antipsychotics, with a median follow-up of 45 weeks. Chlorpromazine produced the most weight gain (mean difference to placebo: 5.13 kg, 95% credible interval, CrI: 1.98 to 8.30), followed by clozapine (4.21 kg, 95% CrI: 3.03 to 5.42), olanzapine (3.82 kg, 95% CrI: 3.15 to 4.50), and zotepine (3.87 kg, 95% CrI: 2.14 to 5.58). The findings did not substantially change in sensitivity and network meta-regression analyses, although enriched design, drug company sponsorship, and the use of observed case instead of intention-to-treat data modified the mean difference in weight gain to some extent. Antipsychotics with more weight gain were often also among the drugs with worse outcome in fasting glucose and lipid parameters. The confidence in the evidence ranged from low to moderate. In conclusion, antipsychotic drugs differ in their propensity to induce metabolic side effects in mid- to long-term treatment. Given that schizophrenia is often a chronic disorder, these findings should be given more consideration than short-term data in drug choice.     

In Vivo Pharmacological Evaluations of Novel Olanzapine Analogues in Rats: A Potential New Avenue for the Treatment of Schizophrenia

Olanzapine (Olz) is one of the most effective antipsychotic drugs commonly used for treating schizophrenia. Unfortunately, Olz administration is associated with severe weight gain and metabolic disturbances. Both patients and clinicians are highly interested in the development of new antipsychotics which are as effective as atypical antipsychotics but which have a lower propensity to induce metabolic side effects. In the present study, we examined two new derivatives of Olz; OlzEt (2-ethyl-4-(4′-methylpiperazin-1′-yl)-10Hbenzo[b]thieno[2,3-e][1,4]diazepine), and OlzHomo (2-ethyl-4-(4′-methyl-1′,4′-diazepan-1′-yl)-10H-benzo[b]thieno[2,3-e] [1,4]diazepine), for their tendency to induce weight gain in rats. Weight gain and metabolic changes were measured in female Sprague Dawley rats. Animals were treated orally with Olz, OlzEt, OlzHomo (3 or 6 mg/kg/day), or vehicle (n = 8), three times daily at eight-hour intervals for 5 weeks. Furthermore, a phencyclidine (PCP)-treated rat model was used to examine the prevention of PCP-induced hyperlocomotor activity relevant for schizophrenia therapy. Male Sprague Dawley rats were pre-treated with a single dose (3 mg/kg/day) of Olz, OlzEt, OlzHomo, or vehicle (n = 12), for 2 weeks. Locomotor activity was recorded following a subcutaneous injection with either saline or PCP (10 mg/kg). Olz was found to induce weight gain, hyperphagia, visceral fat accumulation, and metabolic changes associated with reduced histamatergic H₁ receptor density in the hypothalamus of treated rats. In contrast, OlzEt and OlzHomo presented promising antipsychotic effects, which did not induce weight gain or fat deposition in the treated animals. Behavioural analysis showed OlzEt to attenuate PCP-induced hyperactivity to a level similar to that of Olz; however, OlzHomo showed a lower propensity to inhibit these stereotyped behaviours. Our data suggest that the therapeutic effectiveness of OlzHomo may be delivered at a higher dose than that of Olz and OlzEt. Overall, OlzEt and OlzHomo may offer a better pharmacological profile than Olz for treating patients with schizophrenia. Clinical trials are needed to test this hypothesis.     

1-Aminoindanes as novel motif with potential atypical antipsychotic properties

As part of an on-going effort to investigate the chemical space requirements for D(2)/5-HT(2A) receptor antagonists as atypical antipsychotics, new 1-aminoindanes were synthesized. The replacement of the heterocycle (oxindole) in ziprasidone with a carbocycle (indane) was well tolerated and was found to retain binding affinities for dopamine D(2), serotonin 5-HT(2A), and serotonin 5-HT(1A). Such compounds hold promise as a new chemical motif with atypical antipsychotic properties for the treatment of schizophrenia and related disorders.     

