Erectile Dysfunction: Causes, a Serious PDE5 Comparison and Ways to Treat It

At a glance

What is it? When you cannot reliably get or keep an erection sufficient for sex over a longer period.
How common? Very common: about one in two men between 40 and 70 knows it to some degree.
Causes Mostly blood flow (vascular), plus psychological and medication-related triggers.
Important to know Erection problems can be an early warning sign for the heart.
Treatment Lifestyle, treating the cause, PDE5 inhibitors (prescription only), further options.
ICD-10 N48.4 (organic), F52.2 (psychogenic)

What is erectile dysfunction?

Erectile dysfunction (also called an erection problem) is when, over a longer period, usually several months, you cannot or cannot reliably get or keep an erection sufficient for sexual intercourse. The fact that it occasionally does not work is completely normal and not yet erectile dysfunction.

Erection problems are very common and increase with age. About half of men between 40 and 70 know them to varying degrees. Important: it is a medical topic, not a sign of lacking manhood, and in the vast majority of cases something can be done about it.

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The causes: vascular, psychological or medication-related?

An erection is an interplay of blood vessels, nerves, hormones and the mind. A disturbance anywhere in this chain can lead to erection problems. For the right treatment, it matters to identify the cause. Roughly, three groups can be distinguished.

Physical (vascular) causes. These are the most common, especially from about 40. Usually poorer blood flow is behind it, for example due to high blood pressure, diabetes, high blood lipids, smoking or excess weight. Nerve damage (for example after pelvic surgery or with long-standing diabetes) and hormone disorders such as testosterone deficiency can also play a role.

An important warning sign Erection problems caused by poor blood flow can be an early sign of cardiovascular disease, often years before a heart attack or stroke. A medical work-up therefore protects not only your sex life but also your heart.

Psychological causes. Stress, performance anxiety, depression, exhaustion or relationship problems. These are more common in younger men. A clue: the problems tend to come on suddenly or only in certain situations, and morning erections are still present.

Medication-related causes. Some medicines can trigger or worsen erection problems, for example certain blood pressure medicines (above all beta-blockers and water tablets), some antidepressants or finasteride for prostate enlargement. This matters because such problems often improve when the medication is adjusted together with your doctor. Some of these medicines can also dampen desire. More on this: Loss of libido.

Often several causes come together, for example a physical basis with an added psychological strain. That is exactly why it is worth getting to the root of the matter instead of just covering up the symptom.

Diagnosis: getting to the root of the cause

It starts with an open conversation. It helps to narrow down the cause, which is why these questions are typical: since when have the problems existed, do they occur always or only sometimes, are there still morning erections, which medicines are being taken, what is the psychological situation?

In addition there are usually:

  • a physical examination.
  • blood tests, for example blood sugar, blood lipids and the testosterone level.
  • measurement of blood pressure and an assessment of the cardiovascular risk.
  • if needed, further examinations, such as an ultrasound of the blood flow in the penis.

The aim is not only to treat the erection problem but also to detect possible underlying conditions.

Treatment: what really helps

The good news: erection problems can be treated well in most cases. What helps depends on the cause, and a combination is often sensible.

  • Tackle the root: a healthier lifestyle often works surprisingly well. Regular exercise, losing weight, stopping smoking, less alcohol and good control of diabetes, blood pressure and blood lipids can improve erectile function and at the same time protect the heart.
  • Review medicines: if a medicine could be the cause, an alternative can often be found together with your practice. Never stop medicines on your own.
  • Tablets (PDE5 inhibitors): these are the most common drug treatment (see next section).
  • For psychological causes: sex therapy or psychotherapy, ideally together with your partner, can help a great deal.
  • Further options: if tablets do not work or are not suitable, there are for example vacuum pumps, an injection or gel treatment directly on the penis, hormone treatment in case of a proven deficiency or, as a last option, a penile prosthesis.

PDE5 inhibitors compared, soberly

PDE5 inhibitors are the most common drug treatment for erectile dysfunction. There are four active substances. Sildenafil and tadalafil are the best known, alongside vardenafil and avanafil. They differ above all in how quickly and how long they work.

