Novel hyperpigmentation pathophysiology following a prolonged course of imipramine therapy.

Imipramine is a tricyclic antidepressant typically reserved for patients with treatment-resistant mood disorders. A rare side effect of long-term use of imipramine is a slowly progressive melanin-associated, slate gray-blue hyperpigmentation of the skin in a photo-distributed pattern. We report a case of imipramine-induced hyperpigmentation developing 50 years after initiating imipramine therapy, whose lesions were essentially devoid of melanin on histopathological exam. This differs from all other reported cases of imipramine-induced hyperpigmentation in two notable respects. First, the time between initiating imipramine therapy and the onset of pigmentation changes was nearly 30 years longer than prior case reports. Second, the lack of melanin in our samples suggests a divergence from the hypothesized melanin-imipramine complex mechanism of hyperpigmentation. Instead, we propose a novel pathogenesis of imipramine-induced hyperpigmentation that is unrelated to melanin.

Imipramine-Induced Cutaneous and Iris Hyperpigmentation: A Case Report and Literature Review.

Objective: To describe a novel case of imipramine-induced hyperpigmentation and characterize the literature pertaining to imipramine-induced hyperpigmentation to this point.Data Sources: PubMed and Google Scholar were searched through July 2021 utilizing various combinations of imipramine, discoloration, and hyperpigmentation. The references of initial articles were searched for more case reports and imipramine-related literature. Also, articles that cited the references identified in the literature search were reviewed using Google Scholar. Only articles published in English were included.Study Selection: A total of 19 cases of imipramine-induced hyperpigmentation were found in 15 publications to date. All cases were included to determine the variation in clinical presentations of this rare condition.Data Extraction: The case reports were reviewed in their entirety for information concerning patient demographic, clinical presentation, histologic findings on biopsy, and treatment options for imipramine-induced hyperpigmentation.Results: This presentation, to our knowledge, represents the third case of imipramine-induced iris hyperpigmentation, the first case of iris hyperpigmentation occurring in a blue-eyed individual, and the first report to include pictures of the hyperpigmented irides. A novel proposed pathophysiologic mechanism is also provided.Conclusions: Imipramine is a tricyclic antidepressant with a rare side effect of cutaneous and iris hyperpigmentation. Granular dermal deposits in microscopy appear to be the cause of this discoloration. Treatment primarily focuses on discontinuing imipramine or laser therapy.

Tricyclic antidepressant-induced photosensitivity; A case report and systematic review.

BACKGROUND/PURPOSE: Tricyclic antidepressants (TCAs) are still widely used and are available to purchase without prescription in some countries. Awareness of adverse cutaneous drug reactions is essential. METHOD: We reported a case of photo-distributed hyperpigmentation due to imipramine and carried out a systematic search of the related articles using the search terms "tricyclic antidepressants" or "tricyclic antidepressive agents", and "hyperpigmentation" or "photosensitivity disorder". Fifty non-duplicate citations were identified of which 28 articles which were independently assessed in full. The review was registered in PROSPERO, CRD42018107338. RESULTS: The remaining 25 articles met our inclusion criteria. Photo-distributed hyperpigmentation tricyclic antidepressant-induced photosensitivity reactions (TIPs) was the most common presentation. In 21 cases, this presented as an asymptomatic discolouration of exposed sites. Imipramine (81%), amitriptyline (9.5%), desipramine hydrochloride (4.8%) and mirtazapine (4.8%) were reported to be the culprit drugs. Nineteen were female with a mean age at presentation of 55 years. Mean duration from commencing the culprit drug until the development of discolouration was 10.4 years. Mean daily dose was 222.7 mg for imipramine. Histology was characteristic with golden-brown or brownish granules deposited in dermis. Staining for Masson-Fontana and MEL-5 was positive in all cases. Phototesting had not been done in cases prior to ours (negative 3 months after discontinuation of imipramine). Three further reports of suspected TIP presented with non-specific and eczematous eruption. The two presentations were reported along with systemic problems (thrombocytopenia and hepatic injury). CONCLUSIONS: This systematic review highlights the characteristic features of exposed site hyperpigmentation of TCA-induced photosensitivity occurring after prolonged drug exposure in many cases.

