Among all medicines, Viagra worthily takes the place of one of the most recognizable drugs. It even managed to take it`s place in the culture, due to anecdotes, programs and some pop groups. It is difficult to find a person who would not know what kind of drug it is. Even harder – to find a man older than 30-40 years, who never took, or at least did not think about taking Viagra.
Main active ingredient
The drug of the company Pfizer Viagra contains in its composition sildenafil. This active ingredient belongs to the class of phosphodiesterase-5 inhibitors (PDE-5), for treating erectile dysfunction.
One can buy Viagra online and in the pharmacy chains in the form of a pill. One tablet contains 50 mg of sildenafil.
Operating principle
The basis of the mechanism of action of Viagra is the suppression by sildenafil of PDE-5 activity. This leads to the prevention of the breakdown of the cGMP enzyme in the cavernous bodies of the penis and the accumulation of this substance. Since cGMP relaxes smooth muscles, an increase in its concentration leads to an expansion of the lumen of the vessels. Due to the increase in blood flow to the penis, comes an erection.
In an insignificant volume, PDE-5 is present in platelets, vessel walls and internal organs. Due to this, taking sildenafil can reduce blood clotting, prevent the development of vascular spasm.
Viagra in relation to phosphodiesterase-5 is much more active in comparison with other forms of PDE, due to which it has practically no effect on other organs and systems. Binding of sildenafil with PDE-6 may result in impaired color perception.
Indications
Viagra is used for various erectile dysfunctions in order to improve the blood supply to the cavernous bodies of the penis.
Another indication for using this drug is high blood pressure in the pulmonary circulation. Sildenafil contributes to the expansion of blood vessels of the pulmonary artery, thereby reducing pulmonary hypertension.
Contraindications
There are absolute and relative contraindications to taking Viagra. The absolute are:
- Individual intolerance to sildenafil or Viagra itself;
- Taking nitrates.
Since nitrates (nitroglycerin, nitrogranulong, nitrospray, izoket, isosorbide dinitrate, etc.) contribute to vasodilation, with the simultaneous use of Viagra, a sharp drop in blood pressure up to loss of consciousness and shock.
Relative contraindications include:
- Penile deformity:
- Angulation;
- Cavernous fibrosis;
- Peyronie’s disease;
- Tendency to priapism (uncontrolled erection) on the background of myeloma, sickle cell anemia, leukemia;
- Increased risk of bleeding;
- Peptic ulcer of the stomach or duodenum in the acute stage;
- Erosive and ulcerative lesions of the gastrointestinal tract;
- Retinitis pigmentosa (degenerative eye disease);
- Impaired liver function with hepatitis, cirrhosis or other damage of any etiology;
- Severe renal dysfunction;
- Blood pressure level over 170/110 mm. Hg v .;
- Blood pressure less than 90/50 mm. Hg v .;
- Postponed over the past six months:
- Infarction;
- Arrhythmias of high gradations;
- Unstable angina;
- Heart failure;
- Stroke;
- Intracranial hemorrhage.
- Acceptance of cytochrome P450 inhibitors:
- Macrolide antibiotics (Azithromycin, Clarithromycin, etc.);
- Antifungal drugs of the azole group (Fluconazole, Itraconazole, etc.);
- Fluoxetine;
- Diltiazem;
- Cimetidine;
- Grapefruit juice.
Side effects
Viagra can cause the following undesirable reactions:
- Pain in the head;
- Feeling hot flushes, facial flushing;
- Digestive disorders;
- Nasal congestion;
- The development of urinary tract infections;
- Changing color perception;
- Dizziness;
- Skin rashes;
- Drop in blood pressure;
- Orthostatic hypotension;
- Cardiopalmus.
The remaining side effects are much less common. And the frequency is less than 2%, and they develop, as a rule, with non-compliance with contraindications. The most significant of them are:
- Migraine;
- fainting;
- Hemorrhage in the eyeball;
- Impaired blood supply to the myocardium (angina, heart attack);
- Heart rhythm disorders;
- Stroke;
- An attack of bronchial asthma;
- Internal bleeding;
- tendon ruptures;
- Dermatitis;
- Allergic reactions.
Instructions for use
Viagra tablets dissolve in the mouth. They do not require entire chewing or swallowing. In order to achieve an improvement in erectile function, Viagra should be taken 30 to 60 minutes before the intended sexual intercourse. To do this, put one tablet of the drug on the tongue and wait for it to dissolve. Then you can drink the drug with a small amount of water.
If you want to take 100 mg of the drug, then the second pill should be used immediately after the first dissolution.
Do not use Viagra more than 1 time per day. The maximum therapeutic dose is 100 mg.
Analogs and Substitutes
This Viagra has a tangible value and most men are suitable, perhaps, for periodic use. However, you can try to find more affordable counterparts. However, one should take to consideration that such a cheap “Viagara” may have a different active ingredient, but with a similar mechanism of action.
Another disadvantage of the popular blue pills is the frequency of side effects. They are connected with the fact that sildenafil has a certain effect on other types of phosphodiesterase. Not all men are satisfied when, during intimacy, their face begins to blush or they start to see strange things around.
Cialis
Cialis is another drug from the group of PDE-5 inhibitors. Its cost is 3 – 4 times more than Viagra. But its main advantage is the almost complete absence of side effects. The active ingredient tadalafil is so selective with respect to PDE-5 that it practically does not touch other forms of this enzyme.
Cialis can be found only in a dosage of 5 mg.
Levitra
Levitra also affects on the PDE-5, but its properties are intermediate between Viagra and Cialis. This drug is available in three dosages: 5, 10 and 20 mg, which allows a man to choose a convenient dosage for himself.
Generic viagra
The drug company of Pfizer. It`s the brand, on the creation and advertising of which was spent a lot of money. Of course, this could not affect its value. But, buying generic Viagra can be much cheaper. Some drugs can reduce the amount of 4 – 5 times. In addition, generics provide a much larger selection of dosages (tablets from 20 to 100 mg), which greatly facilitates the selection of the optimal amount of medication.
The lower cost of these drugs is connected with the fact that the manufacturer did not spend huge amounts on their creation. It was enough just to buy the rights for usage and start production of tablets.
Main Viagra generics are:
- Vildegra;
- Sildenafil-C3;
- Sildenafil vertex;
- Effex.
This cheap Viagra is sold online and in various pharmacy chains.
Can I buy without a prescription
Officially, Viagra should be available by prescription only, like many other drugs. However, it`s registration is not so strict as psychotropic or narcotic substances. In this regard, it can be purchased at the pharmacy even without a prescription. Though, if you ace with principal seller, you will feel like a schoolboy who buys cigarettes with beer – they will look at you strictly, ask for documents and leave you empty-handed.
Coming to the doctor for a prescription with your problems is sometimes uncomfortable, sometimes you just don`t have enough time for that. In such cases, the next question appears: “Where can I buy cheap Viagra online?”. You can buy a brand-name drug, as well as any generics, on a variety of Internet sites, among which are online pharmacies, online stores, just people selling for some reason their medicines.