Men with erectile dysfunction may benefit from taking the medication purple viagra. sildenafil is one of the components of this medication. This medication is intended to improve blood flow to the panel. This medication can be taken with or without food. Before using this medication, speak with your doctor because overuse can have negative health effects. Here you can see how long purple viagra is. Meals that are cold or heavy should be avoided while taking this medication as they will lessen its efficacy. You won't need to take this prescription again because its effects last for five hours after taking it.