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.

Adverse events related to alpha-blockers: analysis of real-life data from Eudra-Vigilance.

BACKGROUND: Patients on alpha-blockers (ABs) treatment may have an increased risk of adverse events (AEs). Aim of our study was to compare real-life data on neuro-vascular and sexual AEs associated with ABs based on Eudra-Vigilance reported AEs. METHODS: Eudra-Vigilance (EV) database is the system for managing and analyzing information on suspected adverse reactions to medicines which have been authorized or being studied in clinical trials in the European Economic Area (EEA). We recorded the number of sexual and neuro-vascular AEs for tamsulosin, alfuzosin, silodosin, prazosin and doxazosin per category and severity until July 30th, 2022. Pooled Relative Risk (PRR) was used to compare data between drugs. RESULTS: Overall the number of AEs were 2842 for Alfuzosin, 11,086 for tamsulosin, 792 for terazosin, 572 for prazosin and 4641 for doxazosin. Different percentages of AEs were obtained for each drug and in different age groups according to EV sub-groups (≤65, 65-85, ≥85). On PRR analysis, the risk of ejaculatory disorders for Silodosin (11%) is 18.5 times higher (PRR 18.5 95%CI; 10.7-31.8; P<0.05) when compared to alfuzosin and the risk of orthostatic hypotension is 2 times lower (PRR=1,84 95%CI 1.32-2.57; P<0.05). CONCLUSIONS: Real life data is consistent with registry studies regarding side effects related to alpha-blockers. Alfuzosin is safer in terms of ejaculatory disorders while silodosin and tamsulosin in terms of orthostatic hypotension. Clinicians should consider these data when prescribing ABs especially in younger and older patients.

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.

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.

History of posttraumatic stress disorder · priapism · Dx?

A 35-year-old African-American man, who was an active duty service member, presented to the Troop Medical Clinic with a 4-hour history of priapism. He had been taking sertraline 100 mg and prazosin 10 mg nightly for 4 months to treat his posttraumatic stress disorder (PTSD) with no reported adverse effects. These doses were titrated 2 months prior to presentation. The patient reported that he took his usual medication doses before bed and awoke at 3 am with a penile erection. At 7 am, he presented to the clinic because of pain from the continued erection.

Trial of Prazosin for Post-Traumatic Stress Disorder in Military Veterans.

BACKGROUND: In randomized trials, prazosin, an α1-adrenoreceptor antagonist, has been effective in alleviating nightmares associated with post-traumatic stress disorder (PTSD) in military veterans. METHODS: We recruited veterans from 13 Department of Veterans Affairs medical centers who had chronic PTSD and reported frequent nightmares. Participants were randomly assigned to receive prazosin or placebo for 26 weeks; the drug or placebo was administered in escalating divided doses over the course of 5 weeks to a daily maximum of 20 mg in men and 12 mg in women. After week 10, participants continued to receive prazosin or placebo in a double-blind fashion for an additional 16 weeks. The three primary outcome measures were the change in score from baseline to 10 weeks on the Clinician-Administered PTSD Scale (CAPS) item B2 ("recurrent distressing dreams"; scores range from 0 to 8, with higher scores indicating more frequent and more distressing dreams); the change in score from baseline to 10 weeks on the Pittsburgh Sleep Quality Index (PSQI; scores range from 0 to 21, with higher scores indicating worse sleep quality); and the Clinical Global Impression of Change (CGIC) score at 10 weeks (scores range from 1 to 7, with lower scores indicating greater improvement and a score of 4 indicating no change). RESULTS: A total of 304 participants underwent randomization; 152 were assigned to prazosin, and 152 to placebo. At 10 weeks, there were no significant differences between the prazosin group and the placebo group in the mean change from baseline in the CAPS item B2 score (between-group difference, 0.2; 95% confidence interval [CI], -0.3 to 0.8; P=0.38), in the mean change in PSQI score (between-group difference, 0.1; 95% CI, -0.9 to 1.1; P=0.80), or in the CGIC score (between-group difference, 0; 95% CI, -0.3 to 0.3; P=0.96). There were no significant differences in these measures at 26 weeks (a secondary outcome) or in other secondary outcomes. At 10 weeks, the mean difference between the prazosin group and the placebo group in the change from baseline in supine systolic blood pressure was a decrease of 6.7 mm Hg. The adverse event of new or worsening suicidal ideation occurred in 8% of the participants assigned to prazosin versus 15% of those assigned to placebo. CONCLUSIONS: In this trial involving military veterans who had chronic PTSD, prazosin did not alleviate distressing dreams or improve sleep quality. (Funded by the Department of Veterans Affairs Cooperative Studies Program; PACT ClinicalTrials.gov number, NCT00532493 .).

