Viagra, scientifically known as sildenafil, is commonly used for treating erectile dysfunction in men. It works by increasing blood flow to the penis, aiding in achieving and maintaining an erection sufficient for sexual activity.
Viagra is absorbed in the small intestine, where pills usually dissolve and their constituents are taken up into the bloodstream. This process is crucial for the drug's effectiveness, allowing it to circulate throughout the body and perform its intended function.
Grapefruit juice has a distinct impact on the absorption of several medications, including Viagra. It increases the bioavailability of these drugs - that is, it increases the amount of the drug that enters the bloodstream after consumption and has an active effect.
Research has indicated that even a small amount of grapefruit juice, such as one grapefruit or an eight-ounce glass of juice, can cause a change in the absorption of Viagra.
This change can last for up to 24 hours.
The juice impacts the absorption of the medication in the small intestine and prevents the breakdown of the drug, leading to increased absorption.Consequently, the oral bioavailability of sildenafil can be increased by 23%.
With increased bioavailability due to grapefruit juice, Viagra is absorbed in larger quantities. This increased absorption can affect the predictability of sildenafil pharmacokinetics, leading to less consistent results and potentially more pronounced effects from the drug.
The interaction between Viagra and grapefruit juice can result in undesirable side effects. These can include symptoms like hot flushes, significantly lower blood pressure, dizziness, and other headaches. In some cases, the levels of Viagra in the body can become toxic, particularly when combined with grapefruit juice. This is due to a serious increase in blood flow around the body, especially problematic when paired with nitrates.
Due to the above-mentioned potential risks and side effects, it is generally not recommended to mix Viagra and grapefruit juice. Furthermore, other fruit juices such as pomelo and potentially pomegranate juice may also interact with Viagra in a similar manner, so caution is advised with these too.
To maximize the efficacy of Viagra and prevent unwanted interactions, it is recommended to avoid taking the drug with fruit juice, particularly grapefruit juice. Instead, taking Viagra with water and on an empty stomach may lead to more predictable results and reduce the risk of side effects.