Adrenaline is a passive item added in The Binding of Isaac: Afterbirth †.
- Gives Isaac a flat damage up based on how many empty Heart containers he has.
- The damage up given is 0.2 for each empty Red Heart container Isaac has.
- Damage ups are only applied for every fully empty heart container.
- The damage up given is ((2 * MissingHearts) ^ 1.6) * 0.1, where MissingHearts is the number of full red hearts of health missing.
- This item belongs to the Spun set. Collecting three items from this set will transform Isaac into a buff berserker.
- This item has no effect on characters that can't have any Red Heart containers.
- This item affects both Keeper and Tainted Keeper; empty Coin Hearts increase damage.
- As The Forgotten, empty Bone Hearts increase damage, but if the Bone Hearts are broken, the damage buff is taken away.
- Blood Oath: Activates the damage up effect of Adrenaline for the resulting empty heart containers at the start of each floor.
- Before v1.06.0190, Adrenaline was named Adderline.
- Despite having its name changed, Adrenaline's item sprite is named collectibles_493_adderline in the game files.
- Adrenaline is a hormone produced by the body in situations of high stress that increases blood circulation, breathing, and other things in preparation for the natural flight or fight reflex.
- Adrenaline causes characters to have an animation that makes them look like they are breathing rapidly. The more health they're missing, the more exaggerated the animation is.