Lipid-Lowering Effects of Tetradecylthioacetic Acid in Antipsychotic-Exposed,Female Rats: Challenges with Long-Term Treatment

Background

Psychiatric patients often require chronic treatment with antipsychotic drugs, and while rats are frequently used to study antipsychotic-induced metabolic adverse effects, long-term exposure has only partially mimicked the appetite-stimulating and weight-inducing effects found in the clinical setting. Antipsychotic-induced effects on serum lipids are also inconsistent in rats, but in a recent study we demonstrated that subchronic treatment with the orexigenic antipsychotic olanzapine resulted in weight-independent increase in serum triglycerides and activation of lipogenic gene expression in female rats. In addition, a recent long-term study in male rats showed that chronic treatment with antipsychotic drugs induced dyslipidemic effects, despite the lack of weight gain.

Aims

In the current study, we sought to examine long-term effects of antipsychotic drugs on weight gain, lipid levels and lipid composition after twice-daily administration of antipsychotics to female rats, and to investigate potential beneficial effects of the lipid-lowering agent tetradecylthioacetic acid (TTA), a modified fatty acid.

Methods

Female rats were exposed to orexigenic antipsychotics (olanzapine or clozapine), metabolically neutral antipsychotics (aripiprazole or ziprasidone), or TTA for 8 weeks. Separate groups received a combination of clozapine and TTA or olanzapine and TTA. The effects of TTA and the combination of olanzapine and TTA after 2 weeks were also investigated.

Results

The antipsychotic-induced weight gain and serum triglyceride increase observed in the subchronic setting was not present after 8 weeks of treatment with antipsychotics, while lipid-lowering effect of TTA was much more pronounced in the chronic than in the subchronic setting, with concomitant upregulation of key oxidative enzymes in the liver. Unexpectedly, TTA potentiated weight gain in rats treated with antipsychotics.

Conclusion

TTA is a promising candidate for prophylactic treatment of antipsychotic-induced dyslipidemic effects, but a more valid long-term rat model for antipsychotic-induced metabolic adverse effects is required.     

In vitro and in vivo pharmacological profile of 5-[2-[4-(6-fluoro-1H-indole-3-yl)piperidin-1-yl]ethyl]-4-(4-fluorophenyl)thiazole-2-carboxylic acid amide (NRA0562), a novel and putative atypical antipsychotic

In vitro and in vivo pharmacological properties of 5-[2-[4-(6-fluoro-1H-indole-3-yl)piperidin-1-yl]ethyl]-4-(4-fluorophenyl)thiazole-2-carboxylic acid amide (NRA0562), a novel atypical antipsychotic, were investigated. NRA0562 showed high affinities for human cloned dopamine D(1), D(2), D(3) and D(4) receptors with Ki values of 7.09, 2.49, 3.48 and 1.79 nM. In addition, NRA0562 had high affinities for the 5-HT(2A) receptor and the alpha(1) adrenoceptor with Ki values of 1.5 and 0.56 nM, and moderate affinity for the histamine H(1) receptor. Using in vivo and ex vivo receptor binding studies in rats, we showed NRA0562 occupied frontal cortical 5-HT(2A) receptors and alpha(1) adrenoceptor potently, while occupancy of striatal dopamine D(2) receptor was moderate as were other atypical antipsychotics. NRA0562 dose-dependently inhibited methamphetamine (MAP)-induced locomotor hyperactivity in rats. At higher dosage, NRA0562 dose-dependently antagonized MAP-induced stereotyped behavior and induced catalepsy dose-dependently and significantly in rats. But, the ED(50) value in inhibiting MAP-induced locomotion hyperactivity was 10 times lower than that in inhibiting MAP-induced stereotyped behavior, and 30 times lower than that in inducing catalepsy. In addition, the potency of NRA0562 in antagonizing MAP-induced hyperactivity in rats was higher than that of other antipsychotics, clozapine, risperidone and olanzapine. NRA0562 had favorable properties in view of prediction of extrapyramidal side effects. As this antipsychotic has a unique profile with affinity and occupancy for receptors, we propose that NRA0652 may have unique atypical antipsychotic activities, and a moderate liability of extrapyramidal motor side effects seen in the treatment with classical antipsychotics.     

