Prazosin Potentiates Mast Cell-Stabilizing Property of Adrenaline.

BACKGROUND/AIMS: Adrenaline quickly inhibits the release of histamine from mast cells. Besides ß2-adrenergic receptors, several in vitro studies also indicate the involvement of α-adrenergic receptors in the process of exocytosis. Since exocytosis in mast cells can be detected electrophysiologically by the changes in the membrane capacitance (Cm), its continuous monitoring in the presence of drugs would determine their mast cell-stabilizing properties. METHODS: Employing the whole-cell patch-clamp technique in rat peritoneal mast cells, we examined the effects of adrenaline on the degranulation of mast cells and the increase in the Cm during exocytosis. We also examined the degranulation of mast cells in the presence or absence of α-adrenergic receptor agonists or antagonists. RESULTS: Adrenaline dose-dependently suppressed the GTP-γ-S-induced increase in the Cm and inhibited the degranulation from mast cells, which was almost completely erased in the presence of butoxamine, a ß2-adrenergic receptor antagonist. Among α-adrenergic receptor agonists or antagonists, high dose prazosin, a selective α1-adrenergic receptor antagonist, significantly reduced the ratio of degranulating mast cells and suppressed the increase in the Cm. Additionally, prazosin augmented the inhibitory effects of adrenaline on the degranulation of mast cells. CONCLUSION: This study provided electrophysiological evidence for the first time that adrenaline dose-dependently inhibited the process of exocytosis, confirming its usefulness as a potent mast cell-stabilizer. The pharmacological blockade of α1-adrenergic receptor by prazosin synergistically potentiated such mast cell-stabilizing property of adrenaline, which is primarily mediated by ß2-adrenergic receptors.

Role of prazosin in patients with Guillain-Barré syndrome with sympathetic overactivity: A cohort study.

INTRODUCTION/AIMS: In Guillain-Barré syndrome (GBS), patients with dysautonomia demonstrate sympathetic overactivity (SO). This study assessed the role of prazosin (α1-blocker) in the management of SO. METHODS: This cohort study was conducted from January 2022 to September 2023. Thirty-two GBS patients with SO received prazosin (2.5-10 mg three times a day) (prazosin group). For comparison, we included historical controls that included 33 GBS patients having SO with similar baseline characteristics, including median age and disability, who did not receive prazosin, from a GBS registry of patients admitted during February 2018-December 2021. The primary endpoint was days to resolution of SO. Secondary endpoints were daily fluctuations in the systolic (SBP) and diastolic blood pressure (DBP), duration of hospital stay, in-hospital mortality, and disability at 3 months. RESULTS: The median ages of both the treatment and the control groups were 36 (IQR 25-49) years and 43 (66.2%) were males. The demographic and clinical parameters were comparable. Prazosin resulted in significantly earlier normalization of SO compared to the control group (median 15 vs. 20 days; p = .01). The mean fluctuations in the SBP and DBP at 15 days were significantly lower in the prazosin group. However, the duration of hospital stay and good recovery at 3 months were comparable. Three patients developed hypotension, while two patients died (ventilator-associated pneumonia) in the prazosin group. DISCUSSION: This study provides new evidence supporting the role of prazosin in SO, and needs randomized trials to confirm our findings.

Augmentation with prazosin for patients with depression and a history of trauma: A randomised, double-blind, placebo-controlled study.

INTRODUCTION: Depression with a history of trauma often responds poorly to conventional antidepressants and has a poor prognosis. Prazosin, an α1-adrenoceptor blocker, has shown promise in treating post-traumatic stress disorder symptoms, particularly nightmares. Its potential in treating depression with trauma history warrants investigation. AIMS OF THE STUDY: This randomised, double-blind, placebo-controlled study aimed to investigate the efficacy and tolerability of low-dose prazosin (0.5-1 mg/day) as an augmentation strategy in patients with depression and a history of trauma. We sought to determine if prazosin could provide rapid symptom improvement and enhance overall treatment response compared to placebo in this difficult-to-treat patient population. METHODS: This randomised, double-blind, placebo-controlled clinical study included 59 patients with first-episode or recurrent unipolar or bipolar depression. After basic antidepressant treatment, they were randomly assigned to a prazosin (0.5-1 mg/day) or placebo group for a 6-week double-blind controlled study. The Montgomery-Åsberg Depression Rating Scale, 17-item Hamilton Depression Scale (HAMD-17), and Hamilton Anxiety Scale (HAMA) were used to evaluate efficacy. RESULTS: There were no significant differences in the results of the demographic and clinical symptom assessment between the two groups (p > 0.05). The difference between the HAMD-17 and HAMA scores was statistically significant after 3 days of treatment (p < 0.05). The difference in response rate between the two groups was statistically significant after week 4 of treatment (end of week 4, 56.7% vs. 24.1%, p = 0.011; end of week 6, 80.0% vs. 48.3%, p = 0.011). The incidence of adverse reactions in the prazosin and placebo groups was 20.0% and 24.1%, respectively, with no statistically significant differences (p > 0.05); however, the prazosin group had a lower incidence of sleeplessness or nightmares (3.3% vs. 20.7%, p = 0.039) but a higher incidence of orthostatic hypotension (16.7% vs. 0%, p = 0.007). The severity of orthostatic hypotension was mild to moderate. CONCLUSION: Low-dose prazosin can effectively improve the emotional symptoms of patients with depression and a history of trauma, and the common adverse reaction is mild-to-moderate orthostatic hypotension. CLINICAL TRIAL REGISTRATION: ChiCTR2200063642.

