Objective To examine the risk of suicidal behaviour within clinical trials of antidepressants in adults. Design Meta-analysis of 372 double blind randomised placebo controlled trials. Setting Drug development programmes for any indication in adults. Participants 99 231 adults assigned to antidepressants or placebo. Median age was 42 and 63.1% were women. Indications for treatment were major depression (45.6%), other depression (4.6%), other psychiatric disorders (27.6%), and non-psychiatric disorders (22.2%). Main outcome measures Suicidal behaviour (completed suicide, attempted suicide, or preparatory acts) and ideation. Results For participants with non-psychiatric indications, suicidal behaviour and ideation were extremely rare. For those with psychiatric indications, risk was associated with age. For suicidal behaviour or ideation and for suicidal behaviour only, the respective odds ratios were 1.62 (95% confidence interval 0.97 to 2.71) and 2.30 (1.04 to 5.09) for participants aged <25, 0.79 (0.64 to 0.98) and 0.87 (0.58 to 1.29) for those aged 25-64, and 0.37 (0.18 to 0.76) and 0.06 (0.01 to 0.58) for those aged ≥65. When age was modelled as a continuous variable, the odds ratio for suicidal behaviour or ideation declined at a rate of 2.6% per year of age (−3.9% to −1.3%, P=0.0001) and the odds ratio for suicidal behaviour declined at a rate of 4.6% per year of age (−7.4% to −1.8%, P=0.001).Conclusions Risk of suicidality associated with use of antidepressants is strongly age dependent. Compared with placebo, the increased risk for suicidality and suicidal behaviour among adults under 25 approaches that seen in children and adolescents. The net effect seems to be neutral on suicidal behaviour but possibly protective for suicidal ideation in adults aged 25-64 and to reduce the risk of both suicidality and suicidal behaviour in those aged ≥65.

Intravenous administration of lipid is a relatively new treatment in the management of toxicity from lipophilic compounds. It is used in human medicine in the treatment of toxicity from lipophilic local anaesthetics and cardiotoxic drugs and can result in dramatic improvement in clinical status. We present six cases of poisoning in dogs successfully treated with lipid infusion after ingestion of ivermectin (3), moxidectin (2) and baclofen (1). The dogs ranged in age from eight weeks to 14 years, and weighed 4-30 kg. Intravenous lipid therapy was started between six and eight hours and 22 hours after ingestion, and all the dogs responded well. In four dogs, there was clinical improvement within one hour; one had improved within two hours and the other within 4.5 hours of lipid administration. The only adverse effect of lipid infusion reported was mild swelling and pain after extravasation in one case which resolved with conservative management. All the dogs were discharged within 24-52 hours after exposure (7-46 hours after the start of lipid administration), and none developed any apparent sequelae.

ObjectivesTo characterize individual participant level response distributions to acute monotherapy for major depressive disorder in randomized, placebo controlled trials submitted to the US Food and Drug Administration from 1979 to 2016.DesignIndividual participant data analysis.Population232 randomized, double blind, placebo controlled trials of drug monotherapy for major depressive disorder submitted by drug developers to the FDA between 1979 and 2016, comprising 73 388 adult and child participants meeting the inclusion criteria for efficacy studies on antidepressants.Main outcome measuresResponses were converted to Hamilton Rating Scale for Depression (HAMD17) equivalent scores where other measures were used to assess efficacy. Multivariable analyses examined the effects of age, sex, baseline severity, and year of the study on improvements in depressive symptoms in the antidepressant and placebo groups. Response distributions were analyzed with finite mixture models.ResultsThe random effects mean difference between drug and placebo favored drug (1.75 points, 95% confidence interval 1.63 to 1.86). Differences between drug and placebo increased significantly (P<0.001) with greater baseline severity. After controlling for participant characteristics at baseline, no trends in treatment effect or placebo response over time were found. The best fitting model of response distributions was three normal distributions, with mean improvements from baseline to end of treatment of 16.0, 8.9, and 1.7 points. These distributions were designated Large, Non-specific, and Minimal responses, respectively. Participants who were treated with a drug were more likely to have a Large response (24.5% v 9.6%) and less likely to have a Minimal response (12.2.% v 21.5%).ConclusionsThe trimodal response distributions suggests that about 15% of participants have a substantial antidepressant effect beyond a placebo effect in clinical trials, highlighting the need for predictors of meaningful responses specific to drug treatment.

This study was conducted in order to assess the prevalence of use of selective serotonin reuptake inhibitors (SSRIs) among pregnant women delivering a liveborn infant in the USA. A retrospective study was conducted using the automated databases of 15 health-care systems participating in the Mini-Sentinel program. Diagnosis and procedure codes were used to identify women ages 10 to 54 years delivering a liveborn infant between April 2001 and December 2013. A comparison group of age- and date-matched women without live births was identified. The frequency of use of SSRIs was identified from outpatient dispensing data. Among the 1,895,519 liveborn deliveries, 113,689 women (6.0 %) were exposed to an SSRI during pregnancy during the period 2001-2013; 5.4 % were exposed to an SSRI during 2013. During the corresponding time period, 10.5 % of the age- and date-matched cohort of women without live births was exposed to an SSRI, with 10.1 % exposed to an SSRI during 2013. The most common agents dispensed during pregnancy were sertraline (n = 48,678), fluoxetine (n = 28,983), and citalopram (n = 20,591). Among those women exposed to an SSRI during pregnancy, 53.8 % had a diagnosis of depression and 37.3 % had a diagnosis of an anxiety disorder during pregnancy or within 180 days prior to pregnancy. Our finding that 6 % of women with live births were prescribed SSRIs during pregnancy highlights the importance of understanding the differential effects of these medications and other therapeutic options on the developing fetus and on the pregnant women.

