What is Tadalafil?

Tadalafil is an active substance of the drug Cialis that is used to treat erectile dysfunction (impotence) in men.

Tadalafil improves the circulation in the pelvic organs and increases the blood flow to the penis filling the cavernous bodies which provides a strong and long erection. Cialis (Tadalafil) is used not only for erectile dysfunction but also for benign prostatic hypertrophy. Tadalafil based drug Adcirca is used to treat pulmonary arterial hypertension.

Tadalafil Citrate was approved by the U.S Food and Drug Administration (FDA) responsible for control and supervision of foods, dietary supplements, prescription and over-the-counter pharmaceutical drugs in 2003.

Tadalafil mechanism of action

Tadalafil Citrate is an inhibitor of cGMP-specific phosphodiesterase type 5 (PDE-5). It prevents vessel relaxation caused by the action of PDE-5 and keeps the vessels filled with blood.

The largest concentration of PDE-5 in the body is found in the lungs, retinal tissue and male genitals.

When the vessels in the penis are filled with blood, they widen, blood enters cavernous bodies and all these induce erection.

When the vessels tend to relaxation, erection is weak and short. Inhibiting mechanisms of action of PDE-5, Tadalafil Citrate provides stronger and longer erection.

Tadalafil and other drugs. Interaction, contraindications, side effects

Before taking Tadalafil, consult your doctor and notify him or her about other drugs you are taking and about your current conditions. Taking Tadalafil with certain other medicines can cause serious consequences.


Notify your doctor if you have any of the following symptoms and conditions:

  • Allergy, in general and to PDE-5 inhibitors, in particular.
  • Liver and kidney disease.
  • Symptoms and signs of cardiovascular diseases.
  • Hypertension or hypotension.
  • Eye diseases including hereditary diseases.
  • Heart attack within 3 months and less.
  • Discomfort in the chest during sexual activity.
  • Health problems that make sexual activity unsafe.

Do not take Tadalafil if you are already taking nitroglycerine, isosorbide mononitrate and dinitrate or poppers as it can cause a sudden and serious drop in blood pressure.

Do not take Tadalafil with other PDE-5 inhibitors such as Sildenafil, Vardenafil, Avanafil.  Avoid taking Tadalafil with Adcirca.

Grapefruit or grapefruit juice may interact with Tadalafil and lead to unwanted side effects.

 Tadalafil side effects

Tadalafil was approved by the FDA which is responsible for control and supervision of foods, dietary supplements, prescription and over-the-counter pharmaceutical drugs in 2003. This means that this substance is effective and safe.

In many cases, side effects do not do any lasting harm and go away over time when the body adapts to the medication.

The most common side effects are headache and digestive disorders. Stuffy nose, cough, flushing, backache, pain in the arms and legs are less common.

However, immediately call your doctor if side effects are persistent and affect your day-to-day life.

What side effects require an immediate call to a doctor

  • Persistent headache.
  • Allergic signs such as rash, blistering, skin redness, flaky skin, skin edema.
  • Swelling in the throat, face, lips; difficulty with breathing and swallowing.
  • If you feel that you may fall down, loss of balance, difficulty with speaking and thinking.
  • Light-headed feeling, like you might pass out.
  • Severe vomiting for apparent reason.
  • Loss of vision.
  • Loss of hearing, ringing in the ears.
  • Swelling in the hands and feet.
  • Shortness of breath even at rest.
  • Hematoma and bleeding with no apparent injury.
  • Painful erection that lasts more than 4 hours.

Tadalafil dosage and use

Tadalafil is a prescription drug. Do not increase or decrease the dose. Do not take Tadalafil longer than it was prescribed. Do not break or split a Cialis tablet. Swallow it whole.

The recommended starting dose for most of the patients is 10 mg. The dose may be increased to 20 mg if it is not effective enough or reduced to 5 mg depending on tolerability.

The dose for a regular daily use is 2.5 mg – 5 mg based on individual tolerability and current conditions.

Take Tadalafil at least half an hour before sexual activity. This drug has shown to improve erectile dysfunction up to 36 hours following dosing.

It is not recommended to take Tadalafil more than once a day and it is better to take it in approximately the same time. Tadalafil can be taken with or without food.

A reduced dose of Tadalafil is recommended to the patients with mild to moderate liver or kidney disease. In severe cases, avoid using Tadalafil.

Remember that Tadalafil induces erection only in the presence of sexual stimulation. The medication itself does not induce erection.

The recommended dose of Tadalafil for benign prostatic hypertrophy is 5 mg daily.

Tadalafil generics

Generic drugs are copies of brand-name drugs that have exactly the same active substance.

When a company is developing a new medication, its active substance is thoroughly tested and studied. Of course, it costs millions of dollars. Only when the result of the studies is positive, the company obtains a patent that gives many benefits to the drug developer. While the patent remains in force, only the drug developer can manufacture and sell the drug with this active substance. This is the original drug.

In this way, the company may return its investments in the research and development activities.

When the term of the patent expires, other companies are entitled to manufacture drugs with this active substance. These drugs become generics. Official generics are also tested and studied before they are introduced to the market.

Currently, only Ely Lilly has a right to manufacture Tadalafil based medications. They have developed Tadalafil and now manufacture two medications with it – Cialis and Adcirca. Cialis is used to treat erectile dysfunction. The term of the patent for this drug expires in spring 2020 but it may be extended.

Should Eli Lilly not extend the term of the patent, other pharmaceutical companies will be entitled to manufacture Cialis generics.

On the US market today, there are no FDA approved Tadalafil based generics. But the situation is much more complicated with illegal drugs.

Third countries ignore the international patent law and have been manufacturing generics of the most successful medications for years including Cialis generic.

Obviously, these drugs are not tested and studied but they are much cheaper than original drugs. No wonder, these generics are so popular on the local market. They also make their way to the markets in developed countries, for example, the USA, Canada and some European countries.

Men from developed countries buy illegal generics because they are too shy to go to a doctor to tell him or her about erectile dysfunction. However one can not buy original Cialis without a prescription. Illegal generics are sold in online drugstores and they do not require prescriptions.


Tadalafil is an effective substance to treat erectile dysfunction in men. Cialis (Tadalafil) is a drug that is second only to Viagra in popularity. Cialis side effects are not serious and rare but the effectiveness of the drug is very high. Its duration of action is up to 36 hours. It became a solution for men all around the world. Men go back to their normal life regaining their self-confidence.