Risperidone-induced priapism with rechallenge

A Case of Priapism in a Child With Autism Spectrum Disorder, Possibly Due to Risperidone Treatment With Addition of Atomoxetine

OBJECTIVES

Risperidone is an effective drug used for the treatment of irritability in children with autism spectrum disorder (ASD). Atomoxetine (ATX) is a well-tolerated drug used in first-line therapy in children with attention-deficit/hyperactivity disorder (ADHD). However, uncommon adverse effects of risperidone and ATX are a concern among mental health professionals. To our knowledge, this is the first case report of priapism after addition of ATX upon existing treatment with risperidone.

METHODS

Written informed consent for publication was obtained from the patient and his parents, and their identities were concealed for ethical reasons.

RESULTS

Here, we report a case of priapism as an adverse effect of ATX and risperidone treatment in a 7-year-old boy with ASD and comorbid ADHD. In this case, priapism was not observed with risperidone until ATX was added.

CONCLUSIONS

Priapism is a condition viewed as a medical emergency. Although risperidone-induced priapism is a rare phenomenon, it is advised for clinicians to consider the drug interactions in treatment of ASD and ADHD in terms of early diagnosis and intervention.

Risperidone-induced priapism: a case report and literature review

Priapism is a rare pathological condition defined as painful and persistent penile erection that is unrelated to sexual stimulation. It can be classified as ischaemic or non-ischaemic. Many causes have been attributed to ischaemic priapism, including the use of some medications such as antipsychotics. The mechanism of priapism associated with antipsychotics is thought to be related to alpha-adrenergic blockage that is mediated by the alpha receptors in the corpora cavernosa of the penis. In this paper, we describe a case of a patient who suffered from Risperidone-induced priapism, and how this adverse effect was resolved by switching to olanzapine followed by olanzapine pamoate. A literature search on PubMed/Medline up to 2011 was conducted by some doctors from London and found 30 cases of priapism associated with risperidone. Based on this work, we searched PubMed through 2021, using the keywords 'priapism' and 'risperidone' and found a total of 43 cases of priapism involving risperidone. Priapism is not correlated with the dosage of this psychotropic drug, and has also occasionally occurred when risperidone has been used in conjunction with another drug. The question of choosing a replacement antipsychotic after the first one has induced priapism, remains problematic. It would be preferable to switch to a drug with less marked alpha1-blocking properties, but no consensus has been reached as to the best choice of medication. Finally, any prescription of an antipsychotic treatment must be preceded by a careful interrogation in search of risk factors for priapism, and the patient should be made aware of the possible occurrence of this side effect and the need to then seek urgent medical advice.

[Antipsychotic-induced priapism and management challenges: a case report]

INTRODUCTION

Priapism is a persistent, and often painful, penile erection, lasting more than 3 hours, not usually associated with sexual stimuli. It is a urological emergency that can cause serious complications. Drugs are responsible of the onset of 25 to 40% of cases of priapism. Several classes of medication are involved: antidepressants, antihypertensives, anticoagulants, alpha-blockers and some psychoactive substances (alcohol, cocaine, cannabis...). However, about 50% of drug related priapism is due to antipsychotics (AP). Clinicians should be aware of this rare side effect because of the severity of its complications and the difficulty of its management, especially in non-stabilized psychotic patients.

CASE REPORT

We report a case of a 22-year-old male Moroccan patient, diagnosed with schizophrenia, who had been admitted for the first time to a psychiatric hospital for management of a psychotic episode. First, he received 15 mg per day of haloperidol, and seven days later he developed priapism. The patient was immediately referred for urological care. Aspiration and irrigation of the corpora cavernosa was proposed, but could not be performed because of patient refusal, and the erection resolved spontaneously after 10 hours. Haloperidol was stopped, and four days later the patient was switched to 10mg per day of olanzapine. After 10 days of treatment, he developed a second episode of priapism, and olanzapine was also stopped. A cavernosal aspiration-irrigation was performed in emergency; which resulted in the partial detumescence of the penis. Two days later, and despite therapeutic abstention, the patient presented another episode of priapism. The indication of a revascularization of the corpora cavernosa was proposed, but again the patient refused the surgery. Finally, the patient was administered 400mg/day of amisulpride, with a favorable outcome. Priapism disappeared after a month with the installation of fibrosis and partial loss of erectile function.

DISCUSSION

The precise mechanisms of the role of AP in the occurrence of priapism are not all known and a multifactor etiology seems the most likely. Neuromuscular hypothesis is the most mentioned, involving the blocking action of alpha1-adrenergic receptors of the corpora cavernosa for which most of AP have an affinity. The occurrence of priapism in a psychotic patient, especially during periods of decompensation, raises a number of challenges for the medical staff. First, the non-recognition by the patient of this side effect, and its potentially severe consequences. Second, the absence of link between dose and duration of AP treatment on one side, and the onset of priapism on the other, which makes it hard to predict. The third challenge is the choice and initiation of another AP. The literature reveals many cases of priapism in both conventional and atypical AP, the presence of a predisposition to this type of incident has been reported. However, few authors have focused on alternatives to provide for these patients. Amisulpride is currently the only molecule that does not have alpha-adrenergic affinity and is therefore preferred in these cases.

