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Biomedical subjects

P Bizouard

Publications and source records attributed to P Bizouard.

At least 19 recordsLinked to original sources
PubMed2000

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.

Adult↗
PubMed2000

[Pertinence of the addiction concept in eating behavior disorders].

From a psychodynamic perspective, dependence disorders, irrespective of the object of addiction, can be seen as the expression of the subject's neurobiological, psychopathological, cultural and social vulnerability. Since vulnerability strengthens and reorganizes the personality, it can drive these subjects to perpetuate pathological behaviors. In this light, behavior disorders belong to the field of addiction diseases, especially considering that the underlying psychopathological structures are close to those observed in addiction, that depression plays a central role, and that their development into toxic addictive behavior (drugs, alcohol, psychotrope) is frequent.

Adolescent↗
PubMed1999

Drug extrapyramidal side effects. CYP2D6 genotypes and phenotypes.

OBJECTIVE: Among Caucasians, a lack of cytochrome P450 enzyme CYP2D6 is observed in 5-10% of individuals, named poor metabolizers (PMs). A consequence may be an impaired metabolism of many drugs such as most of the psychotropic drugs with an increased risk of drug side effects. This enzyme is also involved in the metabolism of endogenous compounds, including neurotransmitters such as dopamine and dopamine-related neurotransmitters which play a role in the mechanism of action of extrapyramidal drug side effects. The present study investigates whether patients who have developed and those who have not developed extrapyramidal drug side effects differ in their CYP2D6 genotypes and phenotypes. METHODS: The CP2D6 genotype (method involving restriction length fragment polymorphism and polymerase chain reaction-single strand conformation polymorphism) was determined in 65 drug-treated in-patients, and the CYP2D6 phenotype (with dextromethorphan probe) in 62 of them. Two groups were constituted, one with 22 patients who had developed extrapyramidal drug side effects, and the second with 43 patients without such side effects. RESULTS: In the whole population, there was an over-representation of PM phenotypes--more marked in the first group than the second (45% vs 14%). Concerning the genotypes, we observed that the percentage of functional alleles (with extensive metabolic capacity) was higher in group 2, whereas the percentage of nonfunctional alleles (without metabolic activity) was higher in group 1; this frequency difference was only marginally significant (chi 2 5.95; P < 0.0509; degrees of freedom = 2). Consequently, there was a higher percentage of genotypes with no (extensive) functional alleles in the group of patients suffering from extrapyramidal side effects than in the other group (P < 0.00001). CONCLUSION: CYP2D6-impaired metabolic capacity may be a contributory factor in extrapyramidal drug side effects.

Adolescent↗
PubMed1999

Citalopram: an interaction study with clomipramine in a patient heterozygous for CYP2D6 genotype.

A pharmacokinetic interaction between the selective serotonin reuptake inhibitor citalopram and a tricyclic antidepressant, clomipramine, was noted in a patient treated for major depression and obsessive-compulsive disorder. After the addition of citalopram, a desmethylclomipramine plasma level increase and an 8-hydroacy-desmethylclomipramine plasma level decrease were observed. The CYP2D6 phenotype, determined when the patient received the antidepressant comedication, characterized a poor metabolizer status (dextromethorphan metabolic ratio >0.3), despite a heterozygous genotype containing a wild-type allele with extensive metabolic capacity and a mutant non-functional allele (CYP2D6*1A/CYP2D6*4A). This case seems to be one of the first descriptions of the clinical relevance of a CYP2D6 heterozygous genotype in a patient treated with antidepressant.

Adult↗
PubMed1997

Tricyclic antidepressant-induced extrapyramidal side effects.

Two cases of tricyclic antidepressant-related extrapyramidal side effects are reported and, the authors review the literature describing these effects. Despite clear case reports, these side effects are not well known. Given the wide prescription of tricyclic antidepressants (TCA) and the low number of case reports, the prevalence of these side effects is indeed low, but clinical implications exist. The extrapyramidal symptoms induced by TCA alone are acute or tardive dyskinesia, akathisia, myoclonus, rabbit syndrome and dystonia. These symptoms seem to be non age-related, but often dose-related, and were responders to antiparkinsonian agents or propranolol. The factors that predispose an individual to the development of these side effects are not completely understood. Some risk factors such as prior exposure to neuroleptics and/or lithium or estrogens could facilitate the development of these side effects. In some cases, they can disappear even though the same dose of TCA is continued, and they do not seem to be a drug class reaction. The susceptibility of each individual patient to the development of these disorders may be limited to only one or a few of these agents.