Active substance Onset Duration Special feature
Sildenafil approx. 30 to 60 minutes approx. 4 to 6 hours best on an empty stomach, fatty food delays the effect
Tadalafil approx. 30 to 60 minutes up to 36 hours independent of meals; also possible as a low-dose daily tablet that additionally helps with prostate symptoms
Vardenafil approx. 25 to 60 minutes approx. 4 to 8 hours similar to sildenafil
Avanafil approx. 15 to 30 minutes approx. 6 hours works particularly fast

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Soberly put, beyond the advertising promises:

  • all PDE5 inhibitors work in the same way: they improve blood flow in the penis, but only together with sexual stimulation. So they do not trigger an erection at the push of a button.
  • common side effects are headache, facial flushing, a blocked nose and heartburn. Visual disturbances can occur above all with sildenafil and vardenafil, back or muscle pain rather with tadalafil.
  • these medicines are prescription only. A medical work-up is important, also to rule out heart disease and to check for interactions.
  • stay away from dubious online shops: counterfeits with unknown or wrongly dosed ingredients circulate there frequently. That can be dangerous.
Never together with nitrates Anyone who takes nitrates for heart problems (angina) must not use PDE5 inhibitors. The combination can lower blood pressure dangerously. Caution is also needed with alpha-blockers (for example tamsulosin for prostate symptoms). Before taking them, always talk to your doctor about all of your medicines.
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When to see a doctor

If erection problems last longer, keep recurring or bother you, a doctor's visit is sensible, often in urology. This is worthwhile for two reasons: first, help is almost always possible. Second, an erection problem can be an early warning sign of cardiovascular disease or diabetes that should not be overlooked.

Rare, but an emergency: priapism An erection that persists on its own without sexual stimulation and lasts longer than about four hours, often painful, is called priapism. This is a urological emergency and can permanently damage the tissue. Go to the emergency department at once or call the emergency number (112, in the US: 911). This risk exists above all with injection treatment, very rarely also with tablets.

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  • Intake reminders: for example for the daily, low-dose tadalafil tablet.
  • Interaction check: warns you about critical combinations, such as with nitrates.
  • Symptom notes: record what changes, helpful for your next appointment.
  • Medication plan: all medicines in one place, ready for the next appointment.
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Frequently asked questions

When, over a longer period, usually several months, you cannot reliably get or keep an erection sufficient for sexual intercourse. The fact that it occasionally does not work is normal.

From about 40, above all poor blood flow, for example due to high blood pressure, diabetes or smoking. In younger men, more often psychological causes such as stress or performance anxiety. Medicines can also play a role.

Yes. Erection problems caused by poor blood flow can be an early sign of cardiovascular disease. That is why a medical work-up is sensible, it also protects the heart.

Both are PDE5 inhibitors and improve blood flow. Sildenafil works for about 4 to 6 hours and best on an empty stomach. Tadalafil works for up to 36 hours and independently of food, and is also available as a daily low-dose tablet.

No. PDE5 inhibitors only work together with sexual stimulation and need about 15 to 60 minutes depending on the medicine. They do not trigger an erection at the push of a button.

The combination with nitrates (medicines against angina). It can lower blood pressure dangerously. Caution is also needed with alpha-blockers. PDE5 inhibitors are prescription only and belong in medical hands, not in dubious online shops.

Yes. Exercise, losing weight, stopping smoking and good control of diabetes and blood pressure can clearly improve erectile function and at the same time protect the heart.

When an erection persists on its own and lasts longer than about four hours, often painful (priapism). This is a urological emergency, then go to the emergency department at once or call the emergency number.

Related topics

Quellen

  1. DGN (Deutsche Gesellschaft für Neurologie): S1-Leitlinie „Diagnostik und Therapie der erektilen Dysfunktion“ (AWMF 030-112, 2018). register.awmf.org/de/leitlinien/detail/030-112
  2. EAU (European Association of Urology): Guidelines on Sexual and Reproductive Health (Male Sexual Dysfunction). uroweb.org
  3. IQWiG / gesundheitsinformation.de: Erektionsstörungen. gesundheitsinformation.de
  4. DGU / urologenportal.de: Patienteninformationen zu Erektionsstörungen. urologenportal.de
  5. ISSM (International Society for Sexual Medicine): Patienteninformationen. issm.info
Important note: This article is for general information and does not replace medical advice, diagnosis or treatment. PDE5 inhibitors are prescription only and can have serious interactions. Which treatment is right for you depends on your individual situation and belongs in medical hands. Last updated: June 2026.