From the Guidelines
Low ejaculate volume in this 66-year-old male is likely caused by multiple factors, with retrograde ejaculation being the most probable cause, which is supported by the patient's diabetes and benign prostatic hyperplasia (BPH) with a 48g prostate 1.
Causes of Low Ejaculate Volume
- Retrograde ejaculation, which occurs when semen enters the bladder instead of exiting through the urethra during orgasm, is a significant contributor to low ejaculate volume in this patient, as diabetic neuropathy can affect the nerves controlling the bladder neck closure during ejaculation 1.
- BPH with a 48g prostate may also contribute by altering normal urinary tract anatomy, leading to a decrease in ejaculate volume.
- Medications like antihypertensives (Losartan, Amlodipine) can sometimes affect ejaculatory function, although the exact mechanism is not well understood.
- Age-related changes to the prostate and seminal vesicles naturally reduce ejaculate volume in older men.
Evaluation and Treatment
- The patient's previous partial response to Gemtesa (vibegron) for urinary symptoms suggests bladder dysfunction that may extend to ejaculatory issues, and restarting Gemtesa could help with urinary symptoms but may not significantly improve ejaculate volume.
- The referral to an andrologist is appropriate for specialized evaluation and potential treatments specifically targeting ejaculatory function, which might include different medications or techniques to improve this condition.
- According to the updates to male infertility: AUA/ASRM guideline (2024), a low volume, acidic pH, azoospermic ejaculate is typically indicative of distal obstruction in the genital tract, and clinicians should be suspicious of distal male genital tract obstruction when the ejaculate volume is low 1.
From the FDA Drug Label
The most common side effects of GEMTESA include: ... inability to empty your bladder (urinary retention) GEMTESA may increase your chances of not being able to empty your bladder, especially if you have bladder outlet obstruction or take other medicines for treatment of overactive bladder.
The patient's low ejaculate volume could be caused by retrograde ejaculation, which is not explicitly listed as a side effect of GEMTESA in the provided drug labels. However, the labels do mention urinary retention, which may be related to the patient's symptoms. Additionally, the patient's diabetes and benign prostatic hyperplasia (BPH) may also be contributing factors to the low ejaculate volume. 2 2
From the Research
Possible Causes of Low Ejaculate Volume
- Benign prostatic hyperplasia (BPH) is a common condition in aging men that can cause lower urinary tract symptoms (LUTS) and sexual dysfunctions, such as ejaculatory disorders 3
- Medical therapies for BPH, including 5-alpha reductase inhibitors and alpha-adrenergic antagonists, can cause ejaculatory dysfunction, including low ejaculate volume 4, 5
- The use of 5-alpha reductase inhibitors has been associated with adverse sexual outcomes, including erectile dysfunction, ejaculatory dysfunction, and decreased libido 5
- Surgical therapies for BPH, such as transurethral resection of the prostate (TURP) and incision of the prostate (TUIP), can also cause retrograde ejaculation, which can lead to low ejaculate volume 3
Factors Contributing to Low Ejaculate Volume
- Age and LUTS severity can increase the prevalence of ejaculatory disorders 3
- Diabetes, which is present in the patient's past medical history, can also contribute to ejaculatory dysfunction 3
- The patient's current medications, including imipramine, may also be contributing to the low ejaculate volume, although the exact mechanism is unclear 6