Self-rated residual symptoms do not predict 1-year recurrence of depression

Background

Residual depressive symptoms are generally documented as a risk factor for recurrence. In the absence of a specific instrument for the assessment of residual symptoms, a new 25-item Depression Residual Symptom Scale (DRSS) was elaborated and tested for recurrence prediction over a 1-year follow-up.

Sampling and methods

Fifty-nine patients in remission after a major depressive episode (MDE) were recruited in two centres. They were assessed with the DRSS and the Montgomery-Asberg Depression Rating Scale (MADRS) at inclusion and followed for 1 year according to a seminaturalistic design. The DRSS included specific depressive symptoms and subjective symptoms of vulnerability, lack of return to usual self and premorbid level of functioning.

Results

Severity of residual symptoms was not significantly associated with increased risk of recurrence. However, DRSS score was significantly higher among patients with three or more episodes than one to two episodes. Number of previous episodes and treatment interruption were not identified as significant predictors of recurrence.

Conclusion

The proposed instrument is not predictive of depressive recurrence, but is sensitive to increased perception of vulnerability associated with consecutive episodes. Limitations include small sample size, seminaturalistic design (no standardisation of treatment) and content of the instrument.

Productive and physiological responses of lactating dairy cows supplemented with phytogenic feed ingredients

This experiment compared milk production, milk composition, and physiological responses in lactating dairy cows supplemented with or without a mixture of condensed tannins, encapsulated cinnamaldehyde, curcumin, capsaicin, and piperine. Thirty-six lactating, multiparous, pregnant ¾ Holstein × ¼ Gir cows were maintained in a single drylot pen with ad libitum access to water and a total-mixed ration and were milked twice daily (d -7 to 84). On d 0, cows were ranked by days in milk (86 ± 3 d), milk yield (27.8 ± 1.0 kg), body weight (BW; 584 ± 10 kg), and body condition score (BCS; 3.04 ± 0.06) and assigned to receive (SUPP; n = 18) or not (CON; n = 18) 30 g/cow daily (as-fed basis) of Actifor Pro (Delacon Biotechnik GmbH; Steyregg, Austria). From d 0 to 84, SUPP cows individually received (as-fed basis) 15 g of Actifor Pro mixed with 85 g of finely ground corn through self-locking headgates before each milking of the day. Each CON cow concurrently received 85 g (as-fed basis) of finely ground corn through self-locking headgates. Throughout the experimental period (d -7 to 84), cows from both treatments were administered 500 mg of sometribove zinc at 14-d intervals and were monitored daily for morbidity, including clinical mastitis. Individual milk production was recorded daily, whereas milk samples were collected weekly for analysis of milk composition. Cow BW, BCS, and blood samples were also collected weekly. Cows receiving SUPP gained more BCS (P = 0.05) and had greater (P = 0.04) milk yield during the experiment compared with CON cows (0.22 vs. 0.07 of BCS, SEM = 0.05; 29.5 vs. 27.9 kg/d, SEM = 0.5). Milk composition did not differ (P ≥ 0.15) between SUPP and CON cows; hence, SUPP cows also had greater (P ≤ 0.02) production of fat-corrected and energy-corrected milk. Incidence of clinical mastitis did not differ (P ≥ 0.49) between SUPP and CON cows. No treatment differences were also detected (P ≥ 0.21) for serum concentrations of glucose and serum urea N. Mean serum haptoglobin concentration during the experiment was greater (P = 0.05) in CON vs. SUPP cows. Cows receiving SUPP had less (P ≤ 0.04) serum cortisol concentrations on d 21 and 42, and greater (P ≤ 0.05) serum concentrations of insulin-like growth factor-I on d 7, 35, and 63 compared with CON cows (treatment × day interactions; P ≤ 0.02). Collectively, supplementing phytogenic feed ingredients improved nutritional status and milk production of lactating ¾ Holstein × ¼ Gir cows.

Developmental delay in communication among toddlers and its relationship to caregiving behavior among violence-exposed, posttraumatically stressed mothers

OBJECTIVES

This study aimed to understand if maternal interpersonal violence-related posttraumatic stress disorder (IPV-PTSD) is associated with delayed language development among very young children ("toddlers").

METHODS

Data were collected from 61 mothers and toddlers (ages 12-42 months, mean age = 25.6 months SD = 8.70). Child expressive and receptive language development was assessed by the Ages and Stages Questionnaire (ASQ) communication subscale (ASQCS) that measures language acquisition. Observed maternal caregiving behavior was coded from videos of 10-min free-play interactions via the CARE-Index. Correlations, Mann-Whitney tests, and multiple linear regression were performed.

RESULTS

There was no significant association between maternal IPV-PTSD severity and the ASQCS. Maternal IPV-PTSD severity was associated with continuous maternal behavior variables (i.e. sensitive and controlling behavior on the CARE-Index) across the entire sample and regardless of child gender. Maternal sensitivity was positively and significantly associated with the ASQCS. Controlling behavior was negatively and significantly associated with the ASQCS.

CONCLUSIONS

Results are consistent with the literature that while maternal IPV-PTSD severity is not associated with child language delays, the quality of maternal interactive behavior is associated both with child language development and with maternal IPV-PTSD severity. Further study is needed to understand if the level of child language development contributes to intergenerational risk or resilience for relational violence and/or victimization.

[Psychiatric care for asylum seekers in Geneva: a multidisciplinary approach for individualized care]

Asylum seekers constitute a vulnerable population insofar as they are submitted to numerous stress factors which facilitate the emergence of mental disorders, such as low socio-economic status, forced separation from loved ones and exposure to violence. Asylum seekers who consult at our community psychiatry facility usually have short-term residence permits, live in collective housing and do not speak the local language. The most frequent diagnoses are depressive disorder (64.7%) and post-traumatic stress disorder (34.5%). Due to their specific clinical and social situation and to the involvement of several professionals in these situations, a specialized psychiatric intervention coordinated with the rest of the network seems necessary.

Liver kidney microsomal type 1 antibodies reduce the CYP2D6 activity in patients with chronic hepatitis C virus infection

Liver kidney microsomal type 1 (LKM-1) antibodies have been shown to decrease the CYP2D6 activity in vitro and are present in a minority of patients with chronic hepatitis C infection. We investigated whether LKM-1 antibodies might reduce the CYP2D6 activity in vivo. All patients enrolled in the Swiss Hepatitis C Cohort Study and tested for LKM-1 antibodies were assessed (n = 1723): 10 eligible patients were matched with patients without LKM-1 antibodies. Patients were genotyped for CYP2D6 variants to exclude individuals with a poor metabolizer genotype. CYP2D6 activity was measured by a specific substrate using the dextromethorphan/dextrorphan metabolic ratio to classify patients into four activity phenotypes. All patients had a CYP2D6 extensive metabolizer genotype. The observed phenotype was concordant with the CYP2D6 genotype in most LKM-negative patients, whereas only three LKM-1 positive patients had a concordant phenotype (six presented an intermediate and one a poor metabolizer phenotype). The median DEM/DOR ratio was sixfold higher in LKM-1 positive than in LKM-1 negative patients (0.096 vs. 0.016, P = 0.004), indicating that CYP2D6 metabolic function was significantly reduced in the presence of LKM-1 antibodies. In chronic hepatitis C patients with LKM-1 antibodies, the CYP2D6 metabolic activity was on average reduced by 80%. The impact of LKM-1 antibodies on CYP2D6-mediated drug metabolism pathways warrants further translational studies.

