Omnius: Well, it's understandable... Maybe in Matrix Neo can fight Agent Smith with only one arm but a Witcher needs both of them to stay alive, can't spare one to :
reach a pocket, take the potion, uncap the potion, take the potion to his mouth (while not spilling any drops) AND finally drink the potion (beside the body needs time to be affected by the potion)
It's the great discussion of realism vs playability that's been going on in RPGs even before they appeared on computers. Some concessions must be made for the gameflow to feel as designed, those are always very tough design choices to make.
Gidzin: In battle(TW1) potions still took time to consume and you were subject to attack while consuming!!
I'm thinking pre-meditation isn't realistic on your first playthru.
Yeah but once drunk they've worked instantly. Any drug or poison you take has some time to start acting in your organism, remember that these alchemic potions are in no way magic - it's the wicher's body that reacts to them differently than a human one.
Anyway if you think there's combat coming try preparing yourself. You can always regather the resources later it's easier to mass produce potions this time.
What I don't enjoy is the short length the potions work, but that can be increased with experience I think.