Pharmacology 3620 Lecture Notes - Lecture 10: Lipophilicity, Superior Vena Cava, Portal Venous System
22 Jan 2015
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Document Summary
Enteral means the involvement of the gastrointestinal system. Parenteral means things that do not involve the gastrointestinal system. Parenteral usually refers to the injection route of administration. Advantages: safe, economical; cheapest, convenient, you don"t need a health care professional around to administer a drug orally, not practical in unconscious patients. Following oral administration, drugs pass through the esophagus and into the stomach. This is because the surface area of the stomach is relatively small and the lining of the stomach is covered by a mucous layer. The majority of drug absorption occurs in the small intestine due to the large surface area created by millions of villi. Drug absorbed from the intestine is carried by the portal circulation to the liver, the primary site of drug metabolism. This is why some orally administered drugs undergo a large degree of first pass metabolism. Food can delay the absorption of some drugs. Drugs taken on an empty stomach undergo rapid gastric emptying.