Mindfulness-based cognitive therapy for bipolar disorder: a feasibility trial

BACKGROUND

The present open study investigates the feasibility of Mindfulness-based cognitive therapy (MBCT) in groups solely composed of bipolar patients of various subtypes. MBCT has been mostly evaluated with remitted unipolar depressed patients and little is known about this treatment in bipolar disorder.

METHODS

Bipolar outpatients (type I, II and NOS) were included and evaluated for depressive and hypomanic symptoms, as well as mindfulness skills before and after MBCT. Patients' expectations before the program, perceived benefit after completion and frequency of mindfulness practice were also recorded.

RESULTS

Of 23 included patients, 15 attended at least four MBCT sessions. Most participants reported having durably, moderately to very much benefited from the program, although mindfulness practice decreased over time. Whereas no significant increase of mindfulness skills was detected during the trial, change of mindfulness skills was significantly associated with change of depressive symptoms between pre- and post-MBCT assessments.

CONCLUSIONS

MBCT is feasible and well perceived among bipolar patients. Larger and randomized controlled studies are required to further evaluate its efficacy, in particular regarding depressive and (hypo)manic relapse prevention. The mediating role of mindfulness on clinical outcome needs further examination and efforts should be provided to enhance the persistence of meditation practice with time.

Self- and clinician-rated Montgomery-Asberg Depression Rating Scale: evaluation in clinical practice

BACKGROUND

Time- and cost-effective self-rating scales of depressive symptoms are particularly valuable for frequent use in large-scale effectiveness trials. The aim of the present study was to examine the psychometric properties of the French version of the self-rated Montgomery-Asberg Depression Rating Scale (MADRS-S) and determine whether it might complement the MADRS in monitoring depression severity and change over time in routine clinical practice.

METHODS

Sixty-three adult outpatients with a current depressive episode completed the MADRS-S and were interviewed with the MADRS on two occasions, within a 1-month interval.

RESULTS

All patients readily accepted the MADRS-S. It showed good to excellent internal consistency (Cronbach's alpha 0.85 at Time 1; 0.94 at Time 2). Its factor structure revealed that a single component explained a large proportion of variability (47.0% at Time 1; 68.8% at Time 2). Concurrent validity of the self- and clinician-rated versions was good (Pearson's correlation coefficients for total scores 0.81 at Time 1; 0.91 at Time 2). The MADRS-S was sensitive to change over the 4-week observation period (correlation of 0.71 between change scores on self- and clinician-rated instruments).

LIMITATIONS

Generalizability is restricted to outpatients with moderate to severe depression, and the MADRS-S ability to measure treatment effects needs to be examined.

CONCLUSIONS

The present study indicates that the MADRS-S displays favourable psychometric properties and suggests that it might be a valid complement to the MADRS, both in research settings and clinical practice.

[Current topics in pharmacokinetics and pharmacogenetics of antidepressant drugs]

For antidepressants as well as for other drugs, personalized prescription has become a major challenge, provided the large interindividual variability encountered both at the pharmacokinetic and the efficacy and tolerance levels. Better identification of the numerous relevant factors and quantification of their effects are prerequisites to progress in that direction. On the basis of recent literature, genetic factors are first reviewed, including polymorphisms of genes coding for drug-metabolizing enzymes, transporters and pharmacodynamic target molecules. Current recommendations with respect to therapeutic drug monitoring of antidepressants and use of pharmacogenetic testing are then summarized.

Frequency of dysphoria and mixed states

BACKGROUND

Mixed states are a complex entity in the field of mood disorders. Dysphoria has been advocated as an important clinical dimension of mixed states. The objective of this work is to study the frequency of dysphoria within a population of patients with DSM-IV major depressive and/or manic episodes and to determine if it may help establish diagnostic criteria for subthreshold cases of depressive or manic mixed states.

SAMPLING AND METHODS

A total of 165 patients were assessed using the Mini International Neuropsychiatric Interview complemented by a section defining dysphoria as a constellation of 3 among 4 symptoms (inner tension, irritability, aggressive behavior and hostility).

RESULTS

When classifying patients according to the number of symptoms of the opposite polarity, changes in the frequency of dysphoria revealed a clear contrast between the 2 opposite manic and depressive poles and the full mixed state (DSM-IV definition). The frequency of dysphoria was 17.5% in pure depression, 22.7% in pure mania and 73.3% in full mixed state. Two threshold effects were identified: (1) the frequency of dysphoria increased from 17.5 to 61.1% (p = 0.002) when the number of manic symptoms in DSM-IV depressed patients increased from 0 to 1, and (2) dysphoria increased from 14.3 to 69.2% (p = 0.057) when the number of depressive symptoms increased from 2 to 3 in DSM-IV manic patients.

CONCLUSION

Dysphoria is strongly but not necessarily associated with mixed states. When used as a clinical marker for mixed states, dysphoria confirms the modern delimitations of sub-threshold mixed states by specifying the required number of symptoms of the opposite polarity (which could be lower for depressive mixed states than for manic mixed states). The study has limitations related to the inclusion of patients who are not drug-free, to the definition of dysphoria and to the sample size.

Phenomenology of mixed states: a principal component analysis study

OBJECTIVES

To contribute to the definition of external and internal limits of mixed states and study the place of dysphoric symptoms in the psychopathology of mixed states.

METHODS

One hundred and sixty-five inpatients with major mood episodes were diagnosed as presenting with either pure depression, mixed depression (depression plus at least three manic symptoms), full mixed state (full depression and full mania), mixed mania (mania plus at least three depressive symptoms) or pure mania, using an adapted version of the Mini International Neuropsychiatric Interview (DSM-IV version). They were evaluated using a 33-item inventory of depressive, manic and mixed affective signs and symptoms.

RESULTS

Principal component analysis without rotation yielded three components that together explained 43.6% of the variance. The first component (24.3% of the variance) contrasted typical depressive symptoms with typical euphoric, manic symptoms. The second component, labeled 'dysphoria', (13.8%) had strong positive loadings for irritability, distressing sensitivity to light and noise, impulsivity and inner tension. The third component (5.5%) included symptoms of insomnia. Median scores for the first component significantly decreased from the pure depression group to the pure mania group. For the dysphoria component, scores were highest among patients with full mixed states and decreased towards both patients with pure depression and those with pure mania.

CONCLUSIONS

Principal component analysis revealed that dysphoria represents an important dimension of mixed states.

A stepwise drug treatment algorithm to obtain complete remission in depression: a Geneva study

QUESTIONS UNDER STUDY/PRINCIPLES

We describe the proportion of severely depressed outpatients reaching complete remission at the different stages of a drug treatment algorithm. We compare several treatment options for SSRI (selective serotonin reuptake inhibitor) non-responders and test the feasibility of the algorithm in clinical conditions.

METHODS

Patients with severe depressive disorders (ICD-10; MADRS > or = 25) admitted to an academic outpatient clinic were enrolled in this algorithm-guided sequential treatment protocol (starting with an SSRI and ending with a tricyclic, lithium, triodothyronine combination). The general principle of the algorithm was to boost the drug therapy in the event of non-response.

RESULTS

135 patients entered the study and 131 were eligible for analysis. From this group, 86 patients dropped out (65.6%), 40 reached complete remission (30.5%) and 5 patients did not reach remission at all (3.8%). In the 117 patients to whom a last observation carried forward approach was applied, the median improvement of the MADRS score was 48.0% (range -20.7%-100%), with 48.7% of patients considered responders, 23.1% partial responders and 28.2% non-responders. Median retention time was 8 weeks (range 2-34).

CONCLUSIONS

This algorithm-guided antidepressant treatment was acceptable for clinicians and resulted in an elevated final response rate among study completers. However, the dropout rate was high, mainly due to treatment interruption or non-observance.