CONCLUSION

Priapism is a rare but serious adverse event of AP medication. Informing patient about the risk of priapism would help to report it early and prevent erectile dysfunction. Switching to another AP with less alpha1-blocking properties is generally recommended.

Priapism associated with risperidone: a case report, literature review and review of the South London and Maudsley hospital patients' database

Priapism is a urological emergency defined as persistent penile erection that is unrelated to sexual stimulation and typically involving only the corporal cavernosa. It can occur as a rare side effect of antipsychotic medications and is mediated via their α-adrenergic antagonist effect. In this paper we describe a case of priapism in a patient started on risperidone and sodium valproate. We also review the South London and Maudsley Case Register Interactive Search database to assess how many other cases of priapism were reported in patients taking risperidone. We add this information to a literature review of cases of priapism associated with risperidone.

Priapism and risperidone

A patient taking oral risperidone while using cocaine and alcohol presented with priapism shortly after long-acting, injectable risperidone was prescribed. Another case of priapism was diagnosed in a sickle cell disease patient who was on oral risperidone. A penectomy due to necrosis was required in the first case, while the other patient regained erectile function. Physicians should be aware of priapism-inducing/predisposing factors, such as sickle cell disease, certain medicines or drugs of abuse, and antipsychotic medications. Risperidone is an established cause of priapism. It occurs especially in males with sickle cell disease; use of antipsychotic drugs and/or cocaine further increases risk.

Priapism associated with atypical antipsychotic medications: a review

Priapism defined as persistent, painful and prolonged penile erection, was previously thought to be associated only with the use of the older, conventional first generation or typical antipsychotic medications as well as some other medications, notably, trazodone. The mechanism of priapism associated with antipsychotics is not clear but is thought to be related to alpha-adrenergic blockage that is mediated by the alpha receptors in the corpora cavernosa of the penis. Atypical antipsychotics, also known as second-generation antipsychotics, owing to their favorable side effect profile, are being prescribed with increasing frequency and are not as frequently considered to cause priapism. Some case reports reporting this side effect with their use, however, are found. Pubmed and Ovid databases were searched to obtain all articles and case reports of antipsychotic drug-induced priapism. Key search words included 'priapism', 'antipsychotics' and 'drug-induced priapism'. References of all identified studies were also reviewed. A total of 50 publications were obtained. Most of the atypical antipsychotics have been reported to cause priapism. These cases have occurred in patients shortly after having been started on the antipsychotic medications as well as in those who have been on them for an extended period of time without modification in dosage, and have also occurred sometimes, with the addition of another antipsychotic, lithium or serotonin-specific reuptake inhibitor. Priapism has been documented with nearly all the atypical antipsychotic medications. It is, however, a rarely reported side effect and therefore, underappreciated. Priapism can cause irreversible erectile dysfunction and is a urologic emergency. Clinicians should monitor patients on these medications for this rare, yet significant side effect. Furthermore, caution must be used when adding new drugs to the regimen and patients should be closely monitored for this side effect. Educating patients about the risk of developing priapism would help increase awareness of the side effect and promote early reporting thereby, decreasing long-term morbidity.

Thrombose partielle du corps caverneux. Faut-il rechercher systématiquement une anomalie de la coagulation ?

The authors report a case of partial thrombosis of a corpus cavernosum, confirmed by MRI imaging. In this patient, a neuroleptic had been prescribed several days before the thrombosis and the clotting assessment demonstrated protein C resistance. Conservative management comprising low molecular weight heparin and aspirin was instituted. Three months later, pain had resolved and signs of a thrombotic scar persisted on MRI. The aetiology of thrombosis of the corpus cavernosum, a rare disease, remains unknown. Neuroleptic therapy has been incriminated. In the light of this case, the authors emphasize the value of systematic clotting assessment.

Risperidone-induced priapism

A 31-year-old patient suffering from schizophrenic psychosis was treated with risperidone, and developed priapism which required surgical intervention and resulted in long-term erectile dysfunction.

Priapism associated with the switch from oral to injectable risperidone

Priapism is a rare, but serious, side effect of psychotropic medications. Psychotropic medication-induced priapism is believed to be caused by the alpha-adrenergic antagonism of these medications. Among the atypical antipsychotics, cases of priapism or prolonged erection have been associated with clozapine, olanzapine, risperidone, and quetiapine. Risperidone has primarily serotonergic, dopaminergic, and alpha-adrenergic antagonist properties. It has one of the highest affinities for the alpha1-adrenergic receptor blockade among the atypical antipsychotics. To date, there are 17 case reports of risperidone-associated priapism either in monotherapy or in combination with other psychotropics. To our knowledge, there are no published case reports of priapism on the injectable preparation of risperidone. We report a case of a 50-year-old man who developed priapism while being switched from the oral to the intramuscular preparation of risperidone. The importance of early recognition and intervention in cases of priapism is emphasized. The treatment of priapism with benztropine and other methods is discussed.