Naltrexone augmented with prazosin for alcohol use disorder: results from a randomized controlled proof-of-concept trial.

AIMS: We conducted a proof-of-concept randomized controlled trial of the mu-opioid receptor antagonist, naltrexone, augmented with the alpha-1 adrenergic receptor antagonist, prazosin, for alcohol use disorder in veterans. We sought a signal that the naltrexone plus prazosin combination regimen would be superior to naltrexone alone. METHODS: Thirty-one actively drinking veterans with alcohol use disorder were randomized 1:1:1:1 to naltrexone plus prazosin (NAL-PRAZ [n = 8]), naltrexone plus placebo (NAL-PLAC [n = 7]), prazosin plus placebo (PRAZ-PLAC [n = 7]), or placebo plus placebo (PLAC-PLAC [n = 9]) for 6 weeks. Prazosin was titrated over 2 weeks to a target dose of 4 mg QAM, 4 mg QPM, and 8 mg QHS. Naltrexone was administered at 50 mg QD. Primary outcomes were the Penn Alcohol Craving Scale (PACS), % drinking days (PDD), and % heavy drinking days (PHDD). RESULTS: In the NAL-PRAZ condition, % reductions from baseline for all three primary outcome measures exceeded 50% and were at least twice as large as % reductions in the NAL-PLAC condition (PACS: 57% vs. 26%; PDD: 51% vs. 22%; PHDD: 69% vs. 15%) and in the other two comparator conditions. Standardized effect sizes between NAL-PRAZ and NAL-PLAC for each primary outcome measure were >0.8. All but one participant assigned to the two prazosin containing conditions achieved the target prazosin dose of 16 mg/day and maintained that dose for the duration of the trial. CONCLUSION: These results suggest that prazosin augmentation of naltrexone enhances naltrexone benefit for alcohol use disorder. These results strengthen rationale for an adequately powered definitive randomized controlled trial.

Prospective evaluation of pregnancy outcomes after gestational exposure to prazosin.

AIMS: Prazosin is an antihypertensive medication which can be used to help with post-traumatic stress disorder (PTSD) symptoms. Little data is currently available on its safety in pregnancy. The aim of this study was to assess the fetal and pregnancy safety associated with prazosin exposures in early pregnancy. METHODS: Subjects were 11 patients who took prazosin during pregnancy and were counselled at the FRAME clinic in London Health Sciences Centre (Ontario, Canada) between 1 January 2000 and 31 December 2021. Data on their other exposures and pregnancy outcomes were collected from medical records and through telephone questionnaires. RESULTS: It was found that 6/11 (54.5%) subjects did not report any adverse outcomes and experienced uneventful pregnancies. There were two miscarriages. Birthweights were within the normal range for the remaining nine pregnancies. Adverse events reported were consistent with background population expectation, including: one postpartum haemorrhage, one case of preeclampsia, one preterm birth, two NICU admissions, and two caesarean sections. CONCLUSIONS: For these 11 subjects, pregnancy outcomes after exposure to prazosin were consistent with typical outcomes from unexposed pregnancies. More data are needed to conclude that prazosin is safe for use in pregnant subjects. However, the lack of adverse effects above baseline is reassuring to future patients who may be unintentionally exposed to prazosin while pregnant. Therefore, this study contributes valuable data towards monitoring safety of prazosin in pregnancy.

Randomized controlled pilot trial of prazosin for prophylaxis of posttraumatic headaches in active-duty service members and veterans.