Chalcone derivatives and their antibacterial activities: Current development

The increase in antibiotic resistance due to various factors has encouraged the look for novel compounds which are active against multidrug-resistant pathogens. In this framework, chalcone-based compounds showed a diversity of pharmacological properties, and its derivatives possess a high degree of structural diversity, and it is helpful for the discovery of new therapeutic agents. The growing resistance to antibiotics worldwide has endangered their efficacy. This has led to a surging interest in the discovery of new antibacterial agents. Thus, there is an urgent need for new antibacterial drug candidates with increased strength, new targets, low cost, superior pharmacokinetic properties, and minimum side effects. The present review concluded and focuses on the recent developments in the area of medicinal chemistry to explore the diverse chemical structures of potent antibacterial agents and also describes its structure-activity relationships studies. The various synthetic structures leading to this class of neutral protective compound is common and additional structural optimization is promising for potential drug discovery and development.     

Management of common adverse effects of antipsychotic medications

The benefits of antipsychotic medications are sometimes obscured by their adverse effects. These effects range from relatively minor tolerability issues (e.g., mild sedation or dry mouth) to very unpleasant (e.g., constipation, akathisia, sexual dysfunction) to painful (e.g., acute dystonias) to disfiguring (e.g., weight gain, tardive dyskinesia) to life‐threatening (e.g., myocarditis, agranulocytosis). Importantly, adverse effect profiles are specific to each antipsychotic medication and do not neatly fit into first‐ and second‐generation classifications. This paper reviews management strategies for the most frequent side effects and identifies common principles intended to optimize net antipsychotic benefits. Only use antipsychotics if the indication is clear; only continue antipsychotics if a benefit is discernible. If an antipsychotic is providing substantial benefit, and the adverse effect is not life‐threatening, then the first management choice is to lower the dose or adjust the dosing schedule. The next option is to change the antipsychotic; this is often reasonable unless the risk of relapse is high. In some instances, behavioral interventions can be tried. Finally, concomitant medications, though generally not desirable, are necessary in many instances and can provide considerable relief. Among concomitant medication strategies, anticholinergic medications for dystonias and parkinsonism are often effective; beta‐blockers and anticholinergic medications are useful for akathisia; and metformin may lead to slight to moderate weight loss. Anticholinergic drops applied sublingually reduce sialorrhea. Usual medications are effective for constipation or dyslipidemias. The clinical utility of recently approved treatments for tardive dyskinesia, valbenazine and deutetrabenazine, is unclear.     

Effect of chronic infusion of olanzapine and clozapine on food intake and body weight gain in male and female rats

Many antipsychotics cause weight gain in humans, but usually not in rats, when injected once or twice daily. Since blood antipsychotic half-lives are short in rats, compared to humans, chronic administration by constant infusion may be necessary to see consistent weight gain in rats. Male and female rats were implanted with mini-pumps for constant infusion of olanzapine (5 mg/kg/day), clozapine (10 mg/kg/day) or vehicle for 11 days. Food intake and body weight were measured; blood drug levels were measured by HPLC. Olanzapine increased food intake and body weight in female, but not male rats. Serum olanzapine concentrations were 30-35 ng/ml. Clozapine had no effect on food intake or body weight in female or male rats. Serum clozapine concentrations were about 75 ng/ml. Single-dose pharmacokinetic analysis revealed a serum terminal half-life of 1.2-1.5 h for each drug, with no sex differences. Despite the fact that olanzapine and clozapine promote weight gain in humans, these drugs appear to have minimal effects on body weight and food intake in rats, except for a modest effect of olanzapine in female rats, even though therapeutic levels of olanzapine are achieved in serum during chronic infusion. Hence, the rapid clearance of drug following single administration in previous studies cannot explain the weak or absent effects of antipsychotics on weight gain in this species. The rat thus appears to be an inadequate model of weight gain produced by some antipsychotics in humans.     

