Several studies have supported Dr Gideon Koren’s 1993 landmark article, “Medications Which Can Kill a Toddler with One Tablet or Teaspoonful.” Although each study has its own merits, most focus solely on pediatric overdoses, and few provide an exhaustive reference list for real-time evaluation of ingestions in children and adults. The following xenobiotics warrant special attention because of their potential to cause serious outcomes, even after exposure to small volumes. This list does not imply that all pediatric exposures to these agents result in fatality, and the absence of a xenobiotic from this list does not indicate that it is necessarily safe. α1-Adrenergic agonists and imidazoline receptor agonists: Clonidine, guanfacine, naphazoline, oxymetazoline, tetrahydrozoline, xylazine (veterinary). Sulfonylureas: Chlorpropamide, glyburide, glipizide, glimepiride. Calcium channel blockers: Verapamil, diltiazem, nifedipine, amlodipine, nicardipine, nimodipine; β-Blockers: Metoprolol, labetalol, propranolol, sotalol. Tricyclic antidepressants: Imipramine, desipramine, amitriptyline, nortriptyline. Opioids: Codeine, hydrocodone, methadone, morphine, heroin. Antidiarrheals: Diphenoxylate plus atropine, loperamide. Salicylates and methyl salicylate: Oil of wintergreen, bismuth subsalicylate, mentholated balms, paramao or lawang root oil . Antipsychotics: Loxapine, thioridazine, chlorpromazine. Antimalarials: Chloroquine, hydroxychloroquine, quinine, primaquine. Antiarrhythmics: Quinidine, disopyramide, procainamide, flecainide, amiodarone. Camphor: A terpenoid used as an analgesic, antipruritic agent, and component of cooling gels, ointments, balms, mothballs, household fragrances, and essential oils. Oral camphor use occurs in some regions for religious ceremonies, traditional remedies, aphrodisiacs, or lactation suppression. Nonalkaloid toxic lignan: Podophyllin, podofilox. Unique plant toxins: Colchicine. Oral acetylcholinesterase inhibitors: Rivastigmine, donepezil, galantamine, carbamate pesticides. Methylxanthines: Theophylline, 1,3-dimethylxanthine, caffeine. Other opioids: Buprenorphine, fentanyl. Toxic alcohols: Methanol, ethylene glycol, diethylene glycol. Caustics and other household products: Acidic or alkaline household products, hydrofluoric acid, selenious acid, acetonitrile, methylene chloride. Accidental overdoses continue to occur regularly despite the implementation of various safety measures, including widespread public education, the use of childproof containers, and easy access to poison control centers. In the US, poison control centers receive more than 2.4 million calls annually, with more than 50% involving children younger than 6 years. Most pediatric accidental ingestions involve household cleaning products and analgesics, followed by cosmetics, foreign objects, and dietary supplements. Adult overdoses may be unintentional but often involve larger total doses or high-risk medications, including opioids and sedative-hypnotics. America's Poison Centers identify the 5 most common substance classes as analgesics, household cleaners, antidepressants, cosmetic or personal care items, and cardiovascular drugs. The number of ingestions involving cleaning products increased sharply during the COVID-19 pandemic but has since declined.