Adolescent↗
PubMed1997

Paroxetine and galactorrhea.

The authors report a case of galactorrhea following antidepressant treatment where paroxetine might be responsible. Paroxetine is a selective serotonergic reuptake inhibitor (SSRI). Galactorrhea occasionally is a dopamine-mediated side effect observed with neuroleptic drugs. However, the ability to produce extrapyramidal side effects is known for tricyclic as well as for SSRIs. Thus the potential of SSRIs to induce dopamine-dependent side effects is a clinical reality and it was not surprising to observe galactorrhea due to paroxetine. However, in a review of the literature no reported cases of galactorrhea associated with paroxetine were found.

Adult↗
PubMed1997

[Indications for electroconvulsive therapy].

ECT, in which first experiments were made by the italian Cerletti more than half a century ago, underwent, in the seventies, a definite decline, as it was less and less applied to patients, a result of the influence of anti psychiatry. During the last fifteen years, there has been a legitimate renewal of the interest for this therapy; its indications seem now well codified and its techniques and practises have evolved considerably. Actually, in order to carry out ECT under general anaesthesia, it is necessary to have a pluridisciplinary team, assembling nurses, anaesthesists and psychiatrists that will use more and more effective appliances and adequate anaesthetics. Many of the parameters able to influence ECT's effectiveness are now well known and can be used and adapted according the individual characteristics of each patient. These parameters are: the lateralisation of the electrodes, the intensity of the electric current, the duration of the epileptic fit, the modification that appear in electroencephalography and the frequence of the sessions. According to different investigations, it seems that we must systematically question the medical treatments we associate to ECT. For instance, it is highly recommended not to prescribe with ECT benzodiazepines or antiepileptic mood stabilizers, while antidepressants or neuroleptics do not seem to exert any influence on the effectiveness of the treatment. Some authors think caffeine and triiodothyronin (T3) could have an interesting effect when combined with ECT. As to the indications of shock therapy, they can be now more and more precisely defined making of this treatment an indispensable instrument in the cure of depressive disorders. But ECT is also appropriate in maniac disorders once neuroleptic treatment has failed or else in the very beginning in highly acute cases, and mainly in mixed episodes for which medical treatment is often difficult to adapt. In schizophrenia, ECT can also be prescribed in definite circumstances as catatonia, paranoid states or schizoaffective episodes. Therefore, ECT constitutes a safe and comfortable therapy for the patient since its side effects are essentially characterized by cognitive disorders, and its main contraindications consist of severe cardiovascular diseases. ECT is also an essential tool in some definite cases.

Antidepressive Agents↗
PubMed1996

CYP 2D6 PM phenotype hypothesis of antidepressant extrapyramidal side-effects.

Extrapyramidal symptoms occur as side-effects of neuroleptics. For many years, case reports of such side-effects, linked to antidepressant treatments, have been published, but this phenomenon is not well known. Tricyclic and serotonergic antidepressants are both involved. The authors present an hypothesis which provides one possible neurobiochemical explanation for the aetiology of these side-effects. The proposed explanation is related to the inhibition of the CYP 2D6 isoenzyme by antidepressants (or neuroleptics) that may be involved in the genesis of the observed extrapyramidal side-effects.

Antidepressive Agents↗
PubMed1995

Fluvoxamine and fluoxetine: interaction studies with amitriptyline, clomipramine and neuroleptics in phenotyped patients.

