Drug-induced QT interval prolongation after ciprofloxacin administration in a patient receiving olanzapine

QTc Interval Prolongation with Therapies Used to Treat Patients with Parkinson's Disease Psychosis: A Narrative Review

In addition to the classic motor symptoms of Parkinson's disease (PD), people with PD frequently experience nonmotor symptoms that can include autonomic dysfunction and neuropsychiatric symptoms such as PD psychosis (PDP). Common patient characteristics, including older age, use of multiple medications, and arrhythmias, are associated with increased risk of corrected QT interval (QTc) prolongation, and treatments for PDP (antipsychotics, dementia medications) may further increase this risk. This review evaluates how medications used to treat PDP affect QTc interval from literature indexed in the PubMed and Embase databases. Although not indicated for the treatment of psychosis, dementia therapies such as donepezil, rivastigmine, memantine, and galantamine are often used with or without antipsychotics and have minimal effects on QTc interval. Among the antipsychotics, data suggesting clinically meaningful QTc interval prolongation are limited. However, many antipsychotics have other safety concerns. Aripiprazole, olanzapine, and risperidone negatively affect motor function and are not recommended for PDP. Quetiapine is often sedating, can exacerbate underlying neurogenic orthostatic hypotension, and may prolong the QTc interval. Pimavanserin was approved by the US Food and Drug Administration (FDA) in 2016 and remains the only FDA-approved medication available to treat hallucinations and delusions associated with PDP. However, pimavanserin can increase QTc interval by approximately 5-8 ms. The potential for QTc prolongation should be considered in patients with symptomatic cardiac arrhythmias and those receiving QT-prolonging medications. In choosing a medication to treat PDP, expected efficacy must be balanced with potential safety concerns for individual patients.

Clinically Relevant Interactions between Atypical Antipsychotics and Anti-Infective Agents

This is a comprehensive review of the literature on drug interactions (DIs) between atypical antipsychotics and anti-infective agents that focuses on those DIs with the potential to be clinically relevant and classifies them as pharmacokinetic (PK) or pharmacodynamic (PD) DIs. PubMed searches were conducted for each of the atypical antipsychotics and most commonly used anti-infective agents (13 atypical antipsychotics by 61 anti-infective agents/classes leading to 793 individual searches). Additional relevant articles were obtained from citations and from prior review articles written by the authors. Based on prior DI articles and our current understanding of PK and PD mechanism, we developed tables with practical recommendations for clinicians for: antibiotic DIs, antitubercular DIs, antifungal DIs, antiviral DIs, and other anti-infective DIs. Another table reflects that in clinical practice, DIs between atypical antipsychotics and anti-infective agents occur in patients also suffering an infection that may also influence the PK and PD mechanisms of both drugs (the atypical antipsychotic and the anti-infective agent(s)). These tables reflect the currently available literature and our current knowledge of the field and will need to be updated as new DI information becomes available.

Rational Use of Second-Generation Antipsychotics for the Treatment of ICU Delirium

Delirium, described as an acute neuropsychiatric syndrome, occurs commonly in critically ill patients and leads to many negative outcomes including increased mortality and long-term cognitive deficits. Despite the lack of clinical data supporting the use of antipsychotics for the management of intensive care unit (ICU) delirium, pharmacological interventions are often needed to control acutely agitated patients. Given that the most current guidelines do not advocate the use of haloperidol for either the prevention or treatment of ICU delirium due to a lack of evidence, second-generation antipsychotics (SGAs) have been commonly used as alternatives to haloperidol for ICU patients with delirium. Nonetheless, the evidence supporting the use of SGAs to treat ICU delirium remains limited. This review is designed to assess the available clinical evidence and highlights the different neuropharmacological and safety properties of SGAs in order to guide the rational use of SGAs for the treatment of ICU delirium.

Potential drug-drug interactions in a medical intensive care unit of a university hospital

BACKGROUND/AIM

Drug-drug interactions (DDIs) can impact patient safety. Occurrence of clinically important DDIs is higher for intensive care unit (ICU) patients. This observational study aimed to evaluate the potential DDIs in medical ICU patients of a university hospital.

MATERIALS AND METHODS

The Medical Pharmacology Department organized consultation reports for ICU patients in order to detect the DDIs. To focus on clinically important DDIs, interactions in the C, D, or X risk rating categories of the Lexi-Interact online database were analyzed. Frequency and clinical risk rating categories of DDIs were detected. Relationship between number of prescriptions and DDIs were assessed. The most frequent drug/drug groups were identified.