OBJECTIVE: Evaluate the efficacy and tolerability of prazosin for prophylaxis of headaches following mild traumatic brain injury in active-duty service members and military veterans. BACKGROUND: Prazosin is an alpha-1 adrenoreceptor antagonist that reduces noradrenergic signaling. An open-label trial in which prazosin reduced headache frequency in veterans following mild traumatic brain injury provided the rationale for this pilot study. METHODS: A 22-week parallel-group randomized controlled trial  which included 48 military veterans and active-duty service members with mild traumatic brain injury-related headaches was performed. The study design was based on International Headache Society consensus guidelines for randomized controlled trials for chronic migraine. Following a pre-treatment baseline phase, participants with at least eight qualifying headache days per 4 weeks were randomized 2:1 to prazosin or placebo. After a 5-week titration to a maximum possible dose of 5 mg (morning) and 20 mg (evening), participants were maintained on the achieved dose for 12 weeks. Outcome measures were evaluated in 4-week blocks during the maintenance dose phase. The primary outcome measure was change in 4-week frequency of qualifying headache days. Secondary outcome measures were percent participants achieving at least 50% reduction in qualifying headache days and change in Headache Impact Test-6 scores. RESULTS: Intent-to-treat analysis of randomized study participants (prazosin N = 32; placebo N = 16) demonstrated greater benefit over time in the prazosin group for all three outcome measures. In prazosin versus placebo participants, reductions from baseline to the final rating period for 4-week headache frequency were -11.9 ± 1.0 (mean ± standard error) versus -6.7 ± 1.5, a prazosin minus placebo difference of -5.2 (-8.8, -1.6 [95% confidence interval]), p = 0.005 and for Headache Impact Test-6 scores were -6.0 ± 1.3 versus +0.6 ± 1.8, a difference of -6.6 (-11.0, -2.2), p = 0.004. The mean predicted percent of participants at 12 weeks with ≥50% reduction in headache days/4 weeks, baseline to final rating, was 70 ± 8% for prazosin (21/30) versus 29 ± 12% for placebo (4/14), odds ratio 5.8 (1.44, 23.6), p = 0.013. The trial completion rate of 94% in the prazosin group (30/32) and 88% in the placebo group (14/16) indicated that prazosin was generally well tolerated at the administered dose regimen. Morning drowsiness/lethargy was the only adverse effect that differed significantly between groups, affecting 69% of the prazosin group (22/32) versus 19% of the placebo group (3/16), p = 0.002. CONCLUSIONS: This pilot study provides a clinically meaningful efficacy signal for prazosin prophylaxis of posttraumatic headaches. A larger randomized controlled trial is needed to confirm and extend these promising results.

Alcohol withdrawal symptoms predict corticostriatal dysfunction that is reversed by prazosin treatment in alcohol use disorder.

Chronic alcohol use increases risk of alcohol withdrawal symptoms (AW) and disrupts stress biology and resilient coping, thereby promoting excessive alcohol intake. Chronic alcohol intake and multiple alcohol detoxifications are known to impair brain medial prefrontal cortex (mPFC) and striatal functioning, regions involved in regulating stress, craving and alcohol intake. In two related studies, we examined whether AW predicts this functional brain pathology and whether Prazosin versus Placebo treatment may reverse these effects. In Study 1, patients with Alcohol Use Disorder (AUD) (N = 45) with varying AW levels at treatment entry were assessed to examine AW effects on corticostriatal responses to stress, alcohol cue and neutral visual images with functional magnetic resonance imaging (fMRI). In Study 2, 23 AUD patients entering a 12-week randomised controlled trial (RCT) of Prazosin, an alpha1 adrenergic antagonist that decreased withdrawal-related alcohol intake in laboratory animals, participated in two fMRI sessions at pretreatment and also at week 9-10 of chronic treatment (Placebo: N = 13; Prazosin: N = 10) to assess Prazosin treatment effects on alcohol-related cortico-striatal dysfunction. Study 1 results indicated that higher AW predicted greater disruption in brain mPFC and striatal response to stress and alcohol cues (p < 0.001, family-wise error [FWE] correction) and also subsequently greater heavy drinking days (HDD) in early treatment (p < 0.01). In Study 2, Prazosin versus Placebo treatment reversed mPFC-striatal dysfunction (p < 0.001, FWE), which in turn predicted fewer drinking days (p < 0.01) during the 12-week treatment period. These results indicate that AW is a significant predictor of alcohol-related prefrontal-striatal dysfunction, and Prazosin treatment reversed these effects that in turn contributed to improved alcohol treatment outcomes.

