Antipsychotics ⿿ Postmortem fatal and non-fatal reference concentrations

Fatal concentrations of antidepressant and antipsychotic drugs in postmortem femoral blood

Antidepressants and antipsychotics are both an important class of prescription drugs within postmortem (PM) toxicology because most of the substances are toxic in overdose and the mental disorders being treated may be associated with suicidality. A wide range of antidepressants and antipsychotics are currently included in up-to-date PM toxicology analysis protocols. However, apart from case studies, few reports on fatal concentrations based on large number of cases have been published in the literature. Based on PM investigations in Finland between 2000 and 2020, this study provides fatal reference concentrations in poisonings due to an antidepressant or an antipsychotic drug assigned as the principal intoxicant. Summary statistics for drug concentrations in PM femoral blood (min, max, mean, 10th, 25th, 50th, 75th, 90th percentile) were calculated for 17 antidepressant (N = 2,007) and for 12 antipsychotic drugs (N = 1,161). The proportion of suicide, accident and undetermined manner of death is indicated for each drug. Further, the fatal concentrations obtained in this study were evaluated by comparison with fatal and "normal" PM concentrations reported by two previously published approaches, the grouped causes of death approach and the all causes of death approach, respectively. This study shows that, despite the well-known variation in PM drug concentrations, competently generated fatal concentration results for the drugs studied are consistent to such an extent that they can be used as a reference in the interpretation process.

Common opioids and stimulants in autopsy and DUID cases: A comparison of measured concentrations

Quantitative results from toxicological analyses of autopsy material are widely compared to ranges in reference works to determine if drug concentrations are in relevant levels for establishing intoxication. This study compares concentrations of commonly used opioids and stimulants from drug addict autopsies and driving under the influence of drugs (DUID) cases to supplement current knowledge of the possible span and overlaps of measured concentrations. The study included whole-blood results from forensic autopsies of drug addicts performed from 2015 to 2020 (n = 220) and DUID cases from 2015 to 2019 (n = 7088). The focus was on heroin/morphine, methadone, cocaine, amphetamine and MDMA concentrations because these drugs are commonly encountered in both fatal intoxications and DUID cases and the potential for abuse is well known. In the DUID group, the opioids heroin/morphine and methadone and the stimulants amphetamine and MDMA were often seen in concentrations above the reported lower comatose-fatal level whereas cocaine was almost always below. Thus, based on our data, the potential for false assessment of intoxication cases when comparing to reported comatose-fatal limits appears greatest on lower end concentrations of heroin/morphine, methadone, amphetamine and MDMA, whereas false assessment of cocaine appears less likely because most control cases are below reported comatose-fatal levels.

Oxycodone-Related Deaths: The Significance of Pharmacokinetic and Pharmacodynamic Drug Interactions

BACKGROUND AND OBJECTIVES

Oxycodone is frequently prescribed as well as detected in postmortem cases. Concurrent use of pharmacodynamically or pharmacokinetically interacting drugs can cause adverse effects or even fatal intoxication. The aims of this study were to investigate differences in prescriptions for and toxicological findings of pharmacodynamically and pharmacokinetically interacting drugs in fatal oxycodone-related intoxications and other causes of death. We also aimed to investigate the differences in prevalence of oxycodone prescriptions, and the detected postmortem oxycodone concentrations between fatal oxycodone-related intoxications and other causes of death.

METHODS

Forensic autopsy cases (2012-2018) where oxycodone was identified in femoral blood (n = 1236) were included. Medical history and prescription data were retrieved from national databases and linked to the forensic toxicology findings.

RESULTS

Oxycodone-related deaths were found to have higher blood concentrations of oxycodone (median 0.30 µg/g vs. 0.05 µg/g) and were less likely to have a prescription for oxycodone (OR 0.62) compared to nonintoxication deaths. Pharmacodynamically interacting drugs were prescribed in 79% and found in blood in 81% of the cases. Pharmacokinetically interacting drugs were rarely prescribed (1%). Oxycodone-related deaths were more likely to have prescriptions for a pharmacodynamically interacting drug (OR 1.7) and more often have co-findings of one or multiple pharmacodynamically interacting drugs (OR 5.6).

CONCLUSION

The results suggest that combined use of oxycodone and pharmacodynamically interacting drugs is associated with oxycodone-related death and that non-medical use of oxycodone is a potential risk factor for oxycodone-related intoxication.

