The selective serotonin reuptake inhibitor citalopram relieves the symptoms of diabetic neuropathy.

The effect of the selective serotonin reuptake inhibitor citalopram on diabetic neuropathy symptoms was examined in a double-blind, placebo-controlled, crossover study for two 3-week periods. Citalopram was given as a fixed dose of 40 mg/day. Data from 15 patients could be included in the statistical analysis. Citalopram significantly relieved the symptoms of neuropathy as measured by both observer- and self-rating in comparison with placebo. The steady-state plasma concentration of citalopram was 10 to 890 nmol/L. There was no significant relationship between the plasma concentration of citalopram and the effect of treatment as measured by observer- or self-rating. Two of 17 patients, both receiving citalopram, left the study because of side effects (nausea and vomiting or gastric upset and diarrhea). Side-effect ratings were significantly higher during administration of citalopram than during administration of placebo, but citalopram was generally well tolerated. Compared with earlier results obtained with imipramine administered on the basis of plasma level monitoring, citalopram appeared to be less effective, but seemed to be better tolerated.     

Comparison of citalopram and other selective serotonin reuptake inhibitor ingestions in children

Abstract

Context. In adults, citalopram is more likely to cause seizures and ECG changes than other selective serotonin reuptake inhibitors (SSRIs). Data in children are lacking, yet the 2007 American Association of Poison Control Centers out-of-hospital citalopram consensus guideline mirrors the guideline for other SSRIs. Objective. To compare the clinical effects and hazard index of citalopram with other SSRIs in pediatric ingestions. Methods. An 11-year retrospective analysis of national poison center data was conducted. Acute, known-type SSRI ingestions in children younger than 6 years with known outcome were included. Clinical effects and hazard index (number of major or fatal outcomes/1000 SSRI ingestions) were compared. Citalopram dose-response was evaluated. Results. The 35 296 included cases by SSRI type were citalopram (3747), escitalopram (4815), fluoxetine (5946), fluvoxamine (273), paroxetine (7157), and sertraline (13 358). The overall hazard index was 0.340. The hazard index for citalopram (0.801) was 2.8-fold higher than for non-citalopram SSRIs (0.285). Comparing seizures (single or multiple discrete) and cardiac effects (conduction disturbances, other ECG changes or other dysrhythmia) of citalopram with the other SSRIs, pediatric citalopram ingestions were more likely to develop seizures (5 of 3747 [0.13%] vs. 10 of 31 549 [0.03%], OR = 4.2; 1.4–12.3) and cardiac toxicity (9 of 3747 [0.24%] vs. 25 of 31 549 [0.08%], OR = 3.0; 1.4–6.5). Clinical effects occurring more frequently with other SSRIs included tachycardia (p = 0.0236), oral irritation (p = 0.0412), vomiting (p = 0.0036), agitation/irritability (p = 0.0104), and hyperthermia (p = 0.0314). There was a dose response only for single or multiple discrete seizures, mydriasis and clinically significant responses (a predetermined subset of CNS and cardiopulmonary clinical effects). Meaningful triage thresholds for citalopram could not be determined due to the low frequency of significant clinical effects. Conclusion. Children develop minimal toxicity with SSRI ingestions. Seizures and ECG changes, while uncommon, occur more frequently with citalopram. Doses associated with significant outcomes suggest that the triage guideline for citalopram does not need to be modified.     

The selective serotonin reuptake inhibitor paroxetine is effective in the treatment of diabetic neuropathy symptoms

