Which type of medication is most likely given to a patient with a moderate case of hives after iodinated contrast medium injection?

In the case of a patient experiencing moderate hives following an iodinated contrast medium injection, antihistamines are the most suitable type of medication. Hives, or urticaria, are characterized by raised, itchy welts on the skin that often result from an allergic reaction, which is commonly mediated by histamine release in response to an allergen, in this case, the contrast medium.

Antihistamines specifically work by blocking the action of histamine at H1 receptors, thereby alleviating the itching, redness, and swelling associated with allergic reactions like hives. They are typically the first-line treatment for mild to moderate allergic reactions because they are effective and have a relatively safe profile.

While corticosteroids can also be used to manage more severe allergic reactions and inflammation, they are generally reserved for more serious or systemic reactions, and might not be necessary in cases classified as moderate. Analgesics are used to relieve pain and don’t address the underlying allergic reaction causing the hives. Antibiotics, on the other hand, are intended to treat bacterial infections and are not relevant to an allergic reaction triggered by a contrast medium. Thus, antihistamines are indicated for the moderation of symptoms in instances of hives due to such reactions.