The Future of Analytical and Interpretative Toxicology: Where are We Going and How Do We Get There?

(Forensic) toxicology has faced many challenges, both analytically and interpretatively, especially in relation to an increase in potential drugs of interest. Analytical toxicology and its application to medicine and forensic science have progressed rapidly within the past centuries. Technological innovations have enabled detection of more substances with increasing sensitivity in a variety of matrices. Our understanding of the effects (both intended and unintended) have also increased along with determination and degree of toxicity. However, it is clear there is even more to understand and consider. The analytical focus has been on typical matrices such as blood and urine but other matrices could further increase our understanding, especially in postmortem (PM) situations. Within this context, the role of PM changes and potential redistribution of drugs requires further research and identification of markers of its occurrence and extent. Whilst instrumentation has improved, in the future, nanotechnology may play a role in selective and sensitive analysis as well as bioassays. Toxicologists often only have an advisory impact on pre-analytical and pre-interpretative considerations. The collection of appropriate samples at the right time in an appropriate way as well as obtaining sufficient circumstance background is paramount in ensuring an effective analytical strategy to provide useful results that can be interpreted within context. Nevertheless, key interpretative considerations such as pharmacogenomics and drug-drug interactions as well as determination of tolerance remain and in the future, analytical confirmation of an individual's metabolic profile may support a personalized medicine and judicial approach. This should be supported by the compilation and appropriate application of drug data pursuant to the situation. Specifically, in PM circumstances, data pertaining to where a drug was not/may have been/was contributory will be beneficial with associated pathological considerations. This article describes the challenges faced within toxicology and discusses progress to a future where they are being addressed.

Postmortem Drug Redistribution: A Compilation of Postmortem/Antemortem Drug Concentration Ratios

Postmortem drug redistribution (PMR) is a well-known phenomenon in forensic toxicology with implications for medico-legal death investigations. Paired antemortem (AM) specimen and postmortem (PM) mortuary admission femoral blood drug concentrations from 811 coronial cases were used to construct a retrospective compilation of PM/AM drug concentration ratios for 42 parent drugs and metabolites. The median PM/AM ratios for all antidepressants were > 1 and consistent with PMR In contrast, the median PM/AM ratios of most benzodiazepines were < 1. The antipsychotics were varied (0.63-3.3) and suggest the mixed effects of PMR and drug instability. Amphetamines exhibited no trends (0.90-0.95) and are likely confounded by many factors. The PM/AM ratios of cardiovascular drugs, opioids and other drugs are also reported. This research represents an expansive retrospective compilation of paired AM and PM drug concentrations for many toxicologically relevant drugs. While the median PM/AM ratios demonstrate some drug-dependent trends, there was no obvious relationship between AM specimens and PM femoral blood taken at mortuary admission.

Interpretation of melperone intoxication: post-mortem concentration distribution and interpretation of intoxication data

OBJECTIVES

Since melperone abuse with lethal intoxication is common, expert opinions based on therapeutical and lethal concentration ranges can be considered as important. Because there is a lack of information about fatalities caused by melperone mono-intoxications and data on tissue samples with concentration distribution, the aim of this work is the examination of lethal concentration ranges of melperone and drug quantification in different matrices.

METHODS

An LC-MS/MS method was applied for analyses performed in blood and tissue samples. Quantification based on standard addition and sample preparation on liquid-liquid extraction with 1-chlorobutane. An appropriate tissue homogenization was performed ahead of extraction with an IKA Ultra-Turrax-Tube-Drive^®. A Luna 5 µm C18 (2) 100 Å, 150  × 2 mm analytical column was used for chromatographic separation and the elution was performed with two mobile phases consisted of A (H₂O/methanol = 95/5, v/v) and B (H₂O/methanol = 3/97, v/v) both with 10 mM ammonium acetate and 0.1% acetic acid.

RESULTS

A multi-drug LC-MS/MS analytical method developed was applied successfully for melperone quantification in different post-mortem matrices. No analytical problems could be identified during method development and analyses of real samples. The melperone lethal concentration calculated in femoral blood of the drug mono-intoxication investigated was 10 mg/L. Melperone concentration distribution was presented for the first time.

CONCLUSIONS

The lethal reference concentration of melperone in femoral blood of 17.1 mg/L pointed out in different reference lists should be used with caution. Instead, a lower lethal melperone concentration should be considered. The post-mortem concentration distribution of the drug presented could be helpful in the interpretation of cases where no blood samples are available.

