Which of the following is not a way in which medications can be administered?

The option "Only mixed into food" is accurately identified as not being a standard or recognized method of administering medications. While certain medications can indeed be mixed into food for administration, it is not a primary or formal method of delivery like the other options presented.

Swallowing medications in liquid form, injecting directly into muscle (intramuscular injection), and using transdermal patches are all established methods utilized in clinical practice. Each of these methods has specific mechanisms for delivering medications into the body, be it through the gastrointestinal tract, bloodstream via injection, or absorption through the skin.

Merging medications into food may be practical in some cases, especially for patients with difficulty swallowing. However, it lacks the precision and reliability of other methods, making it less viable as a standalone option for administration. In clinical settings, the medications' effectiveness and absorption can greatly depend on conditions that mixing with food does not guarantee. Therefore, given these considerations, "Only mixed into food" does not fit as a standard method of medication administration.