Simple and high sample throughput LC/ESI-MS/MS method for bioequivalence study of prazosin, a drug with risk of orthostatic hypotension.

OBJECTIVE: The study aimed to develop a rapid, simple and sensitive LC/ESI-MS/MS method to measure prazosin concentration in human plasma and apply bedside sampling in bioequivalence study of two prazosin tablets to resolve the adverse effect of orthostatic hypotension. SIGNIFICANCE: The LC/ESI-MS/MS prazosin method was highly sensitive and selective. Bedside sampling reduced the orthostatic hypotension incidence and subject dropout rate. METHODS: After sample preparation, prazosin and terazosin (IS) were detected on mass spectrometer operating in multiple reaction monitoring mode using positive ionization. Mobile phase flow rate was set at 0.40 mL/min with sample run time of 1.75 min. The bioanalytical method was validated as per EMEA and FDA guidelines. Bedside sampling was performed in bioequivalence study for the first 4 h after dosing. The three primary pharmacokinetic parameters, Cmax, AUC0-t and AUC0-∞ and 90% confidence interval were determined. RESULTS: The small injection volume of 1 µL minimized instrumentation contamination and prolonged the analytical column lifespan. Linearity was obtained between 0.5 and 30.0 ng/mL, with coefficient of determination, r2 ≥ 0.99. The mean extraction recovery of prazosin and IS was >92%, with precision value (CV, %) ≤ 10.3%. Only two orthostatic hypotension adverse events were reported. The two prazosin formulations were found to be bioequivalent. CONCLUSION: The LC/ESI-MS/MS method has shown robustness and reliability exemplified by the incurred sample re-analysis result. Bedside sampling should be proposed for bioequivalence or pharmacokinetic studies of drugs demonstrating adverse event of orthostatic hypotension.

Kidney, Cardiac, and Safety Outcomes Associated With α-Blockers in Patients With CKD: A Population-Based Cohort Study.

RATIONALE & OBJECTIVES: Alpha-blockers (ABs) are commonly prescribed for control of resistant or refractory hypertension in patients with and without chronic kidney disease (CKD). The association between AB use and kidney, cardiac, mortality, and safety-related outcomes in CKD remains unknown. STUDY DESIGN: Population-based retrospective cohort study. SETTINGS & PARTICIPANTS: Ontario (Canada) residents 66 years and older treated for hypertension in 2007 to 2015 without a prior prescription for an AB. EXPOSURES: New use of an AB versus new use of a non-AB blood pressure (BP)-lowering medication. OUTCOMES: 30% or greater estimated glomerular filtration rate (eGFR) decline; dialysis initiation or kidney transplantation (kidney replacement therapy); composite of acute myocardial infarction, coronary revascularization, congestive heart failure, or atrial fibrillation; safety (hypotension, syncope, falls, and fractures) events; and mortality. ANALYTICAL APPROACH: New users of ABs (doxazosin, terazosin, and prazosin) were matched to new users of non-ABs by a high dimensional propensity score. Cox proportional hazards and Fine and Gray models were used to examine the association of AB use with kidney, cardiac, mortality, and safety outcomes. Interactions by eGFR categories (≥90, 60-89, 30-59, and<30mL/min/1.73m2) were explored. RESULTS: Among 381,120 eligible individuals, 16,088 were dispensed ABs and matched 1:1 to non-AB users. AB use was associated with higher risk for≥30% eGFR decline (HR, 1.14; 95% CI, 1.08-1.21) and need for kidney replacement therapy (HR, 1.28; 95% CI, 1.13-1.44). eGFR level did not modify these associations, P interaction=0.3and 0.3, respectively. Conversely, AB use was associated with lower risk for cardiac events, which was also consistent across eGFR categories (HR, 0.92; 95% CI, 0.89-0.95; P interaction=0.1). AB use was also associated with lower mortality risk, but only among those with eGFR<60mL/min/1.73m2 (P interaction<0.001): HRs were 0.85 (95% CI, 0.78-0.93) and 0.71 (95% CI, 0.64-0.80) for eGFR of 30 to 59 and<30mL/min/1.73m2, respectively. LIMITATIONS: Observational design, BP measurement data unavailable. CONCLUSIONS: AB use in CKD is associated with higher risk for kidney disease progression but lower risk for cardiac events and mortality compared with alternative BP-lowering medications.

Prazosin for treatment of post-traumatic stress disorder: a systematic review and meta-analysis.

