paroxetine, Paxil
Psychopharmacological treatment of depression, anxiety, irritability and insomnia in patients receiving interferon-alpha: a prospective case series and a discussion of biological mechanisms.

Maddock C, Baita A, Orru MG, Sitzia R, Costa A, Muntoni E, Farci MG, Carpiniello B, Pariante CM.

Maudsley Hospital, London, UK.

We studied 60 patients receiving a 1-year course of interferon (IFN)-alpha therapy for chronic viral hepatitis. Patients underwent psychiatric assessment before starting the IFN-alpha therapy, and monthly throughout the therapy, using the Structured Clinical Interview for the DSM-III-R, the 17-item Hamilton Depression Rating Scale, the Beck Depression Inventory and the Spielberg State and Trait Anxiety Inventory. Five patients had a baseline diagnosis of major depression and 18 (30%) developed an IFN-alpha-induced psychiatric adverse effect; 12 of these 23 patients received psychopharmacological treatment (patients and clinicians jointly decided the need for treatment). Two of the five patients with baseline depression started an antidepressant treatment (paroxetine) together with the IFN-alpha and successfully completed the IFN-alpha therapy. Ten patients received treatment for the IFN-alpha-induced psychiatric adverse effects (depression in five patients, anxiety in two patients, severe irritability in two patients and insomnia in one patient). Depression was treated with paroxetine, amisulpride or levosulpiride; anxiety and insomnia were treated with benzodiazepines; and irritability was treated with thioridazine. Individual response to medications was measured with the Clinical Global Impression scale. Of the patients with IFN-alpha-induced depression, two received paroxetine (one showed a good response), two received amisulpride (one showed a good response) and one did not respond to levosulpiride but responded to paroxetine. The patients experiencing anxiety or insomnia responded well to benzodiazepines. One patient showed a good response, and one a poor response, to thioridazine for irritability. Only one patient interrupted the therapy because of psychiatric adverse effects. Overall, the 12 patients that received psychopharmacological treatment developed less severe psychopathological symptoms during the IFN-alpha therapy compared to the 11 patients who had untreated baseline depression or untreated IFN-alpha-induced psychiatric adverse effects. Thus, psychopharmacological management can successfully treat psychiatric symptoms in patients who are receiving IFN-alpha.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15107183&dopt=Abstract paroxetine, Paxil, Paxil CR



paroxetine, Paxil
Possible in vivo 5-HT reuptake blocking properties of 8-OH-DPAT assessed by measuring hippocampal extracellular 5-HT using microdialysis in rats.

Assie MB, Koek W.

Neurobiology Division II, Centre de Recherche Pierre Fabre, Castres, France.

1. The 5-hydroxytryptamine (5-HT)1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), has been shown to label 5-HT reuptake sites. 2. To study the functional consequences of this property, the effects of 8-OH-DPAT were compared with those of the 5-HT reuptake inhibitors, paroxetine and clomipramine, and of the 5-HT1A receptor agonist flesinoxan, in vitro on 5-HT reuptake, and in vivo on the extracellular concentration of 5-HT by use of microdialysis, in rat hippocampus. Because 5-HT reuptake inhibitors reportedly attenuate the ability of (+)-fenfluramine to increase the extracellular concentration of 5-HT, the possible reversal of these effects of 8-OH-DPAT and by paroxetine were examined. 3. 8-OH-DPAT, paroxetine and clomipramine inhibited [3H]-5-HT reuptake in rat hippocampal synaptosomes (pIC50: 6.00, 8.41 and 7.00, respectively). In contrast, flesinoxan did not alter 5-HT reuptake (pIC50 < 5). 4. 8-OH-DPAT (10 and 100 microM), paroxetine (0.1 microM) and clomipramine (1 microM), administered through the dialysis probe, significantly increased the hippocampal extracellular concentration of 5-HT. In contrast, flesinoxan (100 microM) did not alter extracellular 5-HT. Moreover, the effects of 100 microM 8-OH-DPAT were not blocked by the 5-HT1A receptor antagonist, WAY-100635 (0.16 mg kg-1, s.c.). 5. The increase in extracellular 5-HT induced by 10 mg kg-1, i.p., (+)-fenfluramine was prevented not only by 0.1 microM paroxetine, but also by 100 microM 8-OH-DPAT. In addition, systemic administration of 10 mg kg-1, but not 2.5 mg kg-1, i.p. 8-OH-DPAT attenuated the increase in extracellular 5-HT induced by 2.5 mg kg-1, i.p., (+)-fenfluramine. 6. These findings suggest that the increase in extracellular 5-HT produced by local administration of 8-OH-DPAT does not involve its 5-HT1A receptor agonist properties, but may result, at least in part, from its 5-HT reuptake blocking properties.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8922730&dopt=Abstract paroxetine, Paxil, Paxil CR



paroxetine, Paxil
Paroxetine shifts imipramine metabolism.

