Viagra ocular side effects
Viagra may cause serious vision side effects such as retinal dysfunction or complete vision loss. Other most common, but less serious ocular side effects are: blurred vision, high light sensitivity.
Viagra clinical trials demonstrated that ocular side effects happen rarely and like other side effects are dose – related. Higher doses produce more serious side effects. In clinical trials about 3 % of men taking doses of 25-50 mg of Viagra experienced blurred vision, about 11 % of men taking 100 mg doses, and about 50 % of men taking 200 mg of Viagra have vision changes. In patients using more than 600 mg vision changes were detected in practically 100% of cases. Vision changes are explained by the property of Viagra to mildly affect the enzyme PDE6. Larger doses increase the blood concentration of the medication and increase the risk of ocular side effects.
Patients with macular degeneration, diabetic retinopathy, retinitis pigmentosa or other retinal disease should consult a doctor before using Viagra. Remember that Viagra may cause complete vision loss in one or both eyes, so if you have any eye conditions, do visit a doctor.
Viagra side effects
The FDA approved Viagra use in men with erectile dysfunction only after several clinical trials. The use of Viagra was estimated in over 3,700 patients (19 to 87 years of age). In these placebo-controlled trials, only 2.5% of males from Viagra group stopped the treatment due side effects occurrence in comparison with 2.3% from placebo group. These numbers show that Viagra is well-tolerated by the majority of patients and the medication causes no or minor side effects in most men. It was detected that the incidence of side effects has been dose-dependent, so a patient should take only the dose prescribed for him and never exceed it to avoid possible side effects.
Viagra should be taken only after a doctor’s consultation. The medication will not cause serious side effects if you take it properly.
Some patients with certain conditions should be especially careful. Some health diseases may increase the possibility of Viagra side effects.
Common Viagra side effects may include:
- warmth or redness in the face, neck, or chest;
- stuffy nose;
- upset stomach;
- back pain of muscle pain.
Serious side effects happen rarely, still if they occur a patient should immediately seek medical help. These severe side effects include:
- sudden hearing loss;
- chest pain;
- irregular, fast heartbeat, tachycardia;
- shortness of breath;
- allergic reactions;
- sudden vision loss.
- painful prolonged penis erection;
Viagra administration and effect
Viagra effect depends on the physical mechanism of erection – a person should be sexual stimulated for the medication to start working. Sexual stimulation provides the release of certain chemicals in the body which are necessary for Sildenafil action.
Viagra should be used as prescribed by a doctor. Follow the doctor’s recommendations and use the dose adjusted for you. Any dose changes should be made only after the consultation with your doctor. The dose choice depends on the individual response of a patient and other unrelated conditions he may have.
Viagra is taken only when needed, 30 minutes – 1 hour before sexual activity. The medication may work within 15 minutes in some patients. A person should notice how the drug works for him individually.
The medication may be taken up to 4 hours before sex. Viagra max frequency of using is one dose per day.
Viagra effect may be impaired or delayed by food. The medication should be taken on an empty stomach.
Men taking Viagra should not give up if the medication does not work in them for the first time. They may need more attempts.
Before using Viagra (Sildenafil)
Viagra (Sildenafil) is a medication available with a doctor’s prescription. Nowadays anyone can purchase Viagra online. Whether you buy Viagra in a local pharmacy with a prescription or online without prescription it is recommended to use this medication only after a consultation with a doctor. Viagra contradict with certain medical health conditions you may have or with certain drugs you may take. So it is absolutely necessary to visit your doctor to find the right dose for you and if you have other unrelated conditions – undergo special tests.
Viagra is contraindicated with any nitrate-based medications taken for chest pain or heart disease. Viagra is not allowed to be used with other blood pressure lowering medications. Viagra in combination with any blood lowering medication may provoke a serious blood pressure reduction and lead to dangerous health state.
Other unrelated conditions that contradict with Viagra intake include:
- a recent history of a heart attack, stroke, or congestive heart failure;
- heart disease or heart rhythm problems;
- high or low blood pressure;
- coronary artery disease;
- liver or kidney impairment;
- sickle cell anemia, multiple myeloma, leukemia, hemophilia;
- a stomach ulcer;
- retinitis pigmentosa;
- a history of priapism condition (a prolonged and painful penile erection);
- Peyronie’s disease;
- traumas to the genital area.
If you have the mentioned above conditions you may need special tests before using Viagra. Your doctor will adjust you the necessary dose which you should not change without talking to your doctor first.
If your doctor recommends you to avoid sexual activity due to your serious cardiovascular status, do not take Viagra.
Viagra metabolism and elimination
Viagra (Sildenafil) is refined basically by the CYP3A4 (main way) and CYP2C9 (secondary way) hepatic microsomal isoenzymes. The basic Sildenafil metabolite is a result from N-desmethylation, and undergoes further metabolism. This main metabolite restricts selectively PDEs like Sildenafil and shows the properties for PDE5 about 50% of the parent medication. This metabolite has 40% plasma levels of those noted for Sildenafil, and thus the metabolite amounts to 20% of Viagra’s pharmacologic effects.
Sildenafil is eliminated as metabolites basically in the feces – about 80% of the received dose and in the urine – about 13% of the dose.
The half life of Sildenafil is about 4 hours, this means that during a period of 4 hours a person may get and maintain an erection. Still the response of a patient decreases after 2 hours after the oral dose. So it is recommended to take Viagra 30 minutes – 2 hours before sexual activity to receive the most pleasant results.