Viagra was first synthesized in the 1970s and was initially used to treat erectile dysfunction. Although the drug was originally developed to be used as a treatment for men with erectile dysfunction, it would go on to become popularly known for its effects on the minds of humans and its ability to increase blood flow throughout the body. In fact, the chemical in question is known as Sildenafil and was first described in the journal article “A New Method of Producing Sildenafil” in 1992. The article’s author, Dr. Charles Runels, noted that “Sildenafil showed interesting inhibitory effects on a number of enzymes, including phosphodiesterase, an enzyme which breaks down cGMP.”
In addition to its unique ability to boost nitric oxide production, Viagra is also known to have anti-anginal properties and has been shown in studies to improve exercise tolerance in rats with heart disease. Moreover, older patients who take the drug experience reduced rates of dementia and memory loss and improved mood and cognitive function. Interestingly, Viagra is classified as both a Selective Cyclooxygenase-2 Inhibitor (SCRI) and a phosphodiesterase 5 inhibitor (PDE5). Further, it has been shown to increase the production of brain-derived neurotrophic factor (BDNF), which promotes the growth and survival of neurons.
Since its discovery, Viagra has been used to treat a variety of conditions, most notably erectile dysfunction and pulmonary arterial hypertension. Additionally, the chemical in question has been used in the treatment of cardiovascular conditions such as congestive heart failure and myocardial infarction (heart attack). In 2014, Viagra was prescribed to 340 million people worldwide and was the best-selling drug in the world during that year. The drug’s manufacturer, Pfizer, anticipated that 450 million prescriptions would be written in 2020.
First Clinical Trials
Prior to its approval by the FDA in April 1997, Viagra was first tested for safety and efficacy in a variety of clinical trials. While the drug was proven to be safe for use in humans, many of the early trials revealed that it did not provide the desired effect of increased erectile function for the participants who took it. As a result of these adverse effects, Pfizer decided to rename the drug sildenafil and subsequently petitioned the FDA to approve it for pulmonary arterial hypertension and erectile dysfunction. In addition, the company began to test the drug combined with vardenafil (Levitra), which is a comparable chemical substance with sildenafil and is often prescribed to treat erectile dysfunction. This combination therapy, which is still sold under the name Staxyn, was tested in clinical trials and was found to be more effective than either sildenafil or vardenafil alone in increasing blood flow to the penis and sustaining an erection for sexual intercourse. Because of its efficacy in treating erectile dysfunction in combination with vardenafil, Staxyn is now considered by many experts to be the gold standard among PDE5 inhibitors for men with erectile dysfunction who are also taking drugs such as nitrates, which are used to treat heart disease.
How Effective Is Viagra In Treating Erectile Dysfunction?
When Viagra was first approved for use in the U.S. in 1997, the dose ranges recommended for treating erectile dysfunction and pulmonary arterial hypertension were 20 mg to 100 mg and 25 mg to 100 mg, respectively. However, since then, new clinical trials have been conducted and the dose ranges recommended for treating these conditions have been reduced. For instance, in March 2024, the FDA approved a new drug, Ziraflex, which is used to treat erectile dysfunction. The recommended starting dose for Ziraflex is 4 mg, and the maximum recommended dose is 24 mg. Moreover, in February 2025, the FDA approved a drug called Flomax, which is used to treat prostate hypertrophy and lower urinary tract symptoms (LUTS) due to prostatic hypertrophy (PE). The recommended dose of Flomax is 4 mg daily; however, the maximum dose is 24 mg daily. As with Ziraflex, the reduced recommended dose range for Flomax reflects the drug’s more potent cousin, Viagra. Based on this and other similar evidence, experts believe that the potency of Viagra has declined significantly, and that the safest and most effective dose range for this chemical substance is now somewhere between 12.5 mg and 25 mg. The precise reason for this is unclear, but many potential causes have been proposed.
Other Medicinal Uses For Viagra
Although Viagra was originally developed as a drug for treating erectile dysfunction, it has since been shown to have a variety of other medicinal properties. For example, clinical trials have revealed that the chemical in question can:
- reduce cardiovascular risk
- lower blood pressure
- improve exercise tolerance
- reduce symptoms of dementia and Alzheimer’s disease
In addition to its unique ability to boost nitric oxide production and increase blood flow throughout the body, Viagra has also been known to have anti-anginal properties and has been shown in studies to improve exercise tolerance in rats with heart disease. Moreover, older patients who take the drug experience reduced rates of dementia and memory loss and improved mood and cognitive function. Interestingly, Viagra is classified as both a Selective Cyclooxygenase-2 Inhibitor (SCRI) and a phosphodiesterase 5 inhibitor (PDE5). Further, it has been shown to increase the production of brain-derived neurotrophic factor (BDNF), which promotes the growth and survival of neurons.
Since its discovery, Viagra has been used to treat a variety of conditions, most notably erectile dysfunction and pulmonary arterial hypertension. Additionally, the chemical in question has been used in the treatment of cardiovascular conditions such as congestive heart failure and myocardial infarction (heart attack). In 2014, Viagra was prescribed to 340 million people worldwide and was the best-selling drug in the world during that year. The drug’s manufacturer, Pfizer, anticipated that 450 million prescriptions would be written in 2020.
Many specialists believe that Viagra will continue to be popularly used to treat erectile dysfunction and that the drug will be available for prescriptions for many years to come.