Mirtazapine for antipsychotic-induced acute akathisia: a systematic review and meta-analysis of randomized placebo-controlled trials

Treatment of Antipsychotic-Induced Akathisia: Role of Serotonin 5-HT2a Receptor Antagonists

Akathisia is one of the most prevalent and distressing adverse effects associated with antipsychotic drug treatment. Propranolol, a non-selective beta-adrenergic receptor antagonist, is currently considered a first-line treatment for antipsychotic-induced akathisia (AIA). Surprisingly, the evidence for its anti-akathisia effect is modest. Propranolol's side effects (e.g. orthostatic hypotension, bradycardia), contraindications (e.g. asthma) and increased complexity in titration schedules limit its use in some patients. Anticholinergic agents and benzodiazepines merely provide symptomatic relief in patients with AIA. Effective and well-tolerated treatment remains a major unmet need in akathisia and warrants a search for new anti-akathisia agents. Accumulating evidence during the last two decades indicates that agents with marked postsynaptic serotonin 5-HT_2a receptor antagonism (ritanserin, cyproheptadine, trazodone, mianserin, mirtazapine) may represent a new class of potential anti-akathisia remedies. Among these agents, low-dose mirtazapine (7.5 mg or 15 mg once daily) has demonstrated the most compelling evidence for therapeutic efficacy. In this narrative review we highlight the clinical significance of AIA, outline major approaches for its management and propose a practical algorithm for its treatment.

HTR1A, HTR1B, HTR2A, HTR2C and HTR6 Gene Polymorphisms and Extrapyramidal Side Effects in Haloperidol-Treated Patients with Schizophrenia

Schizophrenia is a serious, chronic psychiatric disorder requiring lifelong treatment. Extrapyramidal side effects (EPS) are common adverse reactions to antipsychotic medications. In addition to the dopaminergic system, serotonergic mechanisms, including serotonin (5-HT) receptors, might be involved in EPS development. This study aimed to examine molecular associations of HTR1A, HTR1B, HTR2A, HTR2C and HTR6 gene polymorphisms with acute EPS in 229 male schizophrenia patients, following two weeks of haloperidol monotherapy. The Simpson-Angus Rating Scale for Extrapyramidal Side Effects (SAS), Barnes Akathisia Rating Scale (BARS) and Extrapyramidal Symptom Rating Scale (ESRS) were used to evaluate EPS severity. Genotyping was performed using real-time PCR, following extraction of blood DNA. Significant acute EPS appeared in 48.03% of schizophrenia patients. For the rs13212041 HTR1B gene polymorphism, affecting microRNA regulation of HTR1B gene expression, a higher frequency of TT carriers was found among haloperidol-treated patients with akathisia when compared to the group without akathisia symptoms. In comparison to C-allele carriers, patients carrying the TT genotype had higher akathisia severity, as determined by the SAS, BARS and ESRS scales. These molecular findings suggest potential involvement of 5-HT_1B receptors in akathisia development following haloperidol treatment, as well as possible epigenetic mechanisms of serotonergic modulation associated with antipsychotic-induced EPS.

Dopamine-receptor blocking agent-associated akathisia: a summary of current understanding and proposal for a rational approach to treatment

Dopamine-receptor blocking agent-associated akathisia (DRBA-A) is an adverse effect that can significantly limit the use of these important medications for the treatment of a variety of psychiatric diseases, yet there is no unifying theory regarding its pathophysiology. This knowledge gap limits clinicians' ability to effectively manage DRBA-A and mitigate negative outcomes in an already vulnerable patient population. Based on a review of the current literature on the subject, it is hypothesized that dopaminergic and noradrenergic signaling is perturbed in DRBA-A. Accordingly, it is proposed that the optimal agent to manage this extrapyramidal symptom should increase dopamine signaling in the affected areas of the brain and counteract compensatory noradrenergic signaling via antagonism of adrenergic or serotonergic receptors.

