All patients should undergo a history of sexual and psychological disorders, a physical examination, and targeted laboratory tests prior to or during treatment. The purpose is to determine the type and extent of erectile dysfunction (hereafter referred to as ED). It is important to clarify whether there is a primary disease or comorbidity causing the secondary erectile dysfunction. There are several clinical options available for ED treatment, including pharmacological, psychological and surgical treatments. The choice of treatment is based on the patient’s degree of morbidity, treatment needs, personal factors, culture, faith, religion, and financial income. It is best for the patient and spouse to choose treatment together. This is because the ultimate goal of treatment should be to restore a satisfactory sexual life, not simply a physical erection. The steps in the treatment of ED should be guided by the following principles: 1) identification of risk causative factors and complications; 2) counseling and education of the patient and spouse (if possible); 3) oral or topical medication; 4) surgical treatment. Although it is often difficult to completely reverse the causative factors of ED, this step is important in some specific patients. 1.1 Lifestyle and psychological factors: For some specific patients, poor lifestyle habits, such as obesity, smoking, alcohol abuse, or abuse of addictive substances need to be addressed first. Psychological factors include male-female relationships (e.g., strained relationships), emotional problems and depression, or other sexual-psychological abnormalities. 1.2 Effects of prescription or over-the-counter medications: These include commonly used antihypertensive drugs (e.g., diuretics, b-blockers), psychotropic drugs, antiarrhythmic drugs, and antiandrogenic and steroidal drugs. Changing the dose and type of medication may improve ED symptoms in some patients, but this may need to be done in cooperation with a primary care specialist. 1.3 Hormone replacement therapy: Hormone replacement therapy for patients with hormonal abnormalities such as hypogonadism and hyperprolactin. In patients with ED and/or hypogonadism, clinical imaging and biochemical indications of apparent hypogonadism need to be confirmed prior to androgen supplementation therapy. 1.4 Because ED may be a symptomatic manifestation of occult cardiovascular disease, metabolic disease, and depression, the chances of such a combination should be confirmed whenever possible. 2 Counseling and psychoeducation on sexuality The target population includes patients with a lack of knowledge about normal sexual function, changes in sexual function due to increasing age in both men and women, or a lack of necessary knowledge or skills for sexual intercourse. Counseling and education on sexual life for patients or both men and women should focus on specific psychological factors or interpersonal relationships, such as relationship tensions, concerns about one’s sexual activity performance, communication difficulties, etc., and also consider complicating conditions that may affect sexual function. However, disadvantages of psychotherapy include large individual differences in efficacy for ED, high costs, low acceptance by patients and their spouses, and a shortage of qualified psychotherapists. When sex-psychological counseling is really needed, it should be closely integrated with treatment before or during the course of ED treatment. 3 Clinical treatment of ED 3.1 Choice of treatment measures Most patients require direct clinical treatment measures for ED. Physicians usually discuss with patients the pros and cons of treatment, the costs of feasible treatment options are reasonable, and the active cooperation of patients in the process of treatment selection. The choice of treatment is based on: (1) the most obvious symptoms of the patient and his or her partner, the severity of the ED, the level of economic income, and cultural and even religious traditions; and (2) cardiovascular safety: the correlation between ED and cardiovascular disease has been reported in the literature. A thorough evaluation of the patient’s cardiovascular status before determining any treatment. (3) partner factors: partner’s sexual function can affect the patient’s sexual function, so before treatment, if available, should also be evaluated for partner’s sexual function. 3.2 First-line treatment: oral medication Oral medication is the first-line treatment for most ED patients due to its convenience and non-invasiveness. Oral medications have a good pros and cons ratio. However, it should be noted that there are more placebo effects in the clinical treatment of ED. Currently registered oral medications for ED include PDE5 inhibitors, apomorphine, and yohimbine. 