Ideas

Cigar Item
Set up global while(true) for statement (for x time, give player HP+X), then take aay after X-time.

Rings: Set up global script to make enabling one ring disable another;set item active script on each ring to turn on and off bool functions.

Subweapons: In global active script, set up in while)true) loop an if arguement that:
if item X is on (bool functions), remove items XYZ from inventory.
Establish bool functions for each item.
Set pickup script or subweapons to remove old subweapon from inventory. 