[Antipsychotic-induced motor symptoms in schizophrenic psychoses-Part 1 : Dystonia, akathisia und parkinsonism]

Acute antipsychotic-induced movement disorders (AIMD) are clinically relevant since they are frequently associated with high subjective distress, and since over the long-term they can negatively impact treatment adherence of patients with schizophrenic psychoses. This review article summarizes the relevant studies on the prevalence, risk factors, prevention and treatment options and instruments for early prediction of acute AIMD in schizophrenic psychoses. The current evidence and treatment recommendations are divided into three main areas: acute dystonia, akathisia, and parkinsonism. For the treatment of acute dystonia trihexyphenidyl and biperiden have shown their efficacy. Considering pharmacological treatment of akathisia, there is some preliminary evidence for medication with lipophilic beta-receptor blockers (propranolol and pindolol), clonidine, benzodiazepines, mianserin, mirtazapine und trazodone. The treatment options for drug-induced parkinsonism include reduction or switching from one antipsychotic to another with a lower affinity for dopamine D₂ receptors, amantadine or in the regular administration of anticholinergic drugs. In conclusion, acute AIMD is easily to recognize but is not always effectively and durably treated. Early recognition and treatment of acute AIMD could be associated with improved treatment outcomes.

Propranolol for mirtazapine-induced akathisia: Single case report

Despite psychomotor restlessness and akathisia being an occasionally reported side effect of antidepressants as a class, and mirtazapine specifically, there is no general consensus on the best treatment approach. Propranolol may prove to be an effective treatment approach in patients who are not candidates for alternative therapies.

The psychopharmacology of catatonia, neuroleptic malignant syndrome, akathisia, tardive dyskinesia, and dystonia

Although highly prevalent, motor syndromes in psychiatry and motor side effects of psychopharmacologic agents remain understudied. Catatonia is a syndrome with specific motor abnormalities that can be seen in the context of a variety of psychiatric and somatic conditions. The neuroleptic malignant syndrome is a lethal variant, induced by antipsychotic drugs. Therefore, antipsychotics should be used with caution in the presence of catatonic signs. Antipsychotics and other dopamine-antagonist drugs can also cause motor side effects such as akathisia, (tardive) dyskinesia, and dystonia. These syndromes share a debilitating impact on the functioning and well-being of patients. To reduce the risk of inducing these side effects, a balanced and well-advised prescription of antipsychotics is of utmost importance. Clinicians should be able to recognize motor side effects and be knowledgeable of the different treatment modalities.

Very Low-Dose Mirtazapine (7.5 mg) in Treatment of Acute Antipsychotic-Associated Akathisia

BACKGROUND

Some evidence suggests that off-label use of mirtazapine (15 mg) is effective in treatment of acute antipsychotic-associated akathisia (AAA). We analyzed whether a lower dose of mirtazapine (7.5 mg) maintained its antiakathisia properties while exhibiting better tolerability in patients with schizophrenia and mood disorders who developed acute AAA.

METHODS

Medical charts were retrospectively evaluated for 12 patients with AAA. All scored at least 2 (mild akathisia) on the Barnes Akathisia Rating Scale (BARS) and were treated with mirtazapine (7.5 mg) for a mean of 10.3 days.

RESULTS

There was a statistically significant decrease in the BARS subjective, distress, and global (P < 0.01 to P < 0.001), but not objective (P = 0.63), subscales. Five participants (41.6%) fulfilled the predefined criterion of response, a decrease of at least 2 points on the BARS global subscale. The positive antiakathisia effect of mirtazapine was observed predominantly in aripiprazole-treated patients. Mirtazapine (7.5 mg) was well tolerated, and no clinically significant adverse effects, primarily drowsiness or increased appetite, were reported.

CONCLUSIONS

A large-scale controlled evaluation is warranted to substantiate clinical utility of off-label use of mirtazapine (7.5 mg) for patients with AAA.

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 Vitamin B6 Versus Propranolol on Antipsychotic-Induced Akathisia: A pilot Comparative Double-blind Study

Akathisia is a common adverse effect of antipsychotic drugs and is characterized by subjective feelings of restlessness. First-line treatment usually consists of propranolol, a beta adrenergic antagonist. However, propranolol does not seem to be efficacious in up to 70% of patients. This study was aimed to evaluate the effect of vitamin B6 versus propranolol on antipsychotic-induced akathisia (AIA). This study was a comparative, double-blind, randomized trial. In the present study, 66 adult patients with antipsychotic-induced akathisia were enrolled and randomized into three groups, and received vitamin B6 300 mg/12 h or 600 mg/12 h or propranolol 20 mg/12 h. The diagnosis of AIA was made by clinical examination and its severity was assessed by the Barnes Akathisia Rating Scale. Fifty one patients completed 5 days of the trial. The results showed that there was no significant difference in BARS score among the different groups which means that vitamin B6 attenuated the AIA similar to propranolol. However, there wasn't any significant difference between high or low dose of vitamin B6. In conclusion, the results of this trial suggest that vitamin B6 may be beneficial for ameliorating of antipsychotic-induced akathisia.