Albers LJ, Reist C, Helmeste D, Vu R, Tang SW.

Psychiatry Service, Long Beach Veterans Affairs Medical Center, CA 90822, USA.

The combination of selective serotonin reuptake inhibitors with tricyclic antidepressants has proven useful in treatment-resistant depression but has the potential for adverse drug-drug interactions. In the present study, the metabolism of a single dose of imipramine was studied before and after treatment with paroxetine. Paroxetine induced significant elevations of approximately 50% in half-life, area under the curve, and Cmax of imipramine and decreased clearance twofold. The effects on desipramine pharmacokinetics were even more pronounced. These findings indicate a significant interaction of paroxetine with the CYP2D6 isoenzyme.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8930024&dopt=Abstract paroxetine, Paxil, Paxil CR



paroxetine, Paxil
A comparison of the post-marketing safety of four selective serotonin re-uptake inhibitors including the investigation of symptoms occurring on withdrawal.

Price JS, Waller PC, Wood SM, MacKay AV.

Post-Licensing Division, Medicines Control Agency, Vauxhall, London, UK.

1. We have addressed the question of whether there is a 'serotonin withdrawal syndrome' by analysis of spontaneous reports of suspected adverse drug reactions (ADRs) associated with four SSRIs. A comparison of the post-marketing safety profiles of the four SSRIs has also been made. 2. The UK database of ADRs was examined for reactions associated with fluoxetine, fluvoxamine, paroxetine and sertraline. The safety profiles of the four SSRIs were similar. However, withdrawal reactions with paroxetine constitute a greater proportion of reports (5.1%) than with the other SSRIs (0.06-0.9%). They have been reported more often with paroxetine (0.3 reports per thousand prescriptions) than with sertraline and fluvoxamine (0.03), and least often with fluoxetine (0.002). 3. Descriptions of withdrawal reactions received and further details of 217 reports of withdrawal reaction with paroxetine obtained by mailing a questionnaire to the reporting doctor were examined. Withdrawal symptoms were diverse but most commonly comprised dizziness, paraesthesia, tremor, anxiety, nausea and palpitation. They usually occurred after 2 days and lasted for an average of 10 days. There was no evidence of a physical drug dependency syndrome. 4. Symptoms different from the previous depressive illness occur after discontinuing an SSRI, and are reported most often with paroxetine. Paroxetine is the most pharmacologically specific of the SSRIs, but it is not clear whether the reactions constitute a 'serotonin withdrawal syndrome'.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8971432&dopt=Abstract paroxetine, Paxil, Paxil CR



paroxetine, Paxil
Paroxetine is a novel nitric oxide synthase inhibitor.

Finkel MS, Laghrissi-Thode F, Pollock BG, Rong J.

Department of Medicine (Cardiology), University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center, PA, USA.

The selective serotonin reuptake inhibitor, paroxetine, has been reported to inhibit cytochrome P450 activity. Nitric oxide synthase (NOS) is structurally homologous to cytochrome P450. Accordingly, in our study, we observed the effects of paroxetine on NOS activity. Seventeen ischemic heart disease (IHD) patients received paroxetine and fourteen received nortriptyline for treatment of clinical depression defined by a score of 17 or higher on the Hamilton Rating Scale for Depression (HAM-D). Serum nitrite and nitrate levels were significantly decreased following paroxetine treatment but not nortriptyline treatment. Paroxetine was also a more potent inhibitor of NOS enzyme activity than nortriptyline, as measured by the conversion of [14C] arginine to [14C] citrulline by hamster brain cytosols. In addition, paroxetine reversed the force-frequency relationship in isolated hamster papillary muscles in a manner analogous to that of known NOS inhibitors. Thus, paroxetine appears to be a novel NOS inhibitor in vitro and in vivo.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8993087&dopt=Abstract paroxetine, Paxil, Paxil CR



paroxetine, Paxil
Lower 3H-paroxetine binding in cerebral cortex of suicide victims is partly due to fewer high affinity, non-transporter sites.