A stepwise drug treatment algorithm to obtain complete remission in depression: a Geneva study

QUESTIONS UNDER STUDY/PRINCIPLES

We describe the proportion of severely depressed outpatients reaching complete remission at the different stages of a drug treatment algorithm. We compare several treatment options for SSRI (selective serotonin reuptake inhibitor) non-responders and test the feasibility of the algorithm in clinical conditions.

METHODS

Patients with severe depressive disorders (ICD-10; MADRS > or = 25) admitted to an academic outpatient clinic were enrolled in this algorithm-guided sequential treatment protocol (starting with an SSRI and ending with a tricyclic, lithium, triodothyronine combination). The general principle of the algorithm was to boost the drug therapy in the event of non-response.

RESULTS

135 patients entered the study and 131 were eligible for analysis. From this group, 86 patients dropped out (65.6%), 40 reached complete remission (30.5%) and 5 patients did not reach remission at all (3.8%). In the 117 patients to whom a last observation carried forward approach was applied, the median improvement of the MADRS score was 48.0% (range -20.7%-100%), with 48.7% of patients considered responders, 23.1% partial responders and 28.2% non-responders. Median retention time was 8 weeks (range 2-34).

CONCLUSIONS

This algorithm-guided antidepressant treatment was acceptable for clinicians and resulted in an elevated final response rate among study completers. However, the dropout rate was high, mainly due to treatment interruption or non-observance.

Validation du Questionnaire de fonctionnement social (QFS), un autoquestionnaire mesurant la fréquence et la satisfaction des comportements sociaux d’une population adulte psychiatrique

INTRODUCTION

Although everyone working in routine mental health services recognizes the scientific and ethical importance to ensure that treatments being provided are of highest quality, there is a clear lack of consensus regarding what outcome domains to include, what measure of assessment to use and, moreover, who to question when assessing.

LITERATURE FINDINGS

Since the fifties, social functioning is considered as an important dimension to take into account for treatment planning and outcome measuring. But for many years, symptoms scales have been considered as sufficient outcome measures and social functioning improvement expected on the basis of symptoms alleviation. As symptoms and social adjustment sometimes appear relatively independent, no accurate conclusion concerning the patient's social functioning can so be driven on the basis of his clinical symptoms. More attention has then been directed toward the development of instruments specifically intended to measure the extent and nature of social functioning impairments observed in most psychiatric syndromes. Many of these instruments are designed to be completed by caregivers or remain time consuming and difficult to use routinely. Presently, in clinical practice, there is a need to rely on simple and brief instruments considering patients'perspective about their social adjustment as a function of time.

AIM OF THE STUDY

The aim of this study is to present a new instrument, the QFS, initially developed in order to assess social functioning in patients involved in group psychotherapy programs conducted in a specialist mental health setting, as well as its psychometric characteristics.

METHODOLOGY

It was designed to be completed in less than 10 minutes and the questions are phrased in a simple and redundant way, in order to limit problems inherent to illiteracy or language comprehension. The QFS is a 16 items self-report instrument that assesses both the frequency of (8 items) and the satisfaction with (8 items) various social behaviours adopted during the 2 weeks period preceding the assessment. It yields three separate indexes of social functioning, defined a priori and labelled "frequency", "satisfaction" and "global". The higher the scores, the better the social functioning. The QFS was administered to 457 subjects, aged between 18 and 65, including 176 outpatients (99 with anxious or depressive disorders, 25 with personality disorders and 52 with psychotic disorders) and 281 healthy control subjects.

RESULTS

No significant difference was found between patients and controls according to age or gender distribution. Acceptance rate was high (>95%). Moreover, the QFS was generally acceptable to the clinicians who used it. Internal consistency calculated for each index ranged from 0.65 to 0.83 (Cronbach alpha). Test-retest reliability, calculated within a 15 days time interval on a sample of 49 healthy controls, ranged from 0.69 to 0.71 (intraclass correlation coefficient). Discriminant validity was calculated on healthy controls and patients divided into sub-groups according to their diagnosis. It showed to be excellent, with significantly higher scores in control subjects than in psychiatric patients and significant differences across diagnostic categories (Kruskal-Wallis ANOVA with post-hoc tests, all p<0.05). The convergent validity of the QFS with other measures of social functioning was calculated, using the Social Adaptation Self-Evaluation Scale (SASS) and the Social Adjustment Scale Self-Report (SAS-SR). With the SASS, the convergent validity was higher among patients (Spearman rS 0.71 to 0.92, p<0.01) than controls (rS from 0.49 to 0.66, p<0.001). In healthy controls, correlation with the SAS-SR was moderate but statistically significant (rS from - 0.21 to - 0.44, p<0.05). When comparing QFS scores with self-rated symptoms severity, lower levels of social functioning were significantly associated with more severe symptoms according to the Brief Symptom Inventory (BSI: rS from - 0.38 to - 0.65, p<0.001). The QFS indexes demonstrated sensitivity to change (Wilcoxon: all p<0.05) on a sample of 27 out-patients suffering from anxious-depressive disorders questioned before and after 4 months of cognitive behavioural group therapy running on a weekly basis during 16 sessions of 2 hours each.The factorial validity of the QFS was measured through 3 separate factor analysis conducted using the data of 457 subjects. The first analysis considered only Frequency items; 7 out of 8 items had loadings above 0.5 on Factor 1 accounting for 30.7% (unrotaded) of the variance. The second analysis considered only Satisfaction items; all items had loadings above 0.6 on Factor 1 explaining 43.4% (unrotaded) of the variance. And finally, in the third factor analysis, all QFS items were included; 15 out of 16 items had loadings above 0.4 on Factor 1 accounting for 30% (unrotated) of the variance. Concerning the factorial validity of the instrument, these results suggest that all QFS items belong to the same underlying dimension.

DISCUSSION

Finally, provisional norms for the QFS are provided for healthy controls, in order to characterise individual patients or patient subgroups. In conclusion, the need for assessment in clinical routine, in order to estimate different aspects of patients conditions as well as the quality of the treatment provided, has contributed to the development of a large variety of instruments measuring several domains. Concerning the level of social functioning, many instruments fail to meet chief criterion of feasibility, remaining often too complex or time onsuming. Moreover, only few of them are available in French.

CONCLUSION

The QFS presented here is a brief, simple and easy to administer self-rating scale that displays satisfactory psychometric properties. It seems to be a valuable instrument for the monitoring of social functioning in psychiatric patients which, from a therapeutic point of view, may have a clear impact as it sets up expectation of change and allows both to reality test patients and therapists beliefs about the presence of progress or not and to identify if therapy is working on this specific outcome domain. Though, to date, the administration of the QFS to other populations and treatment modalities requires further investigation.

Olanzapine plasma level in relation to antimanic effect in the acute therapy of manic states

The aim of this study was to evaluate internal as well as external validity of the two most frequently used mania scales, the Young Mania Rating Scale (YMRS) and the Bech-Rafaelsen Mania Scale (MAS), in patients with DSM-IV mania. Mokken analysis was used to evaluate internal validity in which a coefficient of homogeneity of 0.40 or higher indicates that the total score is a sufficient statistic. The external validity was evaluated by plasma-level relationship of olanzapine. In total, 20 patients with DSM-IV mania were analysed, and the coefficient of homogeneity was acceptable for the MAS, but not for the YMRS. In a subgroup of females who over 2 weeks had received a fixed dose of 20 mg olanzapine daily, a significant association was found between MAS scores and plasma levels, but this association was not obtained with the YMRS. In conclusion, the MAS was found superior to the YMRS in regard to both internal and external validity.

