My Canadian Pharmacy Review: Sildenafil Citrate (PDE5) and Its Stand in Modern Pharmacology


sildenafil citrate

Even though you haven’t heard of Sildenafil Citrate, you are surely aware of many products that contain it: today these are mainly ED medications sold under numerous trade names. Being the major component of impotence pills, Sildenafil works increasing the blood flow, allowing men worldwide enjoy harder and longer erection. But this encyclopedia line says a little about the element, and you surely have to learn a lot more.

From the History of Sildenafil Citrate

Sildenafil Citrate WorkSildenafil Citrate Work Sildenafil was initially discovered by the British scientists. However, their primary initiative was far from finding the cure for erectile dysfunction in males. The element was found to treat high blood pressure (hypertension) as well as the ischemic heart diseases’ symptoms (angina pectoris).

They hoped for excellent results, yet during multiple tests and trials things appeared to be quite different. The first results have established that Sildenafil Citrate had a little influence on angina or hypertension treatment. At the same time it affected penile erection, improved it and made it last for a long time. This is how a forefather of all modern ED medications was discovered.

After a surprising discovery the scientists decided to continue using Sildenafil for impotence treatment. In 1996 the drug was firstly patented in the USA. It entered the market two years later in 1998 after it got the FDA approval.

This is how, purely by accident, the world got the medication that can treat erectile dysfunction of different categories and difficulty levels.

Sildenafil molecule

Molecular nitrogen monoxide (NO) has a vital role for humans because it starts several vital biochemical processes. One of the effects of the molecule is, among other things, that it helps the muscles of the coronary artery to relax so that blood flow increases to the heart. Sildenafil was also created a little by detour when originally developing heart medicine, but here it was found that the drug also increased blood flow to, inter alia, penis – and this one chose to further develop Sildenafil as a result.

Sildenafil is designed to resemble the cGMP substance, which is naturally found in the body. A high level of this substance, among other things, causes the smooth muscle to relax – and this contributes to increasing blood flow.

How, When and Where Does Sildenafil Citrate Work?

Do you know that the human body is the home for 11 types of phosphodiesterase? Half of them were discovered in 1997. Many of them are found in the penile area (2,3,4,5), but PDE5 is the predominant one.

How does Sildenafil Citrate work? The active ingredient works as a competitive inhibitor of phosphodiesterase type 5 class. When there’s sexual stimulation the neurotransmitter or NO is released across numerous neuromuscular junctions of both the cavernosal smooth muscles as well as the penile arteries. NO triggers the increase in the cGMP release (molecule cyclic guanosine monophosphate). The latter one leads to penile smooth muscle relaxation. It also creates:

  • increased blood flow;
  • cavernosal smooth muscle relaxation;
  • penile rigidity and tumescence.

At this time the inhibitor breaks down the cGMP and results in penile arteries contraction. Anything that can possibly affect cGMP by increasing its production or by preventing its breakdown will have an effect on the erectile function.

What is the chemical structure of Sildenafil Citrate? The chemical structure of the element is similar to that of cGMP. Sildenafil Citrate binds to the PDE-5 enzyme. It prevents the breakdown of cGMP by means of a competitive inhibition.

It’s obvious that many health conditions and other factors are associated with the process. Their list includes:

  • diabetes;
  • hypertension;
  • hypotension;
  • dyslipidemia;
  • age.

Most of these diseases are associated with the decrease of endothelial levels of NOS (it is the nitric oxide synthase). NOS is the enzyme, which produces NO. And when the synthesis of NO is diminished, it may lead to NO decrease as well as the low efficacy of cGMP muscle relaxation. Sildenafil is an active element that assists in coping with any of the tough cases.

When the ED condition occurs due to neuronal loss (the after non-sparing radical prostatectomy case) or the patient is suffering from really severe arterial diseases, Sildenafil is not effective. This is especially true if the arterial disease is characterized by the fixed vasculopathy and the latter one prevents any arterial smooth muscle relaxation.

