The Science Behind Viagra's Effectiveness
PDE5 Inhibition Mechanism
Viagra works by inhibiting phosphodiesterase type 5 (PDE5), an enzyme found in blood vessel walls throughout the body, particularly in penile tissue. During sexual arousal, the body naturally releases nitric oxide, which increases levels of cyclic GMP - a chemical messenger that relaxes smooth muscle and dilates blood vessels. PDE5 normally breaks down cyclic GMP, but Viagra blocks this process, allowing blood vessels to remain dilated and blood flow to increase to the penis.
Timing and Duration
Most men find Viagra becomes effective within 30-60 minutes of taking a tablet, though this can vary based on individual factors and whether it's taken with food. Fatty meals may delay absorption and slow the onset of action. The effects typically last 4-6 hours, though this doesn't mean an erection lasts this duration - sexual stimulation is still required throughout this window for the medicine to be effective.
Dosage Options at EverydayMeds
EverydayMeds stocks Viagra in three strengths: 25mg, 50mg, and 100mg tablets. Most men start with 50mg, which can be adjusted up to 100mg or down to 25mg depending on effectiveness and any side effects experienced. We also offer generic sildenafil in the same strengths, providing patients with a more affordable alternative that contains the same active ingredient. Only one dose should be taken in any 24-hour period.
Clinical Assessment Requirements
Before dispensing Viagra or sildenafil, our UK-licensed prescribers conduct a thorough clinical assessment. This evaluates cardiovascular health, current medications, and medical history to ensure the treatment is safe and appropriate. Men taking nitrate medications or with certain heart conditions may not be suitable candidates due to potentially dangerous drug interactions.