The effect of the selective serotonin reuptake inhibitor paroxetine on diabetic neuropathy symptoms was examined in comparison to imipramine and placebo in a randomised, double-blind, cross-over study. Paroxetine was given as a fixed dose of 40 mg/day, while the dose of imipramine was adjusted to yield optimal plasma levels of imipramine plus desipramine of 400-600 nM. Paroxetine significantly reduced the symptoms of neuropathy as measured by both observer- and self-rating, but was somewhat less effective than imipramine. However, patients showing a weaker response to paroxetine than to imipramine had lower plasma concentrations of paroxetine than patients with similar response to the 2 drugs. On imipramine 5 patients dropped out because of intolerable side effects and 4 of 19 patients completing the study reported withdrawal symptoms after discontinuing imipramine. On paroxetine no patients dropped out due to side effects and no withdrawal symptoms were reported. Self-rating showed no depressive symptoms at baseline, and no changes during the study. Neither paroxetine nor imipramine caused changes in objective measures of peripheral nerve function. In conclusion, 40 mg paroxetine/day significantly reduced the symptoms in peripheral diabetic neuropathy, and it was suggested that by dose adjustment on the basis of drug level monitoring, paroxetine may become as effective as imipramine. Paroxetine was devoid of the often disturbing autonomic side effects limiting the use of imipramine in several patients.     

The serotonin uptake inhibitor citalopram attenuates ethanol intake

No effective drug for decreasing ethanol intake is available for clinical use. Our previous studies showed that zimeldine decreased ethanol intake in rats and nondepressed alcohol abusers. However, zimeldine was withdrawn from the market because of serious toxicity. We tested citalopram, a selective serotonin uptake inhibitor, in 39 male nondepressed early-stage problem drinkers (aged 19 to 61 years). Subjects were randomly allocated to receive either citalopram, 20 (n = 20) or 40 (n = 19) mg/day orally, or placebo in a double-blind, crossover trial. Citalopram administration and ethanol intake were assessed by self-report and objectively. Citalopram, 20 mg/day, did not show an effect. However, citalopram, 40 mg/day, decreased the number of drinks consumed (F1,17 = 5.27; P less than 0.05) and increased the number of abstinent days (F1,17 = 13.18; P less than 0.005). The effect is probably through modulation of the neurobiologic mechanisms regulating ethanol intake. Our results suggest a new pharmacologic approach to decrease ethanol intake.     

Pediatric ingestion of vilazodone compared to other selective serotonin reuptake inhibitor medications

Background: Unintentional ingestion of selective serotonin reuptake inhibitor (SSRI) medications is common amongst children <6 years of age. Current evidence-based management guidelines are based on a low incidence of significant medical outcomes in these children.

Objective: To describe and compare outcomes of pediatric exposures to vilazodone with other SSRIs.

Methods: A retrospective observational case series analysis of both single and polysubstance SSRI exposures amongst children <6 years old reported to the National Poison Data System (NPDS).

Results: 11,384 SSRI exposures in children <6 years of age reported to NPDS between January 2012 and June 2016 were assessed. Vilazodone only accounted for 5.9% of all exposures, but resulted in the highest proportion of health care facility admission compared to other SSRIs, both in single substance (165 of 531 (31.1%); OR 9.0 [7.3–11.2]) and polysubstance (57 of 107 (53.3%); OR 4.1 [2.7–6.2]) exposures. Children exposed to vilazodone also have higher odds of experiencing a major or moderate outcome in single (134 of 531 (25.2%); OR 20.5 [15.5–27.1]) and polysubstance (37 of 107 (35.6%); OR 5.9 [3.7–9.0]) exposures compared to other SSRIs. Several severe clinical outcomes, such as seizure and coma, were more common among the vilazodone exposures.

Conclusions: Exposure to vilazodone in this age group results in an increased rate of hospitalization as well as more severe clinical effects as compared to other SSRIs. Current evidence-based SSRI exposure management guidelines may not be appropriate for the management of vilazodone ingestion in this age group.     