Neuroprotective effect of atypical antipsychotics in cognitive and non-cognitive behavioral impairment in animal models

Antipsychotic drugs are divided into two groups: typical and atypical. Recent clinical studies show atypical antipsychotics have advantages over typical antipsychotics in a wide variety of neuropsychiatric conditions, in terms of greater efficacy for positive and negative symptoms, beneficial effects on cognitive functioning, and fewer extra pyramidal side effects in treating schizophrenia. As such, atypical antipsychotics may be effective in the treatment of depressive symptoms associated with psychotic and mood disorders, posttraumatic stress disorder, and psychosis in Alzheimer’s disease. In this paper, we describe the effects and potential neurochemical mechanisms of action of atypical antipsychotics in several animal models showing memory impairments and/or non-cognitive behavioral changes. The data provide new insights into the mechanisms of action of atypical antipsychotics that may broaden their clinical applications.     

Neuroprotective effect of atypical antipsychotics in cognitive and non-cognitive behavioral impairment in animal models

Antipsychotic drugs are divided into two groups: typical and atypical. Recent clinical studies show atypical antipsychotics have advantages over typical antipsychotics in a wide variety of neuropsychiatric conditions, in terms of greater efficacy for positive and negative symptoms, beneficial effects on cognitive functioning, and fewer extra pyramidal side effects in treating schizophrenia. As such, atypical antipsychotics may be effective in the treatment of depressive symptoms associated with psychotic and mood disorders, posttraumatic stress disorder and psychosis in Alzheimer disease. In this paper, we describe the effects and potential neurochemical mechanisms of action of atypical antipsychotics in several animal models showing memory impairments and/or non-cognitive behavioral changes. The data provide new insights into the mechanisms of action of atypical antipsychotics that may broaden their clinical applications.Key words: atypical antipsychotics, neuroprotective effect, memory, anxiety-like behavior, neurotoxicity     

Multi-receptor drug design: Haloperidol as a scaffold for the design and synthesis of atypical antipsychotic agents

Using haloperidol as a scaffold, new agents were designed to investigate the structural contributions of various groups to binding at CNS receptors associated with atypical antipsychotic pharmacology. It is clear that each pharmacophoric group, the butyrophenone, the piperidine and the 4-chlorophenyl moieties contributes to changes in binding to the receptors of interest. This strategy has resulted in the identification of several new agents, compounds 16, 18, 19, 23, 24 and 25, with binding profiles which satisfy our stated criteria for agents to act as potential atypical antipsychotics. This research demonstrates that haloperidol can serve as a useful lead in the identification and design of new agents that target multiple receptors associated with antipsychotic pharmacology.     

The interaction of clozapine with the metachlorophenylpiperazine (mCPP) discriminative stimulus

The psychotropic effects of the 5-HT_2C agonist mCPP in human subjects are blocked by the atypical antipsychotic clozapine, but not by typical antipsychotics. An understanding of the mechanistic basis for the interaction of clozapine and mCPP would provide further insight into the basis for its unique therapeutic effects in humans. Drug-induced stimulus control provides an animal model for the subjective effects of psychotropic agents in humans. In the present study, the interaction of the atypical antipsychotic clozapine and the typical antipsychotic fluphenazine with the mCPP-stimulus were defined. Neither drug antagonized the stimulus effects of mCPP in vivo. In contrast, clozapine fully antagonized the mCPP-stimulated phosphoinositide turnover at the 5-HT_2C receptor in vitro. The present data indicate that the paradigm of mCPP-induced stimulus control does not facilitate the differentiation of atypical and typical antipsychotic activities.     

