Enteral Administration Flashcards
What is enteral administration?
Enteral administration refers to the delivery of drugs into the body via the gastrointestinal (GI) tract, either orally or through other routes such as sublingual, buccal, or rectal.
What are the two types of effects of enteral administration on the body?
Enteral administration can have:
Systemic effects: The drug is delivered to the body at a distance from the site of administration, affecting the entire body. For example, beta blockers for cardiovascular diseases.
Local effects: The drug works at or near the site of administration, primarily affecting the target area. For example, anti-inflammatory drugs for ulcerative colitis.
What is the function of the gastrointestinal tract?
The gastrointestinal tract (GIT) is responsible for digesting and absorbing nutrients and drugs, as well as excreting waste products of digestion.
What are the four layers of the gastrointestinal tract wall?
The four layers of the GIT wall are:
Mucosa: The epithelial lining responsible for digestion, absorption, and secretion.
Submucosa: Dense connective tissue with blood and lymph vessels.
Muscularis: Contains smooth muscle cells, divided into circular and longitudinal layers.
Serosa: A thin layer of connective tissue with blood vessels, lymph vessels, and a single squamous epithelial layer.
What is the role of microvilli in the gastrointestinal tract?
Microvilli are folds of the mucosa that increase the surface area of the intestines, aiding in the absorption of nutrients and drugs.
What are the primary blood supplies to the gastrointestinal tract?
Celiac artery supplies the stomach and duodenum.
Superior mesenteric artery supplies the rest of the small intestine and the proximal colon.
Inferior mesenteric artery supplies the distal parts of the colon.
What is the significance of the pH levels in the stomach and intestines?
The stomach has a highly acidic pH of around 2, which helps with digestion, while the intestines have a more neutral pH of 7, which is ideal for nutrient absorption and drug processing.
What is the difference between sublingual and buccal administration?
Sublingual administration: The drug is placed under the tongue, where it is absorbed into the bloodstream.
Buccal administration: The drug is placed between the gums and the inner lining of the cheek, where it is absorbed into the bloodstream.
Why might enteral drug administration be performed via a feeding tube?
Enteral drug administration via a feeding tube is used for patients who cannot consume adequate nutrition or medications orally due to conditions such as anorexia, difficulty swallowing, or other metabolic needs. Feeding tubes can be nasogastric (short-term), gastrostomy, or jejunostomy (long-term).
What are the different types of feeding tubes used for enteral administration?
Nasogastric tube: Inserted through the nose and terminates in the stomach. Used for short-term feeding (less than 4 weeks).
Gastrostomy tube: Surgically placed through an external opening into the stomach for long-term feeding.
Jejunostomy tube: Surgically placed into the small intestine for long-term feeding.
Why is rectal administration of drugs sometimes preferred?
Rectal administration is preferred in cases where oral administration is not possible, such as for patients with difficulty swallowing, vomiting, or unconsciousness. The rectum’s thin wall and rich blood supply allow for rapid absorption and bypass of first-pass metabolism by the liver.
What is first-pass metabolism, and how does it affect drug bioavailability?
First-pass metabolism occurs when a drug is absorbed from the gastrointestinal tract and then passes through the liver, where it may be metabolized before reaching systemic circulation. This process can reduce the drug’s bioavailability, meaning less of the drug reaches the target tissues.
How does the gastrointestinal mucus layer contribute to drug absorption?
The mucus layer that covers the luminal side of the gastrointestinal tract acts as a filter, allowing the absorption of molecules with molecular weights between 600-800 Da. This protective layer helps prevent large or harmful molecules from entering the body while facilitating the absorption of smaller drugs.