Terbinafine (TBNF), a lipophilic anti-fungal agent prescribed for onychomycosis distributes extensively into adipose, skin and peripheral tissues. TBNF and metabolite desmethyl terbinafine (DMT) are potent inhibitors of CYP2D6. A combination of prolonged half-life and CYP2D6 inhibition causes clinically significant interactions with drugs involving CYP2D6 metabolism that may persist for weeks after dosing cessation. A physiologically based pharmacokinetic (PBPK) model for TBNF and DMT incorporating in vitro and clinical information was developed and verified to predict their steady state pharmacokinetics. Experimentally determined Kiu,CYP2D6 for TBNF and DMT enabled to predict the interaction with CYP2D6 substrates Desipramine, Amitriptyline and Nortriptyline. The PBPK model predicted steady-state plasma concentration-time profiles of TBNF and DMT after daily administration of 250 mg and 125 mg TBNF were in agreement with the observed data, including sustained plasma concentrations after dosing cessation. This enabled prediction of drug interactions with the CYP2D6 substrates during and after termination of TBNF dosing. The distribution of TBNF into adipose and skin acts as a depot leading to its slow re-distribution back into plasma, followed by sequential metabolism to DMT and CYP2D6 inhibition. The model was validated against data from three independent drug interaction reports. This PBPK framework can be applied in different clinical pharmacology settings for drugs characterized by extensive distribution, formation rate limited metabolism and enzyme inhibition. The framework provides applicability in informing the rational design of clinical trials where sustained plasma drug levels warrant patient monitoring long after termination of dosing.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease with limited treatment options. Depression and anxiety are common comorbidities in patients with IPF, and emerging evidence suggests that neuroactive pathways may also influence fibrotic remodeling. On this basis, we investigated desipramine, a tricyclic antidepressant, as a potential modulator of fibroblast state in lung fibrosis. Desipramine was identified in an FDA-approved compound screen as a pro-lipogenic hit in TGF-β-stimulated fibroblasts and was subsequently evaluated across a stepwise validation pipeline of increasing biological complexity. In WI-38 fibroblasts, desipramine was well tolerated at 10 μM and reduced myofibroblast-associated features while increasing lipid-associated staining. In a fibroblast-supported alveolosphere assay, desipramine altered qualitative organoid clustering and changed the transcript levels of specific mesenchymal markers under profibrotic stimulation, whereas direct treatment of MLE-12 epithelial cells did not elicit a consistent response. While desipramine demonstrated pro-lipogenic and anti-myofibroblastic phenotypic shifts in reductionist 2D cultures, these effects failed to translate robustly into complex 3D human lung tissue slices or in vivo disease models. Ultimately, our findings highlight the critical necessity of utilizing complex translational pipelines to rigorously validate early screening hits before therapeutic efficacy is assumed.

The development of antidepressants has traditionally relied on vertebrate models. Drosophila melanogaster offers a promising alternative approach, yet evidence of antidepressant-like effects is fragmented. The aim of this systematic review was to analyse the literature on the effects of antidepressants on D. melanogaster behaviours. A comprehensive search of a number of bibliographic databases (i.e. PubMed, Web of Science, Scopus and EMBASE) was followed by a further screening of the retrieved articles (i.e. inclusion of studies on any D. melanogaster strain, sex, age, dose or outcome, tested in any behavioural assay; exclusion of reviews, studies on co-treatments and/or on non-prototypical antidepressants, and studies lacking control groups). This resulted in the final selection of 12 articles, comprising 146 studies. Most studies involved adult flies (k = 131), males (k = 56), fluoxetine treatment (k = 109) and courtship outcomes (k = 85). Some studies involved larvae (k = 15), females (k = 39), treatment with other antidepressants (citalopram, k = 12; desipramine, k = 6; amitriptyline, k = 2; imipramine, k = 2) and other outcomes (locomotion, k = 11; sucrose preference, k = 5; light preference, k = 2; aggression, k = 2; climbing, k = 1). Studies on larvae had, on average, larger sample sizes than studies on adult flies, resulting in more conclusive effect sizes. The effect sizes indicated that most studies presented inconclusive effects. However, sucrose preference, courtship and light preference were outcomes with conclusive findings, depending on the conditions (sex, treatment, stress), and thus these may represent more reliable indicators of antidepressant effects. However, the lack of consistency among studies precluded drawing any definitive conclusions on reliable indicators. In addition, incomplete reporting precluded an accurate risk-of-bias assessment. These findings highlight the need for standardisation and transparent reporting, in order to establish flies as a reproducible, ethically acceptable alternative to vertebrates in antidepressant research.

