Antiparkinsonian medications may cause premature ejaculation in men with Parkinson’s, according to a case series that followed eight patients.
The study, “Acquired premature ejaculation in Parkinson’s disease and possible mechanisms,” was published in the International Journal of Impotence Research.
Premature ejaculation is a common male sexual dysfunction and can be a source of significant distress in men and their partners.
This dysfunction can be classified into lifelong premature ejaculation (LPE) and acquired, or secondary, premature ejaculation (APE). While with LPE, patients experience early ejaculation independent of sexual partners and starting in their first sexual encounters, those with APE develop early ejaculation after having previous normal ejaculation experiences.
Information on the prevalence of LPE and APE is scarce, and patient self-reports often conflict with clinician diagnosis.
Among the main causes of APE are sexual performance anxiety, psychological or relationship problems, and erectile dysfunction, as well as medical causes such as hyperthyroidism and prostatitis, or prostate inflammation.
Sexual dysfunction is common in men with Parkinson’s, affecting 40.6-51.5 percent of them; however, these issues have not been studied in detail. Erectile dysfunction and premature ejaculation are the predominant forms of sexual dysfunction in this patient population.
The case series described eight men followed between 2008 and 2014 who attended a sex therapy specialist due to a new onset of premature ejaculation.
Patients’ mean age at Parkinson’s onset was 57.3 years and 62.6 years at study inclusion. Half had normal ejaculatory function before Parkinson’s diagnosis, while the remaining four experienced ejaculation within two to three minutes, though not regarded as problematic.
All patients reported a significant reduction in intravaginal ejaculation latency time (the time taken for a man to ejaculate during vaginal penetration) after Parkinson’s diagnosis.
Three patients experienced severe premature ejaculation, meaning that ejaculation occurred before penetration, while four reported ejaculation immediately following vaginal penetration. In addition, erectile dysfunction and/or altered sexual desire occurred in some of the patients.
Of note, all patients were taking anti-parkinsonian medications at premature ejaculation onset, including levodopa in two patients, dopamine agonist in three, and both in one patient. Azilect (rasagiline), amantadine, and an anticholinergic medication were also used.
Psychiatric medications included amitriptyline, Remeron (mirtazapine), and Zyprexa (olanzapine), taken by three patients. Four patients had hypertension, while ischemic heart disease, diabetes mellitus, hyperlipidemia (high cholesterol), benign prostate hypertrophy (enlarged prostate gland), and chronic heart failure were also reported.
“In this case series of [Parkinson’s] patients with APE, the ejaculatory dysfunction developed when patients were on antiparkinsonian medications, suggesting a possible medication effect,” the researchers wrote.
However, since premature ejaculation appeared a mean of four years after Parkinson’s onset, the authors also suggested that Parkinson’s progression may be an additional cause of premature ejaculation.
“Further research with a larger cohort is required on premature ejaculation in the constellation of Parkinson’s disease with a focus on the impact of Parkinson’s disease medications on the onset of premature ejaculation and the effect of anti-parkinsonian medication adjustment, as well as effects of available medications for premature ejaculation on the severity of this disorder,” the authors concluded.