Long-term pharmacokinetics of clozapine

[Therapeutic drug monitoring of clozapine]

Clozapine is a prototypical atypical antipsychotic used to treat severe schizophrenia and for which a therapeutic drug monitoring (TDM) is quite commonly proposed. Clozapine is rapidly absorbed (maximum concentration reached within 1 to 4hours), and is extensively metabolized in the liver by CYP1A2 to an active metabolite (and to a lesser extent, to inactive metabolites via other enzymes). Its half-life is 8 to 16h. A therapeutic range has been proposed for clozapine as some studies have reported both a relationship between low plasmatic concentrations and resistance to treatment (threshold level is likely between 250 and 400μg/L), and a relationship between high plasmatic concentrations and an increase in the occurrence of toxicity (alert level=1000μg/L). Given the data obtained in different studies, the TDM was evaluated for this molecule, to recommended.

Clozapine and Norclozapine Plasma Levels in Patients Switched Between Different Liquid Formulations

BACKGROUND AND OBJECTIVE

Clozapine is the drug of choice for treatment-resistant schizophrenia. The primary objective of this study was to compare plasma clozapine and N-desmethylclozapine levels in patients switched between 2 liquid formulations [Denzapine suspension and clozapine oral solution (St George's ZTAS)]. Secondary objectives included comparison of safety, tolerability, and patient acceptability.

METHODS

This was a noninterventional, observational, prospective follow-up of patients consecutively switched between formulations of clozapine liquid in a large inner-city NHS mental health trust. The authors also performed retrospective analysis of outcomes from patient case notes.

RESULTS

The authors identified 43 patients receiving Denzapine suspension in the trust. Data were available for 43 patients switched from Denzapine to clozapine oral solution (St George's ZTAS), among whom, 15 (32%) were excluded from the analysis. Of the 28 patients for whom data were available, the 90% confidence interval for the ratio of mean values for corrected Cmin 91.5 (85.2%-98.4%) and uncorrected Cmin 91.2 (84.4%-98.6%) were within the guideline range of bioequivalence (80%-125%). Safety and tolerability profiles were comparable between the 2 formulations (P = 0.10). Patient acceptability was also similar between the brands in most domains. However, there was a taste preference for Denzapine suspension.

CONCLUSIONS

No significant difference in clozapine plasma levels was observed after switching from Denzapine suspension to a recently introduced clozapine solution. This study also highlights the significance of medicinal characteristics such as taste for patient acceptability and compliance.

Intra-individual variation of clozapine and norclozapine plasma levels in clinical practice

INTRODUCTION

Clozapine plasma levels are useful to monitor drug compliance, and also to assess and to prevent some side effects. Recently, routine monitoring to all clozapine-treated patients has been proposed to prevent relapses. However, high intra-individual variability in plasma levels has been reported too, although these studies have some limitations.

METHODS

We analysed differences between 2clozapine plasma levels separated by at least one year in a subgroup of 28 outpatients (82% male, mean age 47.9 years-old) with diagnosis of non-affective psychosis in clinical remission whose clozapine doses and smoking habits remained unchanged.

RESULTS

We found a non-significant increase in clozapine plasma levels [.30mg/L (SD=.14) vs. .32 (SD=.17); t=-.858, p=.40] and a significant decrease in norclozapine plasma levels [.27 (SD=.11) vs. .22 (SD=.10); t=3.27; p=.003]. Absolute coefficient of variation (CV) between first and second assessment were calculated. Forty-six and fifty-seven percent of cases had CV 20% in clozapine and norclozapine, respectively. CV of 50% was seen in 20.7% and 13.8% of clozapine and norclozapine test respectively. We discussed potential causes of such high CV.

CONCLUSIONS

Our study suggest high intra-individual variation even in a subgroup of very stable patients, which suggest that routine monitoring of these levels may be indicated in order to detect significant plasma variations. We think that clinicians should act with caution in case of a sudden decrease in plasma level. In the absence of obvious symptom severity variation, sources of intra-individual fluctuations might be considered first, before assuming poor compliance.

The Effect of Body Weight Changes on Total Plasma Clozapine Concentrations Determined by Applying a Statistical Model to the Data From a Double-Blind Trial

PURPOSE/BACKGROUND

Some therapeutic drug monitoring studies suggest that increased weight is associated with small increases in clozapine concentrations. The goal of this study was to reanalyze a US double-blind study using a sophisticated statistical model to test whether weight gains from baseline or increases in percentage of body fat from baseline, computed from a published equation, are associated with increased total plasma clozapine concentrations after controlling for the effects of smoking and sex.

