**Question:** Which of these is not included in parenteral therapy?

A. Intravenous (IV) infusion
B. Intramuscular (IM) injection
C. Subcutaneous (SC) injection
D. Nasogastric (NG) tube feeding

**Core Concept:**
Parenteral therapy refers to the administration of medication, nutrients, or fluids directly into the bloodstream bypassing the gastrointestinal tract. It includes various methods of administration, some of which are intravenous (IV) infusion, intramuscular (IM) injection, and subcutaneous (SC) injection. Parenteral therapy does not involve administering substances through non-parenteral routes such as nasal, oral, or rectal routes.

**Why the Correct Answer is Right:**
Nasogastric (NG) tube feeding is not considered a part of parenteral therapy because it involves delivering nutrients and fluids directly into the stomach through the nose and pharynx, bypassing the gastrointestinal tract.

**Why Each Wrong Option is Incorrect:**
A. Intramuscular (IM) injection is a correct method of administration in parenteral therapy, as it delivers substances directly into the muscle tissue.
B. Intravenous (IV) infusion is also a correct method of administration in parenteral therapy, as it delivers substances directly into the bloodstream.
C. Subcutaneous (SC) injection is a correct method of administration in parenteral therapy, as it delivers substances directly under the skin into the fatty tissue, which is connected to the bloodstream.

**Clinical Pearl:**
Intralipid is an example of a medication administered via SC injection, which is an essential nutrient used in parenteral nutrition for critically ill patients who are unable to receive nutrients enterally (via the gastrointestinal tract). It is administered SC because the fatty tissue surrounding the injection site is connected to the systemic circulation, ensuring rapid absorption into the bloodstream.

**Core Concept:**
Parenteral therapy involves administering medications or nutrients directly into the bloodstream, bypassing the gastrointestinal tract, for patients who cannot receive medication or nutrients orally or enteral routes. This method is essential in treating patients who are critically ill or have impaired gastrointestinal function.

**Why Each Wrong Option is Incorrect:**
A. Intramuscular (IM) injection is a correct method of administration in parenteral therapy, as it delivers substances directly into the muscle tissue and ensures rapid absorption into the bloodstream.
B. Subcutaneous (SC) injection is a correct method of administration in parenteral therapy for certain medications or nutrients, as it delivers substances directly under the skin into the fatty tissue, ensuring rapid absorption into the bloodstream.
C. Intranasal administration is not considered a part of parenteral therapy because medications administered this way are absorbed into the bloodstream through the nasal mucosa and not directly into the bloodstream as in parenteral therapy.

**Clinical Pearl:**
Intranasal administration is often used for local medications, such as decongestants or antihistamines, which are absorbed through the nasal mucosa and enter systemic circulation via the mucosa and ethmoid sinus