Mechanism of action of dextromethorphan/quinidine: comparison with ketamine

CNS Spectrums ◽  
2013 ◽  
Vol 18 (5) ◽  
pp. 225-227 ◽  
Author(s):  
Stephen M. Stahl

ISSUE:Reports of rapid-onset but short-duration antidepressant effects in patients with treatment-resistant mood disorders after intravenous administration of ketamine have prompted efforts to find an agent with ketamine's properties that can be administered orally in repeated doses in order to sustain that action. One candidate for this is dextromethorphan, and here the pharmacologic mechanism of action is compared and contrasted with that of ketamine.

CNS Spectrums ◽  
2013 ◽  
Vol 18 (4) ◽  
pp. 171-174 ◽  
Author(s):  
Stephen M. Stahl

ISSUE:Ketamine induces rapid-onset and short-duration improvement in depressive and suicidal symptoms in both treatment-resistant unipolar depression and bipolar depression, and also reduces chronic pain after short intravenous infusions. In order to develop long-acting oral agents with the same clinical effects, the pharmacologic mechanism of action must be understood, and the leading hypotheses are discussed here.


2020 ◽  
Vol 31 (6) ◽  
pp. 649-658
Author(s):  
Mohammed Al-Alawi ◽  
Elisa Brietzke ◽  
Adriana Carvalhal ◽  
Claudio N. Soares

AbstractMajor depressive disorder (MDD) is a highly prevalent and disabling condition for which the currently available treatments are not fully effective. Existing unmet needs include rapid onset of action and optimal management of concurrent agitation. Dexmedetomidine (DEX) is a selective and potent α2-adrenergic receptor (α2-AR) agonist, with unique pharmacokinetic and pharmacodynamic properties. In this review, we discuss pre-clinical and clinical studies which focused on DEX in the context of its putative antidepressant effects for the management of MDD. Preliminary data support DEX as an antidepressant with fast onset of action, which would be especially helpful for patients experiencing treatment resistant depression, and agitation. We further explore the mechanistic and clinical implications of considering DEX as a putative antidepressant agent, and the next steps to explore the efficacy of low dose DEX infusion among patients with treatment resistant depression.


2020 ◽  
Vol 237 (11) ◽  
pp. 3295-3302
Author(s):  
Hannelore Findeis ◽  
Cathrin Sauer ◽  
Anthony Cleare ◽  
Michael Bauer ◽  
Philipp Ritter

Abstract Rationale Ketamine is the first widely used substance with rapid-onset antidepressant action. However, there are uncertainties regarding its potential urothelial toxicity, particularly after repeated application. In the context of rising recreational ketamine use, severe side effects affecting the human urinary tract have been reported. It is assumed that ketamine interacts with bladder urothelial cells and induces apoptosis. Objectives This study aimed to assess whether single or repeated doses of esketamine used in an antidepressant indication are associated with urinary toxicity. Methods We included male and female inpatients with a current episode of depression and a diagnosis of recurrent depressive disorder, bipolar disorder or schizoaffective disorder according to ICD-10 criteria (n = 25). The esketamine treatment schedule involved a maximum of 3× weekly dosing at 0.25–0.5 mg/kg i.v. or s.c. The primary outcome was the change in urine toxicity markers (leukocytes, erythrocytes, protein and free haemoglobin). Description of demographic, clinical and laboratory data was conducted using means, standard deviations, frequencies and percentages. Changes in urinary toxicity markers over time were evaluated using linear mixed models with gender as a covariate. Results The participants received an average of 11.4 (SD 8) esketamine treatments, and an average number of 11.2 (SD 8) urine samples were analysed over the course of treatment. Neither urinary leukocyte concentration (F(20; 3.0) = 3.1; p = 0.2) nor erythrocyte concentration (F(20;2.2) = 4.1; p = 0.2) showed a significant trend towards increase during the course of esketamine treatment. Similarly, free haemoglobin and protein concentrations, which were analysed descriptively, did not display a rise during treatment. There was a significant improvement in depression ratings after esketamine treatment (p < 0.001). Conclusions This study is, to the best of our knowledge, the first to focus on urothelial toxicity of esketamine used in antidepressant indication and dose. The results indicate that the use of single or repeated doses of esketamine is unlikely to cause urothelial toxicity. The results are in need of confirmation as sample size was small.


