Try a cough drop or hard candy.

I find chewing gum helps with this, just standard sugar free gum, it makes you produce more saliva because your brain thinks your eating and so it might help.
I also second a hard sweet it would have the same effect as the chewing gum in terms of saliva production.

Hey there.
With your prescribed adderall you have to drink more water as it does dehydrate your body (it's working harder... You're on an amphetamine). And just as you know, the isotretinoin will also dry your body out as well, so your body is extra dried out! I cannot say if you can go without your adderal, but I have personally minimized the amount of adderall I take while I'm on isotretinoin....