You're talking of the powder drinks? If so, no. Well not unless desperate, on the road, and that's your only choice. The whole point of the Dukan diet is losing weight WITH food and not meal replacement powders.
Also, check the ingredients of your whey powder as I think it has carbs and fat in it... (mixed opinions on google)
Great re your attack loss - so why do you need to add in protein drinks (with carbs and fat?). Still to pure protein and check out your losses!
Good luck!