Chronic antidepressant treatment rescues abnormally reduced REM sleep theta power in socially defeated rats.

The effects of chronic antidepressant (AD) treatment on sleep disturbances in rodent chronic stress models have not been thoroughly investigated. Here, we show that chronic social defeat stress (SDS) in rats induces prolonged social avoidance, alterations in sleep architecture (increased total rapid eye movement [REM] sleep duration, bout, and shortened REM latency), and contextual but not cued fear memory deficits, even 1 month after the last SDS. These abnormalities were associated with changes in electroencephalography (EEG) spectral powers, including reduced REM sleep theta power during the light phase. Chronic treatment with two different classes of antidepressants (ADs), imipramine and fluoxetine, significantly ameliorated these behavioral, sleep, and EEG abnormalities. Interestingly, REM theta power was normalized by chronic (1 month) but not 1 week AD administration and solely correlated with the ratio (an objective indicator) of social interaction 1 month after the last SDS. These data suggest that reductions in REM sleep theta power, an EEG parameter that has never been directly investigated in humans, is a core sleep symptom in socially defeated rats, and, potentially, also in patients with stress-related psychiatric disorders, including major depressive and posttraumatic stress disorders.

An approach to evaluate metabolite-related phototoxicity with combined use of photochemical properties and skin deposition.

Some chemicals have been reported to cause metabolite-related phototoxicity, and this study aimed to verify the applicability of photosafety assessment based on photochemical and pharmacokinetic properties to evaluate the metabolite-related phototoxicity risk. The phototoxic risk of imipramine (IMI) and its metabolite, desipramine (DMI), was evaluated by photochemical and pharmacokinetic analyses. IMI and DMI were found to have similar photoreactivities based on the generation of reactive oxygen species. The skin concentrations of IMI and DMI reached maximal levels at approximately 1 and 4 h, respectively, after oral administration of IMI (10 mg/kg), and DMI showed high skin deposition compared with IMI. According to the results, DMI was identified as a contributor to phototoxicity induced by orally-taken IMI. In in vivo phototoxicity testing, ultraviolet A irradiation from 3 to 6 h after oral administration of IMI (100 mg/kg) caused more potent phototoxic reactions compared with that from 0 to 3 h, and DMI yielded by metabolism of IMI would be associated with phototoxic reactions caused by orally-administered IMI. In addition to the data on IMI, a parent chemical, photochemical and pharmacokinetic profiling of its metabolite, DMI, led to reliable phototoxicity prediction of orally-administered IMI. Thus, characterization of the photosafety of metabolites would generate reliable information on the phototoxicity risk of parent chemicals, and the proposed strategy may facilitate comprehensive photosafety assessment of drug candidates in pharmaceutical development.

