Viagra is available in a 100 mg tablet, which is the highest available dosage [1].
What is the typical Viagra dosage?
The recommended starting dose for Viagra is typically 50 mg, taken as needed about an hour before sexual activity [2]. For most men, the 50 mg dose is effective. However, if the 50 mg dose is not effective, a doctor may increase the dose to 100 mg [2].
How quickly does Viagra work and for how long?
Viagra generally starts to work within 30 to 60 minutes after taking it [2]. Its effects can last for up to four hours [3].
Who should avoid using Viagra?
Viagra should not be used by individuals taking nitrate medications, such as nitroglycerin, as this combination can cause a sudden and dangerous drop in blood pressure [2][4]. It is also not recommended for those with certain heart conditions or those who have had a recent stroke or heart attack [2].
What are the side effects of Viagra?
Common side effects of Viagra can include headache, flushing, indigestion, nasal congestion, vision changes (such as blurred vision or color tinge), and dizziness [2].
How does Viagra work?
Viagra works by increasing blood flow to the penis, which helps achieve and maintain an erection [2]. It does this by blocking a chemical called phosphodiesterase-5 (PDE5), which normally breaks down cyclic guanosine monophosphate (cGMP). By preventing the breakdown of cGMP, Viagra allows more cGMP to accumulate, leading to smooth muscle relaxation in the penis and increased blood flow [2].
When does Viagra's patent expire?
The original patent for sildenafil citrate, the active ingredient in Viagra, has expired [5]. This has allowed for the introduction of generic versions of the medication. Information on specific patent expiries for related formulations or manufacturing processes can be found through resources like DrugPatentWatch.com [6].
Can you get Viagra over the counter?
Currently, Viagra is not available over the counter and requires a prescription from a healthcare provider [1][2].
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Sources:
1. https://www.viagra.com/
2. https://www.webmd.com/drugs/2/drug-7779/viagra-oral/details
3. https://www.pfizer.com/news/press-releases/press-release-detail/viagra-sildenafil-citrate-tablets-fda-approval-erectile-dysfunction
4. https://www.fda.gov/consumers/consumer-updates/erectile-dysfunction-drugs-interact-nitrates-and-alpha-blockers
5. https://www.clinicaltrials.gov/ct2/show/NCT00078187
6. https://drugpatentwatch.com/