General characteristics of sildenafil, one of the best-selling drugs in the world
Buy Viagra overnight shipping to all cities worldwide. Sildenafil is a drug that is currently used for the management of erectile dysfunction in men. However, it is important to note that originally this drug was developed for the treatment of other pathologies such as hypertension and angina.
The discovery that led to sildenafil being an effective drug for the treatment of impotence arose casually. Prior to patenting, clinical trials were conducted to test its effects in patients with angina pectoris. In the course of these investigations, the doctors leading the studies observed that sildenafil caused erections of the penis in the male patients. Therefore, Pfizer took this side effect into account and decided to release it to the market for the treatment of erectile dysfunction. It got patent in the 90’s and finally it was approved by the FDA allowing its use for this indication.
Sildenafil became the first medication to deal with the problems of impotence in men and today is one of the best selling drugs in the world. It is widely distributed throughout the world. There are millions of people who decide to buy sildenafil on detection of a physical alteration that prevents them from reaching the erection. The benefits of this drug are remarkable as it is very effective for this indication. Erectile dysfunction represents one of the most common sexual disorders in men and brings with it a very significant emotional burden. People with this disease often feel anguish and experience a decrease in self-esteem so strong that it can be determinant for the well-being of their innermost bonds. When these subjects try sildenafil they feel that their sexual life returns to be full and it has favorable repercussion in the rest of the aspects of the mood that we mentioned. It is estimated that the effectiveness of this drug reaches 80% in men suffering from impotence. One of the advantages of sildenafil is that it is taken orally, unlike other drugs to treat erectile dysfunction that must be injected.
Sildenafil is a selective inhibitor of phosphodiesterase and the mechanism of action that allows the erection of the penis to be achieved is due to the release of nitric oxide into the penis. This means that it functions as a vasodilator allowing the muscles of the cavernous penile body to gain sufficient relaxation to receive blood into it.
Sildenafil is rapidly absorbed in the body, achieving a bioavailability close to 45%. It has been found that this drug begins to act in a range of about half an hour to an hour and a half once it has been taken without food. In cases where it is ingested with meals the absorption can be slowed down and the effect can be delayed by an hour more than usual. The drug is almost completely eliminated by the liver. Only 10% is excreted through the kidneys.
The accepted dosage of sildenafil for the management of erectile dysfunction was established at 50 mg 60 minutes before having sex and should be given once a day in people adults. In any case, it has been observed that it also offers considerable effectiveness when taken half an hour before sexual activity. There are experiences in which the dose did not reach the desired power and the dose increased to 100 mg. Conversely, there is also the possibility of reducing the dose if necessary to about 25 mg. In turn, it should be clarified that this last dosage is the one recommended in patients suffering from hepatic or renal failure and in people over 65 years.
Other indications for which sildenafil is approved are sexual dysfunction in women who are taking drugs for depression. In these patients, the standard dose is established in 50 mg and must be administered orally between one hour and one and a half hours prior to sexual intercourse. As is sometimes the case with male erectile dysfunction, it has also been observed here that this dose is not sufficient for certain women. In these cases, it is permitted to increase the dose of sildenafil to 100 mg.
It should be noted as a warning that this drug does not have FDA approval for use in adolescents because the corresponding clinical investigations have not been performed to ensure its efficacy and safety.
For the management of pulmonary hypertension the recommended dose is 20 mg to be administered divided into three doses per day. Experts suggest that a space of approximately 7 hours should be left between the administration of the different doses. On the other hand, it has been verified that the use of sildenafil in patients older than 70 years is the same as in the rest of the patients; this implies that it is not necessary to adapt the doses for this population. However, because these patients may have multiple physical complications, it is always advisable to follow up with the GP.
The last indication of sildenafil referred to is pulmonary hypertension in neonates. Scientific studies have been carried out on infants who were more than 30 hours old and had severe and long-lasting pulmonary hypertension. The dose administered was 1mg per kilogram and the use of sildenafil was compared with placebo. The results showed favorable data for infants treated with sildenafil since an improvement in their conditions was evident over the next 24 hours. Specifically, only one of the 7 patients evaluated could not survive, whereas 5 patients died out of a total of 6. The maximum established dose for infants suffering from this medical condition is 100 mg daily.
To conclude this article, it is important that the reader knows some of the contraindications of sildenafil. Patients who suffer from blindness in one of their eyes due to ischemic neuropathy should refrain from using this medication. There is a group of patients who are required to start treatment with sildenafil at a lower than standard dose. These are those older than 60 years, those who have liver cirrhosis, severe kidney failure. The initial dose for these patients is set at 25 mg.
One of the most known contraindications of sildenafil is related to possible cardiovascular risks, especially in the elderly. For this reason it is appropriate that before starting the treatment, the patient undergoes a medical examination to control the cardiovascular variables.