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Objective: The primary aim of this study was to examine the association between the different predicted phenotypes of the polymorphic CYP2D6 gene and the prevalence of adverse drug reactions in patients suffering from depressive disorders. The secondary aim was to investigate if comedication with CYP2D6 inhibitors resulted in more adverse drug reactions due to phenoconversion. Methods: Between January 2012 and December 2021, 415 patients with a depressive disorder and insufficient treatment response in secondary psychiatric care were included in the naturalistic observational study Genes, Depression, and Suicidality (GENDS). The patients were subjected to a semistructured interview and diagnosed according to DSM-IV . Patients were also required to complete the self-rating version of the UKU Side Effect Rating Scale. All patients were genotyped for CYP2D6 and assigned a corresponding predicted CYP2D6 phenotype. Results: Out of the 415 patients, 147 patients with available genotyping and UKU scale results were also prescribed 1 or more drugs metabolized by CYP2D6. We did not find any evidence of an effect of the predicted CYP2D6 phenotype on the total burden of adverse drug reactions or in any of the specific symptom domains as measured with the UKU scale among these patients. We also investigated if comedication with 1 or more substances that inhibited the effect of the CYP2D6 enzyme resulted in more reported adverse drug reactions due to phenoconversion. Even though the rate of phenotypic PMs increased from 13 to 38 patients, we did not find any support for increased adverse drug reactions in this group. Conclusions: We did not find that CYP2D6 phenotype could predict the occurrence of adverse drug reactions in patients with depressive disorders in this naturalistic setting. However, information about CYP2D6 genotype may still be important in antidepressant treatment for the selection of appropriate drugs, for dosing recommendations of certain medications, or when t, Funding Agencies|Southern Health Care Region, Sweden; State grants (ALF)

It has been extensively debated whether selective serotonin reuptake inhibitors (SSRIs) are more efficacious than placebo in affective disorders, and it is not fully understood how SSRIs exert their beneficial effects. Along with serotonin transporter blockade, altered dopamine signaling and psychological factors may contribute. In this randomized clinical trial of participants with social anxiety disorder (SAD) we investigated how manipulation of verbally-induced expectancies, vital for placebo response, affect brain monoamine transporters and symptom improvement during SSRI treatment. Twenty-seven participants with SAD (17 men, 10 women), were randomized, to 9 weeks of overt or covert treatment with escitalopram 20 mg. The overt group received correct treatment information whereas the covert group was treated deceptively with escitalopram, described as an active placebo in a cover story. Before and after treatment, patients underwent positron emission tomography (PET) assessments with the [11C]DASB and [11C]PE2I radiotracers, probing brain serotonin (SERT) and dopamine (DAT) transporters. SAD symptoms were measured by the Liebowitz Social Anxiety Scale. Overt was superior to covert SSRI treatment, resulting in almost a fourfold higher rate of responders. PET results showed that SERT occupancy after treatment was unrelated to anxiety reduction and equally high in both groups. In contrast, DAT binding decreased in the right putamen, pallidum, and the left thalamus with overt SSRI treatment, and increased with covert treatment, resulting in significant group differences. DAT binding potential changes in these regions correlated negatively with symptom improvement. Findings support that the anxiolytic effects of SSRIs involve psychological factors contingent on dopaminergic neurotransmission while serotonin transporter blockade alone is insufficient for clinical response.

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient. Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug. Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

Introduction: Misoprostol (Cytotec) was primarily made for treating gastric ulcers. However today it is mostly used for abortion, treating postpartum hemorrhage, and for induction of labor. The tablet contains 200 µg of misoprostol, yet the dosages used for induction of labor are much smaller (25–50 µg), leading to uncertainty of dosage in daily use. Aim: To evaluate and compare the relative bioavailability of two misoprostol products (Angusta 25 µg and Cytotec 200 µg tablets) administered orally or sublingually given in a daily clinical setting to women admitted for induction of labor at term. Methods: Women carrying a live, singleton fetus in a cephalic position and with a gestational age between 259 and 296 days were included. Blood samples were collected at 0, 5, 10, 20, 30, 40, 50, 75, 100, 120, 180, and 240 minutes. A serum analytical assay was performed and pharmacokinetic parameters were calculated. Patients were assigned to one of three groups. Results: A total of 72 patients were included. No significant differences demographic characteristics were found. The ratios for AUC, AUC (0−t), and Cmax were similar in all three groups, but CI-values were outside the required 80–125%. Sublingual administration yielded a 20–30% higher bioavailability and a 50% higher Cmax than compared to the oral route. Conclusion: The relative bioavailability between Angusta and Cytotec could not be confirmed as being equal at the 25 µg or 50 µg level because the 90% CI-values when comparing the ratios for AUC, AUC(0−t), and Cmax were wider than accepted. The reason for this could be the real-life, non-standardized circumstances in which the study was conducted. Sublingual administration seems to have higher bioavailability than oral administration. More studies are needed to ascertain an optimal dosage regime balancing both safety and efficacy for mother and child. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02516631.