Low-dose imipramine for refractory functional dyspepsia: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Guidelines recommend the use of neuromodulators in patients with functional dyspepsia not responding to proton pump inhibitors (PPIs) and prokinetics; however, there is a lack of data from randomised controlled trials supporting their use. We aimed to assess the safety and efficacy of imipramine, a tricyclic antidepressant (TCA), in treatment-refractory functional dyspepsia. METHODS: In this single-centre, double-blind, randomised controlled trial, we enrolled consecutive patients with Rome II functional dyspepsia aged 18-80 years. Eligible patients were Helicobacter pylori-negative, had a normal upper gastrointestinal endoscopy and abdominal ultrasound, and remained symptomatic after open-label treatment with 8 weeks of esomeprazole and 4 weeks of domperidone. Patients completed questionnaires assessing dyspepsia symptoms, mood, and insomnia, and were then randomly assigned (1:1) via a computer-generated list of random numbers to receive imipramine (at a dose of 25 mg once nightly for the first 2 weeks, and then 50 mg thereafter) or placebo for 12 weeks. The primary endpoint was overall satisfactory relief of global dyspepsia symptoms at 12 weeks, via patient-reported assessment in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT00164775, and is completed. FINDINGS: Between Sept 11, 2005, and Aug 20, 2010, 107 patients with treatment-refractory functional dyspepsia were randomly assigned to receive imipramine (n=55) or placebo (n=52). Relief of global dyspepsia symptoms at 12 weeks occurred in 35 (63·6%, 95% CI 50·4-75·1) of 55 patients on imipramine compared with 19 (36·5%, 95% CI 24·8-50·1) of 52 on placebo (p=0·0051). Ten (18%) patients on imipramine discontinued the study due to adverse events (three dry mouth, two constipation, two drowsiness, and one each insomnia, palpitations, and blurred vision), compared with four (8%) on placebo (one dry mouth and constipation, and one each palpitations, worsening of gastro-oesophageal reflux, and limb paraesthesia). There were no serious adverse events. INTERPRETATION: Low-dose imipramine should be considered as a possible therapy for patients with functional dyspepsia refractory to both PPIs and prokinetics, although patients should be cautioned about the adverse event profile. FUNDING: None.

Effect of single-dose imipramine on chronic low-back and experimental pain. A randomized controlled trial.

Antidepressants are frequently prescribed as co-analgesics in chronic pain. While their efficacy is well documented for neuropathic pain, the evidence is less clear in musculoskeletal pain conditions. The present study therefore evaluated the effect of the tricyclic antidepressant imipramine on chronic low-back pain in a randomized, double-blinded placebo-controlled design. To explore the mechanisms of action and the influence of drug metabolism, multimodal quantitative sensory tests (QST) and genotyping for cytochrome P450 2D6 (CYP2D6) were additionally performed. A single oral dose of imipramine 75 mg was compared to active placebo (tolterodine 1 mg) in 50 patients (32 females) with chronic non-specific low-back pain. Intensity of low-back pain was assessed on a 0-10 numeric rating scale at baseline and every 30 minutes after drug intake. Multimodal QST were performed at baseline and in hourly intervals for 2 hours. Pharmacogenetic influences of cytochrome P450 were addressed by CYP2D6 genotyping. No significant analgesic effect was detected neither on low-back pain nor on any of the sensory tests in the overall analyses. However, evidence for an interaction of the imipramine effect and CYP2D6 genotype was found for electrical and for pressure pain detection thresholds. Intermediate but not extensive metabolizers had a 1.20 times greater electrical pain threshold (95%-CI 1.10 to 1.31) and a 1.10 times greater pressure pain threshold (95%-CI 1.01 to 1.21) 60 minutes after imipramine than after placebo (p<0.001 and p = 0.034, respectively). The present study failed to demonstrate an immediate analgesic effect of imipramine on low-back pain. Anti-nociceptive effects as assessed by quantitative sensory tests may depend on CYP2D6 genotype, indicating that metabolizer status should be accounted for when future studies with tricyclic antidepressants are undertaken.

Prostate cancer and antidepressants: A nationwide population-based nested case-control study.

BACKGROUND: We aimed to evaluate the association between antidepressant and prostate cancer by comparing exposures to antidepressants between those with and without prostate cancer. METHODS: A nationwide insurance claims database was used to identify our case subjects. Age- and gender-matched controls were selected at a 1:5 ratio. Conditional logistic regression model was used. RESULTS: 11,515 patients with prostate cancer were identified and matched with 55,373 controls. No increased associations between prostate cancer and most classes of antidepressants were found. However, a positive association with adjusted odds ratios ranged from 1.20 to 1.35 was noted in different doses of imipramine. Nevertheless, this association became statistically insignificant at higher cumulative doses. CONCLUSIONS: Our results indicate that there is no association between mechanistically dissimilar antidepressants and increased hazard for prostate cancer.

Imipramine-induced hyperpigmentation.

