Erectile Dysfunction (ED)

How an erection works

Sexual arousal sends nerve signals that release nitric oxide in the penis. This raises a messenger chemical called cGMP, which relaxes smooth muscle in the arteries and spongy erectile tissue (corpora cavernosa). Blood rushes in, the tissue expands, and veins are compressed so blood stays in. An enzyme called PDE5 breaks down cGMP and ends the erection. ED results when any step fails: poor arterial inflow, leaky veins, damaged nerves, low hormones, or brain signals dampened by anxiety.

For a symptom-first look at causes and when to worry, see trouble getting an erection.

Causes and risk factors

• Vascular (most common): atherosclerosis, high blood pressure, high cholesterol, smoking.
• Metabolic: diabetes, obesity, metabolic syndrome.
• Neurological: diabetic neuropathy, prostate or pelvic surgery, spinal cord injury, multiple sclerosis, Parkinson's disease.
• Hormonal: low testosterone, high prolactin, thyroid disease.
• Structural: Peyronie's disease, prior penile fracture.
• Medicines: some antihypertensives, antidepressants, antipsychotics, 5-alpha-reductase inhibitors, opioids, antiandrogens.
• Psychological: depression, anxiety, relationship stress, performance anxiety.
• Other: age, chronic kidney disease, sleep apnea, alcohol and drug use, benign prostatic hyperplasia with urinary symptoms.

Diagnosis

History

A doctor asks how long ED has been present, whether it is constant or situational, about morning erections, desire, ejaculation, relationship, medicines, alcohol, smoking and drug use. Standard questionnaires such as the International Index of Erectile Function (IIEF-5 or SHIM) score severity.

Examination

Blood pressure, weight and waist, pulses, the penis (for plaques or curvature) and testicles, signs of low testosterone, and sometimes a prostate exam.

Tests

• fasting glucose or HbA1c
• cholesterol panel
• morning total testosterone, repeated if low, plus LH and prolactin in some men
• kidney function and thyroid tests when indicated

Specialist tests (selected cases)

• Penile duplex ultrasound after an injection, to measure arterial flow and venous leak, mainly before surgery
• Nocturnal penile tumescence testing to confirm whether nighttime erections occur
• Cardiac evaluation if heart risk is high or symptoms suggest heart disease

Treatment

Treatment is usually stepwise, chosen by preference, effectiveness and side effects. Addressing heart risk factors is part of every plan.

Lifestyle

Regular aerobic exercise, weight loss, stopping smoking, limiting alcohol and treating sleep apnea improve erectile function and sometimes restore it. They also improve the response to medicines.

PDE5 inhibitor tablets

These block PDE5, so the natural erection lasts. They need sexual stimulation to work.

They work for about 60 to 70% of men, and less often after prostate surgery or with severe diabetes. Many men who think the tablets failed have not tried enough attempts (at least 6), the correct timing, or the right dose.

Safety: PDE5 inhibitors must not be taken with nitrates (nitroglycerin, isosorbide) or riociguat, because blood pressure can fall dangerously. Caution is needed with alpha-blockers. Common side effects include headache, flushing, blocked nose, indigestion and back pain (tadalafil). Rare effects include sudden vision or hearing loss. Your doctor will check your heart is fit for sexual activity.

Other treatments

• Intracavernosal injections: alprostadil, or combinations (Trimix), injected into the side of the penis with a fine needle. They produce an erection in 5 to 15 minutes in most men, including many who do not respond to tablets. The main risks are pain and priapism.
• Intraurethral alprostadil: a small pellet inserted into the urethra. Less effective than injections.
• Vacuum erection device: a cylinder and pump draw blood into the penis, and a constriction ring holds it. It is drug-free, but the erection can feel cold and hinged at the base.
• Testosterone therapy: only for men with confirmed low testosterone. It improves desire and can improve the response to PDE5 inhibitors.
• Penile prosthesis (implant): inflatable or malleable devices placed surgically. Satisfaction rates are high, above 85% in most studies. It is permanent and is considered when other options fail.
• Psychosexual therapy: cognitive behavioral and couples therapy help when anxiety, depression or relationship issues contribute, often combined with medicine.
• Low-intensity shockwave therapy: being studied. Guidelines consider it investigational or of uncertain benefit.

ED after prostate cancer treatment

Nerve-sparing surgery preserves function for some men, but recovery can take 1 to 3 years. Early "penile rehabilitation" with tablets, injections or a vacuum device is often recommended.

Complications and associated problems

ED can cause low self-esteem, anxiety, depression and relationship strain. More important medically, it is an independent marker of cardiovascular risk. Men with ED have a higher risk of heart attack and stroke, so finding and treating heart risk factors is a key benefit of seeing a doctor.

Outlook

Most men with ED can have satisfying sex again with treatment. ED caused by modifiable factors can improve or resolve. Even when the cause is permanent, such as nerve damage, injections, vacuum devices or implants allow erections.

Frequently asked questions

What is the best treatment for erectile dysfunction?

For most men, the best first step is lifestyle change plus a PDE5 inhibitor such as sildenafil or tadalafil, which work for most users. The best option depends on cause, health, timing preferences and side effects. Injections and implants are highly effective when tablets fail.

How is erectile dysfunction diagnosed?

ED is diagnosed mainly from your history and an examination. Blood tests check glucose, cholesterol and testosterone to find causes and assess heart risk. Specialist tests such as penile Doppler ultrasound are needed only in specific situations, for example before surgery.

Who should not take ED pills?

Men taking nitrates for angina or riociguat should not take PDE5 inhibitors, because blood pressure can drop dangerously. People with recent heart attack or stroke, very low blood pressure, unstable angina, severe liver or kidney problems, or certain eye conditions need a doctor's assessment first.

Can erectile dysfunction be cured?

When ED comes from a reversible cause, such as a medicine, smoking, obesity, low testosterone or anxiety, treating that cause can cure it. ED from permanent nerve or blood vessel damage is usually managed rather than cured, but treatment restores erections for most men.

Does insurance cover erectile dysfunction treatment?

Coverage varies by plan and country. Generic sildenafil and tadalafil are now inexpensive. Many insurers cover implants and injections when ED has a medical cause, such as after prostate surgery. Check with your plan or pharmacist.