RESULTS

Of 101 ICU patients, 45.5% were found to have DDIs. We detected 125 C (72.2%), 37 D (21.4%), and 11 X (6.4%) risk category interactions. A statistically significant increase in the number of DDIs was shown with the number of prescriptions (P = 0.002). The most frequent DDIs were between agents acting on the cardiovascular system and corticosteroids (12.8%).

CONCLUSION

Results of this study show that pharmacological consultation plays a critical role in the recognition of DDIs for improvement of medication management and effective therapeutic endpoints without any adverse or toxic reactions.

QTc interval prolongation and torsade de pointes associated with second-generation antipsychotics and antidepressants: a comprehensive review

We comprehensively reviewed published literature to determine whether it supported the link between corrected QT (QTc) interval prolongation and torsade de pointes (TdP) for the 11 second-generation antipsychotics and seven second-generation antidepressants commonly implicated in these complications. Using PubMed and EMBASE, we identified four thorough QT studies (one each for iloperidone, ziprasidone, citalopram, and escitalopram), 40 studies specifically designed to assess QTc interval prolongation or TdP, 58 publications based on data from efficacy and safety trials, 18 toxicology studies, and 102 case reports. Thorough QT studies, QTc prolongation-specific studies, and studies based on efficacy and safety trials did not link drug-associated QTc interval prolongation with TdP. They only showed that the drugs reviewed caused varying degrees of QTc interval prolongation, and even that information was not clear and consistent enough to stratify individual drugs for this risk. The few toxicology studies provided valuable information but their findings are pertinent only to situations of drug overdose. Case reports were most informative about the drug-QTc interval prolongation-TdP link. At least one additional well established risk factor for QTc prolongation was present in 92.2 % of case reports. Of the 28 cases of TdP, six (21.4 %) experienced it with QTc interval <500 ms; 75 % of TdP cases occurred at therapeutic doses. There is little evidence that drug-associated QTc interval prolongation by itself is sufficient to predict TdP. Future research needs to improve its precision and broaden its scope to better understand the factors that facilitate or attenuate progression of drug-associated QTc interval prolongation to TdP.

Effects of the fluoroquinolone antibacterial drug ciprofloxacin on ventricular repolarization in the halothane-anesthetized Guinea pig

The fluoroquinolone antibiotic ciprofloxacin has been reported to block delayed rectifier K(+) channels at much higher concentrations than those at which it exerts its bactericidal activity. In this study using the halothane-anesthetized guinea pig, we assessed whether ciprofloxacin has a proarrhythmic activity. Ciprofloxacin at a clinically relevant dose of 3 mg/kg, i.v. did not affect any electrocardiographic parameters. At 10 mg/kg, it prolonged the QT interval and the duration of the monophasic action potential of the ventricle under sinus rhythm and constant ventricular pacing (n = 6). The extents of its effects on the ventricular repolarization phase were comparable to those of another fluoroquinolone antibiotic moxifloxacin at a clinically relevant dose of 3 mg/kg (n = 6). Meanwhile, the PR interval and QRS width were also increased by ciprofloxacin at 10 mg/kg, suggesting that the drug inhibited cardiac K(+) channels as well as Na(+) and Ca(2+) channels in vivo. These results suggest that ciprofloxacin exerted a multi-ion channel-blocking action in the heart within the supra-therapeutic dose range. Therefore, careful observation may be necessary for patients with heart disease receiving a higher dose of ciprofloxacin in order to prevent the emergence of resistance.

Use of QT-prolonging medications in US emergency departments, 1995-2009

PURPOSE

Emergency department (ED) patients receive medications that place them at risk for adverse events, including drug-induced prolongation of the QT interval, which can lead to Torsade de Pointes and sudden cardiac death. We report the frequency of prescription and co-prescription of QT-prolonging medications in US EDs and factors associated with high-risk prescribing practices.

METHODS

We analyzed the ED component of the National Hospital Ambulatory Medical Care Survey for 1995 through 2009. Yearly rates of visits involving the prescription of QT-prolonging medications were determined. Multivariate regression analyses identified factors associated with the prescription of two or more QT-prolonging medications.

