Tadalafil

Tadalafil is an active ingredient from the group of PDE-5 inhibitors used to treat erectile dysfunction. Originally marketed by Lilly under the brand name Cialis®, tadalafil has also been available as a generic since the patent expired.

What sets tadalafil apart is its long duration of action of up to 36 hours – considerably longer than with other PDE-5 inhibitors. This has earned the medication the nickname "weekend pill," since a dose taken on Friday evening can theoretically work until Sunday morning.

In addition to on-demand treatment, tadalafil is also approved for daily use at a low dose (5 mg). With this form of use, there is no need to take it before sexual intercourse.

Like all PDE-5 inhibitors, tadalafil inhibits the enzyme phosphodiesterase-5. As a result, the messenger substance cGMP, which is responsible for relaxing the vascular muscles in the penis, remains active for longer. The result: during sexual arousal, more blood flows into the penis, and an erection can develop and be maintained more easily.

What makes tadalafil special: Tadalafil has a considerably longer half-life than other PDE-5 inhibitors. While half of a dose of sildenafil is broken down after about 4 hours, this takes about 17 hours for tadalafil. That is why the effect lasts so long.

Onset of action: The effect can begin as early as 30 minutes after taking it; in some men it takes up to 2 hours. Unlike with short-acting products, however, the timing of the dose does not have to be planned as precisely.

Important: Tadalafil, too, only works with sexual stimulation. Without arousal, no erection occurs.

Tadalafil is particularly suitable for men who:

• Want more spontaneity – The long duration of action allows sexual activity without precise timing

• Are sexually active more often – Taking 5 mg daily can be beneficial for couples with a regular sex life

• Have trouble taking a pill "at the push of a button" – The pressure of taking a medication immediately before sex is removed

Suitable patient groups:

• Men with erectile dysfunction of various causes
• Patients with diabetes and erectile problems
• Men with psychologically caused erection problems for whom time pressure is an issue

Special feature: Tadalafil is also approved for the treatment of benign prostatic hyperplasia (BPH) and can have a dual effect in men with both conditions.

Tadalafil is available in different strengths:

For on-demand treatment (before sexual intercourse):

• 10 mg – Recommended starting dose
• 20 mg – Maximum single dose

For daily use:

• 5 mg – Once daily, regardless of sexual activity

Dosage recommendation: For on-demand treatment, the usual starting dose is 10 mg. Depending on effectiveness and tolerability, the dose can be increased to 20 mg. With good tolerability and frequent sexual activity (more than twice a week), taking 5 mg daily can be a sensible option.

For older patients: No dose adjustment is required for men over 65 years of age, provided there is no severe kidney or liver impairment.

On-demand treatment (10 mg or 20 mg):

• Take at least 30 minutes before planned sexual intercourse
• The effect can last up to 36 hours
• No more than one tablet per day
• Can be taken regardless of meals

Daily use (5 mg):

• Take at about the same time every day
• Regardless of sexual activity
• After a few days, a constant level of the active ingredient is reached
• Sexual activity is then possible at any time

Taking with food: Tadalafil can be taken with or without food. Unlike with some other PDE-5 inhibitors, a high-fat meal has no relevant effect on absorption.

Alcohol: Moderate alcohol consumption is possible. However, excessive alcohol can impair the ability to get an erection and increase side effects such as dizziness.

Tadalafil must not be taken in cases of:

• Use of nitrates – such as glyceryl trinitrate (nitro spray), isosorbide mononitrate, or amyl nitrite (poppers). The combination can cause a life-threatening drop in blood pressure.

• Use of guanylate cyclase stimulators such as riociguat – the combination can cause a drop in blood pressure with symptoms (symptomatic hypotension).

• Severe heart disease – in particular a heart attack within the last 90 days, unstable angina pectoris, heart failure (NYHA II or higher) within the last 6 months, uncontrolled cardiac arrhythmias

• Stroke within the last 6 months

• Low blood pressure (below 90/50 mmHg) or uncontrolled high blood pressure

• Hereditary retinal disorders such as retinitis pigmentosa

• Recent loss of vision due to non-arteritic anterior ischemic optic neuropathy (NAION)

Use with caution in cases of:

• Anatomical deformities of the penis
• Conditions with an increased risk of priapism
• Concurrent alpha-blocker therapy
• Severe hepatic insufficiency – before prescribing, the doctor should weigh the benefits and risks carefully and individually

Common (1 to 10 in 100):

• Headache
• Facial redness (flushing)
• Stuffy nose, sinus problems
• Back pain
• Muscle pain
• Pain in the arms and legs
• Indigestion
• Heartburn

Uncommon:

• Dizziness
• Blurred vision
• Racing heart
• Skin rash

Notes on side effects: Back pain and muscle pain occur more often with tadalafil than with other PDE-5 inhibitors. They are usually mild and go away within 48 hours.

When to see a doctor immediately:

• Painful erection lasting longer than 4 hours (priapism)
• Sudden loss of vision or loss of hearing
• Chest pain during or after sexual activity

Absolute contraindication:

• Nitrates and NO donors: The combination is strictly contraindicated because of the risk of a severe drop in blood pressure.
• Guanylate cyclase stimulators such as riociguat: Concomitant use is contraindicated because a drop in blood pressure with symptoms (symptomatic hypotension) may occur.

Important interactions:

• Alpha-blockers: Can increase the blood-pressure-lowering effect. If used at the same time, tadalafil should be started at the lowest dose.

• Strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir): Increase the tadalafil concentration. The dose should not exceed 10 mg in 72 hours.

• CYP3A4 inducers (rifampicin, phenytoin, carbamazepine): Can reduce the effectiveness of tadalafil.

• Other PDE-5 inhibitors: Do not use at the same time.

• Blood pressure medications: Possible additive blood-pressure-lowering effect.