Interpretation of melperone intoxication: post-mortem concentration distribution and interpretation of intoxication data

OBJECTIVES

Since melperone abuse with lethal intoxication is common, expert opinions based on therapeutical and lethal concentration ranges can be considered as important. Because there is a lack of information about fatalities caused by melperone mono-intoxications and data on tissue samples with concentration distribution, the aim of this work is the examination of lethal concentration ranges of melperone and drug quantification in different matrices.

METHODS

An LC-MS/MS method was applied for analyses performed in blood and tissue samples. Quantification based on standard addition and sample preparation on liquid-liquid extraction with 1-chlorobutane. An appropriate tissue homogenization was performed ahead of extraction with an IKA Ultra-Turrax-Tube-Drive®. A Luna 5 µm C18 (2) 100 Å, 150  × 2 mm analytical column was used for chromatographic separation and the elution was performed with two mobile phases consisted of A (H2O/methanol = 95/5, v/v) and B (H2O/methanol = 3/97, v/v) both with 10 mM ammonium acetate and 0.1% acetic acid.

RESULTS

A multi-drug LC-MS/MS analytical method developed was applied successfully for melperone quantification in different post-mortem matrices. No analytical problems could be identified during method development and analyses of real samples. The melperone lethal concentration calculated in femoral blood of the drug mono-intoxication investigated was 10 mg/L. Melperone concentration distribution was presented for the first time.

CONCLUSIONS

The lethal reference concentration of melperone in femoral blood of 17.1 mg/L pointed out in different reference lists should be used with caution. Instead, a lower lethal melperone concentration should be considered. The post-mortem concentration distribution of the drug presented could be helpful in the interpretation of cases where no blood samples are available.

Oxycodone findings and CYP2D6 function in postmortem cases

Genetic disposition can cause variation in oxycodone pharmacokinetic characteristics and decrease or increase the expected clinical response. In forensic medicine, determination of cause of death or assessing time between drug intake and death can be facilitated by knowledge of parent and metabolite concentrations. In this study, the aim was to investigate if CYP2D6 genotyping can facilitate interpretation by investigating the frequency of the four CYP2D6 phenotypes, poor metabolizer, intermediate metabolizer, extensive metabolizer, and ultra-rapid metabolizer in postmortem cases, and to study if the CYP2D6 activity was associated with a certain cause of death, concentration, or metabolic ratio. Cases positive for oxycodone in femoral blood (n = 174) were genotyped by pyrosequencing for CYP2D6*3, *4, and *6 and concentrations of oxycodone, noroxycodone, oxymorphone, and noroxymorphone were determined by LC-MS/MS (LLOQ 0.005 µg/g). Digital droplet PCR was used to determine the copy number variation for CYP2D6*5. Cases were categorized by cause of death. It was found that poor and intermediate CYP2D6 metabolizers had significantly higher oxycodone and noroxycodone concentrations compared to extensive and ultra-rapid metabolizers. CYP2D6 phenotype were equally distributed between cause of death groups, showing that no phenotype was overrepresented in any of the cause of death groups. We also found that the concentration ratio between oxymorphone and oxycodone depended on the CYP2D6 activity when death was unrelated to intoxication. In general, a low metabolite to parent ratio indicate an acute intake. By using receiver operating characteristic (ROC) analysis, we conclude that an oxymorphone/oxycodone ratio lower than 0.075 has a high sensitivity for separating intoxications with oxycodone from other intoxications and non-intoxications. However, the phenotype needs to be known to reach a high specificity. Therefore, the ratio should not be used as a biomarker on its own to distinguish between different causes of death but needs to be complemented by genotyping.

