Imipramine in Dogs: A Pharmacokinetic Study Following Oral Administration under Fasted and Fed Conditions.

This study investigates the pharmacokinetics (PK) of imipramine, a tricyclic antidepressant used in human psychiatric disorders and increasingly considered in veterinary medicine. Despite its longstanding use in canines, prior research on imipramine's PK in dogs is lacking. This study aimed to determine the PK of imipramine in dogs in regards to feeding conditions, and to ascertain whether desipramine (active metabolite) is formed or not. In this study, six male Labrador dogs underwent oral administration (1.5mg/kg) of imipramine tablets (10mg each; Tofranil®, Novartis) in both fasted and fed conditions. Dogs were randomly allocated to one of two treatment groups, employing an open, single-dose, two-treatment, two-phase, cross-over design, with a washout period of one week. Blood was drawn from the left cephalic vein to heparinized tubes at 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 10, 24, and 48hr. Plasma concentrations were quantified using a validated HPLC method, and the data were analyzed using PKanalixTM software with a non-compartmental approach. Concentrations of imipramine remained quantifiable up to 1.5hr after administration under both conditions. Desipramine, in both feeding states, was detectable for a short duration, but not quantifiable. No significant differences were observed in the PK parameters of imipramine between the fasting and fed states. The rapid attainment of maximum concentration (Cmax) occurred within 0.25hr, indicating a swift absorption rate. Notably, the terminal half-life in dogs was remarkably short at 0.25hr, prompting a re-evaluation of dosing strategies. Considering the recommended therapeutic plasma concentrations in humans, the administered dose might result in effective levels for a brief period of time. Future research should explore intravenous administration, multiple-dose studies, and metabolic investigations to further elucidate imipramine's PK in dogs.

Potentiation of Imipramine-Induced Anti-hyperalgesic and Anti-Nociceptive Effects by Citicoline in the Sciatic Nerve Ligated Mice.

BACKGROUND: Peripheral neuropathic pain is a result of damage/illness of the peripheral nerves. The mechanisms caused by its pathophysiology are not completely understood. METHODS: Imipramine is a tricyclic antidepressant that is sometimes used to treat neuropathic pain. Moreover, citicoline is considered a novel adjuvant for painful disorders such as neuropathic pain. So, a possible interaction between imipramine and citicoline on pain behavior was examined in nerve-ligated mice using tail-flick and hot plate tests. RESULTS: The results indicated that induction of neuropathic pain by sciatic nerve ligation caused hyperalgesia in nerve-ligated mice. On the other hand, intraperitoneal (i.p.) administration of citicoline (50, 75, and 100 mg/kg), and imipramine (2.5 and 5 mg/kg) induced anti-hyperalgesic and anti-nociceptive effects in nerve-ligated mice. Furthermore, citicoline potentiated the anti-hyperalgesic and anti-nociceptive effects of imipramine when they were co-administrated in nerve-ligated mice. Interestingly, there was an additive effect between imipramine and citicoline upon induction of anti-hyperalgesic and anti-nociceptive effects in nerve-ligated mice. CONCLUSION: Therefore, it can be concluded that citicoline (as an adjuvant substance) enhanced the efficacy of imipramine for the modulation of pain behavior in nerve-ligated mice.

Long-term effects of a single high-dose intraperitoneal injection of lipopolysaccharide on depression-like behavior in adolescent mice.

The commonly used lipopolysaccharide (LPS)-induced depression models often evaluate depression-like behaviors in the acute phase after a single intraperitoneal injection of LPS, and are not suitable for examining long-term depression-like behaviors. To overcome this limitation, we developed a mice LPS model for elucidating the long-term pathophysiology of depression. Using the tail-suspension test, we show that a single intraperitoneal injection of a high dose (1.66 mg/kg) of LPS prolonged depression-like behavior to 14 days after LPS administration unlike 4 days after administration for the most commonly used LPS dose (0.83 mg/kg). Upon high-LPS dose administration, TNF-α levels in the cerebrospinal fluid were increased only on the first day after administration. Moreover, LPS-induced depression-like behavior on day 10 after LPS administration was prevented by imipramine or minocycline. Immunohistochemical analysis revealed reduced neurogenesis in the hippocampal dentate gyrus of LPS-treated mice on day 10 of LPS administration. The LPS model, in which a single intraperitoneal administration of LPS at a dose double of the standard dose used currently, exhibits depression-like behavior via reduced neurogenesis mediated by neuroinflammation, and should be useful for elucidating the long-term pathophysiology of depression and for studying antidepressant drugs.

Imipramine Increases Norepinephrine and Serotonin in the Salivary Glands of Rats.

