International guidelines today emphasize the need for screening for hypogonadism in patients with erectile dysfunction.6 Impaired erectile function is a classical symptom of hypogonadism.7 The prevalence for male hypogonadism amongst men with erectile dysfunction is estimated to be around 20%.8,9
Testosterone therapy of hypogonadal men significantly improves erectile function. Positive effects of testosterone are mediated by central stimulation of libido and sexual activity. Loss of libido has been shown to be one of the first symptoms of declining testosterone levels and may occur already at low-normal testosterone concentrations.10
However, also has a direct effect on the penis.11 Recent studies have shown that more than 50% of hypogonadal ED patients reported restored erectile function sufficient for sexual intercourse after 10 to 12 weeks of testosterone therapy alone12,13, indicating that men with erectile dysfunction and low serum testosterone may benefit from testosterone treatment alone. Testosterone given as adjunctive therapy with phosphodiesterase-inhibitors (PDE-5i) converts the majority of hypogonadal non-responders to monotherapy with PDE-5 inhibitors into responders within 10 to 12 weeks of added testosterone therapy14. The combination of phosphodiesterase 5-inhibitors and testosterone may be indicated in hypogonadal men who do not respond sufficiently to either treatment alone.15
Although, from a scientific perspective, it would be best to start the evaluation of a patient with erectile dysfunction by measuring testosterone, psychological facts have to be considered. A patient presenting with ED has usually been waiting for years to come forward with an embarrassing condition. He expects a quick solution to his problem. Since the majority of men will respond favorably to treatment with a PDE5 inhibitor such as Levitra®, he should receive a prescription for a PDE5 inhibitor. At the same time, the physician should keep in mind that “ED does not come alone”16 and take the opportunity to examine risk factors such as blood pressure and waist circumference (for assessing visceral obesity) and draw a blood sample to measure testosterone, lipids and blood sugar. In a very simplified phrase: “Treat ED and check for T.” This will also help to keep the patient who is at risk for cardiometabolic diseases under surveillance. If only a PDE-5 inhibitor is prescribed, many patients never return to the doctor’s office, and an opportunity is lost to assess the patient’s overall health.
Nebido® is not indicated to treat erectile dysfunction. Standard therapy for the treatment of erectile dysfunction are oral phosphodiesterase type 5-inhibitors (PDE5i; such as Viagra®, Cialis®, Levitra®). Nebido® restores sexual desire, i.e., it increases libido, and has a positive effect on erectile function in cases of testosterone deficiency. Lack of libido is only one symptom of hypogonadism. Further signs are: fatigue, concentration problems, changes in body composition (muscle breakdown/increase in fat).17 In order to determine the cause of sexual dysfunction, a thorough medical examination is required. However, it has also been shown that a certain threshold level of testosterone may be necessary for the full effect of ED medications. This threshold level might vary greatly between patients.
Frequent causes for erectile disorder can be:
peripheral nerve diseases
excessive alcohol and nicotine consumption
Even when testosterone therapy alone fails to improve erectile function, and PDE-5I therapy is instituted, continuing with testosterone substitution in combination with the latter is often indicated as:
providing testosterone therapy is the only way of restoring sexual desire which is often low in such ED patients, while additional low sexual desire is a frequent cause of discontinuation of therapy with PDE 5-inhibitors
testosterone therapy may also improve other symptoms associated with hypogonadism, including lack of energy, mood disturbances and negative changes in body composition