A novel water-soluble cyclosporine A prodrug: ocular tolerance and in vivo kinetics

The purpose of this study is to demonstrate that a novel water-soluble prodrug of cyclosporine A (CsA) intended for topical ocular administration, does not induce eye irritation in a rabbit model and is able to generate therapeutic concentrations of CsA in the precorneal area immediately after administration. The eye irritancy of the prodrug and CsA control solution was assessed by the Draize test and by confocal laser ophthalmoscopy (CLSO). Residence time and tear concentrations of prodrug and CsA in the rabbit eye were assessed by HPLC. The Draize test showed an excellent tolerance for the prodrug solution while the reference CsA oil solution induced lachrymation and irritation. The CLSO-measured corneal lesions, subsequent to treatment with the prodrug and reference solutions, were 3% and 9%, respectively. The prodrug transformed rapidly, leading to relatively stable CsA concentrations in tears with a maximal concentration of 94 microg ml(-1) over the observation period. This study demonstrated that the prodrug solution was well tolerated and that clinically significant CsA tear concentrations were achieved. UNIL088 is a promising molecule in the treatment of immune-related disorders of the eye.

[Translation and validation of a French version of the Young Mania Rating Scale (YMRS)]

Both the Young Mania Rating Scale (YMRS) and the Mania Assessment Scale (MAS) have been widely used during the last decade for the evaluation of severity of mania in clinical trials. For both scales good inter-rater reliability, validity and sensitivity to change have been reported. The French version of the MAS has been validated. To our know-ledge, the YMRS has not yet been translated into French and validated. The main objective of the present study was to validate a French version of the YMRS and to test its use in manic patients entering a study on the effectiveness of valproic acid and olanzapine combination. After translating the items in French, we tested this version of the YMRS on two samples of psychiatric patients recruited in a ward of adult inpatients (18 to 65 Years old) at the Department of Psychiatry, Geneva University Hospital. The first sample included 18 (hypo) manic inpatients (10 males, 8 females). Mean age was 37.0 (standard deviation 10.1). Interviews were video taped and assessed by three different judges on both scales (YMRS and MAS). The second sample included 20 inpatients (5 males, 15 females) who provided written informed consent to enter a study on the association of valproic acid and olanzapine in the treatment of mania. Mean age was 40.0 (standard deviation 11.3). Patients were followed over four weeks and assessed on both scales (YMRS and MAS) every seven days (day 0, 7, 14, 21 and 28). On day 7, patients were assessed during a joint interview by two of three judges who independently administered both scales in permuted order. On days 0, 14, 21 and 28, patients were evaluated by one of the same three raters. Inter-rater reliability was assessed by comparing item scores and total scores assigned by different judges with intra-class correlation coefficient ICC (2,1). Three judges were considered for patients in sample 1. Two judges were considered for patients in sample 2 (day 7 assessment). Concurrent validity with the MAS was analysed in sample 2 on days 0, 7, 14, 21 and 28 using Spearman rank-order correlation coefficient. Sensitivity to change was assessed in sample 2 by comparing total score at inclusion and at last observation using Wilcoxon signed ranks test. For both the MAS and YMRS, intraindividual change was calculated as the difference between total scores at inclusion and discharge (last observation carried forward approach). The relationship between changes on the two scales was analysed through Spearman correlation coefficient. Significance level was set to 0.05 for each test. Ranges of YMRS total scores were 2 to 32 in sample 1 and 1 to 28 in sample 2, indicating symptom severity from euthymic to moderately manic. Inter-rater reliability was very good for the total scores in both samples, both for the MAS and the YMRS (ICC>0.89). When considering YMRS individual items, correlation coefficient varied from 0.61 to 0.96 in the first sample. In the second sample, 9 of 11 items displayed values above 0.63. The remaining two items, increased motor activity and energy and Language-thought disorder, presented modest inter-rater reliability (ICC=0.54 and 0.50 respectively). This was largely attributable to a single patient, who was perceived very differently by the two judges (scores 0-2 for increased motor activity and energy; 1-4 for Language-thought disorder). When this patient was excluded, intra-class correlation coefficients were above 0.69 for both items. Overall, inter-rater reliability of the YMRS items was in the same range as for the MAS items (0.61-0.96 vs 0.61-0.93 in sample 1; 0.50-0.93 vs 0.54-0.83 in sample 2). Correlation between the two instruments was very high and statistically significant at each weekly assessment (rs>0.91, p<0.001) except for day 21 which displayed a somewhat lower correlation (rs=0.75, p<0.01). This latter result was attributed to a reduced spread of values and number of patients on day 21. YMRS and MAS total scores as a function of time in patients receiving combined treatment with olanzapine and valproic acid (sample 2) show that for both at for both scales, total scores significantly decreased from day 0 to last observation (Wilcoxon signed ranks test, p<0.001), with median decrease of 18 points both on the YMRS (range 9-32) and MAS (range 10-33). Median relative decrease was 67% for the YMRS and 69% for the MAS. When analysing the relationship between intraindividual changes on the YMRS and MAS, highly significant correlation was observed (Spearman rs=0.93, p<0.001), showing that the two scales were virtually interchangeable in assessing treatment efficacy. In conclusion, the YMRS is a simple and easy-to-use instrument for measuring severity of manic symptoms The newly translated French version was satisfactory in terms of inter-rater reliability, concurrent validity with the MAS, and sensitivity to change in patients receiving treatment for manic symptoms. This should allow its future use for international comparison studies.

Therapeutic drug monitoring databases for postmarketing surveillance of drug-drug interactions

Drug-drug interactions can be associated with patient morbidity due to either increased toxicity or a potentially ineffective concentration. Because interactions cannot always be anticipated during drug development and actual patients receiving a drug for therapeutic use often differ from those included in clinical trials, postmarketing surveillance is essential. Therapeutic drug monitoring (TDM) databases offer a unique opportunity in this respect. Prerequisites for TDM databases to provide valid information in a pharmacoepidemiological perspective include the following: precise description of exposure to the potentially interacting drugs; measurement of parent compound and active metabolites through accurate and precise analytical techniques; documentation of relevant patient characteristics that may act as confounding factors (e.g. gender, age, smoking habits); repeated assessments over time if possible; and sound pharmacokinetic framework for data selection, analysis and interpretation. The contribution of TDM to the documentation of drug-drug interactions takes advantage of different possible study designs, discussed on the basis of recently published studies. The single case report plays an important role as an alert signal. It is illustrated for a patient on long-term treatment, who displayed an unexpectedly high clozapine concentration after the introduction of ciprofloxacin comedication. The prospective on and off comedication panel study shows advantages in terms of carefully selected inclusion criteria and control of treatment modalities. A study of the thioridazine-fluvoxamine interaction is presented, with patients followed on thioridazine monotherapy, after introduction of fluvoxamine and after its discontinuation. The main advantage of the retrospective large-scale TDM database screen is representativeness of patients actually treated, whereas drawbacks are related to quality of data and suitability for valid interpretation. Such an approach is illustrated by a review of data collected over 10 years of routine TDM that allowed documenting induction of nortriptyline metabolism by carbamazepine and inhibition by several phenothiazines. Finally, population pharmacokinetics is well suited to observational data collected for TDM purpose, provided quality is ascertained. Focus is placed on interindividual variability and relationship between pharmacokinetic parameters and patient characteristics, including comedication. The population approach is discussed with respect to a study that documented a 32% increase of haloperidol clearance associated with anticonvulsant comedication, in addition to effects of age and bodyweight. Among factors to consider for improved effectiveness in the use of TDM databases for postmarketing surveillance of drug-drug interactions, integration of efficacy and safety data in future studies and communication of expert recommendations to prescribing physicians are essential.

