How Viagra Works
Viagra (Sildenafil) is an oral drug for male impotence (ED). Having been around for a lot longer, Viagra has a great safety track record and proven effects that start acting in 30 minutes and last for about 5 hours. However, it is not a hormone or an aphrodisiac.
Viagra, or Sildenafil Citrate, is considered by many as being a ‘wonder drug’. Viagra (Sildenafil) belongs to a group of medicines that delay the enzymes called phosphodiesterase from working too quickly. By controlling phosphodiesterase, Sildenafil helps to maintain an erection that is produced when the penis is physically stimulated. In fact, men of all ages are finding a new found sexual youth because of the little blue pill. But like any prescription medication, Viagra is not without its pitfalls and problems.
Side Effect of Viagra
Very few drugs work perfectly, and Viagra is no exception. Just about every drug has side effects that arise because the drug is flowing throughout the body and may affect parts of the body unintentionally. For example, aspirin is a drug that relieves pain, but this same drug can also erode the stomach lining and thin the blood. Those are side effects of aspirin.
Viagra has several side effects of which patients need to be aware:
The first problem comes because Viagra happens to have a spillover effect. It blocks PDE5, but it also has an effect on PDE6. It turns out that PDE6 is used in the cone cells in the retina, so Viagra can have an effect on color vision. Many people who take Viagra notice a change in the way they perceive green and blue colors, or they see the world with a bluish tinge for several hours. For this reason, pilots cannot take Viagra within 12 hours of a flight.
The second problem comes for people who are taking drugs like nitroglycerin for angina. Nitroglycerin works by increasing nitric oxide, and it helps with angina by opening up the arteries that supply the heart with oxygen. If you take nitroglycerin and Viagra together, the increased nitric oxide plus the blocking of PDE5 can lead to problems.
Other problems with Viagra can include little things like headaches (the drug, as a side effect in some men, opens up arteries in the brain's lining and causes excess pressure) and more serious conditions, like heart attacks. The possibility of heart attacks is one reason why Viagra is a prescription drug rather than an over-the-counter drug like aspirin. A doctor needs to understand your medical history and make sure that Viagra won’t cause a heart attack. Occasional patients who take Viagra get painful, long-lasting erections and have to see a doctor to solve the problem.
Finally, there is some concern that some men, especially younger men who take Viagra recreationally and who don’t really need it for physical reasons, may end up with a dependency on the drug. That is, they may become unable to maintain an erection without taking Viagra.
Precautions while Taking Viagra
Caution is of utmost importance in patients with drug allergies, or if they have:
- Heart disease or heart rhythm
- Recently had a heart attack, stroke, or heart rhythm disorder
- Congestive heart failure
- High or low blood pressure
- Coronary artery, liver, or kidney disease
- Blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia
- Bleeding disorder such as hemophilia
- Stomach ulcer
- Retinitis pigmentosa (an inherited condition of the eye)
- Physical deformity of the penis (such as Peyronie's disease); and /or
- You have been told you should not have sexual intercourse for health reasons.
If you have any of these conditions, you may need a dose adjustment or special tests to safely take Viagra. Before taking Viagra, tell your doctor about all other medications you use for erectile dysfunction, or if you are using any of the following medications:
- Bosentan
- Warfarin (a blood thinner)
- Cimetidine
- Antibiotic (erythromycin)
- Doxazosin, prazosin or Terazosin
- HIV medicines
- Antifungal medication
- Carbamazepine, phenobarbital or phenytoin; and/or
- Rifampin or Rifabutin
Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