Mann JJ, Henteleff RA, Lagattuta TF, Perper JA, Li S, Arango V.

Department of Neuroscience, New York State Psychiatric Institute, NY, USA.

Suicide has been associated with decreased serotonin transmission. Measurement of concentrations of serotonin, its precursors tryptophan (TRY) and 5-hydroxytryptophan (5-HTP) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), have been used as indices of serotonin activity, and with serotonin transporter binding, are indices of the integrity of serotonin nerve terminals. Most previous studies have not distinguished high affinity transporter binding from a very similar nontransporter binding site, where binding is not dependent on Na+ or Cl- and that does not have a known functional role. We therefore, assayed binding kinetics in prefrontal (PFC) and temporal cortex (TC) in matched pairs of suicide victims and controls using the selective ligand 3H-paroxetine, and employing 1 microM sertraline to define specific binding to the transporter and 10 microM sertraline which also displaces binding to the high affinity, nontransporter site. In addition, we measured concentrations of TRY, 5-HTP, serotonin and 5-HIAA in the same brain areas. The total number of 3H-paroxetine transporter and nontransporter binding sites (Bmax), was lower in the suicide group compared to controls in both Brodmann area 9 (prefrontal cortex; p = 0.02) and in Brodmann area 38 (temporal cortex, p = 0.01). In contrast, no differences were found in the number of high affinity transporter binding sites and concentrations of serotonin, 5-HIAA, 5-HTP or TRY (p > 0.05). We conclude that the number of serotonin transporter sites is not altered in Brodmann area 9 in suicide, and that fewer 3H-paroxetine and 3H-imipramine binding sites found in this region of cerebral cortex of suicides may be explained by a reduction in the nontransporter binding sites.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9013420&dopt=Abstract paroxetine, Paxil, Paxil CR



paroxetine, Paxil
The treatment of depression with paroxetine in psychiatric practice in Germany: the possibilities and current limitations of drug monitoring.

Zaninelli R, Meister W.

Department of Clinical Research, SmithKline Beecham Pharma GmbH, Munich, Germany.

A drug monitoring of the antidepressant paroxetine was carried out in Germany from August 1992 to November 1993. The principal aim of this study was to collect demographic, diagnostic, efficacy, and medical-safety data regarding patients who were treated for up to 12 weeks with this SSRI. A secondary goal was the investigation of differences between patients who left treatment after 6 weeks or earlier and those who continued treatment. Evaluable data were obtained from 507 psychiatrists for 2817 patients, 1301 of whom extended treatment beyond 6 weeks. 64% of the patients had been pretreated for the current episode of depression. 50% were considered by their doctors to have either chronic or recurrent illness and 92% to possess moderate to severe symptomatology. Concomitant psychotropic medication was reported in 43% of cases, the most frequent medications being benzodiazepines, neuroleptics, and/or tricyclic antidepressants. Clear or complete improvement was noted for 63% of assessable patients by the end of week 6 and for 79% of the patients who extended treatment to 12 weeks. There were significantly more patients with DSM major depression and severe symptoms in the treatment-extender than in the 6-week treatment group. Paroxetine was tolerated well by most patients: of the 1009 adverse events reported, only 17 were considered "serious". There were no suicides or cases of overdose attributable to paroxetine. The discussion of these results is the basis for a critical appraisal of postmarketing-surveillance methodology. It is concluded that, despite its present structural weaknesses as compared to controlled investigations, drug monitoring of a new medication in the immediate postmarketing period can give insights into the treatment of large numbers of patients under private-practice conditions. However, drug monitoring as it is conducted in Germany can have different and perhaps conflicting functions which may limit its effectiveness. The authors recommend that all interested parties (physicians, the pharmaceutical industry, regulatory bodies) engage in a continuous dialog aimed at clearly formulating the goals and improving the methodology of drug monitoring.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9035223&dopt=Abstract paroxetine, Paxil, Paxil CR