Population pharmacokinetics of clomipramine, desmethylclomipramine, and hydroxylated metabolites in patients with depression receiving chronic treatment: model evaluation

Because metabolites play a major role in the clinical response to clomipramine, the objective of the current study was to develop a population model and evaluate its performance to describe the pharmacokinetic profiles of clomipramine (C) and its active metabolites desmethylclomipramine (DC), 8-hydroxy-clomipramine (OHC) and 8-hydroxy-desmethylclomipramine (OHDC). A first sample of 14 patients served for development of a 2-molecule C and DC model, which was shown to provide reasonable estimates of AUC-based clearances, as well as precise estimation of interindividual variability. Simulated data, generated to mimic a semi-rich sampling design and chronic treatment with clomipramine, indicated that clearance estimation was feasible under routine treatment conditions. A second sample of 30 patients, recruited prospectively and followed for a median 4-week period, was used to extend the 2-molecule model to a 4-molecule model. Goodness-of-fit assessment revealed that model-predicted concentrations were reasonably close to observed concentrations for a majority of patients. Interindividual variability was 50% to 60% for hydroxylation and desmethylation clearances, and residual variability was 30%. The proposed model incorporates much of what is known about the metabolism of clomipramine and may valuably integrate the influence of genetic and environmental factors on each metabolic pathway.

Modelling during drug development

With the advancement of both biological and computer sciences, new drug development faces the challenge to integrate a huge amount of knowledge accumulated from the very early quantitative structure-activity relationship investigations of the candidate molecule to the large scale clinical trials in patients. Whereas pharmacokinetics and pharmacodynamics are fields in which modelling has long demonstrated its value, its potential in many other areas of drug development has recently been the object of intensive scientific activity. The present review places emphasis on these newer applications; it includes the opinion of many experts in often highly specialised areas such as in vitro to in vivo extrapolation, toxicokinetics, non-continuous response models, population approaches and computer assisted simulation of clinical trials. It is most probable that in the near future many of these areas of research will be the objects of intensive and interesting developments. This will undoubtedly lead to improve developmental strategies for new drugs as well as more individualised pharmacological strategies for patients.

Development of validated stereoselective methods for methadone determination in clinical samples

A stereoselective analysis of methadone (Mtd) in whole blood and serum was developed using liquid chromatography on a protein based chiral stationary phase. Liquid-liquid extraction (LLE) and solid phase extraction methods were applied before chromatographic analysis. The extraction procedure, as well as the choice of the biological matrix, showed significant differences in the extraction yield and in the precision of the assays. Serum was selected for this assay and LLE was chosen as the preparation step because of its simplicity and rapidity. The total procedure was validated and applied to clinical samples. Samples taken from 45 heroin-addicted patients were analyzed. A correlation was found between the dose administered and Mtd concentration (total and R-form), but interindividual variability of the total normalized Mtd was seen (concentration varied from 90 to 530 ng/ml). Furthermore, two populations were apparently observed with a mean Mtd concentration of 200 and 475 ng/ml, respectively. Stereoselective analyses showed that more than 50% of the patients presented a nonracemic ratio, and particularly about 25% showed a preferential metabolism of the active R-Mtd enantiomer. Therefore, the stereoselective determination of Mtd is necessary to improve the quality of the treatment of heroin addiction.

Clomipramine concentration as a predictor of delayed response: a naturalistic study

OBJECTIVES

The aim of the present study was to characterise onset of response to clomipramine treatment in a naturalistic setting and to investigate the relationship between concentration and delayed response, postulated to reflect drug-specific response to antidepressant therapy.

METHODS

Ninety-eight depressed patients were prescribed clomipramine in an open flexible manner and followed for depressive symptoms (Montgomery-Asberg depression scale) over a maximum 12 weeks follow-up period. All patients had at least one concentration measurement for therapeutic drug monitoring purpose.

RESULTS

Firstly, survival analysis revealed a probability of 15.4% for patients not to show 50% improvement over baseline by week 12, and thus to be considered as non-responders. Median time to onset of response was 31 days for responders, indicating a relatively high probability of delayed response under routine treatment. Secondly, pattern analysis indicated a significant association between early and abrupt response on the one hand and delayed and gradual response on the other. A tendency towards an association between delayed and persistent response was also observed. Finally, receiver operating characteristics analysis allowed identification of a highly significant lower threshold of 230 ng x ml(-1) for the sum of clomipramine and desmethyl-clomipramine, as measured at week 3, with respect to response from week 3 onward. Predictive values were 68.8% and 81.0% for concentrations above and below this threshold to predict delayed response and non-response, respectively. Thresholds were 55 ng x ml(-1) for parent compound and 180 ng x ml(-1) for metabolite.

CONCLUSION

This approach supports the hypothesis that delayed response may be concentration dependent and thus may reflect true drug effect. As a consequence, monitoring clomipramine concentration about 3 weeks after initiation of therapy may valuably contribute to help clinicians decide about the adequacy of ongoing therapy.

Therapeutic drug monitoring of risperidone using a new, rapid HPLC method: reappraisal of interindividual variability factors

Because of the enormous gap between premarketing studies in physically healthy subjects and clinical practice in patients, the present study reconsidered interindividual variability factors affecting risperidone concentrations under routine therapeutic drug monitoring conditions. The study included 92 patients, 27% of whom were 70 years or older. The patients received risperidone orally (dose range, 0.5-11 mg per day) and had concentrations of risperidone and the active metabolite 9-hydroxyrisperidone measured at steady state by a new, rapid, and sensitive method of high-performance liquid chromatography (HPLC). After normalization to a dose of 4 mg/day, median concentrations were 2.9 ng/ml (80% range, 0.9-27.9 ng/ml) for the parent compound and 24.1 ng/ml (80% range, 12.0-57.6 ng/ml) for the metabolite. When considering linear regression models, age was identified as a major source of interindividual variability, with expected increases of 340% and 220% for concentrations of parent compound and metabolite, with age increasing from 20 to 80 years. Body weight provided an additional significant contribution to the variability of 9-hydroxyrisperidone concentration, a 20-kg higher body weight associated with a concentration decrease of 23%. Serotonin-specific reuptake inhibitor (SSRI) comedication (fluoxetine, two patients; citalopram, two patients; paroxetine, one patient; fluvoxamine, one patient) was significantly associated with 4.6-fold higher concentrations of parent compound, in keeping with an inhibitory action on CYP2D6 enzyme. Significantly higher concentrations of 9-hydroxy-risperidone (+ 29%) were also observed in the 17 patients with biperiden comedication. Therapeutic drug monitoring data, collected in patients representative of the population for which the drug was intended, allowed us to quantify the dose reduction needed in elderly patients and thus provided valuable information in addition to the one collected during premarketing studies performed with strict inclusion and exclusion criteria.

Comparative pharmacokinetic study of a floating multiple-unit capsule, a high-density multiple-unit capsule and an immediate-release tablet containing 25 mg atenolol

The purpose of this study was to evaluate the possible advantages of floating and high-density dosage forms and their influence on pharmacokinetic parameters. Atenolol was chosen as a model drug because of its poor absorption in the lower gastrointestinal tract. Three formulations containing 25 mg atenolol, a floating multiple-unit capsule, a high-density multiple-unit capsule, and an immediate-release tablet were compared with respect to estimated pharmacokinetic parameters. The two multiple-unit dosage forms were composed of compressed minitablets and had sustained release properties. The bioavailability of the two gastroretentive preparations with sustained release characteristics was significantly decreased when compared to the immediate-release tablet. The floating minitablets seemed to be retained longer in the stomach than the high-density dosage form. The first atenolol concentration detectable in the plasma and the time to peak Tmax were delayed for the floating dosage form. For the parameters Cmax and AUC 0-infinity, the lower limit of the 90% confidence interval was outside the bioequivalence range (0.80-1.25). This study showed that it was not possible to increase the bioavailability of a poorly absorbed drug such as atenolol using gastroretentive formulations. Atenolol absorption was delayed and the maximum plasma concentration was diminished.