Pharmacokinetics of selective serotonin reuptake inhibitors

The five selective serotonin reuptake inhibitors (SSRIs), fluoxetine, fluvoxamine, paroxetine, sertraline, and citalopram, have similar antidepressant efficacy and a similar side effect profile. They differ, however, in their pharmacokinetic properties. Under steady-state concentrations, their half-lives range between 1 and 4 days for fluoxetine (7 and 15 days for norfluoxetine) and between 21 (paroxetine) and 36 (citalopram) hr for the other SSRIs. Sertraline and citalopram show linear and fluoxetine, fluvoxamine, and paroxetine nonlinear pharmacokinetics. SSRIs underlie an extensive metabolism with high interindividual variability, whereby cytochrome P450 (CYP) isoenzymes play a major role. Therefore, resulting blood concentrations are highly variable between individuals. Except for N-demethylated fluoxetine, metabolites of SSRIs do not contribute to clinical actions. Therapeutically effective blood concentrations are unclear so far, although there is evidence for minimal effective and upper-threshold concentrations that should not be exceeded. Paroxetine and, to a lesser degree, fluoxetine and norfluoxetine are potent inhibitors of CYP2D6 and fluvoxamine of CYP1A2 and CYP2C19. This can give rise to drug-drug interactions that may have no effect, lead to intoxication, or improve the therapeutic response. These different pharmacokinetic properties of the five SSRIs, especially their drug-drug interaction potential, should be considered when selecting a distinct SSRI for treatment of depression or other disorders with a suggested dysfunction of the serotonergic system in the brain.     

中国人群5-羟色胺转运蛋白基因多态性与抑郁症及5-羟色胺摄取抑制剂类抗抑郁药治疗效果的关系

背景:研究发现在大脑中与情感和行为有关的皮质和边缘区域5-羟色胺转运蛋白的表达特别丰富。调节5-羟色胺能神经反应的强度和持久性改变大脑5-羟色胺能神经传递,同时5-羟色胺转运蛋白也是5-羟色胺摄取抑制剂的重要靶标。目的:观察南京地区人群中5-羟色胺转运蛋白基因多态性与血浆5-羟色胺浓度及5-羟色胺摄取抑制剂的临床疗效是否存在相关性。设计:病例-对照观察。单位:南京医科大学脑科医院精神科。对象:于2001-01/2003-12选择南京医科大学脑科医院精神科住院的抑郁症患者132例和健康志愿献血者100例作为观察对象。方法:采用聚合酶链式反应多态性分析技术对抑郁症患者和健康者进行基因型分析;采用高效液相电化学法分析血浆中5-羟色胺浓度;用汉密顿抑郁量表评定抗抑郁药的疗效。主要观察指标:两组5-羟色胺转运蛋白基因型频率和等位基因频率分析结果,5-羟色胺转运蛋白基因型与5-羟色胺摄取抑制剂治疗前后血浆5-羟色胺浓度的关系。结果:132例抑郁症患者和100例正常健康者均采集到血样,并完成量表测试,全部进入结果分析。①抑郁症5-羟色胺转运蛋白基因基因型频率与正常对照组基因型频率比较差异无显著性,[(LL24.2%,LS44.7%,SS31.1%),(LL29.0%,LS47.0%,SS24.0%),χ2=1.4058,P>0.05];等位基因频率与正常对照组比较差异无显著性[(L46.59%,S53.41%),(L52.5%,S47.5%),χ2=0.6962,P>0.05]。②不同基因型抑郁症患者治疗前汉密顿抑郁量表总分差异有显著性(F=6.48,P=0.0021);经4周5-羟色胺摄取抑制剂类抗抑郁药治疗后,汉密顿抑郁量表总分均显著下降,减分值差异有显著性(F=3.38,P=0.037)。③治疗前不同基因型患者5-羟色胺浓度差异有显著性(F=5.38,P=0.0057);4周治疗后,血浆中5-羟色胺浓度均升高,不同基因型的增高值差异有显著性(F=23.55,P<0.01)。结论:南京地区人群中5-羟色胺转运蛋白基因多态性与抑郁症的发病不存在相关性,但与抑郁症疾病严重程度和5-羟色胺摄取抑制剂治疗效应存在显著的相关性,这一区域的基因型可能成为抑郁症患者实现个体化治疗的一个参考指标。     

