Do You Need a Prescription for Viagra?
Viagra, or sildenafil, was the first oral pill approved by the FDA to treat erectile dysfunction. Pfizer released Viagra in 1998 and, since then, generic versions of the drug have become available, too. To get more news about 威而鋼哪裡買, you can visit our official website.
Viagra, along with other ED medications such as Cialis (tadalafil) and Levitra (vardenafil), functions as a phosphodiesterase 5 (PDE5) inhibitor. PDE5 inhibitors increase blood flow to the penis by causing the blood vessels in penile tissue to relax.
This increased blood flow makes it easier for people to get and maintain an erection with sexual stimulation. (Note that ED medication doesn’t cause spontaneous erections without stimulation — so don’t worry, you’re not at risk of getting an erection on, say, the subway.)
Potential drug interactions with Viagra
When you get a prescription for Viagra, your healthcare provider will ask whether you’re taking any other medications. It’s important to be honest about your other prescriptions, so your doctor can give you the best advice about taking Viagra.
Viagra shouldn’t be used with medications that lower blood pressure, particularly nitrates — nitrates are an absolute contraindication to PDE5 inhibitors like Viagra. People who are taking nitrates cannot, under any circumstances, use ED medication.
Alpha blockers, antihypertensives, and riociguat can be taken with Viagra, but only under supervision because there are some specifics about how to take the medications together.
Antibiotics, antifungals, and HIV protease inhibitor drugs are all processed in the liver, just like Viagra. That means they can increase the amount of Viagra in your body, which can cause unwanted side effects. The dose of Viagra would need to be adjusted with this in mind.
And what about drugs that decrease the effect of Viagra on your erections? Anticonvulsants (like phenytoin or carbamazepine) and an antibiotic called rifampin can all cause Viagra to not do its job.
A final heads up on interactions: Alcohol and grapefruit juice can also increase the likelihood that you’ll experience Viagra side effects.
