Which of the following is a common indication for starting IV therapy?

Dehydration is a common indication for starting intravenous (IV) therapy because it involves the loss of fluids and electrolytes from the body, which can occur due to various reasons such as prolonged vomiting, diarrhea, excessive sweating, or insufficient fluid intake. When a patient is dehydrated, they may not be able to drink enough fluids to adequately rehydrate, making IV administration a necessary and effective method for restoring fluid volume more rapidly and efficiently. IV therapy can provide immediate access to vital fluids and electrolytes, ensuring that the body's hydration and homeostasis are quickly re-established.

In contrast, while headaches, coughing, and cold symptoms may warrant medical attention, they do not typically require IV therapy, as they usually can be managed through oral hydration and other treatments. Therefore, dehydration stands out as a clear and recognized reason for initiating IV treatment.