Should changing 20mg of paxil to 75mg (starting dose) of effexor (venlafaxine) be an easy transition?

SSRI: Paxil is a Selective serotonin reuptake inhibitor. Effexor (venlafaxine) is a Serotonin–norepinephrine reuptake inhibitor. They do share many properties in regards to effects and side effects when changing. In this case, the transition should be rather easy. Keep in mind that you may experience a little dizziness, nausea, insomnia..but don't let this scare you. Just keep your doctor in the loop.