You can expect stronger and longer-lasting erections, but this does not happen automatically. You still need to be sexually aroused to get an erection. ED medication does not change your libido or sexual desire. The vast majority of men experience a clear improvement in their sex life. The medication can be taken with or without food, although a heavy meal may delay the effect by about an hour.xperience any side effects from ED medication. When side effects do occur, these are usually headache, dizziness, nasal congestion, hot flushes (flushing), nausea, indigestion, or changes in vision. These side effects are generally mild and temporary. The patient information leaflet contains a complete list of possible side effects. Always read it carefully before using the medication for the first time.