Final answer:
The epinephrine auto-injector is administered intramuscularly, and it is used during an anaphylactic shock to deliver a rapid dose of epinephrine. Oral administration is convenient for home treatment of systemic infections, with parenteral routes used for higher plasma levels in healthcare settings.
Step-by-step explanation:
The correct answer to the question regarding the administration of an epinephrine auto-injector is that it is administered intramuscularly. Epinephrine auto-injectors, such as EpiPens®, are designed to deliver a rapid dose of epinephrine to individuals experiencing an anaphylactic reaction, which is a severe allergic response. These injectors are preloaded syringes that can be used easily without special training, and are intended to be administered into the thigh muscle to ensure the medication is absorbed quickly into the bloodstream.
For treating systemic infections, the appropriate and convenient route of administration at home would be oral. However, if a medication is not effectively absorbed through the gastrointestinal (GI) tract, parenteral routes such as intramuscular or intravenous injections are preferred. These are usually performed in health-care settings because they can achieve higher plasma levels more quickly than oral administration.
During an anaphylactic emergency, self-administering an epinephrine shot is critical to counteract the effects of shock. This is followed by additional treatment with antihistamines and corticosteroids, which are administered to manage and prevent late-phase reactions, even though their effects have not been thoroughly studied.