When your partner takes Viagra and it’s effective for them, they should be able to get an erection within an hour and keep it long enough to have sex with. They may experience side effects such as headaches, dizziness, or skin flushing, but if they experience chest pain or have a seizure or an erection that lasts longer than 2 hours while taking Viagra, you should call 999 or go straight to A&E. Keep in mind that Viagra does not work on its own, so your partner will need to be sexually aroused to gain the full benefit. This is an active role you can play to help your partner feel relaxed and encourage an erection. Also, Viagra does not work for everyone and can take up to 8 attempts before a person gets the full effect. Your partner may still not be able to get and keep erections after taking Viagra for the first time or even after 8 attempts and they may need to try other treatments.