RARE DISEASE
Low-flow priapism
Low-flow priapism
Low-flow priapism
Drug discovery
2
drugs
With orphan designations
Overview
Low-flow priapism is a urologic emergency characterized by a painful, persistent erection (>4 hours) due to venous occlusion and ischemia. It is most commonly idiopathic or associated with sickle cell disease, hematologic disorders, or medications (e.g., erectile dysfunction drugs). Untreated, it leads to corporal fibrosis and permanent erectile dysfunction within 24–36 hours, necessitating immediate intervention to restore venous outflow [1][3][6].
Population
Bimodal age distribution: peaks in children (5–10 years, often sickle cell-related) and adults (30–50 years, idiopathic/drug-induced) [7][15].
33% of adults with sickle cell disease experience recurrent episodes [9][12].
Median hospitalization age: 46 years, with higher rates of diabetes/chronic kidney disease [4][6].
Therapies
First-line: Corporal aspiration + intracavernosal phenylephrine (α-adrenergic agonist), achieving ~80% resolution within 12 hours [3][14][8].
Refractory cases: Distal shunts (Winter’s procedure) or proximal shunts (Quackels/Grayhack), with surgical success rates ~75% [3][18].
SCD-specific: Hydration, oxygenation, alkalinization, and transfusion if initial measures fail [3][17].
Categories: rare urogenital diseases
Research Papers
261 drug discovery papers about Low-flow priapism, with 2 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
261 drug discovery papers about Low-flow priapism, with 2 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-02-23 | Presentations Due to Priapism in an Urban Hospital in Switzerland.
Priapism, a persisting erection not associated with sexual stimulation, can be ischaemic, with the risk of permanent erectile dysfunction, or nonischaemic. Drugs-e.g., injection therapies for erectile dysfunction, as well as neuroleptics, antidepressants and various other medicines-can also cause priapism. This study aimed to describe presentations due to priapism and provide insights into specific causes, clinical presentations, diagnostic strategies and emergency management. A single-centre, retrospective, observational study of patients (≥ 16 years old) presenting to the University Hospital of Bern, Switzerland, between January 2010 and June 2023 due to priapism. The cases were retrieved from the electronic health records using full-text search. During the study period, 40 cases corresponding to 32 patients were included. The mean ± SD age was 48 ± 15 years, and pain was present in 21 cases (53%) on presentation. Median time of erection was 15 h (range: 1-80, n = 23). A penile blood gas analysis was performed in 32 cases (80%), and 29 of these (91%) were of the low-flow type. Most commonly suspected causes were idiopathic (n = 25, 63%) and drug-induced (n = 10, 25%). Suspected agents in the drug-induced cases were corpus cavernosum autoinjection therapy (n = 4), trazodone (n = 3), sildenafil (n = 2) and urapidil (n = 1). Puncture of the corpus cavernosum and injection of noradrenalin and adrenalin were the therapeutic measure in 35 cases (88%). In 13 cases, there was at least one recurrence, including 10 within one week. Drugs given as recurrence prophylaxis included tadalafil (n = 9) and diazepam (n = 4). Presentations due to priapism appear to be rare, but the majority of the cases presented with ischaemic priapism, which is a medical emergency. The findings can be used to identify areas requiring further research (e.g., drugs used as recurrence prophylaxis) and raise awareness of this potentially severe complication-which patients are often ashamed to report.
2025-10-09 | An update on mechanisms and treatment options for priapism.
Priapism is an abnormal prolonged penile erection that persists in the absence of any sexual stimulation. Priapism can be subcategorized into three types: ischaemic (low-flow or veno-occlusive), non-ischaemic (high-flow or arterial) and stuttering priapism. Ischaemic priapism is the most common subtype and is associated with multiple aetiologies, most commonly haemoglobinopathies and antipsychotic medications. The mechanisms underlying stuttering priapism are complex, and involve dysregulation of the nitric oxide signalling pathway, Rho-Rho kinase pathway, adenosine, opiorphins, oxidative stress and androgens. The investigation and management of priapism involve a stepwise approach. A clinical history, examination and a blood-gas analysis from the corpus cavernosum helps to distinguish between ischaemic and non-ischaemic subtypes. Colour Doppler ultrasonography and penile MRI can be used in more complex cases, or those with a delayed presentation. Treatment involves cavernosal blood aspiration followed by instillation of an α-adrenergic receptor agonist such as phenylephrine, proceeding to penile shunt surgery (within the first 24-48 h) if the priapism persists. Insertion of a penile prosthesis is indicated when a shunting procedure or penoscrotal decompression fails, or if a patient presents with a priapism persisting longer than 36-48 h depending on the guidelines used. For non-ischaemic priapism following failed conservative treatment, selective arterial embolization of the arteriocorporal fistula can be performed. The aetiology and pathophysiology of the different priapism subtypes help to determine the management of specific patients.