METHODS/PROCEDURES

Using data from a multidosage randomized double-blind US clozapine trial previously published, a random intercept linear model of steady-state total plasma clozapine concentrations was fitted to 424 concentrations from 47 patients.

FINDINGS/RESULTS

After adjusting for sex and smoking, (1) a 1-kg gain in body weight during clozapine treatment was significantly associated with a 1.4% increase in total plasma clozapine concentrations (95% confidence interval = 0.55 to 2.3) and (2) a 1-point increase in percentage of body fat during clozapine treatment was significantly associated with a 5.4% increase in total clozapine concentration (2.5 to 8.3) in females and 1.4% (-1.1 to 4.0) in males.

IMPLICATIONS/CONCLUSIONS

As hypothesized, weight increases during clozapine treatment, which probably reflect increases in fat tissue, were associated with increases in total plasma concentrations. Pending further replication in other samples, it seems likely that clozapine may deposit in body fat and that this may decrease clozapine clearance. This change may be small in most patients but may be clinically relevant in females with major gains in body fat.

The value of drug and metabolite concentration in blood as a biomarker of psychopharmacological therapy

Desirable and undesirable effects of a drug are related to its concentration at various sites of actions. For many psychotropic drugs, it has been shown that drug concentration in brain correlates with concentration in blood. The latter is also an available estimate of clearance and bioavailability. Its monitoring enables identification of multiple factors that have an impact on clinical outcomes, especially uncertain compliance and pharmacokinetic peculiarities. For this review we analysed for antidepressants if drug concentration in blood can be used as biomarker for psychopharmacological treatment. Systematic review of the literature revealed for new and old antidepressant drugs that drug and metabolite concentrations in blood are measures of the pharmacokinetic phenotype and related differentially to occupancy of primary target structures, therapeutic effects and unwanted anticholinergic, cardiac and other side effects. Drug concentration in blood can therefore be used as biomarker in clinical practice to guide psychopharmacological treatment with established antidepressant drugs. Monitoring of drug concentration is suitable to improve efficacy and safety of the pharmacotherapy, especially in elderly patients who require complex pharmacological therapies.

Does level of care, sex, age, or choice of drug influence adherence to treatment with antipsychotics?

Rates of nonadherence during treatment with antipsychotics have been found to vary in a wide range from 20% to 90%. The aim of the present study was to investigate the influence of inpatient versus outpatient status on the adherence to treatment with olanzapine and clozapine. In the period from 1999 to 2007, olanzapine and clozapine were the 2 most frequently analyzed antipsychotics at the Department of Clinical Pharmacology at St. Olavs University Hospital, Trondheim, Norway, with more than 24,000 and more than 18,000 samples, respectively. In total, 111 patients on olanzapine and 95 patients on clozapine had provided samples in both the inpatient and outpatient settings and were included in the study. The primary outcome variable was the serum concentration-to-dose ratio (C/D ratio), that is, the serum drug concentration per milligram of drug given. For olanzapine, the C/D ratio in the outpatient setting was 10.7% lower than in the inpatient setting (P = 0.013). No such difference was found for clozapine. The difference in the olanzapine group was exclusively attributed to a lower outpatient ratio in females. For clozapine, no sex influence was found. No effect of age on the C/D ratios was found either for olanzapine or for clozapine. The lower C/D ratio in females using olanzapine in the outpatient setting might imply that they, in contrast to males, are less adherent to their medication when outside hospital. For clozapine, there were no indications of differences in adherence between inpatients and outpatients.

Variability of the in vivo metabolism of clozapine

OBJECTIVES

Clozapine, the gold standard of antipsychotic treatment in treatment-refractory patients with schizophrenia, is metabolized in vivo to clozapine-N-oxide and N-desmethylclozapine (NDMC = norclozapine). N-desmethylclozapine is an active metabolite of clozapine and combines unique pharmacological properties. Because little is known about the rate of metabolic conversion of clozapine in vivo, we assessed the association between clozapine dose and plasma levels for clozapine and NDMC.

METHODS

Plasma levels of clozapine and NDMC were measured in 485 blood samples from 108 patients with schizophrenia treated with clozapine. %NDMC, the ratio of NDMC to total clozapine (NDMC + clozapine), was used as a measure of the in vivo metabolism of clozapine.

