Tadalafil Citrate: Working Mechanism, Adverse Effects, Alternatives

tadalafil-formulaTadalafil is a medication existing on the market in the form of a pill. Tadalafil is prescribed for patients with erectile dysfunction and for patients with pulmonary arterial hypertension. It is branded under the name of Cialis if this is the case of erectile dysfunction, while it goes under the name of Adcirca for the pulmonary hypertension treatment.

Tadalafil was discovered in the US by company Lilly ICOS, which discovered the active components efficient in erectile dysfunction treatment, and which missed the radars of German manufacturers that designed sildenafil to be used as Viagra.

Tadalafil was approved by FDA in 2003. Later tadalafil was approved by FDA as a treatment for benign prostatic hyperplasia, and also as a treatment of erectile dysfunction when it goes in combination with benign prostatic hyperplasia.

The working mechanism of Tadalafil

When a man is aroused, the blood rushes to the genital area and fills the penis up. It is not really healthy to have an erection for a very long period of time, so our bodies are designed that way that overwhelming blood supply to the penis should go away after a while.  The blood is stuck in the penis during the erection; there is no blood circulation whatsoever.

What tadalafil does, it inhibits an enzyme called phosphodiesterase type 5, which is essentially responsible for the blood rushing out of the penis. With tadalafil active, the blood would be trapped in the penis a little bit longer than it would normally be the case for a patient.

Does tadalafil affect sexual desire?

A lot of people do not realize that tadalafil in no way affects desire itself. You need to have a desire for sex, to be sexually aroused or in general to have sexual interest to allow tadalafil to work.

No active component is able to turn a man on. What tadalafil can do, it simply keeps the blood flow that is already there, this way augmenting a naturally occurring erection and ensuring its maintenance.

What conditions can be treated?

Tadalafil is approved to treat the following conditions:

  • erectile dysfunction;
  • the signs and symptoms of benign prostatic hyperplasia;
  • the combination of erectile dysfunction and the signs and symptoms of benign prostatic hyperplasia;
  • tadalafil is used in the treatment of pulmonary arterial hypertension.

The physiological mechanism of an erection

In order to explain how tadalafil works, we have to understand how an erection happens first. In the penis, there are two spongy cavernous bodies. There are the blood vessels that go directly into the penis. When the blood flows through these blood vessels, it eventually fills the two sponges. When a man has an erection, his sponges are filled with blood. That is to say, an erection is simply a blood-filled penis.

How come the blood stays in penis maintaining the erection?

There are the vessels that are responsible for transporting the blood out of the penis, but when there is an erection, this blood vessels is sort of tightened up by a membrane, which ensures that blood doesn’t flow out. The penis stays hard and stiff thanks to that, and this way a man has an erection and is able to maintain it.

What is the difference in the action of various PDE5 inhibitors, where tadalafil belongs?

  • Tadalafil is similar to another active components available on the market: sildenafil citrate and vardenafil.
  • While Tadalafil is branded as Cialis, sildenafil citrate is branded as Viagra and vardenafil branded as Levitra.
  • All three components belong to the class of phosphodiesterase type 5 inhibitors (or PDE5 inhibitors for short.)
  • Even though they are similar in the working mechanisms, they cause slightly different outcomes.

We will list the main differences between tadalafil, sildenafil, and vardenafil.

Sildenafil and vardenafil act in about 40 minutes upon taking a drug. On the other hand, to get appropriate blood levels, tadalafil may take up to two hours.

  • The difference in taking the pills with meal.
  • It is basically recommended for all three medications to be avoided with any meals.
  • Sildenafil citrate and vardenafil are the pills that may be affected by a fatty meal taken within 3 to 60 minutes prior to taking a pill.
  • Tadalafil, on the other hand, shows that there are no significant food interactions with a drug.

The duration

Sildenafil citrate and vardenafil have a time frame of action in between 4 to 12 hours. On the other hand, tadalafil can affect a person for 24 and up to 36 hours. For this reason, a pill with tadalafil has a nickname “weekend pill.”

What are the adverse effects?

The common adverse effects of taking tadalafil include:

  • Headache;
  • Upset stomach;
  • Indigestion;
  • Nasal congestion;
  • Flushing;
  • Muscle aching;
  • Back pain;
  • Acid reflux.

These common adverse effects of tadalafil are associated with the ability of PDE5 inhibition to cause the vessels to become wider. They usually disappear quickly, not longer than after few hours. Back pain and muscle aches usually happen 12 to 24 hours after administering tadalafil. These would normally vanish after 48 hours.

The rare adverse effects of taking tadalafil include:

  • Hearing loss. Sometimes accompanied or preceded by the ringing in the ears and dizziness.
  • In the case of hearing loss, a patient is recommended to stop taking tadalafil and seek an advice of his medical provider.
  • This is an erection that lasts more than 4 hours straight. This is a serious side effect that can potentially be traumatic for a patient. In the case of priapism, a patient is advised to call emergency immediately/.
  • Tadalafil’s interactions with other drugs
  • Some medications do not go well hand-in-hand with tadalafil.
  • Medicines that belong to the group of Nitrates are to be avoided when taking tadalafil. Why? Because Tadalafil creates vasodilating effect of Nitric Oxide (see information about it) from the nitrates, which is inevitably resulting in the significant decrease in the blood pressure. This decrease may be great enough to cause death in some patients.