Identification and Quantification of Antipsychotics in Blood Samples by LC-MS-MS: Case Reports and Data from Three Years of Routine Analysis

Antipsychotic drugs (AP) are widely prescribed for the treatment of schizophrenia and psychosis. The pharmacological treatment of schizophrenia is often performed with the simultaneous use of two or more antipsychotic agents to achieve the desired control of psychotic symptoms Available AP include both conventional (typical) and new (atypical) antipsychotic medications. Atypical AP, such as quetiapine, now account for the vast majority of AP prescriptions. In forensic toxicology, AP are of considerable interest because of their potential abuse and their involvement in intoxications and suicides. The authors retrospectively examined AP positive cases detected in samples collected during autopsies performed in the Forensic Clinical and Pathology Service of National Institute of Legal Medicine and Forensic Sciences Centre Branch or in other autopsies carried out in the central region of Portugal, between January 2016 and December 2018. A quantitative liquid chromatography-tandem mass spectrometry assay was developed for the simultaneous determination of 16 AP (amisulpride, aripiprazole, chlorpromazine, clozapine, cyamemazine, fluphenazine, haloperidol, levomepromazine, melperone, olanzapine, paliperidone, promethazine, quetiapine, risperidone, sulpiride and ziprasidone) in blood samples of postmortem cases. The Laboratory of Forensic Chemistry and Toxicology received 3,588 requests for toxicological analysis: 1,413 cases were positive for drugs from which 351 (24.8%) cases were positive for AP, 60.1% from male individuals and 39.9% from female. Quetiapine was the most prevalent AP (36.5%) followed by olanzapine (20.8%). During this period, there were 25 postmortem cases with AP blood concentrations above therapeutic range, in which 36% of those are in agreement with the information received (psychological history or acute intoxication suspicion) and the manner of death was suicide. Our results point that antipsychotics are an increasingly prevalent class of drugs. AP must be measured not only in toxic concentrations but also in therapeutic levels in postmortem cases; therefore, it is important to come up with a sensitive method to cover the low therapeutic range in which AP are usually present.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

The importance of sample size with regard to the robustness of postmortem reference values

Evaluating postmortem toxicological results is a challenging task due to multiple factors affecting blood concentrations after death. In order to improve the diagnostic accuracy in cases of suspected fatal intoxication different compilations of postmortem reference drug concentrations are often used. However, it is not clear what constitutes a reliable postmortem reference value. The current study presents reference concentrations for 13 substances from seven substance groups according to a standardized protocol. The reference concentrations were gathered from 3767 autopsy cases and subdivided into intoxications by one substance only (Group A, n=611), multi-substance intoxications (Group B, n=1355) and postmortem controls, in which incapacitation by drugs were excluded (Group C, n=1801). In particular, this study presents statistical information about the precision and conformity change with various sample sizes. Based on the present data >10 detections are usually needed, for the substances examined, to differentiate between intoxication cases and controls. Repeated samplings show that the median of small samples (N=≤5) has a high variation (normalized interquartile range 138-75%) and that a high number of detections (N=>20) in each group are needed to reduce the variation.

A Compilation of Serum Concentrations of 12 Antipsychotic Drugs in a Therapeutic Drug Monitoring Setting

BACKGROUND

No comprehensive collection of routine therapeutic drug monitoring data for antipsychotic drugs has been published.

METHODS

In this compilation, data on 12 antipsychotics are presented. The drugs included are amisulpride (n = 506), aripiprazole (n = 1610), clozapine (n = 1189), flupentixol (n = 215), haloperidol (n = 390), olanzapine (n = 10,268), perphenazine (n = 1065), quetiapine (n = 5853), risperidone (n = 3255), sertindole (n = 111), ziprasidone (n = 1235), and zuclopenthixol (n = 691). Because only one sample per patient is included, the number of patients equals the number of samples. For each drug, median serum concentrations as well as that of the 10th and 90th percentiles are given for a range of daily doses. Comparisons are made between males and females, between patients younger than 65 years and 65 years and older, and between those treated with a low and a high dose of each drug. The concentration-to-dose (C/D) ratio is the primary variable used in these comparisons. Coefficients of variation (CVs) for the serum concentrations of each drug within and between subjects are presented.

RESULTS

In general, the C/D ratios were higher in females than in males, higher in those 65 years and older than in younger subjects, and lower in those treated with higher doses than in those treated with lower doses. CVs between individuals were larger than within subjects, and the CVs were highest for the drugs with short elimination half-lives.

CONCLUSIONS

For each antipsychotic drug, the results presented can serve as a reference tool for pharmacokinetic interpretation of the individual patient's serum drug level. The compiled serum concentrations and the C/D ratios can support the physician's decision when individualizing dosing and determining treatment strategies for a specific patient.