RESULTS

Daily clozapine doses correlated significantly with clozapine levels and NDMC levels, whereas %NDMC showed a weaker negative correlation with clozapine dose. The mean %NDMC value was 37.0% +/- 16.8%, with high variability between subjects. Repeated measurements in subjects treated with the same dose of clozapine showed a high within-subject variability of %NDMC.

CONCLUSIONS

Our results suggest a high degree of between-subject and within-subject variability in the metabolism of clozapine in vivo. Direct administration of NDMC may be preferable to reliably achieve sufficient plasma levels of this compound.

Monitoring the safe use of clozapine: a consensus view from Victoria, Australia

Clozapine is an important antipsychotic agent that has a unique profile of clinical benefits, but that has also been associated with several serious and potentially life-threatening safety concerns. In order to minimise the impact of haematological adverse events, health professionals treating patients with clozapine are currently required to register their patients on a centrally administered data network and to conform to strict protocols. The consensus statement documented in this article extends existing protocols by recommending monitoring of patients treated with clozapine for additional adverse effects during treatment. This consensus statement reflects the current practice at five major public psychiatric hospitals in Victoria, Australia, for the monitoring and management of clozapine-related adverse events, and has been implemented at these sites because of emerging safety concerns associating clozapine with cardiovascular and metabolic adverse effects.

Pharmakotherapie der Schizophrenie

The management of schizophrenia patients remains one of the great challenges in psychiatry. Despite the undisputed effectiveness of antipsychotic drugs, patients and their physicians still face considerable difficulties mainly related to incomplete or lacking treatment response and the inability to predict the individual efficacy and tolerability. In this manuscript we review the key elements of pharmacological treatment of this disorder, encompassing acute and long-term management as well as specific management problems ranging from acutely violent patients to treatment-resistant subjects. Along with general treatment principles, the document provides specific information regarding efficacy and safety features of antipsychotics. Many of the currently available treatment recommendations/guidelines are based on the evidence reviewed here. This review is meant to serve as a guide for clinicians involved in managing schizophrenia, whether in a psychiatric hospital setting or as family physicians in private practice.

Guidelines for the use of clozapine in individuals with developmental disabilities

Clozapine is the most effective antipsychotic medication currently in use, but there has been a paucity of well-controlled research on its efficacy with people with developmental disabilities. We present a set of guidelines to ensure proper utilization of clozapine in individuals with developmental disabilities, because it can offer them therapeutic advantages similar to those observed in people with schizophrenia. We provide recommendations regarding the use of clozapine that are based on three main sources: literature and published professional practice guidelines regarding the use of clozapine in individuals who do not have developmental disabilities, the limited literature on the use of clozapine in individuals who have developmental disabilities, and our own clinical experience. The first part of the guidelines contains an overview of necessary practical knowledge regarding side effects, dose and blood level considerations, and interactions with other medications, diet and tobacco smoking. In the second part, we offer procedures for selecting individuals for clozapine therapy based on proper indications and contraindications for treatment. We also include requirements regarding informed consent, dosage and special laboratory and clinical monitoring.

Quetiapine serum concentrations in psychiatric patients: the influence of comedication

Steady-state serum concentrations of quetiapine were recorded in 62 psychiatric patients under routine conditions. Doses were administered twice daily, and serum quetiapine levels were measured in the morning about 12 hours after the last dose. Eight patients were in monotherapy, whereas the rest received various additional psychotropic drugs. For the whole group, the concentration-to-dose ratio (C/D) varied 238-fold, with a median value of 0.41 nmol/L/(mg/24 h). For the administered dose range (37.5-1200 mg/24 h), the serum concentrations ranged from below the detection limit (10 nmol/L) to 999 nmol/L. With the exception of 2 subjects receiving carbamazepine and patients receiving quetiapine outside the recommended dose interval, 80% of the rest had serum levels within the range 50 to 650 nmol/L, which may serve as an orienting interval for serum concentrations observed under routine treatment conditions. Patients (n = 38) comedicated with drugs competing for metabolism by CYP3A4 displayed a median C/D value of 0.48 nmol/L/(mg/24 h), which was 70% higher than the C/D value of the monotherapy group [0.28 nmol/L/(mg/24 h)], in contrast to patients receiving drugs metabolized by CYP2D6 with a median C/D of 0.23 nmol/L/(mg/24 h). None of the comedicated groups were significantly different from the monotherapy group. Two subjects comedicated with carbamazepine had very low C/D values [0.02-0.04 nmol/L/(mg/24 h)].