中国人群5-羟色胺转运蛋白基因多态性与抑郁症及5-羟色胺摄取抑制剂类抗抑郁药治疗效果的关系

背景：研究发现在大脑中与情感和行为有关的皮质和边缘区域5-羟色胺转运蛋白的表达特别丰富.调节5-羟色胺能神经反应的强度和持久性改变大脑5-羟色胺能神经传递,同时5-羟色胺转运蛋白也是5-羟色胺摄取抑制剂的重要靶标.目的：观察南京地区人群中5-羟色胺转运蛋白基因多态性与血浆5-羟色胺浓度及5-羟色胺摄取抑制剂的临床疗效是否存在相关性.设计：病例-对照观察.单位：南京医科大学脑科医院精神科.对象：于2001-01/2003-12选择南京医科大学脑科医院精神科住院的抑郁症患者132例和健康志愿献血者100例作为观察对象.方法：采用聚合酶链式反应多态性分析技术对抑郁症患者和健康者进行基因型分析;采用高效液相电化学法分析血浆中5-羟色胺浓度;用汉密顿抑郁量表评定抗抑郁药的疗效.主要观察指标：两组5-羟色胺转运蛋白基因型频率和等位基因频率分析结果,5-羟色胺转运蛋白基因型与5-羟色胺摄取抑制剂治疗前后血浆5-羟色胺浓度的关系.结果：132例抑郁症患者和100例正常健康者均采集到血样,并完成量表测试,全部进入结果分析.①抑郁症5-羟色胺转运蛋白基因基因型频率与正常对照组基因型频率比较差异无显著性,[（LL 24.2%,LS 44.7%,SS 31.1%）,（LL 29.0%,LS 47.0%,SS 24.0%）,x^2=1.4058,P＞0.05];等位基因频率与正常对照组比较差异无显著性[（L 46.59%,S 53.41%）,（L 52.5%,S47.5%）,x^2=0.696 2,P＞0.05].②不同基因型抑郁症患者治疗前汉密顿抑郁量表总分差异有显著性（F=6.48,P=0.002 1）;经4周5-羟色胺摄取抑制剂类抗抑郁药治疗后,汉密顿抑郁量表总分均显著下降,减分值差异有显著性（F=3.38,P=0.037）.③治疗前不同基因型患者5-羟色胺浓度差异有显著性（F=5.38,P=0.005 7）;4周治疗后,血浆中5-羟色胺浓度均升高,不同基因型的增高值差异有显著性（F=23.55,P＜0.01）.结论：南京地区人群中5-羟色胺转运蛋白基因多态性与抑郁症的发病不存在相关性,但与抑郁症疾病严重程度和5-羟色胺摄取抑制剂治疗效应存在显著的相关性,这一区域的基因型可能成为抑郁症患者实现个体化治疗的一个参考指标.     

Selective serotonin reuptake inhibitor(SSRI)

Selective serotonin reuptake inhibitors(SSRIs) are safe antidepressants and now widely used for the treatment of depression. Although there are five SSRIs(citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline) available in the world, only two(fluvoxamine and paroxetine) are approved in Japan. SSRIs are also used for the treatment of obsessive-compulsive disorders, panic disorders, eating disorders and so on. Major side effects of SSRIs are gastrointestinal symptoms(especially nausea), neurological symptoms (particularly headache and tremor) and psychiatric symptoms(especially anxiety). While therapeutic effects of SSRIs seem to be related to desensitization of somatodendritic serotonin 1A autoreceptors in the raphe nuclei, other neurotransmitters and intracellular mechanisms may be also involved.     

Pharmacokinetics of the selective serotonin reuptake inhibitor paroxetine: nonlinearity and relation to the sparteine oxidation polymorphism.

