Cialis®

Cialis is a prescription-only medication for the treatment of erectile dysfunction, manufactured by Eli Lilly. Its active ingredient, tadalafil, stands out for its particularly long duration of action of up to 36 hours – hence the common nickname "weekend pill".

European marketing authorization was granted on November 12, 2002. This made Cialis the second PDE-5 inhibitor approved in Europe, after Viagra. Because of the long duration of action, it does not have to be taken immediately before sexual intercourse.

Special feature: Cialis is also approved for daily use at a low dose (5 mg). This makes sexual activity possible at any time, without taking a tablet beforehand.

Since the patent expired, the active ingredient tadalafil has also been available as a generic.

Cialis contains the active ingredient tadalafil, which belongs to the group of PDE-5 inhibitors. Its mechanism of action follows the same principle as other medications in this class, with one crucial difference: the duration of action.

The mechanism in detail: During sexual arousal, nitric oxide is released in the penis. This activates an enzyme that produces the messenger substance cGMP. cGMP causes the muscles of the blood vessels in the penis to relax – more blood can flow in, and an erection occurs.

The enzyme PDE-5 normally breaks down cGMP and ends the erection. Cialis inhibits PDE-5 and thus prolongs the effect of cGMP. An erection can develop more easily and be maintained for longer.

Why does Cialis work for so long? Tadalafil has a half-life of about 17 hours – this means that after this time, half of the active ingredient is still active. For sildenafil (Viagra), it is only about 4 hours. That is why the effect of Cialis lasts up to 36 hours.

Important: Cialis, too, only works with sexual stimulation – it does not produce an automatic erection.

Cialis is primarily an option for men who:

Want to stay flexible with timing:

• Do not want to plan on taking it immediately before sex
• Do not want to fix the time of intake
• Do not want to put themselves under time pressure

Are frequently sexually active:

• Couples with an active sex life benefit from the daily 5 mg dose
• The level of active ingredient remains constant, and sex is possible at any time

Want to take psychological factors into account:

• The pressure of "taking it at the push of a button" disappears
• Less performance pressure thanks to the long duration of action
• A more natural experience of sexuality

Also suffer from benign prostatic enlargement:

• Cialis is also approved for this indication
• One medication can treat both conditions

Older men:

• No routine dose adjustment required

For on-demand treatment:

• 10 mg – Recommended starting dose, to be taken before sexual intercourse
• 20 mg – If 10 mg is not sufficiently effective

For daily use:

• 5 mg – Once daily, at approximately the same time of day

Which option is suitable for whom?

*On-demand treatment (10/20 mg):*

• For occasional sexual activity (less than 2 times per week)
• If the flexibility of the long duration of action is to be used
• For men who do not want to take a medication every day

*Daily use (5 mg):*

• For frequent sexual activity (more than 2 times per week)
• If the time of intake should not be fixed in advance
• When prostate symptoms are being treated at the same time

Important: The maximum dose is 20 mg per day. Do not take more than one dose in 24 hours.

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
• Sexual activity is possible at any time during this period
• Take with a glass of water

Daily use (5 mg):

• Take at approximately the same time every day
• Regardless of planned sexual activity
• A stable level of active ingredient is reached after a few days
• Spontaneous sex is then possible at any time

Taking with food: Cialis can be taken with or without food. Unlike some other erectile dysfunction medications, a meal – even a high-fat one – has no relevant influence on the onset or strength of the effect.

Alcohol: Moderate alcohol consumption is acceptable. Larger amounts of alcohol can impair erectile function and intensify side effects such as dizziness and low blood pressure.

Absolute contraindications – Cialis must not be taken in cases of:

Nitrate therapy: If you take nitrates (nitroglycerin, isosorbide mononitrate, isosorbide dinitrate) or use amyl nitrite (poppers). The combination can cause a life-threatening drop in blood pressure.

Severe heart disease:

• Heart attack within the last 90 days
• Unstable angina pectoris
• Heart failure NYHA class II to IV
• Uncontrolled cardiac arrhythmias
• Stroke within the last 6 months

Other contraindications:

• Low blood pressure (below 90/50 mmHg)
• Uncontrolled high blood pressure
• Hereditary retinal disorders
• Loss of vision in one eye due to NAION
• Hypersensitivity to tadalafil

Relative contraindications – particular caution in cases of:

• Anatomical changes of the penis
• Conditions with an increased risk of priapism
• Concurrent alpha-blocker therapy
• Moderate kidney impairment
• Severe liver impairment

Common (1-10%):

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

Uncommon (0.1-1%):

• Dizziness
• Blurred vision
• Eye pain
• Racing heart
• Skin rash

Special feature of Cialis: Back and muscle pain occur more frequently with Cialis than with other PDE-5 inhibitors. They are typically mild to moderate and resolve within 48 hours.

When to see a doctor immediately:

• Painful erection lasting more than 4 hours (priapism)
• Sudden loss of vision in one or both eyes
• Sudden loss of hearing
• Chest pain during or after sexual activity

Absolutely contraindicated:

• Nitrates and NO donors: Combination strictly prohibited due to the risk of a severe drop in blood pressure

Important interactions:

• Alpha-blockers: Taking them at the same time can intensify the blood-pressure-lowering effect. If alpha-blocker therapy is already ongoing, Cialis should be started at the lowest dose.

• Strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir): Considerably increase the tadalafil concentration. The dose should be limited to a maximum of 10 mg within 72 hours.

• CYP3A4 inducers (rifampicin, phenytoin, carbamazepine): Can reduce the effectiveness of Cialis. A higher dose may be required.

• Other PDE-5 inhibitors: No combination with Viagra, Levitra or Spedra.

• Antihypertensives: Can intensify the blood-pressure-lowering effect.

• Alcohol: Can lower blood pressure further and intensify dizziness.