What is the frequency of trimix (phosphodiesterase type 5 inhibitor) causing delayed ejaculation?

Frequency of Delayed Ejaculation with Trimix

Delayed ejaculation is not a commonly reported side effect of trimix (papaverine/phentolamine/prostaglandin E1) injections, with the primary literature focusing on its efficacy for erectile dysfunction rather than ejaculatory issues.

Understanding Trimix and Ejaculatory Function

Trimix is a combination medication containing papaverine, phentolamine, and prostaglandin E1 that is used as an intracavernosal injection therapy for erectile dysfunction. While there is extensive literature on its effectiveness for achieving erections, specific data on its impact on ejaculatory function is limited.

What We Know About Trimix:

• Trimix has a high success rate (89%) for achieving erections sufficient for sexual intercourse 1
• The primary adverse event concern with trimix is priapism, which occurs at a relatively low rate (0.5%) 1
• Unlike PDE5 inhibitors, which have been studied for their potential effects on ejaculation, trimix's specific impact on ejaculatory function is not well documented in the literature

Ejaculatory Disorders and Their Management

To understand the context better, it's important to note that:

• Normal ejaculation latency in Western countries is typically between 5-6 minutes following intromission 2
• Delayed ejaculation (DE) is defined as ejaculatory latency beyond 25-30 minutes with associated distress, or cessation of sexual activity due to fatigue or sense of ejaculatory futility 2
• DE can be lifelong or acquired, and is one of the least studied male sexual dysfunctions 2

Factors That Can Cause Delayed Ejaculation:

1. Medications (particularly certain antidepressants)
2. Hormonal factors (low testosterone)
3. Neurological conditions
4. Psychological factors
5. Age-related changes

Trimix vs. Other Erectile Medications and Ejaculatory Function

While PDE5 inhibitors (like sildenafil) have been studied for their effects on ejaculation:

• Some research suggests PDE5 inhibitors may help with premature ejaculation by:
  • Relaxing smooth muscles of vas deferens, seminal vesicles, prostate and urethra
  • Decreasing central sympathetic output
  • Inducing peripheral analgesia
  • Prolonging erection duration 3, 4

However, trimix works through different mechanisms than PDE5 inhibitors, and these effects cannot be directly extrapolated to trimix.

Clinical Implications

If a patient experiences delayed ejaculation while using trimix:

1. Evaluate for other causes: Consider medications, psychological factors, and hormonal issues that may be contributing
2. Dose adjustment: Consider whether the trimix dose may be excessive, as higher doses might potentially affect ejaculatory function
3. Behavioral interventions: Advise on modifying sexual positions or practices to increase arousal, which may help overcome DE 2
4. Consider testosterone testing: If DE persists, check testosterone levels as low levels can contribute to ejaculatory issues 2

Conclusion

The specific frequency of delayed ejaculation with trimix use is not well established in the medical literature. Most studies on trimix focus on its efficacy for erectile function and safety profile regarding priapism rather than ejaculatory outcomes. Clinicians should be aware that while delayed ejaculation is not prominently reported as a side effect of trimix, individual responses may vary, and patients experiencing this issue should be evaluated for other potential contributing factors.