Plasma clozapine concentration coefficients of variation in a long-term study

Kurz et al. conducted the first study of the intra-individual variability of clozapine plasma concentrations but did not take into account the effect of smoking and co-medication. As patients were receiving varying doses, Kurz et al. standardized plasma levels by using a plasma level/dose/kg ratio. In 15 patients, the mean coefficient of variation (CV) was 53% (S.D. = 21). In this new study, plasma clozapine and norclozapine concentrations were measured every 2 weeks in 47 patients randomized to 100, 300, or 600 mg/day for 16-week double-blind clozapine trials under controlled conditions (stable smoking, limited co-medication and absence of caffeinated beverages). For 100, 300 and 600 mg/day, the respective mean CVs for plasma clozapine concentrations were 23% (S.D. = 14), 19% (S.D.= 11) and 18% (S.D. = 8). For the combined concentrations of clozapine and norclozapine, the respective mean CVs were 20% (S.D. = 13), 16% (S.D. = 9) and 15% (S.D. = 7). Under 100 mg/day, the mean CV for clozapine concentrations was significantly higher for heavy smokers than non-heavy smokers (32%, S.D. = 3 vs. 19%, S.D. = 8) (p = 0.03). Studies of CVs in other environments are needed. Clozapine CVs may be important in order to understand the importance of variations around the therapeutic range and to interpret drug interactions above the usual noise of measuring plasma concentrations.

CYP1A2 activity is an important determinant of clozapine dosage in schizophrenic patients

Clozapine is an effective atypical antipsychotic drug applied in the treatment of resistant schizophrenia. The drug is mainly metabolized by cytochrome P-450 (CYP) enzymes especially the isozyme CYP1A2. Remarkably, the effective dosage varies widely among patients, making it necessary to individualize drug therapy with clozapine. The explanation for dosage variation may be differences in drug metabolism, and more specifically of CYP1A2 activity. This study is aimed at determining to what extent variability in clozapine dose can be explained by pharmacokinetic (PK) factors and more specifically by CYP1A2 activity in effectively treated psychiatric patients. In 22 evaluable patients with a schizophrenic disorder chronically using clozapine, the CYP1A2 activity and the clozapine clearance were estimated. For calculation of the pharmacokinetic parameters of clozapine, population PK software based upon Bayesian analysis was used. Caffeine clearance was estimated with the paraxanthine/caffeine ratio and served as estimate of CYP1A2 activity.A significant linear relationship was found between the clozapine dose and clozapine clearance (R: 0.71; P<0.05), whereas no relationship was found between clozapine dosage and clozapine serum trough concentration. Moreover, individual caffeine and clozapine clearances were found to be significantly related (R: 0.62; P<0.05) as were clozapine dose per kg body weight and P/C mol ratio (R: 0.44; P<0.05). We conclude that CYP1A2 activity is an important determinant of the variability of effective clozapine doses in psychiatric patients.

The World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for the biological treatment of bipolar disorders, part III: maintenance treatment

As with the two preceding guidelines of this series, these practice guidelines for the pharmacological maintenance treatment of bipolar disorder were developed by an international task force of the World Federation of Societies of Biological Psychiatry (WFSBP). Their purpose is to supply a systematic overview of all scientific evidence relating to maintenance treatment. The data used for these guidelines were extracted from a MEDLINE and EMBASE search, from recent proceedings from key conferences and various national and international treatment guidelines. The scientific justification of support for particular treatments was categorised into four levels of evidence (A-D). As these guidelines are intended for clinical use, the scientific evidence was not only graded, but also reviewed by the experts of the task force to ensure practicality.