3.2.1 Phosphodiesterase type 5 (PDE5) inhibitors PDE5 is a catabolic enzyme of the second messenger NO-cGMP in smooth muscle cells in the cavernous body. PDE5 inhibitors can increase the concentration of cGMP, enhance the diastolic effect of cavernous smooth muscle, and promote the erectile response induced by sexual stimulation. The PDE5 inhibitor class of drugs has the widest range of effectiveness and tolerability for ED treatment. Therefore, this class of drugs is used as a reference standard for the efficacy of oral therapeutic agents. Currently, this class includes three drugs: sildenafil, vardenafil, and tadalafil. Sildenafil received global approval in 1998, and vardenafil and tadalafil in 2003. PDE5 inhibitors have been found to be well tolerated and effective in clinical use as well as in controlled clinical studies. In general ED patients, clinical studies have adequately confirmed the effectiveness of all three drugs. The long-term efficacy and safety of sildenafil is well established based on clinical controlled trials, open-label trials, and late-stage market experience. Effectiveness PDE5 inhibitors are taken as needed and drug efficacy may be seen after the first dose. However, patient guidance is still needed to ensure appropriate dosing, as adequate sexual stimulation and appropriate dosing are required for the drug to work. Therefore, repeated doses of the drug may improve the efficacy. The onset of action of these three drugs varies (at least 15-30 minutes). The duration of action is about 8 hours for sildenafil and vardenafil and about 36 hours for tadalafil. Safety Clinical studies have shown that PDE5 inhibitors can potentiate the antihypertensive effect of nitrates, and therefore combination use is contraindicated. In patients taking concomitant α1-blockers, symptomatic hypotension may result, so caution or even contraindication is advised for combining the two drugs. PDE5 inhibitors are metabolized by the liver via cytochrome P450, CYP3A4. CYP3A4 inhibitors, such as ketoconazole, erythromycin and protease inhibitors, can increase the levels of PDE5 inhibitors. Patients taking these drugs should take the lowest dose of PDE5I. Side effects All three PDE5Is have similar side effects, including headaches, indigestion, facial flushing, and nasal congestion. Other side effects include visual changes (due to PDE6 inhibition), myalgia, and back pain that may vary depending on the composition of the drug. These side effects range from mild to moderate in severity. 3.2.2 Other oral medications Apomorphine sublingual tablets: Apomorphine sublingual tablets are central non-selective dopamine antagonists that are moderately effective and well tolerated in patients with mild ED. It may cause mild to moderate nausea and heart rate slowing. Apomorphine sublingual tablets have been registered in several countries since 2002. Yohimbine: Yohimbine is a centrally and peripherally acting alpha blocker with incomplete evidence of therapeutic effectiveness in general ED. 3.2.3 Advantages and disadvantages of oral drug therapy The advantages of oral drug therapy are patient acceptance, ease of use, and relatively good results. The disadvantages include specific contraindications such as inability to use PDE5 inhibitors when taking nitroglycerin at the same time, relatively high costs, and inability to adhere to treatment in moderate patients. Although the percentage of non-adherence to treatment is low in clinical trials, the percentage of non-adherence to treatment is much higher in clinical practice, due to insufficient patient education and follow-up, as well as psychological and economic factors. 4 Local treatment Local treatment includes cavernous injection, transurethral drug delivery and vacuum device, etc. Patients who fail oral drug therapy, have contraindications to drug use and cannot tolerate drug side effects can consider local therapy as an alternative to oral drugs. In addition, some patients prioritize topical therapies because of their own preferences. 4.1 Intracavernosal vasoactive drug injection therapy Prostilbestrol, PGE1, and synthetic endogenous PGE1 can be injected locally into the penile corpus cavernosum to relax smooth muscle by increasing cAMP levels within the smooth muscle cells of the penile corpus cavernosum, which is highly efficacious and slightly less well tolerated with respect to ED. Poppyrine hydrochloride alone or in combination with phentolamine, or the combination of poppyrine, phentolamine and PGE1 has been widely and successfully used in clinical practice. The side effects of cavernous injections are mainly local reactions, including acute pain and abnormal erections (rare), chronic fibrosis and curvature. The advantages of corpus cavernosum injections are their broad efficacy, relative safety and rapid onset of action, while the disadvantages are the invasive local injections and the high cost. Contraindications to cavernosal injections are patients with sickle cell anemia and other conditions that predispose to abnormal erections. Patients receiving anticoagulation therapy are not an absolute contraindication, but extra care should be taken to prevent excessive stasis of blood. 