Before taking tadalafil, a patient is advised to tell his doctor if he takes the following medicines:

  • Medicines to treat pulmonary arterial hypertension and chronic thromboembolic hypertension;
  • Medicines for blood pressure treatment;
  • Alpha-blockers;
  • Some types of antibiotics;
  • Other medicines or treatments for erectile dysfunction (ED).

What must a health provider tell the patients who are to take tadalafil?

A brief guidance is required to ensure a patient understands the directions to use and realizes the potential risk the drug may cause. We list only extreme cases.

For the full list of potential adverse effects make sure to contact your urologists and to tell him all your medical history.

  1. Tadalafil is not effective is there is no sufficient sexual stimulation and arousal.
  2. Tadalafil is recommended to be taken around 2 hours prior to the anticipated sexual intercourse or any other sexual activity. Though it varies from patient to patient, there is around one hour of the timeframe would make possible a complete absorption of tadalafil in the vascular system of a patient to ensure the proper functioning of the drug.
  3. Never take tadalafil if you are administering Nitrates. It can cause very serious side effects. If you have nitrates administering in your medical history, make sure to discuss the matter with a doctor to ensure it is safe for you to take tadalafil
  4. Tadalafil may not work on the very first try. Like all other PDE5 inhibitors you should allow several tries over the course of several days to ensure it is working. Such cases, when tadalafil does not work after 1 pill are rare, but that happens.
  5. Priapism as a rare adverse effect that may happen after taking tadalafil. In the case of priapism, go to an emergency center immediately.

Compared to Sildenafil and Vardenafil

Since 2003 there came to be tadalafil marketed under the name of Cialis, the giant competitor of Viagra. It differs from the most famous blue pill for the duration of the effect that lasts up to 36 hours. It is estimated that in the U.S. there are 10 million men suffering from erectile dysfunction problems. For them, Cialis could represent a new “weapon”. It does not require any programming and has no constraints on food and alcohol intake. It would also offer a further choice of treatment, allowing the physician to locate the drug appropriate to the specific needs of each patient. While in the past products were used to stimulate erection, the future is represented by this new class of drugs: peripheral conditioners that do not cause erection, but facilitate the erection mechanism by acting not at the encephalic but peripheral level, i.e. on the penis.

The molecule is called tadalafil, the commercial name is Cialis. It is a drug of the same family of Viagra, it is a V phosphodiesterase inhibitor, that is, of that enzyme that blocks the release of the cavernous body during the erection phase. By blocking this enzyme, erectile mechanisms are facilitated.

Basically, the duration of action. While sildenafil has a maximum effect of 5/6 hours, the new drug has an effect of at least 36 hours in some subjects up to 48 hours. Additionally, while sildenafil should be strictly taken on an empty stomach and in the absence of alcohol, tadalafil has absorption kinetics so it is not affected by food or alcohol, to avoid difficulties and reduce absorption. All this gives couples more freedom in sexual intercourse programming.

Tadalafil side effects are very similar to those of sildenafil. A study was carried out at the Humanitas Clinical Institute, which involved 14 patients. Of these a group took the product 3 times a day in the morning, another only at the time of need. Two patients had to stop treatment due to gastric pyrosis, probably because they already had gastropathy.

Having no action on the VI phosphodiesterase, which is present at the retina level, does not cause alteration of the color vision, so it can also be taken by people suffering from retinitis pigmentosa, a congenital eye disease for which sildenafil is contraindicated .

Tadalafil duration also beats that of vardenafil (Levitra). Vardenafil has the same characteristics as sildenafil in terms of rapidity and duration of action, but has fewer side effects, representing a further evolution. This molecule, like sildenafil, has a duration of approximately 5/6 hours, so it needs to be taken care of.

In 75% of cases, erectile dysfunction is caused by a mixed component, both physical and psychogenic, which varies in proportion to age: young people prevail in the psychological component, while in the elderly the organic one.

Firstly, important diseases such as neuropathy or diabetes mellitus have to be excluded. The specialist’s approach consists of a careful history and an internist clinical examination to evaluate any signs of reduced virilization and organic suffering. Blood, urine and hormone dosage tests are sufficient to decide on the treatment that will be directed, first, to eliminating the modifiable factors such as smoking and alcohol. In addition, some diseases such as hypertension and gastropathy are often treated with drugs that cause erectile dysfunction. By not always suspending or eliminating these medicines, these patients are candidates for the use of inhibitory drugs. In any case, the pharmacological treatment should be accompanied by a psychological support with the function of supporting the couple and helping when discontinuing the drug.

Sildenafil, tadalafil and vardenafil are contraindicated for coronary arteries in the treatment of nitrates, ie vasodilators. The effect of nitrates on coronary dilatation would be enhanced by phosphodiesterase inhibitors and the action involving all the vessels in the body could result in a pressure reduction that would cause a syncope. People who, for the commitment and the physical exercise they require, are not recommended for sexual activity themselves, of course, cannot take inhibitory drugs.