In case of oral administration Sildenafil is quickly absorbed in the small intestine. The time required to peak sildenafil concentration in plasma is from half an hour to 2 hours. If there’s something that can delay gastric emptying, it will definitely delay the time to peak its concentration in plasma. As a rule, a negative effect is provided by a high-fat meal that delays the effect by 60 minutes as well as reduces plasma concentration by nearly 29%.

What about the peak efficacy? It is seen if Sildenafil is taken on an empty stomach (the observed clinical efficacy equals 19 minutes).

Sildenafil Citrate is metabolized by 3A4, 2C9 or P-450. Erythromycin, along with cimetidine, ketoconazole or any other inhibitor of these enzymes will delay metabolism and will require dose adjustments. However, the latest trials showed that men concomitantly taking P-450 inhibitors experienced no delays or adverse reactions.

How to make this Canadian Pharmacy medication safe? Its safety is established in doses. The maximum recommended dose is 100 mg. Patients shouldn’t take doses that are greater than 25 mg, in case there is the presence of the protease inhibitor ritonavir. Why? The fact is that it shares metabolic ways with Sildenafil. The action duration lasts for nearly 3 half-lives, yet there are men who experience stunning effects during 24 hours.

Does sildenafil work for women?

sildenafil citrate women

Research has shown that sildenafil can be helpful in treating women’s sexual disorders. decreased libido, lack of excitement and inability to achieve orgasm. It should be stressed, however, that the study was short-lived and was performed only in a small group of patients. At the present time, the use of sildenafil is strongly discouraged because the safety of this drug has not been officially confirmed.

The action of sildenafil on a woman’s body is based on increasing blood flow to the genitals, resulting in increased feelings of heat, tingling and increased intensity of sensation. During the four weeks of treatment, women taking sildenafil had a marked increase in excitement and increased ability to achieve orgasm. The drug also affected the improvement of vaginal humidity during cohabitation. The relationship we have had has proven to be far more satisfying.

It is important to remember that the effect of sildenafil on a woman’s body is still in clinical research. All side effects that may occur as a result of long-term use are not known. Sildenafil has been approved by the Federal Food and Drug Administration as an agent for the treatment of erectile dysfunction. Until it is approved for official sale as a drug for female sexual dysfunction, it is not recommended to use sildenafil for women. Patients suffering from intimate intolerance should be patient and wait for the official completion of the test.

What happens in the body after sildenafil intake?

When a man gets erection in the normal way, physically it happens that the body releases some specific blood vessel expanding substances called cGMP. This happens naturally in connection with sexual stimulation. Once release has been achieved, the enzyme PDE5 will degrade cGMP, so the rise will fall again. However, in some men, there is an excessive prevalence of PDE5, which means that cGMP is degraded before the joint is over or before the erection is at all achieved. In these cases, the man will experience erectile dysfunction. Either knows not to be able to get an erection or not being able to maintain the erection throughout the entire intercourse.

Sildenafil is a so-called PDE5 inhibitor. This means that the drug enters and inhibits PDE5, which means that it will again be possible for the man to achieve normal erection at the time when the potency works in the body.

For each time you take a dose of sildenafil, you will be able to achieve erection for up to 4-5 hours. Therefore, you will be able to have intercourse with your partner in the same way as before, and you will therefore again have the opportunity to have a generally satisfactory sex life.

Sildenafil Citrate in Modern Pharmacology

In modern pharmacology this active element is represented by two medication types: Revatio and Viagra.

Revatio inhibits cGMP PDE5 in the pulmonary vasculature smooth muscle, because this is where PDE5 is responsible for cGMP degradation. It increases cGMP within the smooth muscles of the pulmonary vessels, resulting in muscle relaxation. This is how Revatio saves people with pulmonary hypertension.

Viagra is able to enhance the effects of nitric oxide by inhibiting PDE5 (phosphodiesterase type 5) on the penile corpus cavernosum. The effect is both the vasodilation and increase blood flow to the corpus cavernosum. When there is sexual stimulation, great penile erections are guaranteed.