2025-09-15 | Cavernosal Abscess Mimicking Ischemic Priapism in a Diabetic Patient: A Report of a Rare Case.
Cavernosal abscesses are extremely rare and an even rarer precipitant of ischemic priapism. These abscesses may arise due to trauma, intracavernosal injection therapy, foreign bodies, or complications of perianal and perineal infections. Hematogenous spread from distant sources, including dental infections, has also been documented. Diabetic individuals are particularly susceptible due to their immunocompromised status, microvascular disease, and poor glycemic control. Delayed diagnosis risks fibrosis and lifelong erectile dysfunction. A 56-year-old man with poorly controlled type-2 diabetes (HbA1c 10.2 %) presented with fever and painful low-flow priapism of two hours duration. Inspection revealed a perineal abscess that opened and expressed approximately 60 mL of purulent material, resulting in immediate detumescence. A pelvic 3-T MRI performed 40 minutes later demonstrated a T2 hyperintense collection showing diffusion restriction, measuring 7.3 × 5.1 × 7.6 cm, with a volume of 132 cc noted in the left corpora cavernosa and perineum. Intravenous cefoperazone-sulbactam plus metronidazole was started and de-escalated to amoxicillin-clavulanate after cultures grew methicillin-sensitive Staphylococcus aureus. On hospital day 2, a 1-cm perineal incision allowed blunt evacuation and gentamicin-saline irrigation; the drain was removed after 48 hours. Adjuvant tadalafil 5 mg daily and intensified insulin therapy were continued for six weeks. At six months, the patient reported satisfactory erectile function, including normal rigidity and the ability to complete intercourse without the use of pharmacological support. In diabetic men presenting with painful priapism, the presence of a small perineal abscess should raise suspicion of an underlying cavernosal abscess. Early MRI delineation, combined with minimal drainage and culture-directed antibiotics, can eradicate the infection while preserving erectile function.
2025-08-27 | Trazodone-Induced Ischemic Priapism Successfully Managed With Conservative Therapy: A Case Report.
Ischemic priapism is a urological emergency requiring prompt diagnosis and intervention to prevent permanent erectile dysfunction. We present the case of a 29-year-old male admitted for a painful erection lasting 10 hours. The patient had no history of trauma, hematological disease, or use of erectile medications. He had recently started trazodone (Trittico) for insomnia. Clinical examination and Doppler ultrasound confirmed low-flow priapism. Cavernosal blood gas analysis revealed severe hypoxia and acidosis. Conservative management including aspiration, irrigation, intracavernosal ephedrine, anticoagulation, and ice application led to complete detumescence without surgical intervention. The case highlights trazodone as a potential cause of ischemic priapism and the importance of early, structured management.
2024-04-08 | A novel strategy to induce penile erection during penile doppler ultrasound: oral sildenafil administration plus alprostadil injection
To evaluate the efficacy of a novel approach to achieve the optimal penile erection during the penile doppler ultrasound (PDU) examination, which was oral sildenafil combined alprostadil injection. A total of 60 ED patients were enrolled in our prospective study, and they were randomly assigned to two group with different PDU order. The approaches assisted the PDU included two models, mode A meaning injection of 15 μg alprostadil and model B meaning oral sildenafil 100 mg plus injection of 15 μg alprostadil. The PDU parameters were measured continuously before induced erection, and 5, 10, 15, 20, 25 min. Each group included 30 ED patients with similar clinical characteristics. After pooling the results together, the PSV, EDV, and RI were all improved significantly, when adding the oral sildenafil administration to assist PDU. Also, the clinical response of oral sildenafil administration plus alprostadil injection was better than that in alprostadil injection alone (p = 0.016). The arterial ED were decreased from 31.67% to 15.00% with the P value 0.031, and the mixed ED was also decreased statistically (23.33% vs 8.33%, p = 0.024). Oral sildenafil administration plus alprostadil injection could improve the diagnostic accuracy of PDU.