A prerequisite for rational use of medicines is adequate prescribing skills; drug treatment is a complex task requiring diagnostic competence combined with pharmacologic knowledge and patient communication skills. Acquiring professional confidence in the art of prescribing is essential during medical training. The results of this questionnaire study, conducted in four medical schools in Sweden after the course in internal medicine (252 respondents; response rate: 74%; median age: 24 years, 61% female), show that 45% and 62% were confident in performing medication reviews and writing medication summary reports, respectively, i.e. the basics of prescribing. The confidence increased by the number of reviews and reports performed, i.e. the extent of practice (correlation coefficients: 0.41 and 0.38, respectively, both p<0.0001), as did the extent of the students' reflection on important aspects of drug treatment such as adherence, adverse reactions, renal function, dosing, and drug interactions. In multivariate regression analyses, major predictors for confidence in performing medication reviews were extent of practice and extent of clinical supervision. The results suggest that these factors are keys to acquiring professional confidence in the art of prescribing., [Preparing for the licence to prescribe in medical school: a questionnaire study on medical students professional confidence in the art of prescribing]

A prerequisite for rational use of medicines is adequate prescribing skills; drug treatment is a complex task requiring diagnostic competence combined with pharmacologic knowledge and patient communication skills. Acquiring professional confidence in the art of prescribing is essential during medical training. The results of this questionnaire study, conducted in four medical schools in Sweden after the course in internal medicine (252 respondents; response rate: 74%; median age: 24 years, 61% female), show that 45% and 62% were confident in performing medication reviews and writing medication summary reports, respectively, i.e. the basics of prescribing. The confidence increased by the number of reviews and reports performed, i.e. the extent of practice (correlation coefficients: 0.41 and 0.38, respectively, both p<0.0001), as did the extent of the students' reflection on important aspects of drug treatment such as adherence, adverse reactions, renal function, dosing, and drug interactions. In multivariate regression analyses, major predictors for confidence in performing medication reviews were extent of practice and extent of clinical supervision. The results suggest that these factors are keys to acquiring professional confidence in the art of prescribing.

A prerequisite for rational use of medicines is adequate prescribing skills; drug treatment is a complex task requiring diagnostic competence combined with pharmacologic knowledge and patient communication skills. Acquiring professional confidence in the art of prescribing is essential during medical training. The results of this questionnaire study, conducted in four medical schools in Sweden after the course in internal medicine (252 respondents; response rate: 74%; median age: 24 years, 61% female), show that 45% and 62% were confident in performing medication reviews and writing medication summary reports, respectively, i.e. the basics of prescribing. The confidence increased by the number of reviews and reports performed, i.e. the extent of practice (correlation coefficients: 0.41 and 0.38, respectively, both pamp;lt;0.0001), as did the extent of the students reflection on important aspects of drug treatment such as adherence, adverse reactions, renal function, dosing, and drug interactions. In multivariate regression analyses, major predictors for confidence in performing medication reviews were extent of practice and extent of clinical supervision. The results suggest that these factors are keys to acquiring professional confidence in the art of prescribing., Att behandla med läkemedel är en kärnuppgift för läkare; grundutbildningen behöver ge studenterna förutsättningar att klara detta. Enkätresultat från fyra lärosäten visade att 45 procent av studenterna efter sin invärtesmedicinska placering kände sig trygga med att göra läkemedelsgenomgångar och 62 procent med att skriva läkemedelsberättelser. Studenter som gör många läkemedelsgenomgångar/läkemedelsberättelser känner större trygghet och reflekterar mer över patientens behandling. Klinisk handledning gör skillnad. När kursplaner revideras vid införandet av en sexårig läkarutbildning, med förskrivningsrätt direkt efter examen, behöver klinisk träning i läkemedelsarbete inklusive handledning tydliggöras.