Influence of dose, cigarette smoking, age, sex, and metabolic activity on plasma clozapine concentrations: a predictive model and nomograms to aid clozapine dose adjustment and to assess compliance in individual patients

The measurement of plasma clozapine concentrations is useful in assessing compliance, optimizing therapy, and minimizing toxicity. We measured plasma clozapine and norclozapine (N-desmethylclozapine) concentrations in samples from 3782 patients (2648 male, 1127 female). No clozapine was detected in 291 samples (227 patients, median prescribed dose 300 mg/d). In 4963 (50.2 %) samples (2222 patients); plasma clozapine concentration ranged from 10 to 350 ng/mL.Step-wise backward multiple regression analysis (37 % of the total samples) of log10 plasma clozapine concentration against log10 clozapine dose (mg/d), age (year), sex (male = 0, female = 1), cigarette smoking habit (nonsmokers = 0; smokers = 1), body weight (kg), and plasma clozapine/norclozapine ratio (clozapine metabolic ratio, MR) showed that these covariates explained 48% of the observed variation in plasma clozapine concentration (C = ng/mL x 10-3) (P < 0.001) according to the following equation: log 10 (C) = 0.811 log 10 (dose) + 0.332 (MR) + 69.42 X 10 (-3) (sex) + 2.263 x 10 (-3) (age) + 1.976 x 10(-3) (weight) - 0.171 (smoking habit) - 3.180. This model and its associated confidence intervals were used to develop nomograms of plasma clozapine concentration versus dose for male and female smokers and nonsmokers. Predicted plasma clozapine changes by +48% in nonsmokers, +17% in females, +/-8 % for every 0.1 change in MR (reference 1.32), +/-4% for every 5 years (reference 40 years), and +/-5 % for every 10 kg body weight (reference 80 kg). The nomograms can be used (i) to individualize dosage to achieve a given target plasma clozapine concentration, and (ii) for quantitative evaluation of adherence by estimating the likelihood of an observed concentration being achieved by a given dosage regimen. The model has been validated against published data.

What is an adequate trial with clozapine?: therapeutic drug monitoring and time to response in treatment-refractory schizophrenia

Clozapine is the gold standard and 'last resort' in treatment of refractory schizophrenia. It is important to know whether a trial with clozapine is adequate or not. Six studies show a significantly higher response rate at clozapine plasma trough levels above a therapeutic threshold of 350-400 micro g/L. The absolute risk reduction is about 40%. An additional study found best results with plasma levels between 300 and 700 micro g/L, and one (probably too small) study could not detect a significantly different response rate for 350-450 micro g/L in comparison to 200-300 micro g/L. In addition, two extension studies showed conversion from nonresponders to responders if plasma levels increased above the threshold. Investigations on time to response in treatment with clozapine are often hampered by not controlling for time until plateau of dose titration or clozapine concentration. One of the better studies found 34 responders within 8 weeks after the last dose escalation. The remaining 16 non-responding patients did not change their status during a mean follow-up of 75 weeks. A second 1 year trial found a superior differential response rate for clozapine in comparison to haloperidol only during the first 6 weeks. A third study combined regular clozapine plasma level assays with assessment of response status. At the time of response 17 out of 19 responders showed clozapine concentrations above 350 micro g/L. The nine non-responders remained below this threshold throughout the rest of the year. These results favour an approach of raising the clozapine plasma level in treatment-refractory schizophrenic patients who do not respond to an initial low-to-medium dose treatment with clozapine. Some patients, especially young male smokers, will need dosages higher than 900 mg/day. Addition of low-dose fluvoxamine while closely monitoring clozapine levels can help decrease the high number of necessary pills. An adequate trial with clozapine should last at least 8 weeks on a plasma trough level above 350-400 micro g/L.

Toxic rise of clozapine plasma concentrations in relation to inflammation

Recently a small number of patients were observed in two psychiatric hospitals in the Netherlands with clozapine intoxications that complicate or mimic infections. These patients were on chronic medication and normally had stable clozapine blood plasma levels. This article presents four of these cases. Medline was searched for reports of similar cases. A hypothesis was formulated and tested by literature study. Immune modulatory and toxic effects of clozapine protein reactive metabolites or haptens, may play a role in the development of inflammation. Clozapine has a direct influence on different cytokines resembling an inflammatory reaction. Infection or inflammation could induce bioactivation of clozapine into its nitrenium ion that can exert a toxic reaction that induces apoptosis and gives rise to elevated cytokine levels. Clozapine can function as a hapten and induce an IgG, IgM or IgE mediated hypersensitivity reaction. The cytokines released during infection or inflammation downregulate the clozapine metabolism in the P450 system through CYP 1A2. Clozapine plasma levels should be monitored closely if an inflammatory or infectious process is suspected.