cell therapies
2023-04-21 | Systematic review of medicinal leech therapy in urology
Abstract Background Medicinal leech therapy, otherwise known as hirudotherapy or leeching , has been utilized for numerous pathologies over centuries. The technique resurfaced in modern medicine for its beneficial effects in microsurgical complications, particularly venous congestion. Recently, several cases have documented the utilization of medicinal leech therapy for the management of urologic disease states and surgical complications. It is important to understand the past, present, and future possibilities for hirudotherapy in urology. However, a systematic review of medical leech therapy in this context has yet to be conducted. Accordingly, and with an emphasis on salient clinical details, this study aims to systematically review the cases of hirudotherapy applied to urological conditions. Main body of the abstract A systematic review of cases in MEDLINE/PubMed was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Of 49 search results, 11 articles detailing 13 unique cases of medicinal leech therapy used in the urological context were included. Hirudotherapy was conducted in 10 of 13 cases (76.9%) for the management of congested blood occurring in five cases post-penile replantation, two cases of postoperative scrotal hematoma, two cases of venous congestion of the glans post-neonatal bladder exstrophy repair, and one case of refractory priapism. Leeching in the remaining three cases was for the management of penoscrotal edema in patients with hormone refractory prostate carcinoma treated with radical radiation therapy. All 13 cases (100%) reported clinical improvement from hirudotherapy. Venous congestion/hematoma cases noted decreased displaced blood volume. The patient experiencing priapism reported decreased pain despite the persistence of cavernosal swelling. The three cases of penoscrotal edema reported significant decreases in swelling due to serous fluid drainage from leech puncture sites. No complications or side effects were reported in the nine adult patients. The four postoperative neonatal patients all required blood product throughout treatment. Short conclusion The systematic review of the cases demonstrates that medicinal leech therapy is a favorable treatment option for individuals with varied urological pathologies and that hirudotherapy may improve post-surgical outcomes in the urological setting. Hirudotherapy should be considered as a viable treatment modality in specific venostatic urological conditions.
2004-09-01 | Priapism secondary to leukemia: Effective management with prompt leukapheresis
Abstract Priapism is a urological emergency; without prompt treatment the corpora cavernosa undergoes necrosis and fibrosis that may result in erectile dysfunction. Treatment initially involves conservative measures, such as corporeal aspiration and irrigation with saline or dilute phenylephrine. If this fails, embolization or surgical shunting is usually required. Hyperviscosity resulting from leukemia is a rare cause of priapism. We report a case of a 19‐year‐old man with an 18‐hour history of priapism secondary to undiagnosed chronic myeloid leukaemia. We discuss the method of leukapheresis (mechanical white cell depletion) to reduce viscosity and achieve detumescence after failed aspiration.
small molecules
2026-02-23 | Presentations Due to Priapism in an Urban Hospital in Switzerland.
Priapism, a persisting erection not associated with sexual stimulation, can be ischaemic, with the risk of permanent erectile dysfunction, or nonischaemic. Drugs-e.g., injection therapies for erectile dysfunction, as well as neuroleptics, antidepressants and various other medicines-can also cause priapism. This study aimed to describe presentations due to priapism and provide insights into specific causes, clinical presentations, diagnostic strategies and emergency management. A single-centre, retrospective, observational study of patients (≥ 16 years old) presenting to the University Hospital of Bern, Switzerland, between January 2010 and June 2023 due to priapism. The cases were retrieved from the electronic health records using full-text search. During the study period, 40 cases corresponding to 32 patients were included. The mean ± SD age was 48 ± 15 years, and pain was present in 21 cases (53%) on presentation. Median time of erection was 15 h (range: 1-80, n = 23). A penile blood gas analysis was performed in 32 cases (80%), and 29 of these (91%) were of the low-flow type. Most commonly suspected causes were idiopathic (n = 25, 63%) and drug-induced (n = 10, 25%). Suspected agents in the drug-induced cases were corpus cavernosum autoinjection therapy (n = 4), trazodone (n = 3), sildenafil (n = 2) and urapidil (n = 1). Puncture of the corpus cavernosum and injection of noradrenalin and adrenalin were the therapeutic measure in 35 cases (88%). In 13 cases, there was at least one recurrence, including 10 within one week. Drugs given as recurrence prophylaxis included tadalafil (n = 9) and diazepam (n = 4). Presentations due to priapism appear to be rare, but the majority of the cases presented with ischaemic priapism, which is a medical emergency. The findings can be used to identify areas requiring further research (e.g., drugs used as recurrence prophylaxis) and raise awareness of this potentially severe complication-which patients are often ashamed to report.