Determination of Antidepressants and Antipsychotics in Dried Blood Spots (DBSs) Collected from Post-Mortem Samples and Evaluation of the Stability over a Three-Month Period

An LC-MS/MS method for the identification and quantification of antidepressants and antipsychotics was developed on dried blood spots (DBSs). Moreover, analyte stability on DBSs within a 3-month period was monitored. Aliquots of 85 µL of blood from autopsy cases were pipetted onto DBS cards, which were dried and stored at room temperature. DBSs were analyzed in triplicate immediately, within the following 3 weeks, and after 3 months. For each analysis, a whole blood stain was extracted in phosphate buffer and purified using Solid Phase Extraction (SPE) cartridges in order to avoid matrix effects and injected in the LC-MS/MS system. Thirty-nine molecules were screened. Limits of detection (LODs) ranged between 0.1 and 3.2 ng/mL (g) and 0.1 and 5.2 ng/mL (g) for antidepressants and antipsychotics, respectively. Limits of quantification (LOQs) varied from 5 to 10.0 ng/mL for both. Sixteen cases among the 60 analyzed resulted positive for 17 different analytes; for 14 of these the method was fully validated. A general good agreement between the concentrations on DBSs and those measured in conventional blood samples (collected concurrently and stored at -20 °C) was observed. The degradation/enhancement percentage for most of the substances was lower than 20% within the 3-month period. Our results, obtained from real post-mortem cases, suggest that DBSs can be used for routine sample storage.

Metformin - Postmortem fatal and non-fatal reference concentrations in femoral blood and risk factors associated with fatal intoxications

BACKGROUND & OBJECTIVES

To improve the interpretation of fatal intoxications by establishing fatal and non-fatal reference concentrations of metformin in postmortem femoral blood and to further evaluate risk factors associated with fatal metformin intoxication.

METHODS

All forensic autopsies in Sweden where metformin was detected in femoral blood 2011-2016 were identified in the National Board of Forensic Medicine databases (NFMD). The cases were classified as single substance intoxications, A (n = 22), multiple substance intoxications, B (N = 7) and postmortem controls, C (N = 13). The control group consisted of cases where metformin was detected, but the cause of death excluded the incapacitation by metformin or other substances. Strict inclusion criteria were used, and all postmortem cases were assessed by two independent reviewers. All other cases where the inclusion criteria of groups A-C where not met formed group O (N = 78). The forensic findings logged in the NFMD where linked to national registers whereby information on comorbidities, dispensed drugs and clinical data could be obtained.

RESULTS

The mean age was 66 ± 10 years in the total study population and did not differ between the groups. The proportion of men was 64% in group A, 71% in B, 77% in C and 74% in group O. The median values of metformin in group A (48.5 μg/g; range 13.0-210 μg/g) and B (21.0 μg/g; range 4.40-95.0 μg/g) were significantly (p < 0.001 and p = 0.015 respectively) higher than those of the control group C (2.30 μg/g ; range 0.70-21.0 μg/g). The median concentration of metformin in group A and B was also significantly higher than in group O (4.60 μg/g; range 0.64-54.0 μg/g) (p < 0.001 and p = 0.040 respectively). The results suggest that intoxication with metformin as a cause of death should be considered when the postmortem femoral blood level exceeds about 10 μg/g, although higher levels may be seen in postmortem in cases without incapacitation. The metformin intoxication was confirmed to be intentional in 23% (n = 5) of the single intoxications. Underlying factors identified as important for the remaining fatal metformin intoxications included living alone, any contraindication for the use of metformin, known alcohol abuse and a history of stroke or cardiovascular disease.

CONCLUSIONS

The reported post mortem femoral blood concentrations of metformin can hopefully contribute to a better interpretation of results in suspected poisonings and obscure cases. Living in a single household, history of cardiovascular disease and contraindications, predominantly alcohol abuse, were associated with fatal metformin intoxication.

