Sildenafil is a drug used primarily for treating erectile dysfunction victims. It is also used in the treatment of PAH or Pulmonary Arterial Hypertension for clearing clogged arteries to the lung and heart and eventually stabilizing the blood pressure. Pfizer, a manufacturing company, formulated Sildenafil in the year 1989.
Pfizer synthesized Sildenafil as a treatment for hypertension and angina pectoris, also known as heart-related chest pain. But, it caused erections in male patients instead of treating the intended conditions, as a result of which Pfizer discovered that Sildenafil could be useful in treating ED or erectile dysfunction.
It became the first FDA approved oral treatment for erectile dysfunction on 27th March 1998. Pfizer markets Sildenafil as the well known ‘blue pill’ also known as ‘Viagra’. In the case of PAH, Sildenafil is marketed under the brand name ‘Revatio.’
Phosphodiesterase type 5 or PDE5 is an enzyme present in the human body and is responsible for the degradation of the smooth muscle fibers that line the blood vessels. The atrophy of these muscle fibers happens to be the underlying cause of Pulmonary Arterial Hypertension and erectile dysfunction. Sildenafil inhibits the growth of this enzyme and in turn, eases the blood flow into the arteries.
The drug Revatio uses the same principle to target the arteries in the heart and the lungs, hence reducing the high blood pressure which is generally seen in patients diagnosed with PAH, and Viagra uses this theory to stimulate blood flow to the penis. Although for Viagra to be effective, the patient needs to be in a state of sexual arousal.
Although both Revatio and Viagra contain Sildenafil as their core ingredient, their usage depends largely upon the medical conditions being addressed. Revatio is administered in 20 mg doses at intervals of 4 to 6 hours whereas Viagra is taken in doses of 50 mg or 100 mg, usually an hour before sexual intercourse. Modes of administering the two drugs also vary.
Revatio can be administered orally or via an intravenous syringe. On the other hand, Viagra is taken orally in the form of pills. The acting time and the half-life for which Sildenafil remains inside the human body are generally estimated to be around 30 minutes and 5 to 6 hours respectively. These durations are just an average and the effects of Sildenafil vastly vary from person to person. It also varies due to several other factors such as the dosage, age, diet, medications, etc. Read further to know about each of the factors.
- Dosage: Dosage of Sildenafil is an important factor when considering how long the effects of the drug last. For example, Revatio is administered in small doses of not more than 20 mg which is metabolized completely by the human body within 4 hours. On the other hand, a 50 mg dose of Viagra is absorbed by the digestive system partially within 4 hours, but its effects may last for up to 6 or even 8 hours. An even heavier dose will require more time to be metabolized and therefore have longer-lasting effects.
- Age: Age plays a vital role in the absorption of any kind of medication into the bloodstream. Younger patients and adults undergoing Sildenafil treatment are more likely to feel the effects of the drug faster than their elder counterparts, due to their more active metabolism. As a result, Sildenafil lasts longer in older patients, especially the ones aged 65 or above, due to their slowed metabolism.
- Diet: A diet consisting of high-fat foods will slow down the absorption of Sildenafil as the body is busy dealing with digesting fatty foods. But, it will also result in the effects lasting for a longer period as the onset is delayed. Consumption of alcohol reduces the blood pressure, as a result of which Sildenafil may become less effective for the patient to comfortably generate an erection.
- Medications: Any existing medications taken by the patient can also impact the effectiveness and absorption of Sildenafil in the human body. For example, antibiotics like ciprofloxacin interact with Sildenafil and affect how long it lasts.
- Psychological State: Psychological state is more important in the specific case of Viagra. Feelings of performance anxiety, discomfort, nervousness, stress, etc. may affect the effectiveness of Viagra. Hence, one should be relaxed and comfortable when taking Viagra so as not to negatively impact the intended functionality of the medication.