2025-10-09 | An update on mechanisms and treatment options for priapism.
Priapism is an abnormal prolonged penile erection that persists in the absence of any sexual stimulation. Priapism can be subcategorized into three types: ischaemic (low-flow or veno-occlusive), non-ischaemic (high-flow or arterial) and stuttering priapism. Ischaemic priapism is the most common subtype and is associated with multiple aetiologies, most commonly haemoglobinopathies and antipsychotic medications. The mechanisms underlying stuttering priapism are complex, and involve dysregulation of the nitric oxide signalling pathway, Rho-Rho kinase pathway, adenosine, opiorphins, oxidative stress and androgens. The investigation and management of priapism involve a stepwise approach. A clinical history, examination and a blood-gas analysis from the corpus cavernosum helps to distinguish between ischaemic and non-ischaemic subtypes. Colour Doppler ultrasonography and penile MRI can be used in more complex cases, or those with a delayed presentation. Treatment involves cavernosal blood aspiration followed by instillation of an α-adrenergic receptor agonist such as phenylephrine, proceeding to penile shunt surgery (within the first 24-48 h) if the priapism persists. Insertion of a penile prosthesis is indicated when a shunting procedure or penoscrotal decompression fails, or if a patient presents with a priapism persisting longer than 36-48 h depending on the guidelines used. For non-ischaemic priapism following failed conservative treatment, selective arterial embolization of the arteriocorporal fistula can be performed. The aetiology and pathophysiology of the different priapism subtypes help to determine the management of specific patients.
2025-09-15 | Cavernosal Abscess Mimicking Ischemic Priapism in a Diabetic Patient: A Report of a Rare Case.
Cavernosal abscesses are extremely rare and an even rarer precipitant of ischemic priapism. These abscesses may arise due to trauma, intracavernosal injection therapy, foreign bodies, or complications of perianal and perineal infections. Hematogenous spread from distant sources, including dental infections, has also been documented. Diabetic individuals are particularly susceptible due to their immunocompromised status, microvascular disease, and poor glycemic control. Delayed diagnosis risks fibrosis and lifelong erectile dysfunction. A 56-year-old man with poorly controlled type-2 diabetes (HbA1c 10.2 %) presented with fever and painful low-flow priapism of two hours duration. Inspection revealed a perineal abscess that opened and expressed approximately 60 mL of purulent material, resulting in immediate detumescence. A pelvic 3-T MRI performed 40 minutes later demonstrated a T2 hyperintense collection showing diffusion restriction, measuring 7.3 × 5.1 × 7.6 cm, with a volume of 132 cc noted in the left corpora cavernosa and perineum. Intravenous cefoperazone-sulbactam plus metronidazole was started and de-escalated to amoxicillin-clavulanate after cultures grew methicillin-sensitive Staphylococcus aureus. On hospital day 2, a 1-cm perineal incision allowed blunt evacuation and gentamicin-saline irrigation; the drain was removed after 48 hours. Adjuvant tadalafil 5 mg daily and intensified insulin therapy were continued for six weeks. At six months, the patient reported satisfactory erectile function, including normal rigidity and the ability to complete intercourse without the use of pharmacological support. In diabetic men presenting with painful priapism, the presence of a small perineal abscess should raise suspicion of an underlying cavernosal abscess. Early MRI delineation, combined with minimal drainage and culture-directed antibiotics, can eradicate the infection while preserving erectile function.
2025-08-27 | Trazodone-Induced Ischemic Priapism Successfully Managed With Conservative Therapy: A Case Report.
Ischemic priapism is a urological emergency requiring prompt diagnosis and intervention to prevent permanent erectile dysfunction. We present the case of a 29-year-old male admitted for a painful erection lasting 10 hours. The patient had no history of trauma, hematological disease, or use of erectile medications. He had recently started trazodone (Trittico) for insomnia. Clinical examination and Doppler ultrasound confirmed low-flow priapism. Cavernosal blood gas analysis revealed severe hypoxia and acidosis. Conservative management including aspiration, irrigation, intracavernosal ephedrine, anticoagulation, and ice application led to complete detumescence without surgical intervention. The case highlights trazodone as a potential cause of ischemic priapism and the importance of early, structured management.