Dwarfism and insulin resistance in male offspring caused by α1-adrenergic antagonism during pregnancy.

OBJECTIVE: Maternal and environmental factors control the epigenetic fetal programming of the embryo, thereby defining the susceptibility for metabolic or endocrine disorders in the offspring. Pharmacological interventions required as a consequence of gestational problems, e.g. hypertension, can potentially interfere with correct fetal programming. As epigenetic alterations are usually only revealed later in life and not detected in studies focusing on early perinatal outcomes, little is known about the long-term epigenetic effects of gestational drug treatments. We sought to test the consequences of maternal α1-adrenergic antagonism during pregnancy, which can occur e.g. during hypertension treatment, for the endocrine and metabolic phenotype of the offspring. METHODS: We treated C57BL/6NCrl female mice with the α1-adrenergic antagonist prazosin during pregnancy and analyzed the male and female offspring for endocrine and metabolic abnormalities. RESULTS: Our data revealed that maternal α1-adrenergic blockade caused dwarfism, elevated body temperature, and insulin resistance in male offspring, accompanied by reduced IGF-1 serum concentrations as the result of reduced hepatic growth hormone receptor (Ghr) expression. We subsequently identified increased CpG DNA methylation at the transcriptional start site of the alternative Ghr promotor caused by the maternal treatment, which showed a strong inverse correlation to hepatic Ghr expression. CONCLUSIONS: Our results demonstrate that maternal α1-adrenergic blockade can constitute an epigenetic cause for dwarfism and insulin resistance. The findings are of immediate clinical relevance as combined α/ß-adrenergic blockers are first-line treatment of maternal hypertension.

The efficacy of prazosin for the treatment of posttraumatic stress disorder nightmares in U.S. military veterans.

BACKGROUND AND PURPOSE: Nightmares associated with posttraumatic stress disorder (PTSD) are a hallmark symptom among U.S. military veterans who have seen combat. Management of combat-related nightmares can be difficult and current pharmacologic options are limited and tend to have adverse side effects. The aim of this review is to explore recent literature regarding the efficacy of prazosin for the treatment of nightmare disorder in the veteran population. METHODS: Recent literature consisting of three systematic reviews was reviewed, as well as current clinical guidelines published by The Department of Veterans Affairs (VA) and The Department of Defense (DoD) and the American Academy of Sleep Medicine (AASM). CONCLUSIONS: Prazosin has been shown to be effective in the treatment of PTSD trauma-related nightmares. As a result of its low side effect profile and abilities to improve both sleep and reduce trauma nightmares, prazosin has been recommended as an adjunct therapy. IMPLICATIONS FOR PRACTICE: Prazosin should be initiated as an adjunctive treatment to promote sleep in those suffering from PTSD nightmares. It should be initiated at 1 mg and then titrated upward until absence or desired reduction of nightmares is achieved, with a maximum dosage recommendation of 20 mg at bedtime and 5 mg midmorning.

Assessment of Urologists' Knowledge of Intraoperative Floppy Iris Syndrome.

OBJECTIVES: To assess urologists' awareness of intraoperative floppy iris syndrome. MATERIALS AND METHODS: A questionnaire composed of 21 questions was emailed to all of the Urology residency programs in the U.S. and all members of the Western section of the American Urological Association. Responses were collected and analyzed using statistical software. RESULTS: A total of 175 responses were collected from residents, fellows, and attending physicians from a wide range of geographic locations, subspecialties, and practice settings. Thirty percent of the urologists would routinely discuss intraoperative floppy iris syndrome with patients prior to start of benign prostate hyperplasia treatment. Twenty-one percent of the respondents never asked patients about ophthalmologic conditions prior to benign prostate hyperplasia treatment. If patients had concurrent visual complaints, only 37% of the respondents would routinely encourage patients to speak to an ophthalmologist and only 13% would routinely refer patients to an ophthalmologist. A comparison among the subgroups based on training status and practice settings further showed that a significantly higher percentage of residents would not ask about visual complaints or refer patients with visual complaints to an ophthalmologist compared with fellows and attending physicians (P <.01); however, there was no significant difference between urologists in academic and nonacademic settings (P >.05). CONCLUSION: Despite continuing effort to educate physicians about intraoperative floppy iris syndrome, there still exists a knowledge gap that may compromise patient care and further education is needed.