Imipramine is a tricyclic medication that has been used for the treatment of depression and other mood disorders. Although rare, a slate gray discoloration of sun-exposed skin may occur in patients taking this medication. We present the case of a 63-year-old woman who had been taking imipramine for depression for more than 20 years when she developed a bluish gray discoloration on the face and neck that was diagnosed as imipramine-induced hyperpigmentation based on histopathology and clinical history. A number of other drugs that may cause hyperpigmentation also are reviewed as well as their histopathologic staining characteristics.

A cell-based assay using HepaRG cells for predicting drug-induced phospholipidosis.

The utility of HepaRG cells as an in vitro cell-based assay system for predicting drug-induced phospholipidosis (PLD) was investigated. In experiment 1, 10 PLD-positive compounds and 11 PLD-negative compounds were selected. HepaRG cells were treated with each compound for 48 hr. In experiment 2, loratadine and desloratadine, a major metabolite of loratadine, were used to assess metabolic activation for PLD. HepaRG cells were treated with loratadine and desloratadine in the presence or absence of 500 µM 1-aminobenzotriazole (ABT), a broad CYP inhibitor, for 48 hr. After treatment with compounds in experiments 1 and 2, the relative fluorescence intensity (RFI) was measured using LYSO-ID Red dye to assess the PLD induction. In experiment 1, our cell-based assay system using HepaRG cells exhibited 100% sensitivity and 100% specificity for predicting drug-induced PLD. In experiment 2, loratadine increased the RFI in the PLD assay. However, the increase in the RFI was not observed in co-treatment with loratadine and ABT. In addition, desloratadine increased the RFI in the presence and absence of ABT. These results suggested that metabolic activation of loratadine may contribute to PLD in HepaRG cells. We newly demonstrated that HepaRG cells have a high ability for predicting drug-induced PLD. In addition, we newly showed that HepaRG cells may predict drug-induced PLD mediated by metabolic activation of loratadine. Thus, a cell-based assay system using HepaRG cells is a useful model for predicting drug-induced PLD.

Study 329 continuation phase: Safety and efficacy of paroxetine and imipramine in extended treatment of adolescent major depression.

OBJECTIVE: This is an analysis of the unpublished continuation phase of Study 329, the primary objective of which was to compare the efficacy and safety of paroxetine and imipramine with placebo in the treatment of adolescents with unipolar major depression. The objectives of the continuation phase were to assess safety and relapse rates in the longer term. The objective of this publication, under the Restoring Invisible and Abandoned Trials (RIAT) initiative, was to see whether access to and analysis of the previously unpublished dataset from the continuation phase of this randomized controlled trial would have clinically relevant implications for evidence-based medicine. METHODS: The study was an eight-week double-blind randomized placebo-controlled trial with a six month continuation phase. The setting was 12 North American academic psychiatry centres, from 20 April 1994 to 15 February 1998. 275 adolescents with major depression were originally enrolled in Study 329, with 190 completing the eight-week acute phase. Of these, 119 patients (43%) entered the six-month continuation phase (paroxetine n = 49; imipramine n = 39; placebo n = 31), in which participants were continued on their current treatment, blinded. As per the protocol, we have looked at rates of relapse (based on Hamilton Depression Scale scores) across both acute and continuation phases, and generated a safety profile for paroxetine and imipramine compared with placebo for up to six months.ANOVA testing (generalized linear model) using a model including effects of site, treatment and site x treatment interaction was applied. Otherwise we used only descriptive statistics. RESULTS: Of patients entering the continuation phase, 15 of 49 for paroxetine (31%), 12 of 39 for imipramine (31%) and 12 of 31 for placebo (39%) completed as responders. Across the study, 25 patients on paroxetine relapsed (41% of those showing an initial response), 15 on imipramine (26%), and 10 on placebo (21%). In the continuation and taper phases combined there were 211 adverse events in the paroxetine group, 147 on imipramine and 100 on placebo. The taper phase had a higher proportion of severe adverse events per week of exposure than the acute phase, with the continuation phase having the fewest events. CONCLUSIONS: The continuation phase did not offer support for longer-term efficacy of either paroxetine or imipramine. Relapse and adverse events on both active drugs open up the risks of a prescribing cascade. The previously largely unrecognised hazards of the taper phase have implications for prescribing practice and need further exploration.