2024-04-08 | A novel strategy to induce penile erection during penile doppler ultrasound: oral sildenafil administration plus alprostadil injection
To evaluate the efficacy of a novel approach to achieve the optimal penile erection during the penile doppler ultrasound (PDU) examination, which was oral sildenafil combined alprostadil injection. A total of 60 ED patients were enrolled in our prospective study, and they were randomly assigned to two group with different PDU order. The approaches assisted the PDU included two models, mode A meaning injection of 15 μg alprostadil and model B meaning oral sildenafil 100 mg plus injection of 15 μg alprostadil. The PDU parameters were measured continuously before induced erection, and 5, 10, 15, 20, 25 min. Each group included 30 ED patients with similar clinical characteristics. After pooling the results together, the PSV, EDV, and RI were all improved significantly, when adding the oral sildenafil administration to assist PDU. Also, the clinical response of oral sildenafil administration plus alprostadil injection was better than that in alprostadil injection alone (p = 0.016). The arterial ED were decreased from 31.67% to 15.00% with the P value 0.031, and the mixed ED was also decreased statistically (23.33% vs 8.33%, p = 0.024). Oral sildenafil administration plus alprostadil injection could improve the diagnostic accuracy of PDU.
cell therapies
2023-04-21 | Systematic review of medicinal leech therapy in urology
Abstract Background Medicinal leech therapy, otherwise known as hirudotherapy or leeching , has been utilized for numerous pathologies over centuries. The technique resurfaced in modern medicine for its beneficial effects in microsurgical complications, particularly venous congestion. Recently, several cases have documented the utilization of medicinal leech therapy for the management of urologic disease states and surgical complications. It is important to understand the past, present, and future possibilities for hirudotherapy in urology. However, a systematic review of medical leech therapy in this context has yet to be conducted. Accordingly, and with an emphasis on salient clinical details, this study aims to systematically review the cases of hirudotherapy applied to urological conditions. Main body of the abstract A systematic review of cases in MEDLINE/PubMed was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Of 49 search results, 11 articles detailing 13 unique cases of medicinal leech therapy used in the urological context were included. Hirudotherapy was conducted in 10 of 13 cases (76.9%) for the management of congested blood occurring in five cases post-penile replantation, two cases of postoperative scrotal hematoma, two cases of venous congestion of the glans post-neonatal bladder exstrophy repair, and one case of refractory priapism. Leeching in the remaining three cases was for the management of penoscrotal edema in patients with hormone refractory prostate carcinoma treated with radical radiation therapy. All 13 cases (100%) reported clinical improvement from hirudotherapy. Venous congestion/hematoma cases noted decreased displaced blood volume. The patient experiencing priapism reported decreased pain despite the persistence of cavernosal swelling. The three cases of penoscrotal edema reported significant decreases in swelling due to serous fluid drainage from leech puncture sites. No complications or side effects were reported in the nine adult patients. The four postoperative neonatal patients all required blood product throughout treatment. Short conclusion The systematic review of the cases demonstrates that medicinal leech therapy is a favorable treatment option for individuals with varied urological pathologies and that hirudotherapy may improve post-surgical outcomes in the urological setting. Hirudotherapy should be considered as a viable treatment modality in specific venostatic urological conditions.
2004-09-01 | Priapism secondary to leukemia: Effective management with prompt leukapheresis
Abstract Priapism is a urological emergency; without prompt treatment the corpora cavernosa undergoes necrosis and fibrosis that may result in erectile dysfunction. Treatment initially involves conservative measures, such as corporeal aspiration and irrigation with saline or dilute phenylephrine. If this fails, embolization or surgical shunting is usually required. Hyperviscosity resulting from leukemia is a rare cause of priapism. We report a case of a 19‐year‐old man with an 18‐hour history of priapism secondary to undiagnosed chronic myeloid leukaemia. We discuss the method of leukapheresis (mechanical white cell depletion) to reduce viscosity and achieve detumescence after failed aspiration.
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Drug Discovery Landscape
2 orphan drug designations for Low-flow priapism.
2 orphan drug designations for Low-flow priapism.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
Abarelix [Plenaxis] | peptides | EMA | — | [INACTIVE] Speciality European Pharma Limited |
Etilefrin | small molecules | EMA | — | Laboratoires SERB |
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