I take 50,000 ius of vitamin d once a week. will taking a daily multi-vitamin cause me to be taking in too much vitamin d?

Hardly...: ur multi likely has 400iu - less than 1% of 50,000iu. it wont matter. whats more important to know is that if ur an average size the 50,000 weekly will only get u a level in the 30s. to get closer to a level of 50 u will need at least 5000 iu a day. daily doses yield higher levels with less total dose.

No, but...: MVIs have 400 IU of vitamin D compared to the 50,000 IUs you're taking a week this is insignificant (5.6%/wk). Vitamin D3 should be what you take if poss. There is a lot of evid it helps & prev many cond's like DM/pain/mood/heart dz...High-dose vitamin D replacement should be MONITORED, its a fat soluble vitamin (actually a hormone) w a target level about 60 (not 30), but to much is toxic!