Comparative efficacy and tolerability of antidepressants for major depressive disorder in children and adolescents: a network meta-analysis.

BACKGROUND: Major depressive disorder is one of the most common mental disorders in children and adolescents. However, whether to use pharmacological interventions in this population and which drug should be preferred are still matters of controversy. Consequently, we aimed to compare and rank antidepressants and placebo for major depressive disorder in young people. METHODS: We did a network meta-analysis to identify both direct and indirect evidence from relevant trials. We searched PubMed, the Cochrane Library, Web of Science, Embase, CINAHL, PsycINFO, LiLACS, regulatory agencies' websites, and international registers for published and unpublished, double-blind randomised controlled trials up to May 31, 2015, for the acute treatment of major depressive disorder in children and adolescents. We included trials of amitriptyline, citalopram, clomipramine, desipramine, duloxetine, escitalopram, fluoxetine, imipramine, mirtazapine, nefazodone, nortriptyline, paroxetine, sertraline, and venlafaxine. Trials recruiting participants with treatment-resistant depression, treatment duration of less than 4 weeks, or an overall sample size of less than ten patients were excluded. We extracted the relevant information from the published reports with a predefined data extraction sheet, and assessed the risk of bias with the Cochrane risk of bias tool. The primary outcomes were efficacy (change in depressive symptoms) and tolerability (discontinuations due to adverse events). We did pair-wise meta-analyses using the random-effects model and then did a random-effects network meta-analysis within a Bayesian framework. We assessed the quality of evidence contributing to each network estimate using the GRADE framework. This study is registered with PROSPERO, number CRD42015016023. FINDINGS: We deemed 34 trials eligible, including 5260 participants and 14 antidepressant treatments. The quality of evidence was rated as very low in most comparisons. For efficacy, only fluoxetine was statistically significantly more effective than placebo (standardised mean difference -0·51, 95% credible interval [CrI] -0·99 to -0·03). In terms of tolerability, fluoxetine was also better than duloxetine (odds ratio [OR] 0·31, 95% CrI 0·13 to 0·95) and imipramine (0·23, 0·04 to 0·78). Patients given imipramine, venlafaxine, and duloxetine had more discontinuations due to adverse events than did those given placebo (5·49, 1·96 to 20·86; 3·19, 1·01 to 18·70; and 2·80, 1·20 to 9·42, respectively). In terms of heterogeneity, the global I(2) values were 33·21% for efficacy and 0% for tolerability. INTERPRETATION: When considering the risk-benefit profile of antidepressants in the acute treatment of major depressive disorder, these drugs do not seem to offer a clear advantage for children and adolescents. Fluoxetine is probably the best option to consider when a pharmacological treatment is indicated. FUNDING: National Basic Research Program of China (973 Program).

Modulation of triglyceride accumulation in adipocytes by psychopharmacological agents in vitro.

Weight gain is a major problem during psychopharmacological treatment. Research has concentrated on the appetite inducing properties and mechanisms of these drugs in the central nervous system. The potential contribution of direct effects of drugs on metabolically relevant peripheral cells such as adipocytes is less well understood. We examined the influence of the antidepressant imipramine, the antipsychotic clozapine, and the mood stabilizer lithium on preadipocytes and adipocytes in vitro, using Simpson-Golabi-Behmel syndrome (SGBS) cells, an established human preadipocyte model. Parameters of cell differentiation and signaling, and cell metabolism were measured. We found significantly increased triglyceride accumulation in adipocytes after supplementation with imipramine and lithium at therapeutic concentrations, compared to non-supplemented control samples. However, gene expression levels of an early marker of adipogenesis, the peroxisome proliferator-activated receptor gamma (PPAR-γ) and a late marker of adipogenesis, the fatty acid binding protein 4 (FABP4), as well as expression of adiponectin (ADIPOQ) did not change significantly in the presence of these psychopharmacological agents. The results suggest a direct influence of imipramine and lithium but not clozapine on fat storage of adipocytes. The underlying mechanisms of fatty acid storage and adipocyte differentiation however remain to be elucidated.