In Sweden, information on drug use during pregnancy is obtained through an interview and recorded in a standardized medical record at every visit to the antenatal care clinic throughout the pregnancy. Antenatal, delivery, and neonatal records constitute the basis for the Swedish Medical Birth Register (MBR). The purpose of this exploratory study was to investigate the reliability of reported drug use by simultaneous screening for drug substances in the blood stream of the pregnant woman and thereby validate self-reported data in the MBR. Plasma samples from 200 women were obtained at gestational weeks 10-12 and 25 and screened for drugs by using ultra-high performance liquid chromatography with time of flight mass spectrometry (UHPLC-TOF-MS). The results from the analysis were then compared to medical records. At the first sampling occasion, the drugs found by screening had been reported by 86% of the women and on the second sampling, 85.5%. Missed reported information was clearly associated with drugs for occasional use. The most common drugs in plasma taken in early and mid-pregnancy were meclizine and paracetamol. Two types of continuously used drugs, selective serotonin reuptake inhibitors and propranolol, were used. All women using them reported it and the drug screening revealed a 100% coherence. This study shows good coherence between reported drug intake and the drugs found in plasma samples, which in turn positively validates the MBR., Funding Agencies|Medical Research Council of Southeast Sweden [FORSS-385451]

BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for depression and anxiety, but their efficacy relative to placebo has been questioned. We aimed to test how manipulation of verbally induced expectancies, central for placebo, influences SSRI treatment outcome and brain activity in patients with social anxiety disorder (SAD). METHODS: We did a randomized clinical trial, within an academic medical center (Uppsala, Sweden), of individuals fulfilling the DSM-IV criteria for SAD, recruited through media advertising. Participants were 18years or older and randomized in blocks, through a computer-generated sequence by an independent party, to nine weeks of overt or covert treatment with escitalopram (20mg daily). The overt group received correct treatment information whereas the covert group was treated deceptively with the SSRI described, by the psychiatrist, as active placebo. The treating psychiatrist was necessarily unmasked while the research staff was masked from intervention assignment. Treatment efficacy was assessed primarily with the self-rated Liebowitz Social Anxiety Scale (LSAS-SR), administered at week 0, 1, 3, 6 and 9, also yielding a dichotomous estimate of responder status (clinically significant improvement). Before and at the last week of treatment, brain activity during an emotional face-matching task was assessed with functional magnetic resonance imaging (fMRI) and during fMRI sessions, anticipatory speech anxiety was also assessed with the Spielberger State-Trait Anxiety Inventory - State version (STAI-S). Analyses included all randomized patients with outcome data at posttreatment. This study is registered at ISRCTN, number 98890605. FINDINGS: Between March 17th 2014 and May 22nd 2015, 47 patients were recruited. One patient in the covert group dropped out after a few days of treatment and did not provide fMRI data, leaving 46 patients with complete outcome data. After nine weeks of treatment, overt (n=24) as compa, Vanda Faria and Malin Gingnell contributed equally

Background: There is a need to improve design in educational programmes for the health sciences in general and in pharmacology specifically. The objective of this study was to investigate and problematize pharmacological communication in educational programmes for the health sciences. Methods: An interview study was carried out where final semester students from programmes for the medical, nursing and specialist nursing in primary health care professions were asked to discuss the pharmacological aspects of two written case descriptions of the kind they would meet in their everyday work. The study focused on the communication they envisaged taking place on the concerns the patients were voicing, in terms of two features: how communication would take place and what would be the content of the communication. A phenomenographic research approach was used. Results: The results are presented as outcome spaces, sets of categories that describe the variation of ways in which the students voiced their understanding of communication in the two case descriptions and showed the qualitatively distinct ways in which the features of communication were experienced. Conclusions: The results offer a base of understanding the students perspectives on communication that they will take with them into their professional lives. We indicate that there is room for strengthening communication skills in the field of pharmacology, integrating them into programmes of education, by more widely implementing a problem-based, a case-oriented or role-playing pedagogy where final year students work across specialisations and there is a deliberate effort to evoke and assess advanced conceptions and skills., Funding Agencies|Department of Pedagogical; County Council Ostergotland [LIO-198671]; Mellon Foundation at the Faculty of Humanities, University of the Witwatersrand, South Africa