Alternatives of Tadalafil

The drugs to fight erection are divided into central and peripheral initiators, peripheral and peripheral depending on whether they act at the peripheral or central nervous system. Initiators cause erection, while conditioners favor erection. Papaverine and prostaglandins are peripheral injection drugs, which are injected into the cavernous body and cause an erection even if the patient is not psychologically predisposed. Instead, sildenafil, tadalafil and vardenafil should be more accepted by the couple because they do not act if the patient is not predisposed, unless he is attracted to the partner and is not excited. These drugs are a positive evolution since they offer man the opportunity to have an erection only if he is in the ideal condition.

Cialis is a medicine that helps men who suffer from erectile dysfunction (impotence). The active substance tadalafil improves blood flow to the penis, which in combination with sexual stimulation increases the ability to achieve and maintain an erection.

Tadalafil and Alcohol

The active substance tadalafil is a phosphodiesterase type 5 inhibitor that inhibits the enzymes that cause the penis to relax. By widening the blood vessels in the penis, tadalafil improves blood flow. Together with sexual excitement, the penis becomes stiffer and retains stiffness for a long time.

In sexual arousal, subjects are released into the male body, which causes the swelling bodies of the penis to soften. Now the enzyme phosphodiesterase has formed, which breaks down the substances that promote the erection. In some men, this process goes very fast, resulting in an unusually fast relaxation of the penis or the penis does not get stiff at all. Tadalafil works by preventing the formation of the enzyme that inhibits erection and allows the erection to be maintained for longer. For men suffering from erectile dysfunction, tadalafil is an effective way to re-enjoy sexual activity again, without the embarrassment of intercourse.

Alcohol can have both positive and negative effects on penile erectile function. The effect of alcohol is individual and also depends on the amount of alcohol consumed and the frequency of consumption. A smaller amount of alcohol in the blood promotes the expansion of the blood vessels.

Basically, tadalafil can be used in combination with small amounts of alcohol, but it is assumed that certain basic rules are followed. Alcohol consumed in smaller amounts can have a positive effect on sexual activity. This is because the mood can be more relaxed and that there may be less emotional stress and thoughts about everyday problems involved, which may be a strain.

This relaxing effect is beneficial for the widening of the blood vessels in the penis, and increased blood flow means that the erection can be maintained longer. However, the low alcohol consumption can be adjusted and give negative effects, which can lead to an increase in side effects.People taking tadalafil or other antidote drugs should not under any circumstances have a higher alcohol level (more than 0.5 per cent). Although there is no direct biochemical interaction between alcohol and PDE5 inhibitors, alcohol may cause a delayed effect or even the effect of the potency completely disappears.

In addition, the side effects that can be caused by taking the drug can be significantly impaired. Larger amounts of alcohol cause paralysis of the nerves, which interferes with the communication between the genitals and the brain, thus eliminating the effect of PDE5 inhibitory potency. Therefore, the interaction between the cGMP PDE5 tadalafil effect interferes, which makes an erection usually no longer possible. The side effects of the medicine are the same as may occur with tadalafil. However, there are certain effects that are canceled, which may ultimately lead to increased side effects.

The following side effects may occur when using tadalafil with alcohol:

  • Common side effects include: headache and migraine, nasal congestion, body aches, back pain, redness of the face and upper body, warmth, nausea and vomiting, heartburn caused by backflow of stomach acid, bloating and lighter diarrhea, and dizziness.
  • Uncommon side effects: stomach pain, blurred vision, eye pain, increased tear flow, difficulty breathing, altered blood pressure, tinnitus, palpitation, conjunctivitis, unnatural sweating, penile bleeding, blood in urine or sperm, arrhythmias, nasal blood, and shivering.
  • Rare side effects include: swollen eyelids and red eyes, anxiety, powerlessness, chest tightness, increased muscle stiffness, hypersensitivity, memory loss, altered blood sugar levels, and prolonged and / or painful erection.

Excessive alcohol consumption has a negative effect on penile function and increases drug side effects. It is known, for example, that side effects such as fatigue, diarrhea, redness of the face and visual disturbances may be exacerbated. By drinking alcohol, the blood pressure lowering effect of the potency is enhanced, while the heart rate increases. This can lead to dizziness, nausea, problems with blood circulation and altered heart rhythm. Extra care should be taken if the patient walks after having left the bed after intercourse.

Consumption of very small amounts of alcohol is considered safe. However, it should be noted that the full effect of tadalafil can only be reached in sober condition. Increased alcohol consumption also increases the risk of stronger side effects, and that the erectile function decreases or completely decreases. The effect of the drug can also be delayed or decreased in connection with alcohol consumption. From 0.8 promille and upward, often the effect of tadalafil disappears in connection with sexual activity, and if not, the effect is greatly impaired by excessive consumption of alcohol.

Note: As a disclaimer, we should mention that this article was created with the intention of providing educational materials. It cannot be viewed or used as a substitute for professional medical advice. We are not responsible for any health concerns.