BACKGROUND: Prazosin has been an accepted treatment for patients with post-traumatic stress disorder (PTSD) who experience sleep disturbances, including nightmares. Results of a recent large randomized control trial did not find benefit of prazosin vs placebo in improving such outcomes. A meta-analysis that includes this most recent trial was conducted to examine the pooled effect of prazosin vs placebo on sleep disturbances and overall PTSD symptoms in patients with PTSD. METHODS: A systematic review of the published literature on trials comparing prazosin vs placebo for improvement of overall PTSD scores, nightmares, and sleep quality was conducted. Hedges' g standardized mean differences (SMD) between prazosin and placebo were calculated for each outcome across studies. RESULTS: Six randomized placebo-controlled studies representing 429 patients were included in the analysis, including two studies with a crossover design. Results showed prazosin significantly improved overall PTSD scores (SMD = -0.31; 95% confidence intervals [CI]: -0.62, -0.01), nightmares (SMD = -0.75; 95% CI: -1.24, -0.27), and sleep quality (SMD = -0.57; 95% CI: -1.02, -0.13). In the largest trial, prazosin showed a reduction in clinical outcome measures similar to past studies, but a relatively large placebo effect size, particularly for nightmares, contributed to no treatment differences. CONCLUSIONS: Despite the results of a recent, large randomized study, pooled effect estimates show that prazosin has a statistically significant benefit on PTSD symptoms and sleep disturbances. Limitations that should be considered include heterogeneity of study design and study populations as well as the small number of studies conducted and included in this meta-analysis.

A retrospective chart review to determine the safety and efficacy of prazosin for nightmares related to posttraumatic stress disorder in veterans.

OBJECTIVE: To evaluate the efficacy of prazosin for posttraumatic stress disorder (PTSD)-related nightmares in veterans and to analyze subgroup benefit/risk to guide prescribing. METHODS: Patients with a previous prescription for prazosin between 1 June 2007 and 30 June 2017 were collected from the institution's electronic records. Efficacy (including nightmare frequency, and clinical PTSD rating scales) and safety (including blood pressure) data were retrospectively analyzed. RESULTS: Eighty-four patients were included in the analysis. The primary outcome, item 2 of the PTSD checklist, decreased from 4.00 to 3.19 (on a scale of 1-5), which was statistically significant (p < 0.05). Nightmare frequency was found to have a statistically significant decrease from four to two times per week on average (p = 0.00002, 95% CI 2.36 [1.39-3.33]). Of the patients who reported the greatest response (n = 23), 91% (n = 21) were on an antidepressant and 61% (n = 14) were receiving concurrent psychotherapy. This is compared to 90% (n = 76) and 44% (n = 37) of the total cohort, respectively. No significant differences were found in blood pressure or suicidal ideation (p = 0.58 and p = 0.22, respectively). CONCLUSION: Prazosin may be considered as an adjunct option to decrease nightmare frequency in patients already receiving first-line treatment.

Pharmacological management of post-traumatic stress disorder and its associated nightmares: A survey of psychiatrists.

WHAT IS KNOWN AND OBJECTIVE: To describe the pharmacological management of post-traumatic stress disorder (PTSD) by psychiatrists, with a focus on their use of clinical guidelines and the role of prazosin for nightmares. METHODS: An online survey of Australian and New Zealand psychiatrists was conducted. Aspects included respondent demographics, familiarity and usage of guidelines for PTSD, and opinions on the safety and efficacy of prazosin for PTSD-associated nightmares. RESULTS AND DISCUSSION: A total of 157 responses were recorded, 106 of which were complete. The most frequently used guideline for PTSD management was over 10 years old and used by only 48% of respondents. Peer-reviewed scientific journals were the most common additional source used by psychiatrists to inform their practice. For the targeted treatment of nightmares, 35 different medications had been trialled by respondents. Prazosin had been prescribed by 86% of psychiatrists for PTSD-associated nightmares, with only 2% reporting it to be ineffective in reducing nightmare frequency and/or intensity. Psychiatrists who were familiar with prazosin-mentioning guidelines (P < .05) and those who more frequently treat patients with PTSD (P < .01) were most likely to have prescribed prazosin. WHAT IS NEW AND CONCLUSION: Psychiatrists generally do not rely on guidelines to inform the treatment of PTSD. Off-label prescription of prazosin for PTSD-associated nightmares occurs frequently, with positive perceived outcomes, despite conflicting published evidence and a lack of local guideline recommendations for its use.

