Erectile dysfunction

A focus on the intracavernous injections (ICI)

Erectile dysfunction is more likely to affect men older than 40 years. In the United States, over 18 million males who are 20 years of age and older are having erectile dysfunction which represent 18.4% of the male population.

Erectile dysfunction commonly exists in patients with vascular, neurogenic, endocrinologic, or psychogenic diseases and patients with congenital, respiratory, liver, or renal disorders disease. Risk factors of erectile dysfunction include hypertension, diabetes mellitus, smoking, and chronic alcohol use.

Some medications are considered risk factor such as anticholinergics, dopamine antagonist, estrogen, CNS depressants, diuretics, and opiates. Erectile dysfunction complications include decreased quality of life of patient and his partner. Erectile dysfunction is highly prevalent in patients diagnosed with inflammatory bowel disease.

The American urology association (AUA) guidelines for erectile dysfunction recommend counseling the patient about the importance of lifestyle modifications, including healthy diet and increased physical activity that can improve erectile function.

The AUA guidelines recommend using phosphodiesterase type 5 inhibitor (PDE5i) as first line therapy unless contraindicated and to discuss benefits and risks with all patients, PDE5i doses should be titrated to achieve the best efficacy. The second line treatment for patients who failed PDE5i include the following options, intraurethral alprostadil, intracavernous injections (ICI), or vacuum erection device.

The four ICI treatments commonly used as ICI are alprostadil, papaverine, phentolamine, and atropine. Alprostadil is the only agent that can be used as a single treatment. Combinations of medications also are used. The most serious adverse event associated with ICI treatments is the priapism, that’s why slow dose titration is recommended with all ICI to avoid the risk of priapism. The other common side effect is penile pain which was reported mostly with alprostadil when used as a single agent compared to the combination ICI.

The doses and efficacy of ICI medications or medication combinations is different among patients because erectile dysfunction patients usually present with different ED severity, that’s why a stepped care approach should be used successfully achieve ED treatment using ICI. The ICI guidelines recommend that any patient should get an in office test to determine effective dose and to teach the patient the technique.

the AUA guidelines recommend referring patients being treated of erectile dysfunction to a mental health professional to help the patient reduce performance anxiety, to promote treatment adherence, and integrate the treatments into a sexual relationship. The guidelines recommend counselling the patient that erectile dysfunction is a risk factor for an underlying cardiovascular disease (CVD).

A Randomized study:

Seyam et al conducted a prospective randomized study to compare the efficacy and safety of trimix with prostaglandin E1. The authors included participants who had erectile dysfunction for more than 6 months and they excluded patients who had sickle cell anemia, history of priapism. The authors recruited 180 participants between July 2000 until December 2002 and randomized them randomly among to groups to receive one dose of either trimix or 20 mcg PGE1 and one week later the participants in each group received the alternative treatment. The authors used different nine doses of trimix that consisted of 1mg of phentolamine, plus 5, 10, or 25 mg of papaverine, and 2.5, 5, or 10 mcg of PGE1. Patients were randomly assigned to group and to the dose of trimix.

Participants were examined at clinic using a duplex ultrasound of cavernous arteries and axial rigidometry. Participant’s blood pressure readings were recorded 5 min after injection, the time taken to complete erection was reported, grading of erection obtained by participants and by examiners were reported. Participants were asked to report pain degree, patient’s satisfaction of erection (%), complications at the injection site, patient’s preference for one treatment.

The results showed that there were no significant differences in peak cavernous artery flow among the two groups, peak systolic velocity (psv) cm/s ± SD was on the right side 30.12 ± 12.17in the PGE1 group and 29.06 ± 12.48 in the trimix group (p=0.33) and on the left side 29.69 ± 12.45in the PGE1 group and 28.58 ± 12.20 in the trimix group (p=0.27).Degree of erection (1–5 ±S.D.) was 3.90 ± 1.04 in the PGE1 group versus 3.87 ± 1.14 in trimix group (p=0.5), no significant difference. Satisfaction (% ± S.D.) was 64.36 ± 26.21 with the PGE1 versus 63.41 ± 28.06 with the trimix (p=0.48), no significant difference. Time to erection (min ± S.D.) was 10.40 ± 5.51 with the PGE1 versus 10.70 ± 5.52 with the trimix (p=0.29), no significant difference. Duration of erection (min ± S.D.) was 92.6 ± 66.71 with the PGE1 versus 20.4 ± 91.2 with the trimix (p=0.001). Trimix resulted in significantly longer duration of erection compared to the PGE1.

0.6% of participants had priapism after receiving PGE1 versus 5% of participants received trimix (p= 0.022). Trimix resulted in significantly higher priapism compared to PGE1.

Trimix is not commercially available and it has to be compounded by pharmacy. Due to the high risk of priapism, it is recommended to start with the lowest possible dose and titrate the dose up slowly.

Important patient education tips before using ICI:

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

Warnings While Using This Medicine:

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

Thanks,

Marina

References

4. Burnett AL, Nehra A, Breau RH, et al. Erectile Dysfunction: AUA Guideline. J Urol. 2018;200(3):633–641. doi:10.1016/j.juro.2018.05.004

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