RESULTS

Approximately 16.5 million visits annually (15.0%) involved prescription of a QT-prolonging drug, with 1.7 million (1.6%) involving multiple prescriptions. Visits associated with QT-prolonging drugs more than doubled over the study period (10.4% to 22.2%). Diphenhydramine, azithromycin, and ondansetron were most frequently implicated (46.1% of cases). The most commonly prescribed combination was diphenhydramine and famotidine, both QT-prolonging medications available over-the-counter. Female gender and older age were associated with co-prescription of QT-prolonging medications. The rate of EKG screening among visits associated with QT-prolonging drug combinations was low (20.9%), but more common than among visits without a QT-prolonging drug (OR 1.3; 95% CI 1.2-1.5).

CONCLUSION

Use of QT-prolonging medications is increasing in EDs nationally. A small number of agents account for a large proportion of these visits and may represent an area for targeted screening or monitoring interventions in the ED.

Clinical pharmacology of dopamine-modulating agents in Tourette's syndrome

Forty years of research and clinical practice have proved dopamine (DA) receptor antagonists to be effective agents in the treatment of Tourette's syndrome (TS), allowing a significant tic reduction of about 70%. Their main effect seems to be mediated by the blockade of the striatal DA-D2 receptors. Various typical and atypical agents are available and there is still discord between experts about which of them should be considered as first choice. In addition, there are suggestions to use DA receptor agonists such as pergolide or non-DA-modulating agents. The present chapter is focusing on the clinical pharmacology of DA-modulating agents in the treatment of TS. The introduction outlines their clinical relevance and touches on the hypotheses of the role of DA in the pathophysiology of TS. Subsequently, general information about the mechanisms of action and adverse effects are provided. The central part of the chapter forms a systematic review of all DA-modulating agents used in the treatment of TS, including an overview of studies on their effectiveness, and a critical discussion of their specific adverse effects. The present chapter closes with a summary of the body of evidence and a description of the resulting recommendations for the pharmacological treatment of TS.

Therapeutic drug monitoring of common antipsychotics

The aim of this review is to provide information for interpreting outcome results from monitoring of antipsychotics in biological samples. A brief overview of the working mechanisms, pharmacological effects, drug interactions, and analytical methods of classical and atypical antipsychotics is given. Nineteen antipsychotics were selected based on their importance in the worldwide market as follows: amisulpride, aripiprazole, asenapine, bromperidol, clozapine, flupenthixol, haloperidol, iloperidone, lurasidone, olanzapine, paliperidone, perphenazine, pimozide, pipamperone, quetiapine, risperidone, sertindole, sulpiride, and zuclopenthixol. A straightforward relationship between administered dose, plasma or serum concentration, clinical outcome, or adverse effects is often lacking. Nowadays, focus lies on therapeutic drug monitoring and individualized therapy to find adequate treatment, to explain treatment failure or nonresponse, and to check patient compliance. However, extensive research in this field is still mandatory.

Clinically significant psychotropic drug-drug interactions in the primary care setting

In recent years, the growing numbers of patients seeking care for a wide range of psychiatric illnesses in the primary care setting has resulted in an increase in the number of psychotropic medications prescribed. Along with the increased utilization of psychotropic medications, considerable variability is noted in the prescribing patterns of primary care providers and psychiatrists. Because psychiatric patients also suffer from a number of additional medical comorbidities, the increased utilization of psychotropic medications presents an elevated risk of clinically significant drug interactions in these patients. While life-threatening drug interactions are rare, clinically significant drug interactions impacting drug response or appearance of serious adverse drug reactions have been documented and can impact long-term outcomes. Additionally, the impact of genetic variability on the psychotropic drug's pharmacodynamics and/or pharmacokinetics may further complicate drug therapy. Increased awareness of clinically relevant psychotropic drug interactions can aid clinicians to achieve optimal therapeutic outcomes in patients in the primary care setting.