Norepinephrine May Oppose Other Neuromodulators to Impact Alzheimer's Disease.

While much of biomedical research since the middle of the twentieth century has focused on molecular pathways inside the cell, there is increasing evidence that extracellular signaling pathways are also critically important in health and disease. The neuromodulators norepinephrine (NE), serotonin (5-hydroxytryptamine, 5HT), dopamine (DA), acetylcholine (ACH), and melatonin (MT) are extracellular signaling molecules that are distributed throughout the brain and modulate many disease processes. The effects of these five neuromodulators on Alzheimer's disease (AD) are briefly examined in this paper, and it is hypothesized that each of the five molecules has a u-shaped (or Janus-faced) dose-response curve, wherein too little or too much signaling is pathological in AD and possibly other diseases. In particular it is suggested that NE is largely functionally opposed to 5HT, ACH, MT, and possibly DA in AD. In this scenario, physiological "balance" between the noradrenergic tone and that of the other three or four modulators is most healthy. If NE is largely functionally opposed to other prominent neuromodulators in AD, this may suggest novel combinations of pharmacological agents to counteract this disease. It is also suggested that the majority of cases of AD and possibly other diseases involve an excess of noradrenergic tone and a collective deficit of the other four modulators.

Effects of Prazosin on Provoked Alcohol Craving and Autonomic and Neuroendocrine Response to Stress in Alcohol Use Disorder.

BACKGROUND: Chronic alcohol use results in changes to stress biology and autonomic arousal contributing to acute alcohol withdrawal symptoms, neuroendocrine tolerance of the hypothalamic-pituitary-adrenal axis responses, high stress-induced craving, and risk of alcohol relapse. Thus, stress coping and recovery from alcohol during early abstinence may be jeopardized by such stress system dysfunction. Significant preclinical evidence suggests that noradrenergic disruption may contribute to these alcohol-related stress arousal changes and that alpha-1 adrenergic antagonists, such as prazosin, may normalize these stress system adaptations and reduce alcohol intake. Thus, we hypothesized that prazosin would reduce stress-induced craving and improve neuroendocrine and autonomic response to stress and alcohol cue exposure during early abstinence. We secondarily also assessed the role of lifetime anxiety disorders on these prazosin effects. METHODS: Forty inpatient treatment-seeking alcohol-dependent individuals were randomly assigned to receive placebo (n = 18) or 16 mg/d, T.I.D., prazosin (n = 22) in a double-blind manner, titrated over 2 weeks. In weeks 3 to 4 after achieving full dose, patients were exposed to 3 5-minute personalized guided imagery conditions (stress cue, alcohol cue, neutral/relaxing cue), on 3 consecutive days in a random, counterbalanced order. Alcohol craving, anxiety, heart rate, cortisol, and adrenocorticotropic hormone (ACTH) levels were assessed at baseline, following imagery and at repeated recovery timepoints. RESULTS: Prazosin reduced stress cue-induced alcohol craving (p < 0.05) and stress- and alcohol cue-induced anxiety (p < 0.05) and increased heart rate responses in all imagery conditions (p < 0.05). Prazosin lowered basal cortisol and ACTH (p's < 0.05) and attenuated stress cue-induced rises in cortisol (p < 0.05) versus placebo. Finally, in those without lifetime anxiety disorder, the placebo group showed stress- and alcohol cue-induced increases in cortisol (p's < 0.05), while the prazosin group did not. CONCLUSIONS: Prazosin may attenuate stress cue-induced alcohol craving and anxiety during early abstinence while improving adrenergic and stress system function, effects which are independent of a history of lifetime anxiety disorders.

Negative relationship between brain α1A-AR neurotransmission and ßArr2 levels in anxious adolescent rats subjected to early life stress.

