Revatio (Sildenafil Suspension) made by Pfizer is a Sildenafil Citrate-containing compound or drug preparation which is used for the management of Pulmonary Arterial Hypertension in patients. Viagra and Revatio, both products from the massive company Pfizer, contain the same active pharmaceutical ingredient, although in varied doses . It seems surprising that the drug for impotence has the same active content as the drug for pulmonary hypertension. This is not impossible, though, as the same PDE5 enzyme is present in both the penile tissues and the pulmonary vascularity .
Sildenafil Suspension or Revatio is used by both pediatric and adult patients suffering from PAH. The drug exists in oral suspension form and has the dose of 10 mg per 1 mL of the oral suspension. Oral suspensions are those drugs which require you to shake them after a while in storage, as the drug usually sediments at the bottom (although there are suspensions which do not require this action).
You can say that the drug can be used for impotence, however, since there is already a specified product for erectile dysfunction (Viagra), there is no reason to take Revatio for impotence treatment, as there are numerous Sildenafil-for-ED options for patients suffering from impotence. However, due to the lower cost of Revatio compared to Viagra, patients are actually using Revatio as an alternative to the famed impotence drug.
The Company: Pfizer
Of all the companies existing in the pharmaceutical industry, one of the most recognizable names is the company, Pfizer. It is a company which began its operations in the early 1800s (1849 to be exact), which makes the company almost 200 years old . Pfizer is stationed in New York, although its research facility is based in another location in the United States (in Connecticut) .
According to Wikipedia information, Pfizer has 75,300 people (as of the year 2015) and it has a number of subsidiaries which makes the company currently the largest in the world . Other companies which Pfizer has merged with or acquired are the following: GD Searie, Greenstone, Agouron Pharmaceuticals, Hospira, Parke-Davis, InnoPharma, Pfizer UK, and also the three largest mergers Wyeth (2009), Pharmacia (2003), and Warner-Lambert (2000) .
Besides its iconic Viagra, the company Pfizer is rather well-known for its pool of first-to-market medications. For instance, the company was the first to introduce the statin for hypercholesterolemia which we know as Lipitor, Prevnar (pneumococcal vaccine), Norvasc/amlodipine (calcium blocker for hypertension), Diflucan/fluconazole (oral drug for grave fungal infestations), Lyrica/pregabalin for neuropathic pain, Zoloft/sertraline (anti-depressant/SSRI), and other famed medications . The list is long for the drugs made famous by Pfizer and which are now widely utilized in the medical profession, which only goes to show the company’s commitment to research and development for the betterment of the patient population.
Scientific Research on Sildenafil
Sildenafil Citrate belongs to the category of the PDE5 or phosphodiesterase type 5 inhibitors, along with the drugs Tadalafil and Vardenafil. Due to the similarity in function of these medications, researchers are studying the replacement of one of these drugs by the other, such as the study of Shapiro et al in 2013, “Safety, tolerability, and efficacy of overnight switching from sildenafil to tadalafil in patients with pulmonary arterial hypertension” . In this study’s case, however, the authors studied the switch from Sildenafil to Tadalafil for pulmonary arterial hypertension . The switch to Tadalafil is considered by the clinicians due to its convenience (needs only 1 administration in a day, as opposed to Sildenafil’s 3 times a day) of administration . The data for the review suggested that the patients who were on Sildenafil (98 patients) were able to transition properly to Tadalafil 40 mg . Side effects were minimal, such as headache and heartburn; so overall, the transition from Sildenafil to Tadalafil for PAH was a success .
The efficacy of the drug Sildenafil Citrate has already been warranted by a number of studies, but, there were no studies on Sildenafil’s actual effect on the coronary arteries. The study by Medina et al in 2000, “Relaxation induced by cGMP phosphodiesterase inhibitors sildenafil and zaprinast in human vessels” sought to find out the effect of Sildenafil in the human (contracted) arteries in from the coronary, redial, and internal mammary regions . Zaprinast was also used for comparison to get a clearer view on the effects of Sildenafil. The arteries were administered with Sildenafil and the drug was observed to instigate a relaxation mechanism in all the arteries described in the study . It was also determined that the relaxation initiated by Sildenafil was dose-dependent . Compared with the action of Zaprinast, the drug Sildenafil is from 8-10 times more potent than the Zaprinast . This study’s results are significant to patients planning to be administered with Sildenafil but have considerations for their arterial conditions .
For erectile dysfunction, the study of Padma-Nathan and several authors in 2003, “Minimal time to successful intercourse after sildenafil citrate: results of a randomized, double-blind, placebo-controlled trial” ascertained the least time to successful coital activity post- administration of Sildenafil as an impotence treatment . The investigation involved patients who were already responsive to the 100 mg of Sildenafil for 2 months or more, and the patients were randomized to either placebo or Sildenafil . The goal of the study was to determine how long Sildenafil is able to elicit a sufficient erectile response in patients (sufficient/hard enough for intercourse) . Some patients were able to have the hard enough erection within 14 minutes and 51% of the patients responded to Sildenafil in just 20 minutes . Overall, the patients responded to Sildenafil in an average time of 36 minutes after intake . The results of this study indicated that more than half of the patients treated with Sildenafil were able to experience Sildenafil’s results in below 30 minutes after intake .
Mechanism of Sildenafil Mode of Action
The main function attributed to Sildenafil Citrate is its ability to stimulate the vasodilation of arteries . In the erectile dysfunction model, this capability of Sildenafil Citrate to initiate the relaxation of the blood vessels translates to the surge of blood flow to the penile area. The engorgement of the tissues of the corpus cavernosum is the cause of the hydraulic erectile response in patients.