The in vivo pharmacokinetic interaction between two selective serotonin reuptake inhibitors (SSRI) (fluvoxamine, fluoxetine) and tricyclic antidepressants (TCAs) (amitriptyline, clomipramine) or neuroleptics (haloperidol, cyamemazine, levomepromazine, propericiazine) was assessed in 29 in-patients. They were phenotyped twice with dextromethorphan and mephenytoin: first in steady state conditions while under treatment with TCAs or neuroleptics; and also 10 days after an associated treatment with fluvoxamine (150 mg day(-1)) or fluoxetine (20 mg day(-1)). A clear and statistically significant increase in the mean urinary metabolic ratio (MR) of dextromethorphan/dextrorphan and in the mean mephenytoin S/R ratio (S/R) was seen with the fluvoxamine and fluoxetine treatment. The mean MR increased from 0.13 to 0.27 (P<0.01) with fluoxetine and from 0.34 to 0.84 with fluvoxamine (P<0.05). The (dextromethorphan) 'extensive metabolizer' phenotype switched to the 'poor metabolizer' phenotype in six patients by the 10-day fluoxetine treatment, and in two patients by the fluvoxamine treatment. The mean S/R increased from 0.24 to 0.34 (P<0.05) with fluoxetine, and from 0.33 to 0.58 (P<0.002) with fluvoxamine. These results are in agreement with the observed modification of TCA plasma levels after the SSRI association. During fluvoxamine treatment, amitriptyline and clomipramine plasma levels (P<0.06 both) tendentially increased, and those of demethylclomiprarnine decreased (P<0.06). Fluoxetine addition lead to a significant increase (P<0.02) of the desmethylclomipramine plasma levels. Fluvoxamine induced a moderate augmentation of the plasma levels of haloperidol and its reduced metabolite and no change in the plasma levels of cyamemazine and levomepromazine. But patients treated with neuroleptics are to few to draw any firm conclusion. This study suggests, that fluoxetine and fluvoxamine differ in their interaction with the metabolism of some other basic psychotropic drugs, by a mechanism which implies CYP2D6 and CYPmeph and possibly other isoformes of cytochrome P-450. Moreover, the interactions produced varied with the TCA prescribed.

Adult↗
PubMed1994

[Value of plasma assays of psychotropic drugs].

An increased use of determinations of psychotropic drug levels has been noted during recent years. The contribution of "biological techniques" has led to a change in the relationship between physician and patient by rationalizing medical prescription and by augmenting the medical nature of this relationship. Follow-up of plasma levels is of interest for psychotropic drugs having therapeutic and (or) side effects that are linked to blood concentrations. Such drugs include the imipraminic antidepressants and regulators of thymic function. There is no consensus concerning the benzodiazepines and neuroleptic drugs. Their clinical effect does not seem to be strictly linked to plasma levels and the range of dosages is greater. Such determinations have proved to be particularly interesting in "resistant" cases, in surveillance of drug interactions and to evaluate treatment compliance.

Causality↗
PubMed1992

Tricyclic antidepressant plasma levels after fluoxetine addition.

After a review of a pharmacokinetic interaction between tricyclic antidepressants (TCA) and fluoxetine the authors report their own data. They confirm the existence of an interaction of TCA with fluoxetine, in clinical practice, but the fluoxetine was not associated in all cases with a marked increase of TCA plasma levels. The increase appeared especially high with clomipramine (n = 4) and imipramine (n = 3), and lower or dose-dependent with amitriptyline (n = 4). The pharmacokinetic change did not induce side effects in the patients, even when the total TCA plasma level increased to 965 (clomipramine) or 785 (imipramine) ng/ml. The authors then discuss the clinical implication and the possible mechanism of action.

Adult↗
PubMed1991

[Prediction of suicide risk].

Suicide is a great problem for public health. In France it causes more than 12,000 deaths every year, and it has been estimated that 45 to 70% of these subjects were suffering of affective disorders. Some epidemiological aspects of the links between suicide and depression are analytic and concern the risk factors of suicide among depressed patients: sociodemographic factors: risks are more important for men and for people living alone or suffering of social and affective isolation. Violent suicides increase with age; clinical and evolutive characteristics of the illness: the risk of suicide is correlated with the global severity of the depression, whatever are the nosographic subtypes, with anxiety, sleep disorders and anhedonia, with personal and familial history of suicide; among biological factors, a decrease of 5-HT transmissions has been implicated, but it seems to be more correlated with a modification of the ability to delay, with a poor impulse control. The association of several of these factors increases suicidal risk but it is impossible to describe a specific picture of the depressed suicidal patient, and clinical scales to estimate suicide risk are of limited interest. Finally, the clinical vigilance adapted to each individual case and the quality of the therapeutical relation remain the most important point for preventing suicide.

Causality↗