Optimized release of dexamethasone and gentamicin from a soluble ocular insert for the treatment of external ophthalmic infections

In the case of external ophthalmic infections, repeated instillations of antibiotics are required to reach therapeutic level, above the minimal inhibitory concentration (MIC). An additional administration of a corticosteroid is often needed, in order to limit the precorneal damages caused by the infection. However, repeated administration of a corticosteroid can increase intraocular pressure and thus lead to glaucoma. To overcome the disadvantages of separated and repeated instillations of two products and to avoid the side effects of dexamethasone, a soluble insert containing gentamicin sulfate and dexamethasone phosphate was developed. The new system ensures the concomitant release of the two drugs during the first 10 h of treatment, followed by an adequate concentration of gentamicin sulfate, above the MIC of 4.0 microgram ml-1, during 50 h, due to a combination of gentamicin sulfate with cellulose acetate phthalate, which reduces the solubility of gentamicin.

Therapeutic drug monitoring databases for postmarketing surveillance of drug-drug interactions: evaluation of a paired approach for psychotropic medication

The present study investigated the potential of therapeutic drug monitoring data to document pharmacokinetic drug interactions with psychotropic medication, both in terms of methodology and applicability. It focused on 105 patients exposed to one of five agents known for their capacity to induce (phenytoine, phenobarbital, and carbamazepine) or to inhibit (thioridazine and levomepromazine) the metabolism of psychotropic drugs. These patients were matched by gender, age, and monitored psychotropic medication to 105 patients randomly selected from a pool of subjects nonexposed to target comedication. Such a paired approach was shown to be effective in reducing variability for a majority of substances. Power analysis suggested that eight to 10 pairs of exposed and nonexposed patients would effectively allow the detection of twofold effects of interacting substances. In keeping with the literature, analysis of the ratios of dose-normalized exposed to nonexposed concentrations indicated that phenothiazine comedication led to significantly higher concentrations of desmethylated metabolites but not parent compounds, when clomipramine, imipramine, or amitriptyline were administered. A similar, as yet undocumented interaction was observed for the tetracyclic antidepressant mianserine. In contrast, the present study revealed that maprotiline concentrations were increased, but its metabolite was largely unaffected by phenothiazine comedication. Increased concentrations were also observed for moclobemide, but not citalopram or its metabolite. In addition to its long recognized capacity to decrease haloperidol concentrations, carbamazepine was shown to induce the metabolism of clopenthixol and possibly flupenthixol. The consistency of such a picture substantiates the need to consider therapeutic drug monitoring databases as cost-effective and reliable tools for postmarketing surveillance.

Therapeutic drug monitoring and drug-drug interactions: a pharmacoepidemiological perspective

The present study investigates the potential of therapeutic drug monitoring databases to document co-medication as a possible risk factor for subtherapeutic or excessively high concentrations of psychotropic drugs. Exposure was defined with respect to co-medication including one of five agents known for their capacity to induce (phenytoin, phenobarbital and carbamazepine) or to inhibit (thioridazine and levomepromazine) the metabolism of psychotropic drugs. 87 patients exposed to such co-medication were matched by sex, age and monitored psychotropic medication with 87 patients randomly selected from a pool of subjects whose co-medication did not include any substance known to interact. Outcome was defined with respect to dose-normalized concentrations being below or above therapeutic range. When taking all psychotropic drugs together, the estimated relative risk to reach concentrations above the therapeutic range was 7.8 for patients exposed to phenothiazine co-medication. The relative risk to remain at subtherapeutic level was 2.7 for patients with inducers. When considering the different psychotropic drugs separately, a coherent picture was observed, with increased risk ratios for all substances.

Drug metabolism as a confounding factor in PK/PD population approaches

Pharmacokinetic/pharmacodynamic population approaches aim at establishing relationships between dose, drug concentration of active principles and clinical response, accounting for factors responsible for inter-individual variability. Additional difficulties in the presence of metabolites include the need to decide a priori which metabolites should be monitored according to their respective role in efficacy and/or toxicity, the need to select appropriate selective analytical methods, and the requirement for more complex pharmacokinetic and/or pharmacodynamic models. These points are discussed more extensively for psychotropic drugs, and in particular for the active metabolites of phenothiazines, for reduced haloperidol, for the desmethylated and hydroxylated metabolites of tricyclic antidepressants, and for the desmethyl metabolites of the serotonin-specific reuptake inhibitors fluoxetine and citalopram.

Basis for dosing time-dependent changes in the ocular and systemic absorption of topically applied timolol

The objective of the present study was to determine the basis for dosing time-dependent changes in the ocular and systemic absorption of topically applied timolol in pigmented rabbits. The gamma scintigraphic technique was used to monitor the changes in precorneal solution retention following instillation. Changes in timolol concentration in the plasma over 120 min and in various anterior segment eye tissues at 30 min following the topical instillation of 25 microliters of 0.65% timolol maleate solutions at various dosing times were monitored using reversed phase HPLC. Corneal and conjunctival permeability at various dosing times was evaluated in the modified Ussing chamber. The results indicated that precorneal solution drainage was slowest at noon. Suppressing tear production by anesthesia led to an increase in ocular timolol absorption at 6 a.m. but not at other dosing times, in spite of the lowest corneal permeability then. There was no statistically significant dosing time influence on systemic timolol absorption following nasal or conjunctival dosing. In conclusion, possible diurnal changes in precorneal solution clearance may be the main factor underlying the diurnal changes in ocular as well as systemic timolol absorption in rabbits. In addition, diurnal changes in corneal permeability may also contribute to diurnal changes in ocular timolol absorption.

Ocular availability of gentamicin in small animals after topical administration of a conventional eye drop solution and a novel long acting bioadhesive ophthalmic drug insert

PURPOSE

Gentamicin eye drop solutions have a short precorneal residence time. The present study investigates the effect of gentamicin using a new long acting delivery Bioadhesive Ophthalmic Insert (BODI) in healthy dogs and rabbits and compares the results with a conventional regimen using an eye drop solution.

METHODS

In vivo assays were performed on animals after deposition of one BODI and instillations of an eye drop solution. Tear samples were collected over 72 hours and 60 minutes, in the case of inserts and eye drop solution respectively. The gentamicin concentration profiles in tear fluid (determined by a fluorescent polarization immunoassay technique) was individually analyzed, in each animal, in relation with the minimum inhibitory concentration observed in vitro against some bacteria. A non classical pharmacokinetic approach was used for the analysis of the topically applied drug substance, involving two parameters: the efficacy area under the curve (AUCeff) and the efficacy time (teff).

RESULTS

In the case of the eye drop solution, the AUCeff were higher in dogs (2.80 10(3) - 3.64 10(3) [micrograms ml-1 h]) than in rabbits (0.64 x 10(3) - 0.95 x 10(3) [micrograms ml-1 h]); the teff had a similar behavior: 6-15 [h] in dogs and 2-6 [h] in rabbits. In the case of BODIs, the AUCeff and the teff were quite similar between dogs and rabbits: 190 10(3) - 205 10(3) [micrograms ml-1 h] and 70-76 [h], respectively. The AUCeff and the teff were always much higher in the case of BODIs than for the eye drop solution both in dogs and rabbits.