2021 ◽  
Vol 89 (9) ◽  
pp. S160-S161
Author(s):  
Fumie Oka ◽  
Kamile Weischedel ◽  
Amanda Bakian ◽  
Brian Mickey

2021 ◽  
Vol 534 ◽  
pp. 988-994
Author(s):  
Tomohisa Mori ◽  
Yoshinori Takemura ◽  
Takamichi Arima ◽  
Yoshiyuki Iwase ◽  
Michiko Narita ◽  
...  
Keyword(s):  

2018 ◽  
Author(s):  
Bashkim Kadriu ◽  
Subha Subramanian ◽  
Zhi-De Deng ◽  
Ioline D. Henter ◽  
Lawrence T. Park ◽  
...  

Major depressive disorder (MDD) is a highly prevalent and debilitating illness and closely linked to suicide risk. Currently available antidepressants take weeks to work and have low remission rates; indeed, about a third of individuals with MDD fail to fully remit in response to these agents. Novel therapies that target the glutamatergic system—such as ketamine—offer rapid antidepressant effects as well as high remission rates, making them attractive therapeutic options. This chapter reviews the evidence for the antidepressant efficacy of several novel therapeutics, including ketamine, esketamine, nitrous oxide, scopolamine, GLYX-13, and buprenorphine, as well as interventional techniques such as sleep deprivation. Notably, ketamine and esketamine also rapidly reduce suicidal thoughts, making them attractive solutions in an emergency setting. Because studying the rapid onset of antidepressant effects associated with these agents has also improved our understanding of the neurocircuitry and neural signaling systems underlying MDD, some pivotal drug trials using rodents, neuroimaging, and electrophysiological studies are also reviewed.


2018 ◽  
Vol 49 (4) ◽  
pp. 655-663 ◽  
Author(s):  
Fernanda Palhano-Fontes ◽  
Dayanna Barreto ◽  
Heloisa Onias ◽  
Katia C. Andrade ◽  
Morgana M. Novaes ◽  
...  

AbstractBackgroundRecent open-label trials show that psychedelics, such as ayahuasca, hold promise as fast-onset antidepressants in treatment-resistant depression.MethodsTo test the antidepressant effects of ayahuasca, we conducted a parallel-arm, double-blind randomized placebo-controlled trial in 29 patients with treatment-resistant depression. Patients received a single dose of either ayahuasca or placebo. We assessed changes in depression severity with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hamilton Depression Rating scale at baseline, and at 1 (D1), 2 (D2), and 7 (D7) days after dosing.ResultsWe observed significant antidepressant effects of ayahuasca when compared with placebo at all-time points. MADRS scores were significantly lower in the ayahuasca group compared with placebo at D1 and D2 (p= 0.04), and at D7 (p< 0.0001). Between-group effect sizes increased from D1 to D7 (D1: Cohen'sd= 0.84; D2: Cohen'sd= 0.84; D7: Cohen'sd= 1.49). Response rates were high for both groups at D1 and D2, and significantly higher in the ayahuasca group at D7 (64%v.27%;p= 0.04). Remission rate showed a trend toward significance at D7 (36%v.7%,p= 0.054).ConclusionsTo our knowledge, this is the first controlled trial to test a psychedelic substance in treatment-resistant depression. Overall, this study brings new evidence supporting the safety and therapeutic value of ayahuasca, dosed within an appropriate setting, to help treat depression. This study is registered athttp://clinicaltrials.gov(NCT02914769).


Peptides ◽  
1992 ◽  
pp. 88-90 ◽  
Author(s):  
H. B. Long ◽  
J. C. Baker ◽  
R. M. Belagaje ◽  
R. D. DiMarchi ◽  
B. H. Frank ◽  
...  

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