Narrative review: pathogenesis, diagnosis, and treatment of sleep-related painful erection

Objective

Through critical analysis and comprehensive review of the limited literature, this paper can help clinicians better identify the pathophysiology of sleep-related painful erections (SRPE) and provide direction for future treatment research.

Background

Patients with SRPE will be awakened by painful erections during sleep, which affects their sleep process and general health. At present, literatures of experimental and clinical research on SRPE disease are limited, as well as long-term reports on its pathogenesis and clinical management.

Methods

We use the PubMed database to obtain sleep-related peer erection literature. The search terms used include sleep, painful, penis and erection. After rigorous screening, the search returned 21 references published between 1987 and 2021.

Conclusions

The main cause of SRPE is obstructive sleep apnea (OSA) syndrome, psychological and spiritual factors, androgen elevation, neuroendocrine regulation and threshold of pain in the REM phase. The combination of multiple medications is the most effective approach to treat sleep-pain-related erections. The combination of CPAP, REM inhibitors and Baclofen has significant effect on SRPE caused by OSA syndrome. This article provides effective support and strategies for doctors to manage SRPE patients through a comprehensive analysis of the pathogenesis mechanism and clinical treatment strategies of SRPE.

Nonischaemic priapism associated with selective serotonin-3 receptor antagonist

Priapism is a rare but severe urological emergency of erection of penis in the absence of physical and psychological sexual stimulation. Priapism is often idiopathic and is commonly associated with medications and underlying medical or traumatic causes. In this report, we present a case of a 70-year-old White Caucasian man who developed priapism after the administration of ondansetron, which is a selective serotonin type-3 (5-HT3) receptor antagonist. This case is unique, because, to date, there are only two presented cases in literature. The objective of this case report is to highlight the importance of recognising the possibility of priapism with ondansetron because this condition is not commonly seen in clinical practice to be associated with ondansetron and may go unrecognised. Also, potential pathophysiological mechanisms involved in the development of ondansetron-induced priapism are presented.

Are 5-HT3 antagonists effective in obsessive-compulsive disorder? A systematic review of literature

OBJECTIVE

The purpose of this literature database search-based review was to critically consider and evaluate the findings of literature focusing on efficacy and safety of 5-HT3 antagonists in the treatment of obsessive-compulsive disorder (OCD), so as to test whether preclinical data match clinical therapeutic trials.

DESIGN

The PubMed database has been searched for papers on 5-HT3 antagonists and OCD in humans and for animal models of OCD and 5-HT3 receptors.

RESULTS

Of the clinically tested 5-HT3 receptor antagonists, ondansetron has been used to treat OCD in five therapeutic studies, whereas granisetron only in one recent trial. Both showed some efficacy in open studies and superiority to placebo in double-blind studies, along with fair safety. No animal OCD model directly implicated 5-HT3 receptors.

CONCLUSIONS

Overall, results indicate some utility, but the available literature is too scanty to allow for valid conclusions to be drawn. The mismatch between animal models of obsessive-compulsive disorder and clinical data with 5-HT3 antagonists needs more clinical data to ensure that it is not an artefact.

Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction

Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.