CONCLUSIONS

This study shows that topical administration of gentamicin using BODIs can improve treatment due to the decreasing number of applications while ensuring an effective level of antibiotic in tears controlled by the device.

Potential of concentration monitoring data for a short half-life drug: analysis of pharmacokinetic variability for moclobemide

The pharmacokinetic variability of moclobemide, a new short half-life reversible selective inhibitor of monoamine oxidase (MAO) was investigated through analysis of concentrations measured during early open clinical use. Eighty-nine depressed patients, aged 21-96 years, were included in the present study. Doses ranged from 200 to 900 mg/day, and the time interval between blood sampling and last drug intake on the previous day was between 8 and 23 h. Intraindividual variability was generally moderate, with a few patients displaying consistently high concentrations despite moderate doses. Interindividual variability for measured concentrations was approximately 300-fold. After concentration decrease with time was taken into account (average half-life estimate of 4.6 h), age was identified as a major factor responsible for between-patient variability. Average concentration increase per decade of age was 38%. Neither gender, weight, height, smoking, nor alcohol intake explained a significant additional part of the variance. Analysis of residuals also suggested that phenytoin co-medication may induce moclobemide metabolism. The present study indicates that concentration monitoring of a newly marketed drug can contribute to gaining insight into its pharmacokinetic behavior and to enhancing its rational use in clinical practice.

Clomipramine therapy in the geriatric hospital: experience with therapeutic drug monitoring

Sixty-nine patients, aged 63-98 years and admitted at the Geneva Geriatric Hospital, were included in the present retrospective study. They received clomipramine orally, 50 or 75 mg/day. Blood concentrations of clomipramine were measured as part of a routine drug monitoring program. Comparison with a reference population of patients aged < or = 65 years indicated that elderly patients with concomitant somatic diseases reach higher dose-normalized concentrations of clomipramine and increased parent drug to demethylated metabolite ratios, as a consequence of impaired demethylation (approximately 50%) and hydroxylation (approximately 25%). Sixty-five percent of patients showed clinical improvement, with a maximum rate of satisfactory response observed in major depression. Severe side effects, such as symptomatic hypotension or confusion, were seen in 20% of patients. Because of 10- and 15-fold interindividual variations in the concentrations of clomipramine and its metabolite, respectively, therapeutic drug monitoring can provide valuable assistance to clinical judgment in individual dose adjustment for patients whose old age, associated somatic diseases, and comedication necessitate additional precautions.

Crisis intervention in depressed patients with and without DSM-III-R personality disorders

We compared the relationships between response to a crisis intervention program and long-term outcome in 31 depressed outpatients with and without DSM-III-R personality disorders (PD). The presence of PD predicted a poorer 2-year outcome. PD subjects with better working alliance and increased insight at termination of crisis intervention had increased compliance with long-term psychiatric treatment (p < .005) and better 2-year outcome (p < .005). Increased compliance with long-term psychiatric treatment predicted better long-term outcome in PD patients (p < .005). None of these significant relationships was observed in the comparison group without PD, suggesting that establishing an effective treatment process may be especially important for outcome in PD patients.

Persistent impairment of clomipramine demethylation in recently detoxified alcoholic patients

The purpose of the present study was to investigate whether the metabolism of clomipramine is altered by chronic alcohol drinking. Eleven recently detoxified alcoholic patients were included (experimental group EG) and compared to a reference group of patients with no history of alcoholism (reference group RG, n = 102). Blood concentrations of clomipramine and its metabolites were measured as part of the routine drug monitoring program. Clearances were estimated from trough concentrations, according to a model developed previously. Results indicate strong inhibition of demethylation clearance in group EG, when compared to group RG (median values 9.9 and 24.2 L/h), with significant increase of the clomipramine to desmethylclomipramine ratio (median values 1.00 and 0.36). No difference was found for hydroxylation. In addition, high correlation is observed between hydroxylation and demethylation clearances in group EG (Spearman rs = 0.82), but not in reference group RG (rs = 0.29). Follow-up data indicate that impairment of demethylation capacity can persist for several weeks or months after withdrawal from alcohol. The interest of calculating clomipramine to desmethylclomipramine ratios during routine drug monitoring is emphasized, values of 1 or larger often being associated with liver disease and/or alcohol-related problems.

Clinical pharmacokinetics of clomipramine

Clomipramine is a tricyclic antidepressant medication widely used in Western Europe. Its pharmacokinetics have been studied essentially in healthy volunteers. By combining published information obtained during observational studies, it has been possible to derive a fairly precise picture of the behaviour of both parent compound and main metabolite (demethyl-clomipramine) in humans. Clomipramine can be compared with amitriptyline or imipramine so far as its physicochemical properties are concerned. As a consequence, its pharmacokinetic profile is also similar to that observed for these 2 drugs. Clomipramine is well absorbed from the gastrointestinal tract, but undergoes an important first-pass metabolism to demethyl-clomipramine which is pharmacologically active and participates in both therapeutic and unwanted effects. Protein binding is high, and the apparent volume of distribution is very large (i.e. greater than 1000L). After reaching the systemic circulation, clomipramine is further biotransformed into demethyl-clomipramine, and both active principles are hydroxylated to metabolites which are further conjugated before being excreted in urine. Hydroxylation of parent drug and metabolite is under polymorphic genetic control by the same cytochrome P450 as debrisoquine and sparteine. The apparent elimination half-life of clomipramine is about 24h and that of demethyl-clomipramine, 96h. Accordingly, the time to reach steady-state for both active moieties is in general around 3 weeks. Various pathological or environmental factors influence the behaviour of clomipramine and demethyl-clomipramine. Patients genetically deficient in hydroxylation accumulate demethyl-clomipramine at high concentrations that can produce serious side effects and/or nonresponse. The same is true for the coadministration of neuroleptics, in particular phenothiazines. Smoking induces demethylation, whereas long term alcohol intake appears to reduce this metabolic pathway. Finally, age usually diminishes both demethylation and hydroxylation, leading to a lower daily dose of clomipramine in most elderly patients. Studies relating blood concentrations of clomipramine and demethyl-clomipramine are conflicting. However, analysis of the available information indicates that blood concentrations lower than 150 micrograms/L are usually associated with nonresponse, whereas those above 450 micrograms/L seldom lead to an improvement in the efficacy of therapy. As a consequence clomipramine, like the other tricyclics, is an antidepressant with a fairly narrow therapeutic range. This property, combined with a high interindividual variability, makes this class of drugs ideal candidates for blood concentration monitoring.

Physiological pharmacokinetic modelling

1. The different types of models are described, with emphasis on the clearance-based one-compartment model, and on full physiological models which distinguish between a number of anatomical compartments interconnected through the body fluid system. 2. The clearance-based, one-compartment model incorporates physiological concepts, such as apparent volume of distribution, systemic availability, hepatic and renal clearance. As opposed to the classical rate constant-based model, it allows a study of the influence of plasma protein binding, hepatic intrinsic clearance and blood flow. The advantages of such an approach are illustrated in two typical situations, namely renal insufficiency and saturable protein binding. 3. In full physiological models each compartment represents a particular organ or tissue, further divided into vascular, interstitial and cellular spaces. Mass balance equations are written for each of these subcompartments. Shortcomings of such comprehensive models include difficulty in collecting tissue data, especially human, and sophisticated numerical techniques needed for parameter estimation. The main advantages are specific organ metabolism and transport, and the possibility of scaling up from animal to human. 4. The pharmacokinetic parameters important for new drug registration are also listed.