Interactions and monitoring of antipsychotic drugs

As a consequence of individualized antipsychotic pharmacotherapy, many patients need more than a single drug, since they do not respond sufficiently to monotherapy. Other patients suffer from comorbid diseases and therefore require additional drugs from other pharmacological classes. Drug combinations, however, can give rise to pharmacokinetic and/or pharmacodynamic drug-drug interactions. Evaluation of pharmacokinetic interactions with antipsychotic drugs must consider substrate, inhibitor, and inducer properties for the cytochrome P450 (CYP) isoenzymes of all combined drugs. For consideration of pharmacodynamic interactions, special attention must be given to effects on dopamine D(2), histamine H(1), and acetylcholine M(1) receptors and on cardiac potassium channels. Additive pharmacological actions of combined drugs on these target structures can induce adverse reactions such as extrapyramidal symptoms, drowsiness, metabolic disturbances leading to weight gain and cardiac problems, cognitive impairment, delirium, or ventricular arrhythmia. Measuring plasma concentrations, i.e., therapeutic drug monitoring (TDM), is valuable to adjust antipsychotic medication when drug combinations contain inhibitors or inducers that alter plasma concentrations of the antipsychotic drugs. Amalgamating the broad knowledge on drug-drug interactions and using appropriately the option to monitor plasma concentrations in blood will help to apply complex combination therapies with antipsychotic drugs with maximal efficiency and safety.

Pharmacokinetic drug interactions of antimicrobial drugs: a systematic review on oxazolidinones, rifamycines, macrolides, fluoroquinolones, and Beta-lactams

Like any other drug, antimicrobial drugs are prone to pharmacokinetic drug interactions. These drug interactions are a major concern in clinical practice as they may have an effect on efficacy and toxicity. This article provides an overview of all published pharmacokinetic studies on drug interactions of the commonly prescribed antimicrobial drugs oxazolidinones, rifamycines, macrolides, fluoroquinolones, and beta-lactams, focusing on systematic research. We describe drug-food and drug-drug interaction studies in humans, affecting antimicrobial drugs as well as concomitantly administered drugs. Since knowledge about mechanisms is of paramount importance for adequate management of drug interactions, the most plausible underlying mechanism of the drug interaction is provided when available. This overview can be used in daily practice to support the management of pharmacokinetic drug interactions of antimicrobial drugs.

Cardiovascular and metabolic safety profiles of the fluoroquinolones

INTRODUCTION

Certain fluoroquinolones share similar indications of use. A comparison among Cardiovascular and metabolic (i.e., dysglycemia) safety profiles of the fluoroquinolones might be particularly useful for the prescribers' decision-making process as well as to hypothesize future researcher purposes.

AREAS COVERED

A literature search was conducted using keywords apt to identify information on safety profile of the fluoroquinolones. Publications concerned with descriptive and etiological surveys were manually reviewed.

EXPERT OPINION

Cardiac alterations and blood glucose impairments might be associated with any fluoroquinolone. However, the benefit/risk profile of these agents could be stratified for the single compounds. Several predisposing factors, such as diabetes, heart illnesses and their related pharmacotherapies, might exacerbate the risk of potentially serious adverse events. In this context, the opportunity of the more appropriate choice among different fluoroquinolones could be applicable.

The effects of intravenous ciprofloxacin on the electrocardiogram of healthy dogs

The purpose of this study was to evaluate the electrocardiographic effects of single intravenous dose of ciprofloxacin in dogs. Ten adult cross-breed dogs of both sexes were selected as the sample population. Baseline electrocardiographic values were recorded just before drug administration. Then the dogs received intravenous infusion of ciprofloxacin (10 mg/kg) over the fifteen minutes. The ECGs recorded at 15, 30, 60 and 120 minutes after ciprofloxacin administration. The ECG measurements of heart rate, PR interval, QRS interval, ST segment, T-wave amplitude and QT interval were taken from lead II. There was a small but significant increase in the longest QT intervals over baseline at T₆₀ (P = 0.041). The mean PR intervals, QTc intervals, JT intervals, ST segment, T-wave amplitude did not differ significantly before and after ciprofloxacin except for JT intervals at T₆₀ (P = 0.041). At this measurement point, there was an increased QT interval value of 0.02 second or 9.51% in comparison to the baseline. In Conclusions, Only minor QT intervals changes were observed after ciprofloxacin injection. Despite the occurrence of ECG changes following intravenous ciprofloxacin administration neither dangerous rhythm disturbances nor serious ECG changes were seen in this study.

QT interval prolongation and torsade de pointes

Torsade de pointes is a form of polymorphic ventricular tachycardia occurring in a setting of prolonged QT interval on surface electrocardiogram. Several drugs have been shown to prolong cardiac repolarization predisposing to torsade de pointes ventricular tachycardia. We present a case of torsade de pointes in a 72-year-old Italian woman in treatment with sotalol, sertraline, digoxin and acenocumarine.