Myocardial infarction induced by oral terazosin in a patient with predisposing structural cardiomyopathy: case report. / Infarto agudo de miocardio asociado al uso de terazosina oral en presencia de cardiopatía estructural predisponente: reporte de caso.

We describe a 71-year-old male patient who developed acute myocardial infarction (AMI) due to a dynamic left ventricular outflow tract obstruction induced by terazosin. After receiving terazosin, the patient had a syncope followed by angina. The electrocardiogram showed Q waves and ST segment elevation in the precordial and inferior leads. Coronary angiography evidenced a chronically occluded left anterior descending artery. Doppler-echocardiography revealed apical akinesia, hyperdynamic basal segments, systolic anterior motion of the mitral valve (SAM) and dynamic left ventricular outflow tract obstruction. Therapy with intravenous fluids and atenolol resulted in marked clinical improvement. Acute myocardial infarction resulted from low coronary perfusion pressure in a patient with a chronically diminished coronary reserve.

Describimos el caso de un hombre de 71 años de edad, que presentó un infarto agudo de miocardio debido a la obstrucción dinámica del tracto de salida del ventrículo izquierdo inducida por la terazosina. Luego de recibir dicha medicación el paciente presentó un síncope y posteriormente angina de pecho. El electrocardiograma evidenció ondas Q y sobreelevación del segmento ST en las derivaciones precordiales e inferiores. La angiografía coronaria evidenció una oclusión crónica de la arteria descendente anterior y el ecocardiograma Doppler reveló aquinesia apical, segmentos basales hiperdinámicos, movimiento anterior sistólico de la válvula mitraI y obstrucción dinámica del tracto de salida del ventrículo izquierdo. La administración intravenosa de suero fisiológico y atenolol determinó una clara mejoría clínica. Un infarto agudo de miocardio hemodinámico fue el resultado de la caída de la presión de perfusión coronaria en un paciente con disminución crónica de la reserva coronaria.

Sleep Disturbances and Nightmares in a Patient Treated with Prazosin.

Prazosin is increasingly being used off-label to treat nightmares in patients with posttraumatic stress disorder. The literature about the psychiatric adverse effects of prazosin is very limited. We present a case in which low-dose prazosin was associated with nightmares and sleep disturbances in an elderly patient without previously diagnosed mental illness or coexisting environmental risk factors for nightmares. Insomnia and hallucinations are listed as some of the rare side effects of prazosin by the manufacturer. Prazosin could be associated with rare psychiatric adverse effects and sleep disturbances. Particular attention is required in identifying these adverse effects, which can be difficult to distinguish from other drug-related side effects in the elderly particularly because they are often using multiple medications.

Targeting the Noradrenergic System in Posttraumatic Stress Disorder: A Systematic Review and Meta-Analysis of Prazosin Trials.

Post-traumatic stress disorder (PTSD) is a chronic psychiatric disorder that may develop after exposure to a life-threatening trauma. As veterans and armed forces may deal with diverse health problems compared with civilians, they have a greater risk for psychiatric disorders, including PTSD, than civilians, even if the disorder may be also frequent in the general population. PTSD is associated with significant comorbidity, especially with mood disorders and substance abuse. Moreover, the suicide risk is higher in PTSD patients than in the general population. Selective Serotonin Reuptake Inhibitors (SSRIs), atypical antipsychotics and benzodiazepines are commonly employed in the management of PTSD, but often these treatments fail or are discontinued due to adverse effects. It has been demonstrated that high noradrenergic activity may be associated with hyperarousal, trauma nightmares and sleep disturbances in PTSD subjects, probably through the stimulation of α -1 adrenergic receptors in the brain prefrontal cortex. The α -1 adrenoreceptor antagonist prazosin decreases noradrenaline effects at brain α-1 adrenoreceptors and may be a promising agent in the treatment of PTSD, as some studies have found it effective and well tolerated. Therefore, the present review is aimed to examine the role of noradrenergic system in the pathophysiology of PTSD. Moreover, we conducted a systematic review to evaluate the effectiveness and tolerability of prazosin in PTSD patients. Meta-analysis was used to combine data from multiple studies and better estimate the effect of prazosin on specific outcomes. We found prazosin to be significantly more efficacious than placebo in reducing distressing dreams in PTSD patients, even though our results should be interpreted with caution due to the small number of studies included in our quantitative synthesis.

