I jsut started that myself but alls I was warned about was that it may effect the affect of medication so you shouldnt' take it three hours prior or or after taking yoru pill just like food, vitamins shouldnt' be different then any other medication I woudl think but dont quote me on it ...

Vitamins are just like food from my research. You get vitamins from your food. So taking your viatmins when you eat your food (3 hours before or after your tetracycline dose) should not affect your tetracycline. Thats my logic. I've never tried it and I don't take tetracycline anymore so I can't try it. I do take vitamins now that I didn't take when I was on tetracycline.