Exposure to antibacterial agents with QT liability in 14 European countries: trends over an 8-year period

AIMS

(i) To classify antibacterial agents with QT liability on the basis of the available evidence, and (ii) to assess trends in their consumption over an 8-year period (1998-2005) in 14 European countries.

METHODS

Current published evidence on QT liability of antibiotics was retrieved through MEDLINE search and joined to official warnings from regulatory agencies. Each drug was classified according to an already proposed algorithm based on the strength of evidence: from group A (any evidence) to group E (clinical reports of torsades de pointes and warnings on QT liability). Consumption data were provided by the European Surveillance of Antibacterial Consumption (ESAC) project and were expressed as defined daily doses per 1000 inhabitants per day (DID).

RESULTS

Among 21 detected compounds, nine [six fluoroquinolones (FQs) and three macrolides (MACs)] belonged to group E. Use of group E drugs ranged from 1.3 (Sweden) to 4.1 DID (Italy) in 1998 and from 1.2 (Sweden) to 6.5 DID (Italy) in 2005. Significant exposure was observed in Italy and Spain (6.5 and 3.8 DID, respectively, in 2005). Only Denmark, Sweden and UK showed a slight decrease in use. Exposure to clarithromycin increased in 10 out of 14 countries, with a marked increment in Italy (3 DID in 2005).

CONCLUSIONS

Notwithstanding regulatory measures, in 2005 there was still significant exposure to antibacterials with strong evidence of QT liability and, in most countries, it was even increased. This warrants further investigation of appropriateness of use and suggests closer monitoring of group E drugs. Physicians should be aware when prescribing them to susceptible patients.

Ciprofloxacin-induced torsades de pointes in a methadone-dependent patient

ABSTRACT Background Methadone has been associated with QT prolongation and Torsades de pointes. Ciprofloxacin may prolong QT interval and induce Torsades de pointes when other risk factors are present. Case description A case is described in which a patient receiving methadone treatment developed Torsades de pointes following the addition of ciprofloxacin. Conclusion Ciprofloxacin should be used with caution in patients receiving methadone.

Ciprofloxacin-induced Q-T interval prolongation

PURPOSE

A case of Q-T interval prolongation in a pediatric patient with no known risk factors for the development of a long Q-T syndrome is reported.

SUMMARY

A 16-year-old boy arrived at a children's hospital reporting mucous diarrhea that had lasted two weeks, light-headedness with two blackouts on the day before his arrival to the hospital, and a 4.3-kg weight loss over the previous three weeks. He had a 3.5-year history of Crohn's disease and had been hospitalized for two months with a diagnosis of colitis with cryptitis. He was admitted for the treatment of an acute flare of Crohn's disease and a perirectal abscess. The patient was started on i.v. ciprofloxacin 400 mg twice daily and metronidazole 500 mg every six hours. The selected agents provided adequate empirical coverage of the suspected organisms and would not be contraindicated with the patient's allergy to penicillin. Within 48 hours of administration of ciprofloxacin, the patient became bradycardic. The cardiology service was consulted, and an electrocardiogram showed a mildly prolonged Q-T interval (corrected Q-T interval, 486 msec) and low heart rate (42 beats/min). Antimicrobial therapy was changed to ampicillin and then to linezolid. The patient's Q-T interval normalized within seven days of ciprofloxacin discontinuation. The patient had no further cardiac anomalies. Two weeks later, he was discharged on linezolid and aztreonam for the treatment of his abscess and was responding to treatment.

CONCLUSION

A pediatric patient with Crohn's disease and colitis with cryptitis developed a prolonged Q-T interval within 48 hours of treatment with ciprofloxacin.

QT interval prolongation, torsade de pointes and renal disease

Torsade de pointes is a form of polymorphic ventricular tachycardia occurring in a setting of prolonged QT interval on surface electrocardiogram. Several non-antiarrhythmic drugs including antibiotic and antipsychotic agents have been shown to prolong cardiac repolarization predisposing to torsade de pointes ventricular tachycardia. Blockade of the delayed rectifier (repolarising) potassium current and drug interactions with inhibitors of the cytochromes P450 (CYP)-mediated metabolism are the most common underlying mechanisms. Many antiarrhythmic drugs have been also implicated in prolonging QT interval and triggering torsades de pointes, especially during chronic therapy or in case of acute high dose toxicity. Progressive renal disease is associated from the earliest stages with increased QT interval and dispersal and with an increased risk of cardiovascular death, specifically sudden death. It has also been reported that cCorrected QT (QTc) interval prolongation and torsade de pointes are associated with end-stage renal disease (ESRD) and that they can be a cause of sudden death in ESRD. We present a case of torsade de pointes in a 82-year-old Italian woman with chronic renal failure.