Intravenous administration of lipid is a relatively new treatment in the management of toxicity from lipophilic compounds. It is used in human medicine in the treatment of toxicity from lipophilic local anaesthetics and cardiotoxic drugs and can result in dramatic improvement in clinical status. We present six cases of poisoning in dogs successfully treated with lipid infusion after ingestion of ivermectin (3), moxidectin (2) and baclofen (1). The dogs ranged in age from eight weeks to 14 years, and weighed 4–30 kg. Intravenous lipid therapy was started between six and eight hours and 22 hours after ingestion, and all the dogs responded well. In four dogs, there was clinical improvement within one hour; one had improved within two hours and the other within 4.5 hours of lipid administration. The only adverse effect of lipid infusion reported was mild swelling and pain after extravasation in one case which resolved with conservative management. All the dogs were discharged within 24–52 hours after exposure (7–46 hours after the start of lipid administration), and none developed any apparent sequelae.

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Following a decision to require label warnings for concurrent use of opioids and benzodiazepines and increased risk of respiratory depression and death, the US Food and Drug Administratioin (FDA) recognized that other sedative psychotropic drugs may be substituted for benzodiazepines and be used concurrently with opioids. In some cases, data on the ability of these alternatives to depress respiration alone or in conjunction with an opioid are lacking. A nonclinical in vivo model was developed that could detect worsening respiratory depression when a benzodiazepine (diazepam) was used in combination with an opioid (oxycodone) compared to the opioid alone based on an increased arterial partial pressure of carbon dioxide (pCO2). The current study used that model to assess the impact on respiration of non‐benzodiazepine sedative psychotropic drugs representative of different drug classes (clozapine, quetiapine, risperidone, zolpidem, trazodone, carisoprodol, cyclobenzaprine, mirtazapine, topiramate, paroxetine, duloxetine, ramelteon, and suvorexant) administered alone and with oxycodone. At clinically relevant exposures, paroxetine, trazodone, and quetiapine given with oxycodone significantly increased pCO2 above the oxycodone effect. Analyses indicated that most pCO2 interaction effects were due to pharmacokinetic interactions resulting in increased oxycodone exposure. Increased pCO2 recorded with oxycodone‐paroxetine co‐administration exceeded expected effects from only drug exposure suggesting another mechanism for the increased pharmacodynamic response. This study identified drug‐drug interaction effects depressing respiration in an animal model when quetiapine or paroxetine were co‐administered with oxycodone. Clinical pharmacodynamic drug interaction studies are being conducted with these drugs to assess translatability of these findings.

ImportanceOpioids can cause severe respiratory depression by suppressing feedback mechanisms that increase ventilation in response to hypercapnia. Following the addition of boxed warnings to benzodiazepine and opioid products about increased respiratory depression risk with simultaneous use, the US Food and Drug Administration evaluated whether other drugs that might be used in place of benzodiazepines may cause similar effects.ObjectiveTo study whether combining paroxetine or quetiapine with oxycodone, compared with oxycodone alone, decreases the ventilatory response to hypercapnia.Design, Setting, and ParticipantsRandomized, double-blind, crossover clinical trial at a clinical pharmacology unit (West Bend, Wisconsin) with 25 healthy participants from January 2021 through May 25, 2021.InterventionsOxycodone 10 mg on days 1 and 5 and the following in a randomized order for 5 days: paroxetine 40 mg daily, quetiapine twice daily (increasing daily doses from 100 mg to 400 mg), or placebo.Main Outcomes and MeasuresVentilation at end-tidal carbon dioxide of 55 mm Hg (hypercapnic ventilation) using rebreathing methodology assessed for paroxetine or quetiapine with oxycodone, compared with placebo and oxycodone, on days 1 and 5 (primary) and for paroxetine or quetiapine alone compared with placebo on day 4 (secondary).ResultsAmong 25 participants (median age, 35 years [IQR, 30-40 years]; 11 female [44%]), 19 (76%) completed the trial. The mean hypercapnic ventilation was significantly decreased with paroxetine plus oxycodone vs placebo plus oxycodone on day 1 (29.2 vs 34.1 L/min; mean difference [MD], −4.9 L/min [1-sided 97.5% CI, −∞ to −0.6]; P = .01) and day 5 (25.1 vs 35.3 L/min; MD, −10.2 L/min [1-sided 97.5% CI, –∞ to –6.3]; P &amp;lt; .001) but was not significantly decreased with quetiapine plus oxycodone vs placebo plus oxycodone on day 1 (33.0 vs 34.1 L/min; MD, −1.2 L/min [1-sided 97.5% CI, −∞ to 2.8]; P = .28) or on day 5 (34.7 vs 35.3 L/min; MD, −0.6 L/min [1-sided 97.5% CI, −∞ to 3.2]; P = .37). As a secondary outcome, mean hypercapnic ventilation was significantly decreased on day 4 with paroxetine alone vs placebo (32.4 vs 41.7 L/min; MD, −9.3 L/min [1-sided 97.5% CI, −∞ to −3.9]; P &amp;lt; .001), but not with quetiapine alone vs placebo (42.8 vs 41.7 L/min; MD, 1.1 L/min [1-sided 97.5% CI, −∞ to 6.4]; P = .67). No drug-related serious adverse events were reported.Conclusions and RelevanceIn this preliminary study involving healthy participants, paroxetine combined with oxycodone, compared with oxycodone alone, significantly decreased the ventilatory response to hypercapnia on days 1 and 5, whereas quetiapine combined with oxycodone did not cause such an effect. Additional investigation is needed to characterize the effects after longer-term treatment and to determine the clinical relevance of these findings.Trial RegistrationClinicalTrials.gov Identifier: NCT04310579