Boots variable teats taking longer?

[Pumpkinb]

Our little boy is 5 weeks now and seems to be suffering from colic in the evenings. We use the Dr Brown bottles with first stage teats and have started Infacol, we have bought some Boots variable flow teats to try before switching to Comfort milk (as we did with DD).
For our daughter we bought Asdas own variflow teats and they were great and had numbers 1-3 on which you would position under the nose. However Asda appear to have stopped selling these hence we have bought the Boots ones to try.
Anyway just tried them for the first time and he is taking ages to drink anything, ended up switching back to an old teat to let him get his feed.
I actually gave them a go myself using water once the feed was finished and I can get more from the stage one teat than I can the Boots Variflow teat myself!...is this normal? There is no way he could suck a Comfort milk through these things

 

[skunkpixie]

Are you using the boots teats with the dr brown bottles? If so then I would advise sticking with dr brown teats for dr brown bottles as Ive read on their website that you shouldnt use a different brand teat with a dr brown bottle due to the advance anti-colic system. Maybe try the level 2 dr brown teats instead? xxx