New onset of atrial fibrillation after introduction of azathioprine in ulcerative colitis: case report and review of the literature

CASE REPORT

We present the case of a 52-year-old man with steroid-dependent ulcerative colitis, needing immunosuppressive therapy with azathioprine. The drug had been started 3 years earlier, but stopped after a few months because the patient reported palpitations, lipothymia, nausea and vomiting. Given the continued steroid-dependent ulcerative colitis and the lack of clinical documentation about a reaction with a dubious relationship to azathioprine, we decided to rechallenge the patient with the drug under clinical monitoring and after informed consent. After starting 50 mg of azathioprine, the patient showed general malaise, nausea and vomiting. An ECG showed atrial fibrillation, and the patient reported that the symptoms were similar to those previously experienced.

DISCUSSION

We have found two other cases of similar onset of atrial fibrillation after azathioprine use, although some confounding elements in these episodes make the possible causal relationship between the drug and this adverse event uncertain.

Metabolic drug interactions with newer antipsychotics: a comparative review

Newer antipsychotics introduced in clinical practice in recent years include clozapine, risperidone, olanzapine, quetiapine, sertindole, ziprasidone, aripiprazole and amisulpride. These agents are subject to drug-drug interactions with other psychotropic agents or with medications used in the treatment of concomitant physical illnesses. Most pharmacokinetic interactions with newer antipsychotics occur at the metabolic level and usually involve changes in the activity of the major drug-metabolizing enzymes involved in their biotransformation, i.e. the cytochrome P450 (CYP) monooxygenases and/or uridine diphosphate-glucuronosyltransferases (UGT). Clozapine is metabolized primarily by CYP1A2, with additional contribution by other CYP isoforms. Risperidone is metabolized primarily by CYP2D6 and, to a lesser extent, CYP3A4. Olanzapine undergoes both direct conjugation and CYP1A2-mediated oxidation. Quetiapine is metabolized by CYP3A4, while sertindole and aripiprazole are metabolized by CYP2D6 and CYP3A4. Ziprasidone pathways include aldehyde oxidase-mediated reduction and CYP3A4-mediated oxidation. Amisulpride is primarily excreted in the urine and undergoes relatively little metabolism. While novel antipsychotics are unlikely to interfere with the elimination of other drugs, co-administration of inhibitors or inducers of the major enzymes responsible for their metabolism may modify their plasma concentrations, leading to potentially significant effects. Most documented metabolic interactions involve antidepressant and anti-epileptic drugs. Of a particular clinical significance is the interaction between fluvoxamine, a potent CYP1A2 inhibitor, and clozapine. Differences in the interaction potential among the novel antipsychotics currently available may be predicted based on their metabolic pathways. The clinical relevance of these interactions should be interpreted in relation to the relative width of their therapeutic index. Avoidance of unnecessary polypharmacy, knowledge of the interaction profiles of individual agents, and careful individualization of dosage based on close evaluation of clinical response and, possibly, plasma drug concentrations are essential to prevent and minimize potentially adverse drug interactions in patients receiving newer antipsychotics.

Pharmacogenetics of antipsychotics: useful for the clinician?

PURPOSE OF REVIEW

The concept of individualized drug therapy on the basis of pharmacogenetics has become a central focus in psychopharmacology of schizophrenia. This article reviews recent advances in this field with respect to their importance for the clinician.

RECENT FINDINGS

First, there is an increasing agreement about the importance of polymorphisms in cytochrome P450 enzymes and the effects of drug-drug interactions in relation to the incidence of adverse effects. Secondly, prediction of response on the basis of variants in candidate genes is incipient and remains elusive. Thirdly, some advances have been made in understanding the pharmacogenetics of weight gain.

SUMMARY

Despite much effort, only a few of the results are now ready for translation into clinical practice. Cytochrome P450 genotyping would be a big step forward towards a more individualized drug treatment based on molecular diagnostics and could improve treatment, reduce adverse effects and increase compliance of the patients. Another promising field may be that of predicting the antipsychotic-induced weight gain and it is hoped that commercially available DNA tests may be available within the next few years. Prediction of response is still hampered by many methodological and clinical problems and is not yet available to the clinician.