Early-life stress is correlated with the development of anxiety-related behavior in adolescence, but underlying mechanisms remain poorly known. The α1A-adrenergic receptor (AR) is linked to mood regulation and its function is assumed to be regulated by ß-arrestins (ßArrs) via desensitization and downregulation. Here, we investigated correlation between changes in α1A-AR and ßArr2 levels in the prefrontal cortex (PFC) and hippocampus of adolescent and adult male rats subjected to maternal separation (MS) and their relationship with anxiety-like behavior in adolescence. MS was performed 3 h per day from postnatal days 2-11 and anxiety-like behavior was evaluated in the elevated plus-maze and open field tests. The protein levels were examined using western blot assay. MS decreased α1A-AR expression and increased ßArr2 expression in both brain regions of adolescent rats, while induced reverse changes in adulthood. MS adolescent rats demonstrated higher anxiety-type behavior and lower activity in behavioral tests than controls. Decreased α1A-AR levels in MS adolescence strongly correlated with reduced time spent in the open field central area, consistent with increased anxiety-like behavior. An anxiety-like phenotype was mimicked by acute and chronic treatment of developing rats with prazosin, an α1A-AR antagonist, suggesting α1A-AR downregulation may facilitate anxiety behavior in MS adolescent rats. Together, our results indicate a negative correlation between α1A-AR neurotransmission and ßArr2 levels in both adults and anxious-adolescent rats and suggest that increased ßArr2 levels may contribute to posttranslational regulation of α1A-AR and modulation of anxiety-like behavior in adolescent rats. This may provide a path to develop more effective anxiolytic treatments.

The Fall Risk with Alpha blockers Given InitiaL dose or Elderly status (FRAGILE) Study.

Background: α-1 adrenergic antagonists are commonly prescribed, but there is question regarding their safety in patients at increased fall risk. Objective: The purpose of the FRAGILE study was to determine the risk for developing adverse drug events (ADEs) in veterans prescribed α-1 blockers. Methods: A single-center, retrospective, observational cohort analysis was conducted of veterans newly initiated on α-1 antagonists. Veterans were categorized into at-risk (patients who met at least 1 of 2 criteria: age 65 or older or high initial dose of α blockade) or control (veterans without either risk factor) groups. The primary outcome was the composite all-cause ADEs, including hospitalizations or emergency department (ED) visits. Secondary outcomes included number of fall-related ADEs and medication discontinuation rates with follow-up for 12 months. Results: A total of 300 veterans were evaluated. There was no significant difference in the composite outcome of all-cause ED visits between at-risk (n = 169) versus control (n = 131) groups (0.81 vs 1.17, P = 0.09) or all-cause hospitalizations (0.28 vs 0.39, P = 0.25). Seventy-three veterans in the at-risk group experienced an all-cause ADE versus 64 in the control group (P = 0.36). No significant differences in secondary outcomes were found. Fall-related side effects occurred in 8% of the total cohort. Conclusion and Relevance: Rates of all-cause or fall-related ADEs were not significantly different. An 8% discontinuation rate resulting from fall-related ADEs and high rates of coadministered medications that could increase fall risk. Pharmacists can play a key role in optimizing α-1 blocker administration.

α1-AR overactivation induces cardiac inflammation through NLRP3 inflammasome activation.

Acute sympathetic stress causes excessive secretion of catecholamines and induces cardiac injuries, which are mainly mediated by ß-adrenergic receptors (ß-ARs). However, α1-adrenergic receptors (α1-ARs) are also expressed in the heart and are activated upon acute sympathetic stress. In the present study, we investigated whether α1-AR activation induced cardiac inflammation and the underlying mechanisms. Male C57BL/6 mice were injected with a single dose of α1-AR agonist phenylephrine (PE, 5 or 10 mg/kg, s.c.) with or without pretreatment with α-AR antagonist prazosin (5 mg/kg, s.c.). PE injection caused cardiac dysfunction and cardiac inflammation, evidenced by the increased expression of inflammatory cytokine IL-6 and chemokines MCP-1 and MCP-5, as well as macrophage infiltration in myocardium. These effects were blocked by prazosin pretreatment. Furthermore, PE injection significantly increased the expression of NOD-like receptor protein 3 (NLRP3) and the cleavage of caspase-1 (p20) and interleukin-18 in the heart; similar results were observed in both Langendorff-perfused hearts and cultured cardiomyocytes following the treatment with PE (10 µM). Moreover, PE-induced NLRP3 inflammasome activation and cardiac inflammation was blocked in Nlrp3-/- mice compared with wild-type mice. In conclusion, α1-AR overactivation induces cardiac inflammation by activating NLRP3 inflammasomes.

Prazosin induced lysosomal tubulation interferes with cytokinesis and the endocytic sorting of the tumour antigen CD98hc.

