Final answer:
Epinephrine is the drug used to treat anaphylactic shock, and it is typically administered via an autoinjector like an EpiPen for immediate action during severe allergic reactions.
Step-by-step explanation:
The drug used to treat anaphylactic shock is epinephrine. This medication effectively counteracts the severe allergic reaction known as anaphylaxis, which can be life-threatening due to sudden drops in blood pressure and difficulties breathing. Epinephrine injections work rapidly by raising the blood pressure, relaxing bronchial smooth muscles for better air passage, modulating heart rate, and reducing swelling that can block airways. Individuals who are at risk of severe allergic reactions often carry an epinephrine autoinjector, such as an EpiPen®, which allows for immediate self-administration of the drug in emergency situations.