Serum clozapine levels: a review of their clinical utility

Therapeutic drug monitoring (TDM) is frequently utilized in the treatment of psychiatric conditions, but its clinical application concerning the use of clozapine is unclear. We present three case reports of patients taking clozapine, review the relevant literature, and propose guidelines to aid the clinical use of TDM of clozapine. Due to its complex metabolism, there are significant inter- and intra-individual variations in clozapine serum levels, for a given dose. However, the range of serum levels that corresponds with toxicity remains unclear. Although central nervous system side-effects may correlate with serum level, many adverse effects of clozapine appear to be unrelated, including haematological and cardiac events. There are numerous clinically significant interactions between clozapine and other substances, including prescribed medications, nicotine and caffeine. TDM of clozapine may be of clinical value in certain situations, such as poor clinical response; signs of toxicity; onset of seizures; changes in concurrent medication, caffeine or nicotine; liver disease; and suspected non-compliance. The current literature does not support the routine testing of serum clozapine levels in everyday clinical practice.

Pharmacogenetics of bipolar disorder

To review the pharmacogenetics of bipolar disorders, the authors searched databases for genetic association and linkage studies involving response to long-term prophylactic lithium treatment, as well as treatment with antidepressants or clozapine. Significant ethnic variations in the metabolism and efficacy of antidepressants, as well as clozapine, have been reported by several groups. Systematic studies suggest that that genetic factors affect the response to prophylactic lithium treatment. Numerous associations between the three traits of interest and candidate gene polymorphisms have been proposed. Among these, an association between the serotonin transporter gene and response to serotonin reuptake inhibitors appears robust. Considerable interest has also focused on serotonergic gene polymorphisms and response to clozapine. Response to pharmacotherapy in bipolar disorders may be mediated by genetic factors, but the role played by heritability is unknown.

Individual changes in clozapine levels after smoking cessation: results and a predictive model

Published reports document 20-40% lower mean serum clozapine concentrations in smokers compared with nonsmokers due to enzyme induction. Despite the increase in nonsmoking psychiatric facilities in the United States, previous studies have not tracked individual changes in serum clozapine levels after smoking cessation. Clozapine level changes were analyzed in 11 patients at Oregon State Hospital who were on stable clozapine doses, before and after implementation of a hospital-wide nonsmoking policy. A mean increase in clozapine levels of 71.9% (442.4 ng/ml +/- 598.8 ng/ml) occurred upon smoking cessation (p < .034) from a baseline level of 550.2 ng/ml (+/- 160.18 ng/ml). One serious adverse event, aspiration pneumonia, was associated with a nonsmoking serum clozapine level of 3066 ng/ml. Elimination of statistically extreme results generated a mean increase of 57.4 % or 284.1 ng/ml (+/- 105.2 ng/ml) for the remaining cases (p < .001) and permitted construction of a linear model which explains 80.9% of changes in clozapine levels upon smoking cessation (F = 34.9;p = .001): clozapine level as nonsmoker = 45.3 + 1.474 (clozapine level as smoker). These findings suggest that significant increases in clozapine levels upon smoking cessation may be predicted by use of a model. Those with high baseline levels should be monitored for serious adverse events.

Managing antipsychotic-induced acute and chronic akathisia

Akathisia is a frequent and common adverse effect of treatment with antipsychotic (neuroleptic) drugs. This syndrome consists of subjective (feeling of inner restlessness and the urge to move) as well as objective components (rocking while standing or sitting, lifting feet as if marching on the spot and crossing and uncrossing the legs while sitting). Antipsychotic-induced akathisia can be classified according to the time of onset in the course of antipsychotic treatment (acute, tardive, withdrawal and chronic akathisia). Reported prevalence rates vary widely between 5 and 36.8%. Numerous risk factors for acute akathisia have been described and the exact pathophysiology of akathisia is still unknown. Since akathisia is a drug-induced adverse effect, optimal management involves its prevention rather than treatment. Standardised titration and the use of novel antipsychotics are successful measures of prevention. This paper reviews different forms of therapeutic approaches for the treatment of akathisia. Based on the available literature, propranolol or other lipophilic beta-blockers seem to be the most consistently effective treatment for acute akathisia. There is nothing in the literature to guide a clinician when treatment with beta-blockers fails. Addition of benzodiazepines would appear to be a sensible next choice, especially if subjective distress persists. If all of these drugs are unsuccessful, amantadine or clonidine can be tried. Other agents that have been investigated include ritanserin, piracetam, valproic acid (sodium valproate) and tricyclic antidepressants. Evidence on the treatment of tardive akathisia is unsatisfactory.