Distribution of Eight QT-Prolonging Drugs and Their Main Metabolites Between Postmortem Cardiac Tissue and Blood Reveals Potential Pitfalls in Toxicological Interpretation

Femoral blood concentrations are usually used in postmortem toxicology to assess possible toxic effects of drugs. This includes QT-prolongation and other cardiac dysrhythmia, which could have been the cause of death. However, blood concentration is only a surrogate for the active site concentration, and therefore cardiac tissue concentration may provide a more accurate toxicological interpretation. Thus, cardiac tissue and femoral and cardiac blood concentrations were examined for eight frequently used QT-prolonging drugs (QTD) and their metabolites in a mentally ill population. In total, 180 cases were included from the Danish autopsy-based forensic study SURVIVE. The concentrations were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry utilizing stable isotopically labeled internal standards. The results showed that the cardiac tissue concentrations were significantly higher compared to femoral and cardiac blood concentrations, with two exceptions. The median cardiac tissue-to-femoral blood concentration ratio (Kb) ranged from 2.2 (venlafaxine) to 15 (nortriptyline). The inter-individual fold difference between the minimum and maximum Kb ranged from 2.6-fold (Z-hydroxynortriptyline) to 61 (venlafaxine). For 12 compounds, postmortem redistribution appeared to be minimal, whereas four compounds displayed some degree of postmortem redistribution. Citalopram and quetiapine were selected for in-depth analysis of the relation between the toxicological interpretation and femoral blood/cardiac tissue concentrations. Within this dataset, citalopram displayed a wide overlap in cardiac tissue concentrations (~50%) between non-toxic and toxic citalopram cases, as estimated from femoral blood concentrations. In contrast, quetiapine displayed no overlap in cardiac tissue concentrations between non-toxic and toxic quetiapine cases based on femoral blood concentrations. The implication of the citalopram finding is that possible intoxications can be overlooked when only considering femoral blood concentrations. Based on the present findings, non-toxic cardiac tissue 10th-90th percentile concentration ranges were estimated for citalopram (0.93-4.4 mg/kg) and quetiapine (0.0073-0.60 mg/kg).

Treatment With Antipsychotics in Pregnancy: Changes in Drug Disposition

Although pregnancy is known to cause changes in drug pharmacokinetics, little is known about its impact on serum levels of antipsychotics. In this study we retrospectively assessed 201 routine serum antipsychotic therapeutic drug monitoring concentration measurements obtained from a total of 110 pregnancies in 103 women, and 512 measurements from the same women before and after pregnancy. Serum concentrations in the third trimester were significantly lower than baseline for quetiapine (-76%; confidence interval (CI), -83%, -66%; P < 0.001) and aripiprazole (-52%; CI, -62%, -39%; P < 0.001), but not for olanzapine (-9%; CI, -28%, +14%; P = 0.40). For the remaining antipsychotics (perphenazine, haloperidol, ziprasidone, risperidone, and clozapine), our dataset was limited, but it indicates that concentrations may decline at least for perphenazine and possibly also for haloperidol. Even though the clinical consequence of the serum concentrations decline remains to be elucidated, our results warrant close clinical monitoring throughout pregnancy, preferentially supported by therapeutic drug monitoring.

Metabolic risk factors in schizophrenia and bipolar disorder: The effect of comedication with selective serotonin reuptake inhibitors and antipsychotics

BACKGROUND

The aim of this observational study was to investigate the relationship between metabolic factors and use of selective serotonin reuptake inhibitors (SSRIs) combined with olanzapine, quetiapine or risperidone.

METHODS

Data from the Norwegian Thematically Organized Psychosis study, a cross-sectional study on 1301 patients with schizophrenia (n=868) or bipolar disorder (n=433), were analyzed. As exposure variables in the linear regression model were included the dose or serum concentration of SSRIs (n=280) and of olanzapine (n=398), quetiapine (n=234) or risperidone (n=128). The main outcome variables were levels of total cholesterol, low and high density lipoprotein (LDL and HDL) cholesterol, triglycerides and glucose.

RESULTS

One defined daily dose (DDD) per day of an SSRI in addition to olanzapine was associated with an increase in total cholesterol of 0.16 (CI 0.01 to 0.32) mmol/L (P=0.042) and an increase in LDL-cholesterol of 0.17 (CI 0.02 to 0.31) mmol/L (P=0.022). An SSRI serum concentration in the middle of the reference interval in addition to quetiapine was associated with an increase in total cholesterol of 0.39 (CI 0.10 to 0.68) mmol/L (P=0.011) and an increase in LDL-cholesterol of 0.29 (0.02 to 0.56) mmol/L (P=0.037). There were no such effects when combined with risperidone.

CONCLUSIONS

The findings indicate only minor deteriorations of metabolic variables associated with treatment with an SSRI in addition to olanzapine and quetiapine, and none when combined with risperidone. These results suggest that SSRIs can be used in combination with antipsychotics, and that the possible increase in cardiovascular risk is negligible.