Sildenafil, Tadalafil and Vardenafil comparison

The problem of erectile dysfunction (ED), which was traditionally addressed only by the urologists and sex therapists, now attracts the attention of doctors of other specialties due to the emergence of new possibilities for conservative treatment of this disorder.

First of all, you should determine the etiology of ED and, if possible, cure the disease itself, and not just eliminate its symptoms. It is known that ED can be caused by different factors. Some of these factors can be influenced, for example, by changing the patient’s lifestyle and cancelling some medications he takes. In many cases, the correction of therapy received by the patient for an internal disease can help overcome negative sexual changes, observed with specific treatments.

To date, the most effective method of treating erectile dysfunction is the usage of PDE-5 inhibitors. The earliest invented medicine from this group was sildenafil, the cost of which currently depends on whether the pill is an original or an analogue. The medication is better known as Viagra, and since its appearance on the pharmaceutical market, another two effective drugs have been released – tadalafil and vardenafil.

The mechanism of action of the medicines is almost identical. After the pill intake and sexual stimulation, special nerve impulses are activated, and nitric oxide is released. After that, cyclic guanosine monophosphate in accumulated in the vascular smooth muscle cells. It triggers a chain of biochemical reactions, which results in erection.

Despite the similar effect of drugs, they have a number of differences.

1. Duration of action. Viagra-Sildenafil (which you can buy in our pharmacy) and vardenafil acts for 5 hours, and tadalafil- for 36 hours. Therefore, tadalafil is popular among the couples who are trying to restore their natural sexual relations.
2. Chemical structure. Sildenafil and vardenafil have a similar chemical composition, while tadalafil has a different structure and pharmacokinetic properties.
3. Onset of action. Sidenafil starts acting after 40 minutes, Tadalafil – after 40-50 minutes, and vardenafil – after 20 minutes (maximum after 30 minutes).
4. The highest concentration. The peak concentration for vardenafil and sildenafil is observed 1 hour after the intake, and for tadalafil – 2 hours after the intake.
5. Simultaneous food intake. It isn’t recommended to mix Vardenafil with fat food. The same applies to Sildenafil. Tadalafil can be taken regardless of the fat content of the food intake.
6. Half-life. Tadalafil is excreted from blood plasma after 20 hours, while vardenafil and sildenafil – after 4 hours.
7. Interaction with alcohol. Vardenafil is compatible with a small dose of alcohol, while tadalafil and sildenafil shouldn’t be mixed with alcoholic beverages.

Released in 1998, the PDE 5 inhibitor sildenafil citrate (Viagra) became the first and only drug providing the opportunity of highly effective drug treatment of ED. Indications for its use are EDs of any genesis, both organic and psycho-emotional. Due to its availability and relatively high security, sildenafil was prescribed to the patients not only by the specialists (urologists and andrologists), but also by the general practitioners, which promoted its wide distribution.

However, many men, especially those with the severe forms of ED, diabetes, arterial hypertension, as well as the patients who have undergone radical prostatectomy, weren’t satisfied with the possibilities offered by the use of sildenafil. Particularly, this is due to the short duration of the drug’s action and specific restrictions on its use (food and alcohol intake).

The next PDE inhibitor that appeared on the world drug market was tadalafil. The characteristics of its pharmacodynamics and selective effects on various types of PDE were intended to neutralize the negative aspects that limited the use of sildenafil. This drug has a longer half-life (17.5 hours versus 4 hours of Sildenafil), which provides its effect on the patient’s body for 36 hours after the intake.

There are separate publications on the prolongation of the effect of Tadalafil up to 48 hours. Its pharmacokinetics doesn’t depend on the intake of food and alcohol, which in combination with a long duration of action allows the patient with ED to avoid rigid planning of sexual activity.

However, some studies have shown that only 13 % of interviewed patients with ED are interested in increasing the duration of the drug action— they are more often interested in the reliability (40 %) and safety (40 %) of their use.

It should be stressed that the absolute contraindication to the prescription of PDE5 inhibitors is their simultaneous use with any NO donators, including nitrates. For the duration of the action of PDE5 inhibitors, the intake of nitrates is forbidden, which can be unacceptable for the patients suffering from ischemic heart disease.

The most novel of selective PDE inhibitor is vardenafil hydrochloride. In vitro studies on the selectivity of action on this enzyme, responsible for erection showed that vardenafil is 10 times better to Sildenafil and 13 times superior to Tadalafil.

As with Tadalafil, the effectiveness of vardenafil doesn’t depend on the reception and type of food and alcohol and is approaching 75—80 %. Vardenafil is issued in three dosages, which makes it possible to individually select the most effective and well-tolerated dose of the drug.