I've been taking 75mg of effexor, (venlafaxine) and a mild dose of vyvanse. i understand that alcohol is not a good mix, but what can i do if i plan on drinking?

Plan for trouble: I think you mean 'hear' by 'understand' - if you really comprehended, you'd know that even mixing your meds is a risk for serotonin syndrome. I know, it's low doses and you're maybe a big guy. Yeah, yeah. So, if you plan to take yet more risk - don't drive or do anything that requires being clear headed and warn people w/ you how to get you to medical care if you have chest pain, rapid pulse, etc.