A pilot trial of prazosin, an alpha-1 adrenergic antagonist, for comorbid alcohol dependence and posttraumatic stress disorder.

BACKGROUND: Posttraumatic stress disorder (PTSD) and alcohol dependence (AD) commonly co-occur and are associated with greater symptom severity and costs than either disorder alone. No pharmacologic interventions have been found to decrease both alcohol use and PTSD symptom severity relative to matched placebo. Prazosin, an alpha-1 adrenoreceptor antagonist, has demonstrated the efficacy of reducing PTSD and AD symptoms among individuals with one or the other disorder and may be useful in addressing comorbid PTSD/AD. METHODS: Prazosin and matched placebo were compared in the context of an outpatient 6-week double-blind randomized controlled pilot trial involving 30 individuals with comorbid PTSD/AD. Medication was titrated to 4 mg q am, 4 mg q pm and 8 mg qhs by the end of week 2. Participants in both conditions received 5 medical management sessions. Information regarding alcohol use, craving, and PTSD was gathered daily using a telephone interactive voice response system. RESULTS: Participants randomized to prazosin had a greater reduction in percent days drinking per week and percent days heavy drinking per week between baseline and week 6 than did placebo participants. No significant differences were detected within or between groups in change from weeks 1 to 6 in total PTSD symptoms. Participants in the prazosin condition reported drowsiness on significantly more days than those in the placebo condition. CONCLUSIONS: Consistent with the extant research evaluating medications for comorbid PTSD/AD, the current evaluation of prazosin also found decreased alcohol consumption but no medication effect on PTSD symptomatology.

Prazosin in the treatment of PTSD.

Posttraumatic stress disorder (PTSD) often follows a chronic course, and the disorder is resistant to treatment with antidepressants and cognitive-behavioral therapy in a proportion of patients. Prazosin, an a1-adrenoceptor blocker, has shown some promise in treating chronic PTSD. A review of this literature was conducted via a search of MEDLINE and SUMMON, using keywords such as PTSD, prazosin, treatment, and resistance. At least 10 clinical studies of prazosin in the treatment of PTSD, including open-label and randomized controlled trials, have been published. All of these studies support the efficacy of prazosin either for treating nightmares and improving sleep or for reducing the severity of PTSD. Treatment of PTSD with prazosin is usually initiated at a dose of 1 mg, with monitoring for hypotension after the first dose. The dose is then gradually increased to maintenance levels of 2-6 mg at night. Studies of military patients with PTSD have used higher doses (e.g., 10-16 mg at night). Prazosin has also been studied in younger and older adults with PTSD and in patients with alcohol problems, in whom it was found to reduce cravings and stress responses. Prazosin offers some hope for treating resistant cases of PTSD in which recurrent nightmares are problematic, with a relatively rapid response within weeks. It is suggested that large-scale civilian trials of prazosin be done, as well as studies concerning the use of prazosin in acute PTSD and as a potential preventive agent.

Comparing the effect of prazosin and hydroxyzine on sleep quality in patients suffering from posttraumatic stress disorder.

OBJECTIVES: In light of the high prevalence of sleep disorders in patients suffering from posttraumatic stress disorder (PTSD), this study sought to compare the effect of prazosin and hydroxyzine on sleep quality in this patient group. METHODS: A total of 100 patients suffering from PTSD were assessed (mean age = 35.51 years, SD = 6.41; 28% females). Next, they were randomly assigned to one of three treatment groups: prazosin (33 patients), hydroxyzine (34 patients) or placebo (33 patients). The trial lasted for 8 weeks. The patients' sleep quality was assessed using the Pittsburgh Sleep Quality Index. Items taken from the Mini International Neuropsychiatric Interview were used to operationalize PTSD. RESULTS: Compared to controls, patients treated with prazosin and hydroxyzine reported improved sleep and less nightmares. Improvement was greatest in patients treated with prazosin compared to hydroxyzine and placebo. Improvement in sleep was associated with an amelioration of their PTSD symptoms. CONCLUSION: Both prazosin and hydroxyzine can be used to treat psychopharmacological sleep disorders and nightmares in patients suffering from PTSD, also leading to reductions in PTSD symptoms.

Comparison of 7 α(1)-adrenoceptor antagonists in patients with lower urinary tract symptoms associated with benign prostatic hyperplasia:a short-term crossover study.