Steady-state plasma concentrations of paroxetine were studied at five or more paroxetine dose levels (10 to 70 mg/day) in each of 13 extensive metabolizers of sparteine and at three or four dose levels (10 to 40 mg/day) in each of three poor metabolizers of sparteine, all treated for diabetic neuropathy symptoms. On a dose of 30 mg/day there was a 25-fold variation in steady-state concentrations (25 to 670 nmol/L). The upper extreme of this variation was made up by the poor metabolizers of sparteine and the lower extreme by some fast extensive metabolizers. Further, within the extensive metabolizer group, steady-state levels showed a significant, positive correlation with sparteine metabolic ratio at all dose levels. On increasing doses, a disproportionate increase in plasma drug levels was observed in the majority of patients. In nearly all extensive metabolizers the concentration-dose data were best described by a pharmacokinetic model assuming elimination by at least two kinetically distinct processes, one a high-affinity saturable process and one a low-affinity linear process. Estimates of clearance at low drug levels of the high-affinity process showed a significant negative correlation with the sparteine metabolic ratio. Clearance of the low-affinity process was not related to the metabolic ratio and was of the same magnitude in extensive and poor metabolizers. The data thus confirmed that the metabolism of paroxetine and sparteine cosegregates and indicated that the enzyme responsible for a high-affinity saturable paroxetine elimination process is identical with CYP2D6, the source of the sparteine oxidation polymorphism.     

Hyponatremia as a complication of selective serotonin reuptake inhibitors

PURPOSE: To review the literature on hyponatremia as a complication of selective serotonin reuptake inhibitors (SSRIs) in the elderly; to summarize the prevalence, clinical findings, treatment modalities, and likely pathophysiological mechanisms related to the problem. DATA SOURCES: All published articles that could be located since Food and Drug Administration approval of this class of medications in 1987, using MEDLINE, CINAHL, and PsychInfo databases and a case study. CONCLUSIONS: Hyponatremia is a potentially serious complication of the use of SSRIs and is statistically more prevalent in the elderly and in females. Few clinical guidelines exist for managing this potential reaction. No evidence-based guidelines could be located. IMPLICATIONS FOR PRACTICE: Since articles describing this phenomenon have been primarily case studies, many healthcare providers may not be aware of this potentially serious complication. Monitoring of serum sodium in elderly female patients starting SSRI therapy seems prudent.     

Effect of the selective serotonin reuptake inhibitor paroxetine on platelet function is modified by a SLC6A4 serotonin transporter polymorphism

Summary. Background: Selective serotonin reuptake inhibitors (SSRIs) have been associated with an increased bleeding tendency. Objectives: To prospectively quantify the dose‐response effects of paroxetine and the influence of the serotonin transporter gene (SLC6A4) promoter polymorphism (5‐HTTLPR) on platelet function. Methods: Nineteen drug‐free psychiatric outpatients (44.5 ± 10.8 years) were tested before and after 6 weeks of paroxetine treatment (20 mg day^?1). Based on clinical symptoms, paroxetine dosages were increased (40–50 mg day^?1) for 6 more weeks in 11 patients. Parameters related to platelet function were assessed by bleeding time, platelet function analyzer (PFA), platelet serotonin, platelet factor 4 (PF4), β‐thromboglobulin (β‐TG), and aggregation tests. Results: Paroxetine 20 mg day^?1 increased mean bleeding time by 1.2 min (95% confidence interval (95% CI) ?0.2–2.7) and reduced median platelet serotonin level (463 ng 10^?9 platelets; inter quartile range (IQR) 361–666), and platelet ß‐TG concentration (3.1 IU 10^?6 platelets; IQR 0.3–6.0). Other platelet parameters did not change significantly. Serial platelet aggregation tests did not become abnormal. Paroxetine dose‐escalation did not further influence platelet function. However, 5‐HTTLPR polymorphisms modified these effects: in L_A/L_A‐carriers, bleeding times did not change (?0.2 min; 95% CI ?0.6 to 0.9), while bleeding times significantly increased in <2L_A‐allele carriers (2.3 min; 95% CI 0.5 to 4.07; P = 0.032). Platelet serotonin decreases were larger in patients without L_A‐alleles (868 ng 10^?9 platelets; IQR 585 to 1213) than in ≥1 L_A‐allele carriers (457 ng 10^?9 platelets; IQR 392 to 598; P = 0.035). PFA closure time and PF4 increased significantly in patients without L_A‐alleles. Conclusions: Paroxetine 20 mg day^?1 does not increase overall bleeding time, but impairs platelet function by decreasing the levels of platelet serotonin and platelet ß‐TG. These paroxetine effects appear to be mediated by 5‐HTTLPR, with most pronounced effects in patients without L_A‐alleles.