 Sildenafil Citrate as Viagra’s Main Component

When in 1998 Sildenafil Citrate was marketed as Viagra and received its FDA approval, it became the first medication to treat erectile dysfunction in men. It was initially prescribed for more than 10,000,000 men around the globe. It gained popularity in the USA, EU, Canada, etc. Today anyone can order the medication from Canadian Pharmacy online and enjoy drug’s excellent effects on his sexual life.

Generic Viagra pills are becoming more popular than brand ones. Their recommended dose is 50 mg. If a male responds to this amount adequately, the dose can either be decreased to 25 mg or increased to 100 mg, depending on doctor’s prescription. When Sildenafil Citrate is taken about 60 minutes before sex, it will remain in the body during 4-5 hours.

Unfortunately, the drug is not able to increase male’s sexual desire. If one wants the medication to become the most effective in his case, he should think of proper sexual stimulation. Don’t mix it up with aphrodisiacs: Viagra is widely used as a recreational drug, yet there isn’t any clinical evidence that prove that its single Sildenafil-containing pill can improve sexual performance in men, who aren’t suffering from impotence.

The usual question that interests men worldwide is whether there are coverage and insurance plans for Sildenafil Citrate. In 1999 a health insurance consulting group indicated that millions of men take Viagra at least once a week, so it means that they can receive a kind of insurance reimbursement for this drug. A single pill costs about $10, so the insurers can limit the coverage to a specified number of pills per month.

What Canadian Viagra Pills Include Sildenafil Citrate?

Canadian Viagra at is available in different sizes, shapes and types. What for? The variety of drug’s forms and shapes allows choosing what one really need, switch from one medication to another, reduce side effects or improve erections. Depending on the ever-changing circumstances of a man’s life, he has a chance to order and get just what is proper for him.

Classic Generic Viagra

It comes in doses of 25 mg, 50 mg and 100 mg. All the pills contain Sildenafil Citrate that helps to restore man’s sexual power via simple and clear mechanisms. As the doses are different, so are their pharmacological forms, continuity of action, etc.

Viagra Professional

This medication can be ordered from Canadian Pharmacy as well. Its characteristics are slightly different from those offered by classic pills. Viagra Professional or PRO, as it is frequently referred, features an enhanced Sildenafil Citrate formula and is characterized by an increased content of its main component. The drug’s efficacy is excellent! It is the optimal medication for men with really severe cases of erectile dysfunction.

Viagra Super Active

It’s a popular generic Sildenafil product with a so-called power-packed formula. Viagra Super Active promotes sexual stamina, allows enjoying sexual recharges more often, and causes fewer side effects. While taking such pills, men don’t have to get worried about their performance.

Viagra Black, Viagra Red and Viagra Super Force

All these drugs are very close in their characteristics. They contain Sildenafil Citrate as well. Unlike other pills, they don’t only help men with ED problems, yet also provide some bonus powers for a great measure.

Those, who are eager to rock within 15 minutes after the intake, should order such Viagra types as Viagra Lozenges, Softabs, Thin-Film, Jelly or Viagra Capsules. They are dissolved in the mouth and get into the bloodstream faster than Sildenafil Citrate from ordinary tablets.

Are Generic drugs fakes?

Generic drugs are substitutes for the original medicine. They contain the same composition and the same amount of active substance as their prototype. For generics to be allowed to sell, they must meet several conditions. The most essential requirement is having the same composition as the original drug. First of all, the amount of active ingredient must be retained. The use of other auxiliary substances is permitted, provided that they do not affect the effectiveness and properties of the agent. In addition, generic agents must have the same bioavailability and identical pharmacological action. Prior to the market, the drugs are subjected to a series of tests. Generic means of potency cannot therefore be treated as counterfeits. They are approved counterparts of the original drugs.


The agent expands the diameter of the veins and arteries within the male genitalia, allowing the free flow of blood to the penis and thus facilitating the attainment of an erection. It should be stressed that the erection only occurs as a result of sexual arousal. If a man is not stimulated erotic, he will not achieve erections. Sildenafil contains exactly the same active and ancillary substances as Viagra. Both drugs work exactly the same way and differ only in name.