A crossover study was conducted to identify the best α1-adrenoceptor (α1AR) antagonist for individual patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). One hundred thirteen patients (mean age 70.8 years) were enrolled. All patients met BPH clinical study guidelines. Seven agents were utilized:tamsulosin 0.2mg, silodosin 8mg, urapidil 60mg, naftopidil 50mg, prazosin 1mg, terazosin 2mg, and doxazosin 1mg. Patients were initially prescribed tamsulosin or silodosin for a week and then urapidil for a week. Two weeks later, they were prescribed the better of the 2 agents for a week and a new agent for the next week. This cycle was repeated until all 7 agents were tested. Efficacy was evaluated with the International Prostate Symptom Score. The agent rankings were doxazosin (25 [22%]), silodosin (22 [19%]), urapidil (19 [17%]), naftopidil (17 [15%]), terazosin (12 [11%]), tamsulosin (11 [10%]), prazosin (7 [6%]). Only 12 patients (11%) changed agents after the crossover study was completed. The major reason was adverse events (83%). We found that each of the 7 α1AR antagonists has its own supporters. Further, the one-week crossover study was useful in identifying the best agent for the treatment of each individual with LUTS.

A trial of prazosin for combat trauma PTSD with nightmares in active-duty soldiers returned from Iraq and Afghanistan.

OBJECTIVE: The authors conducted a 15-week randomized controlled trial of the alpha-1 adrenoreceptor antagonist prazosin for combat trauma nightmares, sleep quality, global function, and overall symptoms in active-duty soldiers with posttraumatic stress disorder (PTSD) returned from combat deployments to Iraq and Afghanistan. METHOD: Sixty-seven soldiers were randomly assigned to treatment with prazosin or placebo for 15 weeks. Drug was titrated based on nightmare response over 6 weeks to a possible maximum dose of 5 mg midmorning and 20 mg at bedtime for men and 2 mg midmorning and 10 mg at bedtime for women. Mean achieved bedtime doses were 15.6 mg of prazosin (SD=6.0) and 18.8 mg of placebo (SD=3.3) for men and 7.0 mg of prazosin (SD=3.5) and 10.0 mg of placebo (SD=0.0) for women. Mean achieved midmorning doses were 4.0 mg of prazosin (SD=1.4) and 4.8 mg of placebo (SD=0.8) for men and 1.7 mg of prazosin (SD=0.5) and 2.0 mg of placebo (SD=0.0) mg for women. Primary outcome measures were the nightmare item of the Clinician-Administered PTSD Scale (CAPS), the Pittsburgh Sleep Quality Index, and the change item of the Clinical Global Impressions Scale anchored to functioning. Secondary outcome measures were the 17-item CAPS, the Hamilton Depression Rating Scale, the Patient Health Questionnaire-9, and the Quality of Life Index. Maintenance psychotropic medications and supportive psychotherapy were held constant. RESULTS: Prazosin was effective for trauma nightmares, sleep quality, global function, CAPS score, and the CAPS hyperarousal symptom cluster. Prazosin was well tolerated, and blood pressure changes did not differ between groups. CONCLUSIONS: Prazosin is effective for combat-related PTSD with trauma nightmares in active-duty soldiers, and benefits are clinically meaningful. Substantial residual symptoms suggest that studies combining prazosin with effective psychotherapies might demonstrate further benefit.

Comparison of terazosin and prazosin for treatment of vesico-urethral reflex dyssynergia in dogs.

Nineteen dogs with vesico-urethral reflex dyssynergia (VURD) were treated with prazosin or terazosin 0.5 mg/kg twice daily to compare efficacy and side effects. Dogs were referred because of signs of (partial) urethral obstruction. Physical examination, abdominal ultrasonography, urinalysis and a radiographic contrast study of bladder and urethra (urethrocystography) were routinely performed. If no mechanical causes of obstruction or disease of the distal urinary tract were observed, the diagnosis VURD was presumed and the dogs were included in our study. Follow-up information was obtained from owners or referring veterinarians. Significantly more side effects were seen in the dogs treated with terazosin (n=14; 93 per cent) compared with the dogs treated with prazosin (n=5; 20 per cent; P=0.002). Effects of the treatment were comparable between prazosin and terazosin. Labradors and dogs that were castrated surgically had a significant better survival (P<0.01) compared with other breeds and animals that were castrated chemically. There was a moderate to good effect in 60 per cent of the dogs treated with prazosin, and in 64 per cent of the dogs treated with terazosin.