The quinazoline based drug prazosin (PRZ) is a potent inducer of apoptosis in human cancer cells. We recently reported that PRZ enters cells via endocytosis and induces tubulation of the endolysosomal system. In a proteomics approach aimed at identifying potential membrane proteins with binding affinity to quinazolines, we detected the oncoprotein CD98hc. We confirmed shuttling of CD98hc towards lysosomes and upregulation of CD98hc expression in PRZ treated cells. Gene knockout (KO) experiments revealed that endocytosis of PRZ still occurs in the absence of CD98hc - suggesting that PRZ does not enter the cell via CD98hc but misroutes the protein towards tubular lysosomes. Lysosomal tubulation interfered with completion of cytokinesis and provoked endoreplication. CD98hc KO cells showed reduced endoreplication capacity and lower sensitivity towards PRZ induced apoptosis than wild type cells. Thus, loss of CD98hc does not affect endocytosis of PRZ and lysosomal tubulation, but the ability for endoreplication and survival of cells. Furthermore, we found that glutamine, lysomototropic agents - namely chloroquine and NH4Cl - as well as inhibition of v-ATPase, interfere with the intracellular transport of CD98hc. In summary, our study further emphasizes lysosomes as target organelles to inhibit proliferation and to induce cell death in cancer. Most importantly, we demonstrate for the first time that the intracellular trafficking of CD98hc can be modulated by small molecules. Since CD98hc is considered as a potential drug target in several types of human malignancies, our study possesses translational significance suggesting, that old drugs are able to act on a novel target.

Alcohol Abstainer Status and Prazosin Treatment in Association with Changes in Posttraumatic Stress Disorder Symptoms in Veterans with Comorbid Alcohol Use Disorder and Posttraumatic Stress Disorder.

BACKGROUND: The noradrenergic system has been implicated in alcohol use disorder (AUD) and posttraumatic stress disorder (PTSD), with adrenergic agents reducing drinking in individuals with AUD and improving sleep disturbances in individuals with PTSD. In a recent clinical trial, prazosin, an α1-adrenergic antagonist, was not superior to placebo in reducing PTSD symptoms, sleep problems, or alcohol consumption in a comorbid population; however, patients in both treatment conditions improved in all symptom domains over the course of treatment. It remains unknown whether alcohol abstinence is related to changes in PTSD symptoms and medication effects in individuals with this comorbidity. METHODS: Veterans with comorbid alcohol dependence and PTSD (n = 96) were randomized to prazosin (16 mg) or placebo in a 12-week outpatient, double-blind clinical trial. In this secondary data analysis, we examined main effects of alcohol abstainer status (abstainer vs. nonabstainer), treatment, and their interaction on changes in PTSD symptoms over time using linear mixed models. RESULTS: There was a main effect of alcohol abstainer status on symptoms of PTSD (p = 0.03), such that nonabstainers had lower total Clinician-Administered PTSD Scale (CAPS) scores than abstainers. There was a significant treatment by alcohol abstainer status interaction (p = 0.01); specifically, among placebo-treated individuals, those who did not abstain from alcohol had lower total CAPS scores compared to alcohol abstainers. Within the prazosin-treated group, abstainers and nonabstainers did not differ on total CAPS scores. Results were similar for the avoidance (p = 0.02), reexperiencing (p = 0.01), and hyperarousal (p = 0.04) subscales, such that placebo-treated nonabstainers had lower CAPS scores overall. CONCLUSIONS: Overall, prazosin treatment was not significantly related to changes in PTSD symptoms over the course of the 12-week clinical trial in a comorbid population. Interestingly, placebo-treated alcohol nonabstainers had a significant reduction in PTSD symptoms. Whether placebo-treated individuals continued to use alcohol because of ongoing symptoms of PTSD is not known.

SERS determination of the antihypertensive drugs prazosin and losartan by using silver nanoparticles coated with ß-cyclodextrin.

A surface-enhanced Raman scattering (SERS) method is described for the determination of prazosin (PRH) and losartan (LOS). Silver nanoparticles modified with ß-cyclodextrin (CD-S-Ag NPs) were prepared and serve as a sensitive SERS substrate. ß-CD is both a reductant for silver ions and a host molecule that binds the analytes which leads to strong SERS enhancement. The method has distinct features: (a) The linear response extends from 0.1 to 60 µM for PRH, and from 1.0 to 100 µM for LOS; (b) the respective limits of detection are as low as 15 nM and 0.92 µM; and (c) the specific SERS bands of PRH and LOS are located at 703 and 1298 cm-1 respectively. The method was successfully applied to the determination of PRH and LOS illegally added to healthcare products. The recovery of PRH and LOS from spiked samples ranges between 91.3 and 109.3%, and from 87.4 to 105.2%, respectively, both with relative standard deviation of <5%. Graphical abstractSchematic representation of a SERS method involving ß-CD-S-Ag nanoparticles for determination of prazosin and losartan via formation of an inclusion complex.