Sildenafil Citrate potentiates the vasodilation of the arteries which prompt the initiation of the erectile response in patients. However, the direct action of Sildenafil is not actually in the arteries; Sildenafil Citrate is actually acting on the PDE5 enzyme which is the one responsible for the insufficient erectile function.
Although the causes of erectile failure are many, it all boils down to the malfunction of the PDE5 enzyme in the patients. In normal circumstances, PDE5 acts after the intercourse is done and disintegrates the cyclic monophosphate in order for the penis to regain its normal size. Sildenafil Citrate, being a PDE5 inhibitor, prevents the PDE5 enzyme from disintegrating the cyclic monophosphate so that the erectile response might take place. This mechanism of Sildenafil Citrate works almost all of the time unless the patients have the more severe and unresponsive form of erectile dysfunction.
Revatio Sildenafil Suspension Benefits for Erectile Dysfunction
Revatio in oral suspension form is used for the management of pulmonary arterial hypertension; the drug is efficacious in relieving the symptoms of the disorder. However, patients are also using the drug for the mitigation of erectile dysfunction symptoms due to its Sildenafil Citrate content which is the same active pharmaceutical ingredient found in the Viagra product of the same company, Pfizer.
The Sildenafil suspension (Revatio) is almost the same product as Viagra, although the dosage of the product is the main difference between the two. Revatio in oral suspension is available in 10 mg/mL and the tablet Revatio is available in 20 mg pills, while Viagra and other erectile dysfunction products are available in 50 mg, 100 mg, and 25 mg. Although Revatio is used for PAH, it is also efficacious when used for alleviating erectile dysfunction in patients. Patients can expect the restoration of erectile function when taking the drug every time.
Recommendation for Safe Doses and Scope of Therapy
Erectile dysfunction patients are recommended to consume 50-100mg of Sildenafil Citrate for impotence. Those concentrations are proven to be sufficient to improve the erectile response of the patients. Currently, there is no recommendation on how long the patients should be taking the product, although the long-term administration of Sildenafil Citrate in patients has yielded good results.
Prior to intercourse, patients should take Sildenafil Citrate 1 hour. Food is usually not recommended to be taken with Sildenafil Citrate since taking the drug with food can impede the drug’s effectiveness in the patients.
Alerts and Side Reactions
Dizziness, headaches, facial flushing and vision changes are some of the side effects patients get to expect experience when taking Sildenafil Citrate. These adverse events may or may not occur in patients taking the drug, but in case they do, patients can also expect them to fade away as soon as the drug’s effect starts to wane.
Patients with other medical conditions aside from impotence should be careful when taking the drug, as their condition may present possible complications. For instance, males with liver disease and kidney disease should not be taking the drug without the doctor’s supervision due to the possible negative outcome as a repercussion for poor medical counseling.
Females, children, and the elderly are also restricted to take the drug without medical consultation. Although females, the geriatric population, and children may take Revatio, the dose for PAH should be optimized/appropriated for their needs.
Drug interactions are almost inevitable for all pharmaceutical products, so patients should take extra precaution when it comes to their drug allocations. Sildenafil is prone to interact with certain drug groups, and Sildenafil becomes volatile or erratic when accidentally administered with other drugs. For instance, the bioavailability of Sildenafil Citrate increases when co-administered with antiretroviral drugs such as Bosentan and similar medications. On the other hand, nitrate products and products for hypertension (calcium blockers and the like) are also not advised to be taken with Sildenafil Citrate due to the interaction’s exacerbation of the side effects (hypotension).
Overall, to maintain safety and avoid unwelcome events, patients should carefully consider what drugs they are taking with Sildenafil Citrate. Illicit drugs/recreational drugs should also be avoided in order to further warrant safety while taking the drug.
Sildenafil Suspension/Revatio, Pfizer’s product did not actually have reviews online. This is maybe due to the product not being sold anywhere on the web. The product Revatio seems uncommon for the patients to use, and maybe it is because there are already numerous of alternatives for Viagra available in the market.
For pulmonary hypertension, Revatio is known to treat the disorder regardless of its available reviews. The product is made by one of the world’s first-class pharmaceutical companies, so there really is no doubt regarding the efficacy of the product.
The lack of reviews for Revatio may only signal that it is not commonly found online. Most of the PAH drugs are sold in physical drugstores and most are not sold online, which gives the product less exposure to clients and the reviewers of the products.
Cost, Dosage, and Market Forms
The Revatio Sildenafil suspension is available in 10mg/mL . The liquid suspension form is not really a common product formulation for Sildenafil products, but the goal of the delivery route may be for pediatric patients and those patients with difficulty in swallowing tablet medication.
Unfortunately, there are no vendors with Revatio oral suspension available. Most of the Revatio products online are those in the tablet form, but since this oral Revatio suspension is unique, it is mostly found in ground pharmacies alone. This means that patients cannot purchase the drug online even if they wanted to. Buyers with the need for Revatio Sildenafil can only secure the drug locally. Since Pfizer has the rights to market Sildenafil products, there is no restriction when it comes to the distribution of its products, which then equates to a greater availability of its products anywhere in the world.
Conclusion and Rating
Although no user/product reviews were accessible for Revatio Sildenafil oral suspension, we can still rate the product with 5 out of 5 due to the fact that it is manufactured by the company Pfizer. The world’s largest company is well-accredited and its products are ensured potent and made in the most rigorous of standards to warrant their excellent quality. Albeit Revatio Suspension is uncommon, it is still recommendable when available and when prescribed by the physicians.