Viagra is not recommended to the patients allergic to sildenafil drugs.
You also should not use Viagra if you are taking any nitrate drugs (in case of heart diseases or chest pains for example). Among these nitrate drugs are nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrate components may be also be included in several recreational drugs (called “poppers”). Taking Viagra with a nitrate drug can result in a sudden and severe blood pressure decrease. If you notice such result you should immediately look for the emergency medical attention. The same is in case of a painful erection or if the erection is present more than within 4 hours. This long erection called priapism is able to harm your penis. The third case when you should immediately ask for the medical attention is if you notice a sudden vision loss.
For two weeks I am taking Viagra and now I see how changed my life. When I was thirty I noticed problems with potency, my erection wasn’t hard and I didn’t have sex with my wife. Many time I didn’t know what to do and decided to visit a doctor. When I came to he and said about problem, the doctor at once said that he can recommend Viagra. I bought it and tried. I said WOW, because I had the best erection in my life. Thanks Viagra!
Before take Viagra you should go to your doctor and get consultation about all drugs which may interact to this drug. Your doctor may recomend to you don’t take Viagra with nitrate drug for heart problems or chest pain. Such as isosorbide mononitrate ( ISMO, Imdur,Monoket), isosorbide dinitrate (Sorbitrate, Isordil, Dilatrate-SR), nitroglycerin (Nitrolingual,Nitrostat, Nitro-Bid, Nitro-Dur and others). Because if patient taking this drug with any of the nitrates which enumerate in the list, he can have a serious and sudden decrease in blood pressure.
Also tell your problems your doctor, especially:
- coronary artery disease;
- heart rhythm problems or heart disease or
- Peyronie’s disease
- low or high blood pressure;
- kidney or liver diseas;
- recent history of a stroke/heart attack/congestive heart failure;
- a bleeding disorder: hemophilia;
- retinitis pigmentosa
- a stomach ulcer;
- a blood cell disorder: leukemia, multiple myeloma, sickle cell anemia.
Sildenafil blocks selectively phosphodiesterase-5 (PDE5) enzyme. Still it may affect the other enzyme PDE6, an enzyme found in the retina photoreceptors. This mild Viagra effect on PDE6 is considered to be the cause for color vision abnormalities in patients especially detected with higher doses or plasma concentration.
Patients may experience increased light sensitivity and so called blue vision.
Viagra side effects are dose-related, which means that the greater the dose increases the risk of a side effect incidence. According Pfizer reports and later Viagra studies ocular side effects happen in:
- approximately 3 % of men taking Viagra in doses of 25-50 mg
- 11 % of men taking Viagra 100 mg
- 50 % of men taking 200 mg
- Practically 100% of men taking 600 to 800 mg.
So it is very important to take the correct dose prescribed for you and never exceed it. Besides, the use of more than 100 mg of Viagra in 24 hours may lead to dangerous side effects.
The ocular as well as other side effects usually appear within 1-2 hours post dose.
Rare ocular side effects (less than 2% of patients) include: mydriasis, conjunctivitis, photophobia, tinnitus, eye pain, deafness, ear pain, eye hemorrhage, cataract, and dry eyes.
There have been several reports of sudden vision loss associated with Viagra intake. This is thought to be caused by the decreased blood flow to the optic nerve of the eye. Still there is no clinical data on this side effect, but some experts suppose that Viagra use may result in damage to photoreceptors in the eye and cause sudden vision loss. This may happen in small number of patients having macular degeneration, diabetic retinopathy, retinitis pigmentosa or other retinal disease. Besides patients with the following conditions should also be careful while taking Viagra: heart disease, diabetes, hypertension, high cholesterol
Smokers and men over 50 years old can also be more sensitive to Viagra effects including ocular side events.
Viagra was clinically tested and demonstrated high rates of success in the treatment of erectile dysfunction in men. Still men often hesitate about the choice of ED medication in reference to side effects occurrence. Viagra is generally safe, this means that if a person takes it properly in the doses recommended by his doctor he will most surely have no or minor side effects. If taken improperly in larger doses Viagra may cause dangerous side effects. Men with certain diseases should talk to their doctors before using Viagra. Some conditions and medications may prevent them from taking Viagra.
Viagra most common side effects are:
- redness in face, neck, or chest;
- stuffy nose;
- upset stomach;
- back or muscle pain
Viagra rarely causes serious side effects still before using this drug, read the information about serious adverse reactions to Viagra and what to do in case of emergency. Serious adverse events may include:
- Severe allergic reactions to Sildenafil;
- Sudden vision loss, vision changes;
- Sudden hearing loss;
- Severe chest pain;
- Irregular heartbeat;
The mentioned above side effects require immediate medical attention. Seek medical help if any serious side effect occurs in you.
The usual Viagra dose is 50 mg prescribed for a healthy man who has no other conditions contradicting with Viagra intake. The dose of Viagra may be changed. Never do it on your own, consult with your doctor. Viagra is taken before sex, commonly 30-60 minutes. For some patients the effect of Viagra is within 15-45 minutes. A man starting this drug should be attentive to his sexual response to the medication.
Sexual stimulation is necessary to release certain chemicals in the body and start the Viagra effect. The effect of Viagra usually lasts for 4 hours, so the drug may be taken up to 4 hours before sexual activity. Still the recommended time is 30-60 minutes due to the fact that Sildenafil effect reduces 2 hours after oral administration.
