My infant is not tolerating feeding for a week now he is bottle fed) nan optipro 1 , i already took him to the paediatrician and prescribed meds. its day 3 now on meds. but he is still vomiting all the milk after feeding. is he lactose intolerance?

Reduce volume: Babies tend to drink larger volumes faster when drinking from a bottle than from a breast. It may be that your infant needs help slowing down. Feed him 1-2 oz at a time while holding him upright, and give him a break by taking time to burp him, then another 1-2 oz 5-7 minutes later until the bottle is done. Keep him upright after feeding (don't lay him down) and make sure he is well burped.