Reversal agent
Formal Definition
A pharmacological agent that rapidly antagonizes or neutralizes the anticoagulant, antithrombotic, or sedative effect of another drug; examples include protamine (for heparin), vitamin K and 4-factor PCC (for warfarin), flumazenil (for benzodiazepines), naloxone (for opioids), and andexanet alfa (for factor Xa inhibitors).
How It's Used on the Ward
"Give reversal" or "reverse the anticoag" — urgent language in bleeding emergencies, before emergent surgery, or in over-sedation scenarios.
Example
""Supratherapeutic INR of 9.8 with active GI bleed — giving 4-factor PCC now for urgent reversal, plus IV vitamin K 10 mg. Repeat INR in 30 minutes. GI on the phone for emergent EGD.""
Clinical Context
Naloxone (Narcan): reverses opioid toxicity; short half-life (~60–90 min) — may need repeat doses or infusion; titrate to respiration, not consciousness (avoid precipitating withdrawal). Flumazenil: reverses benzodiazepines; short acting, rarely used (seizure risk in chronic BZD users). 4-factor PCC (Kcentra): faster and more complete warfarin reversal than FFP; preferred in life-threatening bleeding. DOAC reversal agents are expensive and not universally stocked — verify availability with pharmacy on any emergent bleed.