Background The overall aim of the study was to explore health care students´ understanding of core concepts in pharmacology. Method An interview study was conducted among twelve students in their final semester of the medical program (n = 4), the nursing program (n = 4), and the specialist nursing program in primary health care (n = 4) from two Swedish universities. The participants were individually presented with two pharmacological clinically relevant written patient cases, which they were to analyze and propose a solution to. Participants were allowed to use the Swedish national drug formulary. Immediately thereafter the students were interviewed about their assessments. The interviews were audio-recorded and transcribed verbatim. A thematic analysis was used to identify units of meaning in each interview. The units were organized into three clusters: pharmacodynamics, pharmacokinetics, and drug interactions. Subsequent procedure consisted of scoring the quality of students´ understanding of core concepts. Non-parametric statistics were employed. Results The study participants were in general able to define pharmacological concepts, but showed less ability to discuss the meaning of the concepts in depth and to implement these in a clinical context. The participants found it easier to grasp concepts related to pharmacodynamics than pharmacokinetics and drug interactions. Conclusion These results indicate that education aiming to prepare future health care professionals for understanding of more complex pharmacological reasoning and decision-making needs to be more focused and effective., Also funded by Sahlgrenska Academy, (V 2011/437)

Objectives To investigate the proposed synergistic teratogenic effect of use of selective serotonin receptor inhibitors (SSRI) together with sedatives or hypnotics, primarily benzodiazepines, during pregnancy. Design Cohort study of congenital malformations after maternal use of SSRI, sedatives/hypnotics or the combination of the two drug categories. Setting Swedish national health registers. Participants A total of 10 511 infants born of women who had used SSRI drugs but no other central nervous system (CNS)-active drug, 1000 infants born of women who had used benzodiazepines and no other CNS-active drug, and 406 infants whose mothers had used both SSRI and benzodiazepines but no other CNS-active drug. Results None of the three groups showed a higher risk for any relatively severe congenital malformation or any cardiac defect when comparison was made with the general population risk (adjusted risk ratio (RR) for the combination of SSRI and benzodiazepines and a relatively severe malformation=1.17 (95% CI 0.70 to 1.73). Similar results were obtained for the combination of SSRI with other sedative/hypnotic drugs. Conclusions The previously stated increased risk associated with the combined use of these drug categories, notably for a cardiac defect, could not be replicated., Funding Agencies|Evy and Gunnar Sandbergs Foundation, Lund||Swedish Medical Research Council|2009-4740

Artikelförfattarna har genomfört en pedagogisk hypotesgenererande studie om de medicinska utbildningarna. Deras slutsats är att studenterna behöver bättre förutsättningar för att tillägna sig kunskaper, färdigheter och förhållningssätt i ämnen som anatomi, fysiologi och farmakologi.

Drugs acting on the central nervous system(CNS) and given to a pregnant woman during the latter part of pregnancy may affect neonatal morbidity of the infant. Little is known on the combined effects of different categories of such drugs. The redeeming of prescriptions for CNS-active drugs during the second or third trimester of pregnancy was studied by linkage between a register of prescribed drugs and the Swedish Medical Birth Register for the deliveries during 2006-2008 (n - 15,045 live-born infants). Neonatal morbidity was defined as the presence of neonatal diagnoses of respiratory problems, hypoglycemia, convulsions, or other CNS pathologic abnormalities including intraventricular hemorrhage, or low 5-minute Apgar score. The risk of such neonatal morbidity after maternal use of selective serotonin reuptake inhibitors (SSRIs) with or without other CNS-active drugs were evaluated as odds ratios or risk ratios, comparing with unexposed infants or infants only exposed to SSRI drugs. An increased risk for neonatal morbidity was seen for most studied groups of CNS-active drugs when used alone. Benzodiazepines seemed to have a stronger effect than other sedatives/hypnotics. The combination of SSRIs with 1 or more other CNS-active drug groups increased the risk for neonatal morbidity. This was seen for all types of sedatives/hypnotics, which may suggest a confounding by indication. Polypharmacy with CNS-active drugs during the later part of the pregnancy seems to increase the occurrence of neonatal morbidity but difference in nature or strength of underlying psychiatric pathology may confound the findings., Funding Agencies|Evy and Gunnar Sandberg Foundation, Lund, Sweden||Swedish Medical Research Council|2009-4790

