I've done it. As long as you are giving the correct scoop to water ratio (eg: 1 scoop per 30ml water) then it should be fine. If she's going through a growth spurt then she'll be more hungry.
Also, I know that the recommendation is generally to wait until 6 month before starting solids, but she's 5 months and she may be ready. If formula isn't satisfying her, then it might be time to start some solids. At this age though, always offer a bottle first and if she's still hungry then perhaps try some solids.