Final answer:
Antihistamines can be used as an alternative to epinephrine for bronchospasm that is not relieved. They work by blocking the effects of histamine.
Step-by-step explanation:
For bronchospasm not relieved with epinephrine, a medication called antihistamines can be used as an alternative. Antihistamines work by blocking the effects of histamine, a chemical released by the body during an allergic reaction. Unlike epinephrine, which primarily acts on blood pressure and bronchial smooth muscle, antihistamines target the allergic response itself.