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Background. Concerns have been expressed about possible adverse effects of the use of antidepressant medication during pregnancy, including risk for neonatal pathology and the presence of congenital malformations. Method. Data from the Swedish Medical Birth Register (MBR) from 1 July 1995 up to 2007 were used to identify women who reported the use of antidepressants in early pregnancy or were prescribed antidepressants during pregnancy by antenatal care : a total of 14 821 women with 15 017 infants. Maternal characteristics, maternal delivery diagnoses, infant neonatal diagnoses and the presence of congenital malformations were compared with all other women who gave birth, using the Mantel-Haenszel technique and with adjustments for certain characteristics. Results. There was an association between antidepressant treatment and pre-existing diabetes and chronic hypertension but also with many pregnancy complications. Rates of induced delivery and caesarean section were increased. The preterm birth rate was increased but not that of intrauterine growth retardation. Neonatal complications were common, notably after tricyclic antidepressant (TCA) use. An increased risk of persistent pulmonary hypertension of the newborn (PPHN) was verified. The congenital malformation rate was increased after TCAs. An association between use of paroxetine and congenital heart defects was verified and a similar effect on hypospadias was seen. Conclusions. Women using antidepressants during pregnancy and their newborns have increased pathology. It is not clear how much of this is due to drug use or underlying pathology. Use of TCAs was found to carry a higher risk than other antidepressants and paroxetine seems to be associated with a specific teratogenic property.

A compilation of therapeutic drug monitoring data for 15 antidepressant drugs in a naturalistic routine clinical setting is presented. A substantial number of serum concentrations, at different daily doses, are outlined, and the intraindividual and overall serum concentration coefficient of variation for a respective substance is presented. Also, concentration comparisons between women and men, and patients older or younger than 65 years are made. The drugs included are amitriptyline (n = 394), citalopram (n = 5457), clomipramine (n = 400), escitalopram (n = 3066), fluoxetine (n = 793), fluvoxamine (n = 165), mianserin (n = 1063), mirtazapine (n = 1427), moclobemide (n = 200), nortriptyline (n = 206), paroxetine (n = 1677), reboxetine (n = 85), sertraline (n = 2998), trimipramine (n = 158), and venlafaxine (n = 1781). Of the 9 drugs exhibiting linear (first order) kinetics, all but reboxetine gave a significant negative dose-to-dose-normalized correlation with concentrations, that is an increased clearance with higher dose. When dose was correlated to the metabolite: parent substance ratio for drugs exhibiting linear kinetics, citalopram and mianserin gave a positive slope, contrary to a negative slope shown for sertraline and venlafaxine. The intraindividual variations of the serum concentrations were lower than the overall variations, and the intraindividual variation of the metabolite: parent substance ratio was lower than the intraindividual variation of respective parent substance (except clomipramine and mianserin). Women had significantly higher serum concentrations than men (significant for citalopram, escitalopram, mianserin, mirtazapine, and venlafaxine), and patients older than 65 years had higher serum concentrations than the younger ones for all drugs except amitriptyline, moclobemide, and trimipramine. By presenting a comprehensive compilation of therapeutic drug monitoring data for each drug, a reference toot is created, in addition to improved pharma