The most common side effects of sildenafil are the same as those possessed by Viagra blushing, dizziness, rhinorrhea, indigestion and visual disturbances such as lack of focus, photosensitivity and bluish tint. The reported adverse reactions are experienced by approximately 10% of patients.

Side effects that affect about 1% of all men taking the drug are: vomiting, nausea, rash, palpitations, drowsiness, ringing in the ears, dry mouth, eye pain, eye congestion, muscle aches, chest pain, fatigue, irritability eyes, tearing of the eyes, sensation of touch, bleeding in the back of the eye, penile bleeding, and blood in the sperm or urine.

The most common side effects (occurring in 0.1% of Sildenafil patients) are hypertension, hypotension, syncope, myocardial infarction, stroke, irregular heartbeat, epistaxis and sudden loss or deterioration of hearing. Read the package leaflet before use. It is not recommended to use without prior medical consultation.

The main contraindications for sildenafil also go in line with those stated for the brand drug: allergy to ingredients, serious cardiac problems, liver disorders, recent myocardial infarction or stroke, low blood pressure, rare hereditary eye diseases, and anterior ischemic optic neuropathy. Medical advice should be sought by men suffering from sickle cell anemia, leukemia, multiple myeloma, penile deformity, Peyronie’s disease, haemophilia and stomach ulcers.

Sildenafil should not be combined with the following drugs: nitrates – used to treat angina pectoris. Simultaneous intake of both drugs can lead to too drastic pressure drop. Nitric oxide donors – for example amyl nitrite (so-called poppers). Combination of both drugs can cause dangerous pressure drop. Other impotence measures – such as Cialis, Levitra, Viagra or their generic counterparts. Caution should be exercised when using protease inhibitors (used to treat HIV) and alpha-blocker alpha blockers. If you take these measures, your doctor may recommend the lowest dose of Sildenafil – 25 mg.

Generic Viagra at My Canadian Pharmacy

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  • quality services;
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The high quality of service is the first thing a customer experiences while shopping from Canadian Pharmacy. A reliable pharmacy provides customer support online, accurate and efficient delivering, easy and smooth ordering process, etc. In fact, there are much more other departments that clients don’t see.

What does secure shopping include? The first and foremost position is taken by the safety of personal info, health facts and payment details (private data). The service is protected using SSL encryption of 128 bit or even higher. The website address is preceded by https://, plus there’s a padlock sign placed somewhere in the visibility for clients to see that their information will remain private.

Anonymity takes a huge part in the process of purchasing from Canadian Pharmacy. Though it comes very close to the shopping securing, it still extends beyond it. Considerate billing statement and discreet packaging are a must! In addition to this, a professional pharmacy never uses a spamming approach.

And finally, there is no better way to express care as well as gratitude towards new customers or old-timers than to offer discounts, bonuses, loyalty rewards or special prices. We offer you the best choice of medications and costs from Canadian Pharmacy.

The present day offers many active elements and ingredients that can change one’s life for better. Now that you know what role is taken by Sildenafil Citrate, you need to decide where to get it from. Quality generic pills cost less than their band counterparts. Search for online pharmacies with reliable reputations and positive customer feedback, low prices and pills that aren’t provided by Indian or Pakistani manufacturers. Get to know and learn more from the tips and info provided by My Canadian Pharmacy Make all Sildenafil Citrate’s positive features and aspects work for your benefit!

Sildenafil and diabetes

Sildenafil can be used to treat erectile dysfunction in men with diabetes. Unfortunately, the effectiveness of the drug in diabetics is slightly lower than in the other males. Clinical studies have confirmed that the highest dose of sildenafil delivers the expected results in 50% to 60% of patients with type 1 and type 2 diabetes. For comparison, in healthy men, the positive effects are experienced in 83% of cases.

The most commonly recommended starting dose for people with diabetes is 100 mg. Please note that one-time use may not produce the right results. Before the patient decides that sildenafil is not effective, try the highest dose at least 3 – 4 times.