Xerostomia induced by antidepressants such as imipramine has long been thought to be due to their anticholinergic effects. However, even antidepressants with low anticholinergic effects may have a high incidence of xerostomia. In salivary glands, norepinephrine activates alpha-adrenergic receptors in blood vessels and beta-adrenergic receptors in acinar cells, respectively, causing a decrease in the blood flow and an increase in the protein secretion, resulting in the secretion of viscous saliva with low water content and high protein content. A previous study demonstrated that perfusion of the submandibular glands of rats with serotonin significantly decreased saliva secretion. The results of the present study revealed the following: (1) that norepinephrine and serotonin, but not epinephrine nor dopamine, were detected in the interstitial fluids in rat submandibular glands; (2) that norepinephrine and serotonin concentrations in the dialysate was 4.3 ± 2.8 nM and 32.3 ± 19.6 nM at stable level, respectively; (3) that infusion with imipramine, a reuptake inhibitor of norepinephrine and serotonin, significantly and dose-dependently increased both norepinephrine and serotonin concentrations in the dialysate; and (4) that intraperitoneal administration of imipramine significantly increased both norepinephrine and serotonin concentrations in the dialysate. These results suggested that one of the mechanisms of xerostomia induced by reuptake inhibitors of norepinephrine and serotonin involves the activation of adrenergic and serotonin receptors in the salivary glands, respectively.

Effect of Single-Dose Imipramine on Anal Sphincter Tone in Healthy Women: A Randomized, Placebo-Controlled Study Using Anal Acoustic Reflectometry.

INTRODUCTION AND HYPOTHESIS: Despite the high prevalence of fecal incontinence, existing treatment options may be inadequate. Drugs that enhance the tone of the anal sphincter complex could potentially be an effective pharmacological approach. This study investigated the effect of the tricyclic antidepressant imipramine on anal sphincter tone in healthy women, employing anal acoustic reflectometry as the evaluating method. METHODS: In a double-blind, randomized, placebo-controlled crossover study, 16 healthy female volunteers were randomized to one of two treatment sequences. The participants attended two study visits separated by at least 7 days' washout. At each visit, they received a single dose of 50 mg imipramine or matching placebo, in alternating order. We assessed the anal opening pressure under the resting state and during voluntary squeezing of the pelvic floor. Measurements were performed pre-dose and 1 h after drug administration, corresponding to the estimated time of peak plasma concentration of imipramine. RESULTS: All participants completed the study. In total, 44% of the participants reported at least one adverse effect, primarily anticholinergic. Compared with placebo, imipramine increased anal opening pressure by 15.2 cmH2O (95% confidence interval [CI] 2.0-28.2 cmH2O, p = 0.03) in the resting state and 15.1 (95% CI 4.2-26.0 cmH2O, p = 0.01) cmH2O during squeezing. CONCLUSIONS: The findings indicate that imipramine increases anal sphincter tone in healthy women. However, further research is required to evaluate its clinical impact on individuals with fecal incontinence. This research also demonstrates the effectiveness of using anal acoustic reflectometry for assessing pharmacological effects on anal sphincter function.

Mass Spectrometry Imaging Combined with Sparse Autoencoder Method Reveals Altered Phosphorylcholine Distribution in Imipramine Treated Wild-Type Mice Brains.

Mass spectrometry imaging (MSI) is essential for visualizing drug distribution, metabolites, and significant biomolecules in pharmacokinetic studies. This study mainly focuses on imipramine, a tricyclic antidepressant that affects endogenous metabolite concentrations. The aim was to use atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI)-MSI combined with different dimensionality reduction methods to examine the distribution and impact of imipramine on endogenous metabolites in the brains of treated wild-type mice. Brain sections from both control and imipramine-treated mice underwent AP-MALDI-MSI. Dimensionality reduction methods, including principal component analysis, multivariate curve resolution, and sparse autoencoder (SAE), were employed to extract valuable information from the MSI data. Only the SAE method identified phosphorylcholine (ChoP) as a potential marker distinguishing between the control and treated mice brains. Additionally, a significant decrease in ChoP accumulation was observed in the cerebellum, hypothalamus, thalamus, midbrain, caudate putamen, and striatum ventral regions of the treated mice brains. The application of dimensionality reduction methods, particularly the SAE method, to the AP-MALDI-MSI data is a novel approach for peak selection in AP-MALDI-MSI data analysis. This study revealed a significant decrease in ChoP in imipramine-treated mice brains.

Effect of imipramine on memory, adult neurogenesis, neuroinflammation, and mitochondrial biogenesis in a rat model of alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline and memory loss. Imipramine, a tricyclic antidepressant, has potent anti-inflammatory and antioxidant properties in the central nervous system. The aim of this study was to investigate the neuroprotective effects of imipramine on streptozotocin (STZ)-induced memory impairment. Male Wistar rats received an intracerebroventricular injection of STZ (3 mg/kg, 3 µl/ventricle) using the stereotaxic apparatus. The Morris water maze and passive avoidance tests were used to evaluate cognitive functions. 24 h after the STZ injection, imipramine was administered intraperitoneally at doses of 10 or 20 mg/kg for 14 consecutive days. The mRNA and protein levels of neurotrophic factors (BDNF and GDNF) and pro-inflammatory cytokines (IL-6, IL-1ß, and TNF-α) were measured in the hippocampus using real-time PCR and ELISA techniques, respectively. In addition, real-time PCR was used to evaluate the mRNA levels of markers associated with neurogenesis (Nestin, DCX, and Ki67) and mitochondrial biogenesis (PGC-1α, NRF-1, and TFAM). The results showed that imipramine, especially at a dose of 20 mg/kg, effectively improved STZ-induced memory impairment. This improvement was associated with an increase in neurogenesis and neurotrophic factors and a decrease in neuroinflammation and mitochondrial biogenesis dysfunction. Based on these results, imipramine appears to be a promising therapeutic option for improving cognitive functions in neurodegenerative diseases such as AD.

Management of the refractory nocturnal enuresis patient to desmopressin in a pediatric population: Desmopressin + oxybutynin vs. desmopressin + imipramine.

INTRODUCTION AND OBJECTIVE: Desmopressin is well accepted as first-line medical therapy for enuresis. If ineffective, combination therapy of desmopressin + oxybutynin or desmopressin + imipramine has been used. This study assessed the efficacy of adjunct therapy with either imipramine or oxybutynin in the management of enuresis patients who failed desmopressin treatment. STUDY DESIGN: A retrospective chart review of our database for patients with enuresis was performed. Patients who were prescribed desmopressin, oxybutynin, and imipramine over 14 years for enuresis were included. Two cohorts of patients were examined; group OXY was treated with desmopressin and oxybutynin, and group IMP received desmopressin and imipramine. Pretreatment measurement of Vancouver Symptom Scores (VSS) were used to compare groups using the VSS question "I wet my bed at night" where 4: every night, 3: 4-5 nights per week, 2: 1-2 nights per week, 1: 3-4 nights per month, and 0: never. International Children's Continence Society (ICCS) criteria for continence success was utilized to determine outcomes. RESULTS: 2521 patients prescribed one of the 3 medications were identified. Among them, 81 patients (mean age: 10.5 ± 2.8 years) received combination therapy. Of which, 55 were male and 26 female. Specifically, 58 were prescribed both desmopressin and imipramine (group IMP), 23 desmopressin and oxybutynin (group OXY), and 4 transitioned from OXY to IMP. Mean pretreatment VSS showed no difference between groups. Both groups experienced minimal drops in wet nights with desmopressin alone. A comparison revealed that group IMP reduced wet nights significantly more than group OXY (VSS wet night score 0.7 ± 1.2 vs. 2.3 ± 1.1 respectively, p < 0.0001). Non-intent-to-treat complete response rate was 68% vs 5% (OR = 42.5, p < 0.001) (IMP vs. OXY respectively). Intent-to-treat response rates were 58%. DISCUSSION: Although first-line desmopressin treatment for enuresis is effective, it does not work for all patients, and many parents and children desire nighttime dryness. Clinicians have combined desmopressin with oxybutynin or imipramine for improved results, but research comparing these modalities is scarce. Our study suggests that the desmopressin and imipramine combination is superior at reducing nights wet compared to desmopressin and oxybutynin, attributed to imipramine's probable central mechanism rather than its secondary anticholinergic properties. Limitations include a modest sample size, retrospective design, and subjective responses to the Vancouver questionnaire. CONCLUSION: A combination of desmopressin and imipramine was more effective in reducing wet nights and had a complete response rate that was 42.5 times greater than desmopressin and oxybutynin.

Elucidating Gender-Specific Distribution of Imipramine, Chloroquine, and Their Metabolites in Mice Kidney Tissues through AP-MALDI-MSI.

Knowledge of gender-specific drug distributions in different organs are of great importance for personalized medicine and reducing toxicity. However, such drug distributions have not been well studied. In this study, we investigated potential differences in the distribution of imipramine and chloroquine, as well as their metabolites, between male and female kidneys. Kidneys were collected from mice treated with imipramine or chloroquine and then subjected to atmospheric pressure matrix-assisted laser desorption ionization-mass spectrometry imaging (AP-MALDI-MSI). We observed differential distributions of the drugs and their metabolites between male and female kidneys. Imipramine showed prominent distributions in the cortex and medulla in male and female kidneys, respectively. Desipramine, one of the metabolites of imipramine, showed significantly higher (*** p < 0.001) distributions in the medulla of the male kidney compared to that of the female kidney. Chloroquine and its metabolites were accumulated in the pelvis of both male and female kidneys. Interestingly, they showed a characteristic distribution in the medulla of the female kidney, while almost no distributions were observed in the same areas of the male kidney. For the first time, our study revealed that the distributions of imipramine, chloroquine, and their metabolites were different in male and female kidneys.

Erratum: Effects of imipramine on cancer patients over-expressing Fascin1; description of the HITCLIF clinical trial.

[This corrects the article DOI: 10.3389/fonc.2023.1238464.].