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There is limited information on the pharmacokinetics of ziprasidone (ZIP) in naturalistic clinical settings. The objective of this study was to investigate the concentrations of ZIP and its active metabolite S-methyl-dihydroziprasidone (SMDZ), and the dose-normalized concentrations, using routine therapeutic drug monitoring (TDM) data. A high-performance liquid chromatographic method for determining serum concentrations of these substances for routine clinical use was established at the TDM Laboratory in Linkoping, Sweden. This analytical service was available to all physicians in Sweden. Between January 2001 and December 2004, 545 analyses, representing samples from 370 patients, were performed. The median daily ZIP dose was 120 mg (range 20-320 mg). In all, 121 steady-state trough specimens with essential clinical information were included in the pharmacokinetic evaluation. The median (25th to 75th percentile) serum concentration of ZIP was 125 nmol/L (82-188 nmol/L). The SMDZ:ZIP ratio decreased with increasing serum concentration of ZIP. The median (25th to 75th percentile) dose-normalized concentrations (nmol L-1 mg(-1) d(-1)) for ZIP and SMDZ were 1.13 (0.74-1.77) and 0.62 (0.45-0.86), respectively, with SMDZ:ZIP ratio of 0.57 (0.42-0.79). The overall coefficients of variation for close-normalized scruin concentrations of ZIP, SMDZ, and SMDZ:ZIP ratio were 62%, 56%, and 57%, respectively (n = 121). Smoking women had lower normalized ZIP concentrations than nonsmoking women. Twenty-eight patients with repeated eligible TDM analyses were studied for intraindividual variance over time. In summary, great interindividual and intraindividual differences in ZIP concentrations were observed. TDM of ZIP maybe used for individual dose adjustments and monitoring medication adherence.

The effect of various antipsychotics during pregnancy has repeatedly been studied, but for most atypical antipsychotics, only little information is available. We identified from the Swedish Medical Birth Register 2908 women who had reported the use of any antipsychotic or lithium in early pregnancy and studied malformation rates with data also from the Register of Congenital Malformations and the Hospital Discharge Register. Comparisons were made with all births (n = 958,729) after adjustment for some confounders. Risks were expressed as odds ratios (ORs).Most women had used dixyrazine or prochlorperazine mainly because of nausea and vomiting in early pregnancy. Seventy-nine women had used lithium, and these outcomes are reported separately. Hence, the main analysis was restricted to 570 women (576 infants) using other antipsychotics. There was a statistically significant increase in the risk for a congenital malformation-after exclusion of some common and minor conditions, the OR was 1.52 (95% confidence interval, 1.05-2.19). Exclusion of infants exposed to anticonvulsants reduced the OR only slightly. Most of the increased risk was caused by cardiovascular defects, mainly atrium or ventricular septum defect. No certain drug specificity was found. Except for an increased risk for congenital malformations, a nearly doubling of the risk for gestational diabetes and a 40% increased risk for cesarean delivery was noted. Because there seems to be little drug specificity, it is possible that underlying pathology or unidentified confounding explains the excess risk.

The main objectives of this study were to outline the inter- and intraindividual and overall pharmacokinetic variability of S-citalopram, S-desmethylcitalopram, and S-didesmethylcitalopram in serum by means of therapeutic drug monitoring, and to investigate potential correlations between the serum concentration and simultaneously collected clinical data. The study was conducted on outpatients in Sweden in 2002 to 2005. Included in the pharmacokinetic evaluation were 155 patients (68% women and 32% men) aged 17 to 95 years (average, 51 years). One serum sample per patient, taken as a trough value in steady state, was assessed. For the inter- and intraindividual variation calculation, 16 patients were included with two eligible samples each. The median daily dose was 20 mg/day (range, 5-40 mg). Extensive overall serum concentration variability was seen for all dose levels. The interindividual coefficient of variation for dose-normalized concentrations was 71% for S-citalopram, 36% for S-desmethylcitalopram, and 50% for S- didesmethylcitalopram. The intraindividual variations over time for the same parameters were approximately 30%, except for the ratio S-desmethylcitalopram/S- citalopram, which was 23%. The median S-desmethylcitalopram level was approximately 60% of the parent substance and the S-didesmethylcitalopram level approximately 9%. Higher age was correlated with higher serum concentrations, but no gender-related concentration differences were found. A majority (76%) of the patients took one or more drugs in addition to escitalopram, but concomitant medication did not seem to interact with escitalopram. However, women taking oral contraceptives showed a lower metabolic ratio compared with age-matched women. As a result of the wide range of the ratio in this population, these findings are not considered of clinical relevance.