4.2 Intraurethral Drug Delivery Overall, intraurethral drug delivery is generally efficacious and well tolerated in ED, with hypotension and syncope occurring in some rare cases, in addition to side effects similar to those of prostaglandin cavernous injection. The advantages of intraurethral administration of the drug are less invasive, and the disadvantages include local and systemic side effects, higher cost and vaginal irritation of the spouse, who should use a condom if pregnant. 4.3 Vacuum negative pressure devices Vacuum negative pressure devices are over-the-counter (no prescription required) in some countries and are attractive to patients who do not wish to use medication and have contraindications. Vacuum constriction devices apply negative pressure to the penis, draw blood into the penis, and rely on an elastic bandage at the base of the penis to maintain it. Side effects of the vacuum compression device include penile pain, numbness, ecchymosis, and interruption of ejaculation. Being on anticoagulation therapy is a relative contraindication. Advantages of the vacuum negative pressure device include no medication, can be applied whenever sexual intercourse is required, and is less expensive, with the disadvantages of cumbersome use and minor local side effects. 5 Surgical treatment 5.1 Vascular surgery Young people with inadequate spongy blood supply can be treated and improved with microvascular arterial bypass surgery for ED. the best indication for arterial bypass surgery (also known as revascularization) is in young patients with arterial erectile dysfunction that is mostly due to pelvic or pubic trauma and without systemic atherosclerosis, endocrine and neurological factors in arterial patients with sexual erectile insufficiency. ED patients with venous leaks can be treated with venous surgery to reduce venous reflux. The best candidates for venous surgery are: the presence of erectile dysfunction confirmed by nocturnal penile stiffness measurements; good arterial response on ultrasound Doppler with end-systolic arterial flow greater than 5 cm/s; significant abnormal venous leakage on cavernosography; poor results of medication, cavernosal injection therapy and vacuum negative pressure devices; no severe systemic disease such as diabetes mellitus and atherosclerosis; and age less than 60 years. Repeated preoperative penile corpus cavernosum manometry or penile corpus cavernosum angiography is useful to clarify the path of venous leakage and to determine the surgical approach. Approximately 40% to 50% of vascular procedures will fail, 20% will rely on cavernous injection therapy, and 30-40% will have poor long-term results. Therefore, a thorough preoperative conversation with the patient is needed to avoid a sense of over-expectation. 5.2 Penile prosthesis implantation For patients with severe ED, where drug therapy is ineffective, surgical implantation of a bendable or expandable penile erector can be considered. The advantages of this treatment are long-lasting action and high satisfaction, without affecting sexual pleasure, ejaculation, or urination. Disadvantages of this method include irreversibility, invasiveness, surgical complications and mechanical failure of the penile erector. It should only be considered if all other methods are ineffective, however it should be the first choice of treatment in some cases. The efficacy of penile prosthesis implantation and spousal satisfaction are high if the case is properly selected. Complications of penile prosthesis implantation include infection, erosion, pain, and penile curvature, and are closely related to the quality of the device and surgical technique, with a typical incidence of infection of about 5% and mechanical failure of about 5%. 2006 American Urological Association (AUA) statistics on penile prosthesis implantation procedures performed in the United States between 1988 and 2002 found that the elderly population, minorities, and patients with medical conditions such as diabetes mellitus were the most likely candidates for the procedure. The proportion of ED patients with medical conditions such as diabetes who underwent penile prosthesis implantation was significantly higher than before; the long-term results of the improved penile prosthesis improved again, and the chance of infection was reduced. 6. Treatment outcome reassessment and follow-up Each patient with ED who receives treatment should be evaluated and followed up regularly. The purpose of the follow-up visit is: 6.1 The follow-up visit should be noted for dose adjustment or addition of another method, where the patient can change the treatment method, obtain new information, and reassess the treatment choice; 6.2 Patient communication: the patient may be concerned about the treatment dose, other sexual dysfunction (e.g., premature ejaculation), problems with the spouse (no libido), lifestyle (psychological stress); 6.3 Patients may adjust their treatment because of ED or comorbid other conditions, and side effects of medications and possible interactions with oral ED medications should be monitored more closely; 6.4 Patients’ medical and psychosocial status should be evaluated regularly according to their health, physical, and psychosocial needs. Follow-up visits can provide additional educational opportunities for patients.