Maximize sildenafil efficacy

One tablet should be taken about 30 – 60 minutes before the intended dose, with a glass of water. It is not recommended to take more than one pill daily. Sildenafil can be taken with or without food, but it is not advisable to take it at the same time as high amounts of fatty foods, as this may affect the effect. For the same reason it is advised not to consume grapefruit juice and large amounts of alcohol. Sildenafil is available in three doses – 25 mg, 50 mg and 100 mg. The recommended starting dose is usually 50 mg. Depending on the reaction of the organism, it may be increased or decreased.

Sildenafil is sold in 3 doses: 25 mg, 50 mg and 100 mg. The most commonly prescribed dose is 50 mg (effective in 74% of cases). If the dose is too weak, you can increase it to 100 mg (which is effective in 83% of patients). Before you decide to increase your dose, you should try your current dose at least 3 – 4 times. If 50 mg causes side effects, it is advisable to lower the dose to 25 mg. The lowest dose of sildenafil is effective in 63% of cases. The use of this dose is recommended for men who have small body structures using alpha-blockers (hypertension or prostate hypertrophy) or protease inhibitors (agents used to treat HIV).

Sildenafil vs Tadalafil


Tadalafil is the active ingredient in the product Cialis, which is a new generation of erectile pills with an enhanced effect. It was developed by the pharmaceutical company Lilly and has since 2002 been sold throughout Europe and America. Tadalafil is a very effective substance, which in many men can prevent the symptoms of impotence.

Tadalafil has the same mechanism of action as other erectile agents, such as Viagra (sildenafil) and Levitra (vardenafil). Under normal circumstances, the body will physically stimulate Nitrate Oxide from the nerve end of the penis. The body will detect this signal and begin the production of cGMP. This drug ensures that the blood vessels in the penis relax as they can be filled with blood. The cGMP also ensures that the blood supply to the penis is increased and the veins in the root of the penis become closed, so the blood does not flow back into the body. This together gives an erection. When the body produces cGMP, it also produces the enzyme PDE5 which degrades the active cGMP into the inactive GMP. When the concentration of cGMP decreases, the erection will disappear.

Tadalafil, like the active substances in other erectile pills, is a PDE5 inhibitor. This means that tadalafil can prevent the production of PDE5, so even small amounts of the hormone cGMP can cause an erection. Tadalafil only works by physical stimulation, as this is where the body produces cGMP. It is not abnormal to experience harder and longer erections when taking tadalafil. The advantage of erectile pills is that you will not experience inappropriate and erratic erections.

Tadalafil already works after 30 minutes, while some men report an effect already after 15 minutes. Even if you can get an erection after 30 minutes you will get the maximum effect after 2 hours. Tadalafil half-life is 17.5 hours, so it is possible to get an erection for up to 36 hours after taking the pill.

Sildenafil vs Vardenafil


Vardenafil is the name of the active substance found in the Levitra diet pills. The drug intends to improve and maintain the man’s erection – just like the other potency in the market. Viagra, which is probably the most known remedy for erectile dysfunction, has Sildenafil as active substance while the competitor Cialis uses the active substance tadalafil.

Levitra, on the other hand, uses vardenafil as active substance, and in this article we will look at what it is for a size. Basically, Vardenafil is used to give men a tougher, firmer and, not least, longer-term erection. In this way they will be able to conduct a gathering with greater enjoyment and satisfaction.

Vardenafil has been developed and marketed by the German pharmaceutical company and the French pharmaceutical giant. The closest comparative basis is Viagra’s active substance, the aforementioned sildenafil, but vardenafil is known to be active in the body for a longer period of time, thus contributing to greater enjoyment and less stress in order to achieve a intercourse on the often few hours of other potency promises to work.

After taking vardenafil you will experience the effect of it after half an hour. This means that you will be able to complete a satisfactory intercourse right after the intake. Vardenafil effect echoes after about five hours, but it should also be enough to reach a single intercourse or two. Please note that vardenafil does not work as described here if you are not sexually stimulated. Without sexual stimulation, PDE5 is not present in the bloodstream, and PDE5 must exist before vardenafil acts as a PDE5 inhibitor.

Additional Sildenafil Citrate information: