The Unexpected Journey of a Pharmaceutical Giant
In the world of pharmaceuticals, few drugs are as globally recognized as Viagra. The iconic 'little blue pill' transformed the conversation around men's sexual health and became a multibillion-dollar success for its manufacturer, Pfizer [1.7.3]. However, its path to becoming a household name was entirely accidental. The active ingredient, sildenafil citrate, was not originally intended to treat erectile dysfunction (ED). In fact, its initial purpose was far from it.
So, What Was Viagra Originally Called?
Before it was Viagra, the compound was known by its clinical development name: UK-92,480 [1.2.4, 1.4.4]. In the late 1980s, a team of Pfizer chemists at their research facility in Sandwich, Kent, England, synthesized this compound [1.7.3, 1.4.4]. Their goal was to create a new medication to treat cardiovascular conditions, specifically hypertension (high blood pressure) and angina pectoris, a type of chest pain caused by reduced blood flow to the heart [1.2.1, 1.4.2]. The drug was designed as a phosphodiesterase-5 (PDE5) inhibitor, with the hypothesis that blocking this enzyme would help dilate blood vessels, improve blood flow, and relieve angina symptoms [1.4.1, 1.5.5].
The Failed Heart Medication
Clinical trials for UK-92,480 as an angina treatment began in the early 1990s at Morriston Hospital in Swansea [1.7.3]. The results were underwhelming. The drug showed little effect on angina and had a short half-life in the body, making it an unsuitable candidate for its intended purpose [1.2.1, 1.4.1]. However, during these early trials, researchers led by Ian Osterloh noticed a peculiar and consistent side effect reported by the male volunteers: they were experiencing significant and prolonged penile erections, sometimes for days after receiving a dose [1.2.4, 1.4.1]. This observation was the pivotal moment that shifted the entire direction of the drug's development.
A Serendipitous Pivot to Erectile Dysfunction
Pfizer's researchers quickly recognized the immense potential of this unintended effect [1.2.1]. At the time, treatments for erectile dysfunction were highly invasive, including penile injections and implants [1.2.2]. There was a significant unmet medical need for a simple, oral medication. The company pivoted its research, focusing on the compound's ability to induce erections rather than treat heart pain [1.7.3].
The mechanism of action remained the same. Sildenafil works by inhibiting the PDE5 enzyme. In the context of sexual stimulation, this inhibition allows for the accumulation of cyclic guanosine monophosphate (cGMP), a molecule that relaxes smooth muscle and dilates blood vessels in the penis, allowing blood to flow in and create an erection [1.5.1, 1.5.4]. Without sexual stimulation, it has no effect [1.5.4].
Pfizer patented sildenafil citrate for the treatment of erectile dysfunction in the United States in 1996 and, after a remarkably short approval process, the FDA approved Viagra on March 27, 1998 [1.7.1, 1.7.4]. It became the first oral treatment for ED in the U.S. and its success was nearly instantaneous [1.7.3].
The Other Life of Sildenafil: Revatio
Interestingly, the story of sildenafil came full circle. While Viagra was marketed for ED, Pfizer later sought and received FDA approval in 2005 for the same active ingredient, sildenafil, to treat a different condition: pulmonary arterial hypertension (PAH) [1.4.4, 1.6.4]. Marketed under the brand name Revatio, it works by the same mechanism of dilating blood vessels, but in this case, it targets the arteries in the lungs to lower blood pressure and improve exercise capacity in patients with PAH [1.6.1]. Revatio is administered in lower, more frequent doses compared to Viagra [1.6.2]. This means the compound originally designed for a cardiovascular condition eventually found a place in treating a serious cardiopulmonary disease, in addition to its more famous application.
Comparison of PDE5 Inhibitors for ED
Viagra was the first, but it was soon followed by other PDE5 inhibitors. Each has a slightly different profile.
| Medication | Active Ingredient | Onset of Action | Duration of Effects | Food Interaction |
|---|---|---|---|---|
| Viagra | Sildenafil | 30-60 minutes | 4-5 hours | High-fat meals can delay absorption [1.8.2]. |
| Cialis | Tadalafil | ~30 minutes | Up to 36 hours | Can be taken with or without food [1.8.2]. |
| Levitra | Vardenafil | ~60 minutes | 4-5 hours | High-fat meals can delay absorption [1.8.2]. |
| Stendra | Avanafil | 15-30 minutes | 4-5 hours | Can be taken with or without food [1.8.2, 1.8.1]. |
Conclusion
The answer to 'What was Viagra originally called?' is UK-92,480, a compound that began as a failed treatment for angina [1.4.2, 1.4.4]. Its history is a prime example of drug repositioning—where a compound developed for one purpose is found to be effective for another, often by accident [1.7.3]. The discovery that UK-92,480 could treat erectile dysfunction not only provided a massive commercial success for Pfizer but also revolutionized the medical treatment of sexual dysfunction, bringing a once-taboo subject into the mainstream and encouraging millions of men to seek treatment [1.2.2].
For more information on the history of sildenafil, you can visit the National Institutes of Health's digital archives: https://pmc.ncbi.nlm.nih.gov/articles/PMC7097805/
