Definition and Guidelines Introduction Erectile dysfunction (ED) refers to the inability of the penis to achieve or maintain an erection sufficient for satisfactory sexual intercourse, and the duration of the disease lasts for more than three months. Treatment principles To address the causes, correct poor lifestyle, treatment of underlying diseases, drug-related ED to try to adjust the medication. There are three types of ED have hope of cure. 1, hormone deficiency testosterone, replacement therapy: oral (testosterone undecanoate), intramuscular injections, skin patches. 2, psychogenic: psychological counseling and specialist treatment 3, vascular trauma: young patients consider surgery Most patients can only improve but not cure. Treatment decisions require joint participation of doctors and patients, taking into account its effectiveness, safety, satisfaction of patients and partners, quality of life and other factors. First-line treatment I. Oral phosphodiesterase 5 inhibitors (PDE5 inhibitors) Increase the concentration of cyclic guanosine monophosphate in the smooth muscle of the penile corpus cavernosum, resulting in smooth muscle relaxation, arterial dilation, and enhanced penile erection. 1. The following 4 are currently approved by the European Medicines Agency and are effective for all types of ED, including diabetes. The overall evidence-based level is 1 and the recommendation level is A. Introduced in 1998. Sildenafil takes effect 30 to 60 minutes after administration. Fatty meals affect absorption. Doses of 25, 50 and 100 mg are available. The recommended starting dose is 50 mg. Adjust accordingly to patient response and side effects. Efficacy is maintained for up to 12 hours. Adverse events are mild and self-limiting. Available in February 2003. 30 minutes to 2 hours onset of action, 36 hours duration of action, and independent of food. Doses of 10 and 20 mg are administered on an as-needed basis. The recommended starting dose is 10 mg. Available dosage forms are administered on time (5 mg daily). Introduced in March 2003. Effective 30 minutes after dosing. Its effect is influenced by high-fat meals. Doses of 5, 10 and 20 mg are taken as needed. Recommended starting dose 10 mg. Entered the clinic in 2013. Highly selective PDE5 inhibitor. Higher selectivity for PDE5I than other PDE subtypes with a lower rate of side effects. On-demand (temporary) doses of 50, 100, and 200 mg. 100 mg recommended as a starting dose, taken at least 30 minutes earlier. 47%, 58%, and 59% success rates of intercourse with 50, 100, and 200 mg doses, respectively. The other group showed 64%, 67% and 71% respectively. The maximum daily dose is 200 mg, and there is no need to adjust the dosage according to liver and kidney function and age. It can be taken during meals, and the onset of action of the drug is delayed after eating. 2, the choice of different phosphodiesterase 5 inhibitors individualized principle. According to the frequency of sexual life, regular or impromptu, occasional or conventional treatment, and the patient’s awareness of the drug’s rapid onset of action, usage, and side effects to decide. 3, on time (daily small dose) phosphodiesterase 5 inhibitors long-term use mechanism Studies have shown that long-term use of phosphodiesterase 5 inhibitors, can improve the structure of the penile corpus cavernosum lesions. 4, ED treatment after radical prostatectomy Studies have found that receiving medication early after surgery has a better chance of restoring erectile function. For patients undergoing radical prostatectomy with preservation of the erectile nerve, PDE5 inhibitors are currently the first choice for postoperative ED. The basis of postoperative erectile function recovery is closely related to age and nerve preservation integrity. Study results: Sildenafil 35-75% success rate at intercourse. Tadanafil 5% improvement, 52% intercourse success rate. Avanafil sexual intercourse success rate of 36,4%. 5, cardiovascular disease contraindications: clinical studies have shown that the application of PDE5 inhibitors did not increase the rate of myocardial infarction in patients. However, PDE5 inhibitors are contraindicated in the presence of the following cardiovascular diseases: 6-month endocardial infarction, severe arrhythmia; resting blood pressure < 90/50 mmHg), or hypertension > 170/100 mmHg; unstable angina, angina during intercourse, or congestive heart failure, (New York Heart Association criteria) score >= 2. 6, treatment of angina nitrate drugs Nitrates and PDE5 inhibitors are completely contraindicated. If a patient has an angina attack after taking a PDE5 inhibitor, treatment with nitrates is contraindicated during the following time periods, depending on the half-life of the PDE5 inhibitor: sildenafil, 24 hours; tadanafil, 48 hours; avanafil, 12 hours. 7. Anti-hypertensive drugs Some anti-hypertensive drugs can be combined, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium dissociation antagonists, β-blockers, diuretics, etc. 8, the application of alpha-blockers (prostatic hyperplasia, prostatitis patients, taking the corresponding drugs note) certain drugs may be more likely to cause postural hypotension. Sildenafil is prone to postural hypotension within 4 hours of taking doxazosin. The recommended starting dose of sildenafil is 25 mg, and caution should be exercised when increasing the dose. Vardenafil should be used only after the blood pressure has stabilized in patients taking alpha-blockers. Hypotension has not been observed in combination with tamsulosin. Tadanafil Not recommended for patients taking doxazosin. The effect of combined tamsulosin is small. Avanafil may be considered when taking alpha-blockers at stable blood pressure, starting at a low dose of 50 mg. 9. Dose adjustment when combined with drugs affecting their metabolism (1-) Dose reduction Dose reduction when combined with CYP34A hepatic drug enzyme inhibitors. This includes ketoconazole, itraconazole, erythromycin, clarithromycin, HIV drugs (ritonavir, saquinavir). May increase the concentration of phosphodiesterase 5 inhibitors in the blood. (2) Increases Rifampin, phenobarbital, phenytoin, and carbamazepine may induce CYP34A and increase phosphodiesterase 5 metabolism, and phosphodiesterase 5 inhibitors are increased in combination. Severe renal or hepatic abnormalities also require dose adjustment or caution. 10, phosphodiesterase 5 inhibitors ineffective reasons and countermeasures (1 -) the drug is indeed ineffective (2) incorrect drug usage possible reasons: ① whether the regular way to buy drugs, black market in a large number of drugs can not guarantee the efficacy; ② factors affecting the efficacy: insufficient dose, the drug is not effective or has been metabolized when the life, or diet, sexual stimulation intensity is not enough. Second, the vacuum erection device (VED) VED treatment, often placed at the root of the penis with a constriction ring, blocking venous return to increase erection strength. The constriction ring must be removed within 30 minutes of placement to avoid tissue necrosis. VED is effective up to 90% of the time. For any type of ED, satisfaction rates range from 27-94%. Common adverse effects such as pain, weakness of ejaculation, bruising, abrasions or numbness. Contraindications are patients with coagulation disorders or anticoagulation therapy. More suitable for older people, who can master the relevant operations and have an infrequent sexual life.