Viagra should be taken on an empty stomach. Food, especially high in fats may delay the effect of the drug. Viagra should not be used with alcohol, drugs with potential to interact with Sildenafil and grapefruit products.
In most men with ED Viagra has its effect for the first or second time they take it. The success rates increase with the number of attempts. For some men it is necessary to take Viagra 3 or 4 times before they get the beneficial result. Some patients need a different dose of the drug.
Viagra may be ineffective in small number of men, still clinical studies found that the drug is effective in 4 men out of 5. If Viagra does not work for you, consult your doctor, may be you need more time or you are doing something wrong.
Viagra effect on erectile response
Viagra clinical trials proved that Viagra is helpful for patients with either organic or psychogenic impotence. The studies demonstrated that Sildenafil improved erectile function upon sexual stimulation. The measurements of the hardness and duration of erections were done after Viagra oral administration with the help of RigiScan. The results of Viagra effects were compared with placebo effects, the majority of men taking part in the studies (4 men from 5) reported improved erectile function approximately 60 minutes post dose. The erectile response increased with Sildenafil dose and plasma concentration enlargements. The studies registered the duration of Viagra effect for up to 4 hours still the erectile response was observed to reduce after 2 hours.
Effects of Viagra on blood pressure
According to the results of clinical studies Viagra produced in healthy men clinically insignificant decreases in sitting blood pressure (mean maximum decrease in systolic/diastolic blood pressure of 8.3/5.3 mmHg).
However, the manufacturer warns patients taking nitrate medications not to use Viagra together with any medication containing nitrates. Viagra significant effects on blood pressure were recorded among men receiving concomitant nitrates.
Effects of Viagra on cardiac parameters
Studies of Sildenafil in healthy patients demonstrated no clinically meaningful changes in the ECG. The changes in ECG were observed in patients with cardiovascular disease who were administered Sildenafil in the dose of 100mg.
The effects of Viagra on cardiac output were studied in eight patients with stable ischemic heart disease. The results from this study proved that Viagra should not be administered in patients with serious heart disease, unstable angina, and a history of heart attack or stroke.
Effects of Viagra on vision
The effects of Viagra on vision were assessed in a special study. At single oral doses of 100 mg and 200 mg, transient difficulty of color discrimination (blue/green) was observed using the Farnsworth-Munsell 100-hue test. An estimation of visual function at Sildenafil doses up to 200 mg demonstrated no effects on visual acuity, intraocular pressure, or pupillometry.
Sildenafil absorption process is quick reaching an absolute bioavailability of 41%. Its pharmacokinetic characteristics are dose-dependable over the advised doses. Sildenafil is disposed mainly by hepatic metabolism and transformed to an active metabolite with the similar characteristics of Sildenafil. The increased plasma concentrations of Sildenafil may be provoked by the concomitant use of cytochrome P450 3A4 inhibitors including erythromycin, ketoconazole, itraconazole and nonspecific CYP inhibitor, cimetidine, so these medications should not be used with Sildenafil. Sildenafil has a terminal half life of about 4 hours in some cases it may be greater up to 5 hours.
Sildenafil max noted plasma levels are within 30 to 2 hours after oral administration. High fat food can decrease Sildenafil absorption up to 1 hour.
Sildenafil is eliminated principally by the CYP3A4 and CYP2C9 hepatic microsomal isoenzymes.
Sildenafil is excreted as metabolites mainly in the feces – 80% of administered oral dose and to a lesser degree in the urine – about 13% of the oral dose.
Prior to the treatment with this medication it is absolutely necessary to consult your doctor, especially if you have other serious conditions such as cardiovascular disease, heart disease, heart rhythm problems or if you have experienced a stroke, a heart attack or congestive heart failure.
If your health condition requires avoiding sexual activity, do not take this medication.
Viagra should be taken with caution in the following cases:
If a patient suffers from:
- high or low blood pressure;
- coronary artery disease;
- liver or kidney disease;
- blood cell disorders;
- bleeding disorders;
- a stomach ulcer;
- retinitis pigmentosa (an inherited condition of the eye);
- Peyronie’s disease.
If a patient takes nitrate medications or medications which can potentially lower blood pressure.
The Viagra medication was developed by Pfizer International Inc, the pharmaceutical giant known for its revolutionary medical discoveries and breakthrough technologies. Never before the solution of erectile problems was as quick and efficient as with Viagra appearance. Viagra became the first oral medication that shows a significant and reliable efficacy in the vast majority of patients with impotence problems. The active ingredient of Viagra – Sildenafil citrate was clinically tested approved by FDA to be indicated for the treatment of ED in men. The chemical formulation of Viagra is balanced and has no claims on the part of safety.
Viagra is produced in the tablet form in the doses of 25, 50 and 100 mg, that contain, correspondingly, 25, 50 and 100 mg of Sildenafil citrate.
Unlike other form of treatment ED Viagra medication is simple in use, convenient and highly effective. Besides, Pfizer guarantees high quality of the product it manufactured.
The mechanism of action of Viagra involves the process of improving blood flowing into the penis, which helps to achieve an erection naturally by being sexually aroused.