Imipramine is a tricyclic antidepressant used in the treatment of several psychiatric disorders including major depression, obsessive-compulsive disorder, generalized anxiety disorder, post-traumatic stress disorder, and bulimia. Imipramine may also be useful as an adjunctive treatment in the management of panic attacks, neuropathic pain, attention-deficit disorder, and childhood enuresis (bedwetting) (1). Tricyclic antidepressants (TCAs) primarily mediate their therapeutic effect by inhibiting the reuptake of both serotonin and norepinephrine, leaving more neurotransmitter in the synaptic cleft stimulating the neuron. Because tricyclics can also block different receptors (histamine H1, α1-adrenergic, and muscarinic receptors), side effects are common. As such, more specific selective serotonin reuptake inhibitors (SSRIs) have largely replaced the use of them. However, TCAs still have an important use in specific types of depression and other conditions. Imipramine is primarily metabolized via CYP2C19 to active metabolites, including desipramine, also a tricyclic antidepressant. Further metabolism is catalyzed by CYP2D6. Individuals who are “CYP2D6 ultrarapid metabolizers” carry more than two normal function alleles (i.e., multiple copies) (Table 1, 2), whereas individuals who are “CYP2C19 ultrarapid metabolizers” carry two increased function alleles (Table 3, 4). Individuals who are CYP2D6 or CYP2C19 “poor metabolizers” carry two no function alleles for CYP2D6 or CYP2C19, respectively. The FDA-approved drug label for imipramine states that CYP2D6 poor metabolizers have higher than expected plasma concentrations of tricyclic antidepressants when given usual doses. Their recommendations include monitoring tricyclic antidepressant plasma levels whenever a tricyclic antidepressant is going to be co-administered with another drug known to be an inhibitor of CYP2D6 (1). In 2016, the Clinical Pharmacogenetics Implementation Consortium (CPIC) made dosing recommendations for tricyclic antidepressants based on CYP2C19 and CYP2D6 genotypes. Amitriptyline and nortriptyline were used as model drugs for this guideline because the majority of pharmacogenomic studies have focused on these two drugs. According to the CPIC guideline, because TCAs have comparable pharmacokinetic properties, it may be reasonable to apply the recommendations to other tricyclics, including imipramine (2). For CYP2D6 ultrarapid metabolizers, CPIC recommends avoiding the use of a tricyclic due to the potential lack of efficacy, and to consider an alternative drug not metabolized by CYP2D6. If a TCA is still warranted, CPIC recommends considering titrating the TCA to a higher target dose (compared to normal metabolizers) and using therapeutic drug monitoring to guide dose adjustments. For CYP2D6 intermediate metabolizers, CPIC recommends considering a 25% reduction of the starting dose, and for CYP2D6 poor metabolizers, to avoid the use of tricyclics because of the potential for side effects. If a tricyclic is still warranted for CYP2D6 poor metabolizers, CPIC recommends considering a 50% reduction of the starting dose while monitoring drug plasma concentrations to avoid side effects. For CYP2C19 ultrarapid metabolizers, CPIC recommends avoiding the use of tertiary amines (e.g., imipramine) due to the potential for a sub-optimal response, and to consider an alternative drug not metabolized by CYP2C19, such as the secondary amines nortriptyline or desipramine. For CYP2C19 poor metabolizers, CPIC recommends avoiding tertiary amine use due to the potential for sub-optimal response, and to consider an alternative drug not metabolized by CYP2C19. If a tertiary amine is still warranted for CYP2C19 poor metabolizers, CPIC recommends considering a 50% reduction of the starting dose while monitoring drug plasma concentrations to avoid side effects (2).

Amitriptyline is a tricyclic antidepressant used in the treatment of several psychiatric disorders, including major depression, obsessive-compulsive disorder, panic attacks, generalized anxiety disorder, post-traumatic stress disorder, and bulimia. Amitriptyline also has different off-label uses, including migraine prevention, neuropathic pain management, fibromyalgia, and enuresis (bedwetting) (1). Tricyclic antidepressants (TCAs) primarily mediate their therapeutic effect by inhibiting the reuptake of both serotonin and norepinephrine, leaving more neurotransmitter in the synaptic cleft stimulating the neuron. Because tricyclics can also block different receptors (H1 histamine, alpha 1 α1-adrenergic, and muscarinic receptors), side effects are common. As such, more specific selective serotonin reuptake inhibitors (SSRIs) have largely replaced the use of them. However, TCAs still have an important use in specific types of depression and other conditions. Amitriptyline is metabolized mainly via CYP2C19 and CYP2D6 pathways. Metabolism by CYP2C19 results in active metabolites, including nortriptyline, which is also a tricyclic antidepressant. Metabolism catalyzed by CYP2D6 results in the formation of the less active 10-hydroxy metabolite. Individuals who are “CYP2D6 ultrarapid metabolizers” carry more than two normal function alleles (i.e., multiple copies) (Table 1, 2), whereas “CYP2C19 ultrarapid metabolizers” carry two increased function alleles (Table 3, 4). Individuals who are CYP2D6 or CYP2C19 “poor metabolizers” carry two no function alleles for CYP2D6 or CYP2C19, respectively. The FDA-approved drug label for amitriptyline states that CYP2D6 poor metabolizers have higher than expected plasma concentrations of tricyclic antidepressants when given usual doses. The FDA recommendations also include monitoring tricyclic antidepressant plasma levels whenever a tricyclic antidepressant is going to be co-administered with another drug known to be an inhibitor of CYP2D6 (1). In 2016, the Clinical Pharmacogenetics Implementation Consortium (CPIC) made dosing recommendations for tricyclic antidepressants based on CYP2C19 and CYP2D6 genotypes (2). For CYP2D6 ultrarapid metabolizers, CPIC recommends avoiding the use of a tricyclic due to the potential lack of efficacy, and to consider an alternative drug not metabolized by CYP2D6. If a TCA is still warranted, CPIC recommends considering titrating the TCA to a higher target dose (compared to normal metabolizers) and using therapeutic drug monitoring to guide dose adjustments. For CYP2D6 intermediate metabolizers, CPIC recommends considering a 25% reduction of the starting dose, and for CYP2D6 poor metabolizers, to avoid the use of tricyclics because of the potential for side effects. If a tricyclic is still warranted for CYP2D6 poor metabolizers, CPIC recommends considering a 50% reduction of the starting dose while monitoring drug plasma concentrations to avoid side effects. For CYP2C19 ultrarapid metabolizers, CPIC recommends avoiding the use of tertiary amines (e.g., amitriptyline) due to the potential for a sub-optimal response, and to consider an alternative drug not metabolized by CYP2C19, such as the secondary amines nortriptyline or desipramine. For CYP2C19 poor metabolizers, CPIC recommends avoiding tertiary amine use due to the potential for sub-optimal response, and to consider an alternative drug not metabolized by CYP2C19. If a tertiary amine is still warranted for CYP2C19 poor metabolizers, CPIC recommends considering a 50% reduction of the starting dose while monitoring drug plasma concentrations while monitoring plasma concentrations to avoid side effects (2).

Prenatal herbicide exposure is increasingly linked to neurodevelopmental disorders, yet effective pharmacological interventions remain lacking due to unclear pathogenic mechanisms. Here, we demonstrate that prenatal exposure to glufosinate ammonium (GLA), a widely used herbicide, triggers autism-like behaviors, including social deficits and repetitive grooming, in offspring mice. Whole-brain c-Fos mapping, in vivo calcium imaging, and patch-clamp recordings identified hypoactive pyramidal neurons in the anterior cingulate cortex (ACC) as the neural substrate of these behavioral deficits in prenatally GLA-exposed offspring mice. Mechanistically, transcriptomic and multi-omics analyses revealed that astrocyte activation in the ACC drove Kir4.1 potassium channel upregulation, which suppressed CaMKIIα [+] neuronal excitability via impaired astrocyte-neuron communication. Pharmacological inhibition of astroglial Kir4.1 not only restored neuronal activity but also rescued social deficits in GLA-exposed offspring, underscoring Kir4.1's pivotal role in ACC dysfunction. Our study uncovers a novel astrocyte-neuron axis underlying herbicide-induced neurodevelopmental impairments and identifies Kir4.1 as a therapeutic target for environmental factor-associated autism.

Benzylguanidine, a norepinephrine analogue with high NET affinity, serves as a promising scaffold for visualizing cardiac sympathetic function. This study investigated whether [18]F-labeled benzylguanidine derivatives with systematical meta-halogen substitution could be optimized for PET imaging of cardiac sympathetic innervation. Five derivatives were radiolabeled efficiently with high purity and stability, and aromatic substitution markedly affected in vitro and in vivo. Among them, [18]F-FPFBBG ([18]F-FBr) demonstrated the most favorable profile. Biodistribution in mice revealed high myocardial uptake (12.26 %ID/g). PET imaging in pigs further confirmed the excellent cardiac performance of [18]F-FBr, showing intense and sustained myocardial uptake (SUVmean > 4) with low background activity and favorable myocardial retention. Moreover, desipramine blocking studies confirmed its NET-specific binding. Systematic meta-halogen modification significantly altered the biological and imaging properties of benzylguanidine-based PET radiotracers. [18]F-FBr demonstrated its potential as a PET radiotracer for imaging cardiac sympathetic innervation.