Final answer:
Epinephrine is the medication that should be administered first to counteract the effects of anaphylactic shock.
Step-by-step explanation:
Based on the symptoms described, the client is experiencing an anaphylactic reaction, which is a severe allergic reaction.
The drug used to counteract the effects of anaphylactic shock is epinephrine.
Epinephrine is administered to raise blood pressure, relax bronchial smooth muscles, and reduce swelling, effectively improving breathing and preventing suffocation.