Clomipramine metabolism. Model-based analysis of variability factors from drug monitoring data

A steady-state model is here developed as a framework for the analysis of blood concentrations of clomipramine, obtained during routine drug monitoring. A model is proposed to account for its major metabolic pathways, hydroxylation and demethylation, including first-pass effect. Impaired hydroxylation capacity is shown to lead to a dramatic increase in the concentration of demethyl-clomipramine, with a concomitant moderate increase in that of the parent drug. Deficient demethylation capacity is associated with a reduced ratio of demethyl metabolite to parent drug. A nomogram is provided to allow easy determination of hydroxylation and demethylation capacities from routinely measured blood concentrations. Data from 150 patients are analysed in order to identify interindividual variability factors. Average pseudo-clearances, calculated from trough blood concentrations at steady-state, are 17 L/h for hydroxylation, 23 L/h for demethylation and 40 L/h for elimination of hydroxylated metabolites. Maximum to minimum ratios are 8, 27 and 11, respectively. The metabolising capacity through either process significantly decreases with increasing age, clearance estimates being 40 to 50% lower for patients 75 years or older than for those 40 years or younger. Tobacco smoking and chronic alcohol consumption induce and reduce the demethylation clearance, respectively. Inhibition of hydroxylation in the presence of phenothiazine comedication is also shown. Finally, small but significant differences according to sex are observed. Potential implications of the proposed model-based approach include adaptation of the dosage regimen to individual characteristics at the very beginning of antidepressant therapy, and early detection of patients with impaired metabolising capacities.

Identifying weak signals in the presence of noise: a new method of locating potential ligand contact residues in immunoglobulin-related molecules

We develop and apply a new method for estimating the locations of hypervariable residues in immunoglobulin-related molecules. The method differs from the standard introduced by Wu and Kabat in two essential ways: (1) we take explicit account of the type of substitution at a given position, rather than just the total number of substitutions, and (2) we use an explicit statistical decision criterion for classifying a site into either the complementarity determining or framework category. Simulations indicate that the method is reliable with relatively little data, approximately 5% of the sites being misclassified when 10 sequences are aligned. The method is applied to immunoglobulin light chains and to class 1 and class 2 products of the major histocompatibility complex.

Clinical and pharmacokinetic evaluation of zuclopenthixol acetate in Viscoleo

The purpose of the present study was to evaluate zuclopenthixol acetate in Viscoleo, a new preparation to be administered once every 3 days, in the early treatment of acute psychotic episodes and acute deterioration of chronic psychosis. 21 cases were included in the study: patients received 1 to 3 injections. Clinical evaluation was made at 24, 48 and 72 hours after each injection, using the Clinical Global Impressions (CGI) and the Brief Psychiatric Rating Scale (BPRS). Results at end-point indicated a marked or moderate therapeutic effect in the 11 cases of acute psychosis. A statistically significant decrease was observed for the total BPRS score as well as for its subscales. Among 8 cases of exacerbation of chronic psychosis, 4 patients showed a moderate therapeutic effect, and minimal or no effect was found in the other 4 subjects. The total BPRS decreased significantly, but to a lesser extent than for acute psychosis. Two patients suffering from mania showed a moderate therapeutic effect according to CGI. 8 cases of acute psychosis and 5 cases of chronic psychosis did not suffer from any neurological side-effects. Plasma concentration measurements suggest that a dose of 50 mg per 3 days may be sufficient for early treatment of most acutely ill psychotic patients.

Multivariate analysis of dietary patterns in 939 Swiss adults: sociodemographic parameters and alcohol consumption profiles

A dietary survey of 939 Swiss adults, randomly selected from the population of Geneva and its surrounding communities, was performed according to the history method. A factor analysis, using average weekly intakes for 33 food variables, reveals three principal components of the diet: satiating capacity, healthfulness and culinary complexity. These characteristics, together with the energy content of the diet, were analysed for differences according to sex, age, relative weight index, birthplace, marital status and occupation. All of these sociodemographic variables influence some dimension of dietary habits. Alcohol consumption is positively associated with satiating, protein rich diets, but energy intake from foods does not significantly differ between various groups of abstainers and drinkers. Although the energy contribution of alcoholic beverages is globally additive, we suggest that cultural and societal norms may modulate the relationship of alcohol and diet.

Stereoselective disposition of flupentixol: influence on steady-state plasma concentrations in schizophrenic patients

Steady-state plasma concentrations of cis(Z)-flupentixol (active principle) and trans(E)-flupentixol (inactive) were measured in 41 patients at least on one occasion. Results indicate that concentrations of the trans-isomer are significatively higher. This demonstrates that the two isomers are not handled in the same way by the organism. This may be relevant if plasma level monitoring is performed using non-specific analytical methods.

[The contribution of alcohol to nutrition: addition or substitution according to cultural origins]

The relation of alcohol intake to diet is analyzed through multiple linear regression for a sample of 475 males living in Geneva. Control variables are age, relative weight index, marital status and employment status. Whereas alcohol is associated with higher dietary intake for people of mediterranean origin, it tends to replace food calories for natives of german speaking areas.

Regulation of interacting populations during endocytosis: models of growth factor-tumor promoter dynamics

A model of growth factor-cell receptor interactions, including internalization, sorting, recycling, and degradation and their modulation by tumor promoters, is developed, analyzed, and tested. In keeping with data and concepts based on a large number of systems, the main assumption is that after receptor-ligand binding the complex associates with a second membrane protein, localized in coated pits, and that this event is a necessary condition for receptor-mediated endocytosis and subsequent intracellular processes. As a consequence of the model, ligands having distinct receptors interfere at the cell surface through competition between their receptor complexes for a limited pool of coated pit proteins. The utility of the model is illustrated by a detailed analysis of binding, endocytosis, and degradation of epidermal growth factor (EGF) and their modulation by phorbol esters. The analysis permits quantitative characterization of the dynamics of the endocytic processes and leads to the following conclusions. The Scatchard plot changes from linear to nonlinear as the ratio of the number of coated pit proteins to the number of receptors decreases. Competition between phorbol ester and EGF-bound receptors for coated pit proteins predicts, in agreement with observation, conversion of nonlinear EGF Scatchard plots to linear plots subsequent to reincubation with phorbol esters. The postulated competition suggests a local homology between the phorbol ester receptor and the EGF receptor. Homologous and heterologous downregulations observed in numerous systems are natural consequences of the model. Preincubation with the heterologous ligand increases the time lag between ligand binding and lysosomal degradation and alters intracellular sorting.

Receptor-mediated endocytosis: a model and its implications for experimental analysis

We present a mathematical model for analyzing, simulating, and quantitating the dynamic and steady-state characteristics of receptor-mediated endocytosis. The basic processes considered by the model are ligand-receptor binding, diffusion of receptors and ligand-receptor complexes in the plane of the membrane toward and away from coated pits, binding of ligand-receptor complexes to coated pit proteins, endocytosis of coated pit contents, degradation of ligand, and recycling of undegraded receptors. The model accounts quantitatively for a wide variety of kinetic data and makes new predictions about steady-state characteristics. We show that for homogeneous receptors the slope of the Scatchard plot is not necessarily constant but can have a positive or negative derivative, depending on the concentration of coated pit proteins and their reactivity. This finding suggests that binding data, which show linear and concave curves, might be explainable be a simple coated pit-related mechanism. Similarly the relationship between the x-intercept and the number of receptors is also affected by kinetic parameters controlling endocytosis. We briefly discuss these results in terms of possible mechanisms for the action of tumor promoters, the large variations in receptor number and affinity in the literature, and methods for quantitative characterization of parameters.