Erectile Dysfunction: The inability in the male to have a PENILE ERECTION due to psychological or organ dysfunction.Penile Erection: The state of the PENIS when the erectile tissue becomes filled or swollen (tumid) with BLOOD and causes the penis to become rigid and elevated. It is a complex process involving CENTRAL NERVOUS SYSTEM; PERIPHERAL NERVOUS SYSTEMS; HORMONES; SMOOTH MUSCLES; and vascular functions.Impotence, Vasculogenic: Inability to achieve and maintain an erection (ERECTILE DYSFUNCTION) due to defects in the arterial blood flow to the PENIS, defect in venous occlusive function allowing blood drainage (leakage) from the erectile tissue (corpus cavernosum penis), or both.Penis: The external reproductive organ of males. It is composed of a mass of erectile tissue enclosed in three cylindrical fibrous compartments. Two of the three compartments, the corpus cavernosa, are placed side-by-side along the upper part of the organ. The third compartment below, the corpus spongiosum, houses the urethra.SulfonesPhosphodiesterase 5 Inhibitors: Compounds that specifically inhibit PHOSPHODIESTERASE 5.Penile Prosthesis: Rigid, semi-rigid, or inflatable cylindric hydraulic devices, with either combined or separate reservoir and pumping systems, implanted for the surgical treatment of organic ERECTILE DYSFUNCTION.Purines: A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.Phosphodiesterase Inhibitors: Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.Carbolines: A group of pyrido-indole compounds. Included are any points of fusion of pyridine with the five-membered ring of indole and any derivatives of these compounds. These are similar to CARBAZOLES which are benzo-indoles.Penile Implantation: Surgical insertion of cylindric hydraulic devices for the treatment of organic ERECTILE DYSFUNCTION.PiperazinesPriapism: A prolonged painful erection that may lasts hours and is not associated with sexual activity. It is seen in patients with SICKLE CELL ANEMIA, advanced malignancy, spinal trauma; and certain drug treatments.Alprostadil: A potent vasodilator agent that increases peripheral blood flow.Sexual Dysfunctions, Psychological: Disturbances in sexual desire and the psychophysiologic changes that characterize the sexual response cycle and cause marked distress and interpersonal difficulty. (APA, DSM-IV, 1994)Sexual Dysfunction, Physiological: Physiological disturbances in normal sexual performance in either the male or the female.Penile Induration: A condition characterized by hardening of the PENIS due to the formation of fibrous plaques on the dorsolateral aspect of the PENIS, usually involving the membrane (tunica albuginea) surrounding the erectile tissue (corpus cavernosum penis). This may eventually cause a painful deformity of the shaft or constriction of the urethra, or both.Libido: The psychic drive or energy associated with sexual instinct in the broad sense (pleasure and love-object seeking). It may also connote the psychic energy associated with instincts in general that motivate behavior.Urological Agents: Drugs used in the treatment of urogenital conditions and diseases such as URINARY INCONTINENCE; PROSTATIC HYPERPLASIA; and ERECTILE DYSFUNCTION.Cyclic Nucleotide Phosphodiesterases, Type 5: A cyclic nucleotide phosphodiesterase subfamily that is highly specific for CYCLIC GMP. It is found predominantly in vascular tissue and plays an important role in regulating VASCULAR SMOOTH MUSCLE contraction.Triazines: Heterocyclic rings containing three nitrogen atoms, commonly in 1,2,4 or 1,3,5 or 2,4,6 formats. Some are used as HERBICIDES.Papaverine: An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.Ergoloid Mesylates: A mixture of the mesylates (methane sulfonates) of DIHYDROERGOCORNINE; DIHYDROERGOCRISTINE; and the alpha- and beta-isomers of DIHYDROERGOCRYPTINE. The substance produces a generalized peripheral vasodilation and a fall in arterial pressure and has been used to treat symptoms of mild to moderate impairment of mental function in the elderly.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Coitus: The sexual union of a male and a female, a term used for human only.Sex Counseling: Advice and support given to individuals to help them understand and resolve their sexual adjustment problems. It excludes treatment for PSYCHOSEXUAL DISORDERS or PSYCHOSEXUAL DYSFUNCTION.Urologic Diseases: Pathological processes of the URINARY TRACT in both males and females.3',5'-Cyclic-GMP Phosphodiesterases: Enzymes that catalyze the hydrolysis of cyclic GMP to yield guanosine-5'-phosphate.Ejaculation: The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.Butea: A plant genus of the family FABACEAE that contains butrin and isobutrin.Testosterone: A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.Ventricular Dysfunction, Left: A condition in which the LEFT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE; MYOCARDIAL INFARCTION; and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the left ventricular wall.Hypogonadism: Condition resulting from deficient gonadal functions, such as GAMETOGENESIS and the production of GONADAL STEROID HORMONES. It is characterized by delay in GROWTH, germ cell maturation, and development of secondary sex characteristics. Hypogonadism can be due to a deficiency of GONADOTROPINS (hypogonadotropic hypogonadism) or due to primary gonadal failure (hypergonadotropic hypogonadism).Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Vacuum: A space in which the pressure is far below atmospheric pressure so that the remaining gases do not affect processes being carried on in the space.Injections: Introduction of substances into the body using a needle and syringe.Urethra: A tube that transports URINE from the URINARY BLADDER to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for SPERM.Set (Psychology): Readiness to think or respond in a predetermined way when confronted with a problem or stimulus situation.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Premature Ejaculation: The emission of SEMEN and seminal fluid during the act of preparation for sexual intercourse, i.e. before there is penetration, or shortly after penetration.Tribulus: A plant genus of the family ZYGOPHYLLACEAE. Members contain steroidal saponins. Ingestion by grazing animals causes PHOTOSENSITIVITY DISORDERS called geeldikkop (yellow thick head) in South Africa.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.QatarEpimedium: A plant genus of the family BERBERIDACEAE which is used in DRUGS, CHINESE HERBAL. Members contain flavonol glycosides including epimedins, icariin and noricariin.Prostatectomy: Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic - removal through an incision above the pubis and through the urinary bladder; retropubic - as for suprapubic but without entering the urinary bladder; and transurethral (TRANSURETHRAL RESECTION OF PROSTATE).Penile Diseases: Pathological processes involving the PENIS or its component tissues.Orgasm: The climax of sexual excitement in either humans or animals.Patient Satisfaction: The degree to which the individual regards the health care service or product or the manner in which it is delivered by the provider as useful, effective, or beneficial.Apomorphine: A derivative of morphine that is a dopamine D2 agonist. It is a powerful emetic and has been used for that effect in acute poisoning. It has also been used in the diagnosis and treatment of parkinsonism, but its adverse effects limit its use.Urination Disorders: Abnormalities in the process of URINE voiding, including bladder control, frequency of URINATION, as well as the volume and composition of URINE.Carthamus: A plant genus of the family ASTERACEAE.Cynomorium: A plant genus of the family BALANOPHORACEAE. Members contain stigmastanes and ursanes (TRITERPENES) and lignan glucopyranosides (LIGNANS).Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Phentolamine: A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Imidazoles: Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.Men's Health: The concept covering the physical and mental conditions of men.Lepidium: A plant genus of the family BRASSICACEAE growing in Peru mountains. It is the source of maca root.Nitric Oxide Synthase Type I: A CALCIUM-dependent, constitutively-expressed form of nitric oxide synthase found primarily in NERVE TISSUE.Prostatism: Lower urinary tract symptom, such as slow urinary stream, associated with PROSTATIC HYPERPLASIA in older men.Urinary Incontinence: Involuntary loss of URINE, such as leaking of urine. It is a symptom of various underlying pathological processes. Major types of incontinence include URINARY URGE INCONTINENCE and URINARY STRESS INCONTINENCE.Diabetes Complications: Conditions or pathological processes associated with the disease of diabetes mellitus. Due to the impaired control of BLOOD GLUCOSE level in diabetic patients, pathological processes develop in numerous tissues and organs including the EYE, the KIDNEY, the BLOOD VESSELS, and the NERVE TISSUE.Nitric Oxide: A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.Adrenergic alpha-Antagonists: Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.Cardiovascular Diseases: Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)Panax: An araliaceous genus of plants that contains a number of pharmacologically active agents used as stimulants, sedatives, and tonics, especially in traditional medicine. Sometimes confused with Siberian ginseng (ELEUTHEROCOCCUS).Eunuchism: The state of being a eunuch, a male without TESTES or whose testes failed to develop. It is characterized by the lack of mature male GERM CELLS and TESTICULAR HORMONES.