Okay, for the duration of your manic episode, take your credit card, or cards, and put them in a ziplock bag. Fill a bowl of water, put the ziplock full of card(s) into the water, place something heavy on top of the cards for the for the first few hours, then allow the water to cover over your card.

Now, if you want to make an impulse purchase, you will first have to thaw out the ice block your card(s) is in. The time it takes to thaw the cards out will give you time to decide if this is a rational purchase or a manic one.
Also, you can't do any impulse shopping at the store. Keep your cash, checkbook, or debit card out of the freezer, though.

This should prevent you from going into serious debt until you can get stabilized.