Effects of atypical antipsychotic drugs on body weight and food intake in dopamine D2 receptor knockout mice

Many atypical antipsychotic drugs cause weight gain, but the mechanism of this weight gain is unclear. To dissect the role of the dopamine D2 receptor (D2R), an important receptor in the pharmacology of antipsychotic drugs, we analyzed the effect of olanzapine, risperidone, and ziprasidone on changes in body weight and food intake in male wild-type (WT) and D2R knockout (D2R^−/−) mice. The oral delivery of atypical antipsychotics, olanzapine (5 and 10 mg/kg), risperidone (0.1 and 1.0 mg/kg) and ziprasidone (10 and 20 mg/kg) in both strains mice for 2 weeks suppressed body weight gain, except for olanzapine treatment in D2R^−/− mice. Olanzapine treatment suppressed body weight gain and decreased food intake in WT mice, but also reduced fat body mass and locomotor activity, whereas D2R^−/− mice did not show these changes. Ziprasidone and risperidone treatment produced similar responses in WT and D2R^−/− mice. These data suggest the involvement of D2R in the effect of olanzapine on metabolic regulation. Further studies are required to explore the implications of D2R activity in antipsychotic-mediated metabolic complications.     

Potential utility of histamine H3 receptor antagonist pharmacophore in antipsychotics

Histamine H₃ receptor (H₃R) antagonists have some antipsychotic properties although the clear molecular mechanism is still unknown. As actually the most effective and less side effective antipsychotics are drugs with multiple targets we have designed typical and atypical neuroleptics with an additional histamine H₃ pharmacophore. The 4-(3-piperidinopropoxy)phenyl pharmacophore moiety has been linked to amitriptyline, maprotiline, chlorpromazine, chlorprothixene, fluphenazine, and clozapine. Amide, amine and ester elements have been used generally to maintain or slightly shift affinity at dopamine D₂-like receptors (D₂ and D₃), to decrease affinity at histamine H₁ receptors, and to obtain H₃R ligands with low nanomolar or subnanomolar affinity. Change of effects at D₁-like receptors (D₁ and D₅) were heterogeneous. With these newly profiled compounds different antipsychotic properties might be achieved.     

Atypical antipsychotics in the elderly

Central criteria for the definition of atypical antipsychotics are antipsychotic efficacy and minimal or none extrapyramidal symptoms (EPS). This last criterium is of importance in the differentiation with the traditional antipsychotics. Of the four atypical antipsychotics which are discussed here, clozapine is the most atypical. The best proof is its good efficacy in the treatment of Parkinson psychosis with minimal adverse effects on motor function. Clozapine is the best choice for this indication. At this moment there is not enough evidence available concerning quetiapine. Risperidon and olanzapine give more Dopamine2-occupancy with higher doses and can evoke EPS, but this is still less compared to the traditional antipsychotics. All four atypical drugs cause less tardive dyskinesia. Atypical antipsychotics are not well studied in the treatment of elderly patients with functional psychosis. However the available information and the literature on the treatment of young adults makes it probable that the atypical antipsychotics are at least as effective in the elderly as the traditional antipsychotics. The median daily doses are lower for elderly than for younger patients. Risperidon has been proven effective in the treatment of agressive behaviour in dementia. Atypical antipsychotics have their 'own' adverse effects. Those which have the most impact in the elderly are discussed.     

Treatment of bipolar depression

Antidepressants have insufficient effect in 20-40% of patients treated for depressive disorders. This is particularly true for psychotic and agitated depression. When administered on a long-term basis, antidepressants cause a switch into mania in 25-40% of patients and induce rapid cycling. Classical antipsychotics have exhibited good therapeutic efficacy in the treatment of various forms of depression, especially psychotic and agitated forms, albeit burdened with many, above all extrapyramidal, side effects. When administered over long periods of time, classical antipsychotics may have a depressogenic effect. Second-generation antipsychotics have started to be increasingly used in this indication for a variety of reasons including: their antidepressant effect attributable to raised concentrations of catecholamines in the prefrontal cortex, their impact on serotonin transmission, their antipsychotic effect due to their mode of action including the mesolimbic blockade of dopamine D2 receptors, and the low incidence of extrapyramidal and other side effects. The following text encompasses the results of controlled trials using second-generation antipsychotics in the treatment of acute depressive disorders.