The Pharmacology of Sildenafil: What Happens in Your Body
Understanding PDE5 and How Sildenafil Works
Viagra's active ingredient, sildenafil citrate, belongs to a class of medications called phosphodiesterase type 5 (PDE5) inhibitors. To understand how it works, it's helpful to know what happens naturally during sexual arousal. When a man becomes sexually stimulated, nerve signals trigger the release of nitric oxide in the penis, which increases levels of a chemical called cyclic guanosine monophosphate (cGMP). This chemical causes the smooth muscles in blood vessels to relax, allowing increased blood flow into the penis and creating an erection.
How PDE5 Normally Affects Erections
Under normal circumstances, the enzyme PDE5 breaks down cGMP, which naturally causes the erection to subside. However, men with erectile dysfunction may have overactive PDE5 or insufficient blood flow, making it difficult to achieve or maintain an erection. Sildenafil works by selectively blocking PDE5, which allows cGMP levels to remain elevated for longer periods, promoting better blood flow to the penis when sexually aroused.
Timing and Duration of Effects
Sildenafil typically begins working within 30 to 60 minutes of taking the tablet, though this can vary depending on individual factors such as age, overall health, and whether it's taken with food. Fatty meals may delay absorption and slow the onset of action. The medication's effects can last approximately 4 to 6 hours, but this doesn't mean you'll have an erection for this entire duration. Sexual stimulation is still required for the medication to work effectively.
Available Dosages and Treatment Options
Both Viagra and generic sildenafil are available in three strengths: 25mg, 50mg, and 100mg tablets. Most men start with a 50mg dose, which can be adjusted based on effectiveness and tolerability. Your prescriber may recommend a lower 25mg dose if you experience side effects, or increase to 100mg if the initial dose isn't sufficiently effective. It's important to take only one dose within any 24-hour period.
Choosing Between Viagra and Sildenafil
At EverydayMeds, we offer both branded Viagra and generic sildenafil options. Both contain the same active ingredient and work identically in your body. The main differences are price and packaging - generic sildenafil typically costs significantly less than branded Viagra while providing the same therapeutic benefits. This choice allows you to select the option that best fits your budget and preferences during the checkout process.
Safety Considerations and Contraindications
Sildenafil is generally well-tolerated, but it's not suitable for everyone. The medication can cause a temporary drop in blood pressure, which is usually mild but can be dangerous when combined with certain medications, particularly nitrates used for chest pain. Men taking GTN spray, isosorbide medications, or certain blood pressure treatments should not use sildenafil. Additionally, those with severe heart conditions, recent heart attacks or strokes, or severe liver problems may not be suitable candidates for this treatment.