IL-4/10 prevents stress vulnerability following imipramine discontinuation.

BACKGROUND: Identifying stress vulnerability after antidepressant discontinuation may be useful in treating relapses in depression. Previous studies have suggested significant effects of the immune system as well as the central nervous system (CNS) on progression and induction of major depression. In the present study, we hypothesized that the factors that are not rescued by a tricyclic antidepressant imipramine may be associated with stress vulnerability and relapses in depression. METHODS: To address this issue, mice were exposed to 2 h of restraint stress for 21 consecutive days (chronic restraint stress (CRS)) with or without co-treatment of imipramine. These groups were exposed to an electronic foot shock (FS) as additional stress after imipramine washout. Main targets of stress and antidepressants were analyzed in the hippocampus, lymph node, and serum after a series of depression-like behavior analysis. RESULTS: In this study, we found for the first time that mice exposed to CRS with a tricyclic antidepressant imipramine co-treatment, which did not show depressive-like behaviors, were vulnerable to subsequent stressful stimuli compared to the non-stressed mice after imipramine washout. CRS mice with imipramine co-treatment did not show any difference in BDNF, serotonin receptors, pro-inflammatory cytokines, or kynurenine pathway in the hippocampus compared to the controls. However, peripheral IL-4, IL-10, and alternatively activated microglial phenotypes in the hippocampus were not restored with sustained reduction in CRS mice despite chronic imipramine administration. Supplementing recombinant IL-4 and IL-10 in co-Imi+CRS mice prevented the stress vulnerability on additional stress and restored factors related to alternatively activated microglia (M2) in the hippocampus. CONCLUSION: Thus, our results suggest that the reduced IL-4 and IL-10 levels in serum with hippocampal M2 markers may be involved in the stress vulnerability after imipramine discontinuation, and the restoration and modulation of these factors may be useful to some forms of depression-associated conditions.

Serotonin syndrome overlapping with neuroleptic malignant syndrome: A case report and approaches for differentially diagnosing the two syndromes.

Serotonin syndrome (SS) and neuroleptic malignant syndrome (NMS) are life-threatening adverse reactions caused by serotonergic antidepressants and neuroleptics, respectively. SS and NMS have overlapping clinical features, and thus differentially diagnosing the syndromes can be difficult in patients who are taking both types of drugs. Here, the author reports a unique case of a patient who developed SS that overlapped with NMS after taking imipramine and lithium carbonate with the subsequent addition of metoclopramide. This is the first case report of SS that overlapped with NMS. The author also briefly summarizes the clinical symptoms of each syndrome and describes the approaches that were used to differentially diagnose the two syndromes.

Memantine prevents "bipolar-like" behavior induced by chronic treatment with imipramine in rats.

A great deal of evidence suggests that virtually all antidepressant treatments induce a dopaminergic behavioral supersensitivity. We have suggested that this effect may play a key role not only in the antidepressant effect of these treatments, but also in their ability to induce a switch from depression to mania. In 2003-4 we found that the sensitization of dopamine receptors induced by imipramine is followed, after imipramine withdrawal, by a desensitization of these receptors associated with a depressive-like behavior assessed in the forced swimming test. The dopamine receptor sensitization can be prevented by MK-801, an NMDA receptor antagonist, but not by currently used mood stabilizers (lithium, carbamazepine, valproate). These observations led us to suggest - and later confirm - with preliminary clinical observations that memantine may have an acute antimanic and a long-lasting mood-stabilizing effect in treatment-resistant bipolar disorder patients. Here we present data showing that memantine prevents not only the dopamine receptor sensitization induced by imipramine, as observed with MK-801, but also the ensuing desensitization and the associated depressive-like behaviorq observed after antidepressant withdrawal.