Enteral Routes of Drug Administration
The route of administration of drug is determined by the properties of the drug (e.g. water or lipid solubility,etc.) & by the therapeutic objectives (e.g. the desirability of a rapid onset of action or the need for long-term administration or restriction to a local site).
There are two major routes of drug administration, enteral and parenteral.
Enteral Routes of Drug Administration
Enteral administration, or administering a drug by mouth, is the simplest and most common means of administering drugs. When the drug is given in the mouth, it may be swallowed, allowing oral delivery, or it may be placed under the tongue, facilitating direct absorption into the bloodstream.
Oral: Giving a drug by mouth provides many advantages to the patient; oral drugs are easily self-administered and limit the number of systemic infections that could complicate treatment.
Toxicities or overdose by the oral route may be overcome with antidotes such as activated charcoal.
On the other hand, the pathways involved in drug absorption are the most complicated, and the drug is exposed to harsh gastrointestinal (GI) environments that may limit its absorption. Some drugs are absorbed from the stomach; however, the duodenum is a major site of entry to the systemic circulation because of its larger absorptive surface.
Most drugs absorbed from the GI tract enter the portal circulation and encounter the liver before they are distributed into the general circulation. These drugs undergo first-pass metabolism in the liver, where they may be extensively metabolized before entering the systemic circulation.
Drugs that exhibit high first-pass metabolism should be given in sufficient quantities to ensure that enough of the active drug reaches the target organ. Ingestion of drugs with food, or in combination with other drugs can influence absorption. The presence of food in the stomach delays gastric emptying, so drugs that are destroyed by acid (for example, penicillin) become unavailable for absorption
Sublingual: Placement under the tongue allows a drug to diffuse into the capillary network and, therefore, to enter the systemic circulation directly. Administration of an agent, sublingually, has several advantages including rapid absorption, convenience of administration, and low incidence of infection, avoidance of the harsh GI environment, and avoidance of first-pass metabolism.
There are two major routes of drug administration, enteral and parenteral.
Enteral Routes of Drug Administration
Enteral administration, or administering a drug by mouth, is the simplest and most common means of administering drugs. When the drug is given in the mouth, it may be swallowed, allowing oral delivery, or it may be placed under the tongue, facilitating direct absorption into the bloodstream.
Oral: Giving a drug by mouth provides many advantages to the patient; oral drugs are easily self-administered and limit the number of systemic infections that could complicate treatment.
Toxicities or overdose by the oral route may be overcome with antidotes such as activated charcoal.
On the other hand, the pathways involved in drug absorption are the most complicated, and the drug is exposed to harsh gastrointestinal (GI) environments that may limit its absorption. Some drugs are absorbed from the stomach; however, the duodenum is a major site of entry to the systemic circulation because of its larger absorptive surface.
Most drugs absorbed from the GI tract enter the portal circulation and encounter the liver before they are distributed into the general circulation. These drugs undergo first-pass metabolism in the liver, where they may be extensively metabolized before entering the systemic circulation.
Drugs that exhibit high first-pass metabolism should be given in sufficient quantities to ensure that enough of the active drug reaches the target organ. Ingestion of drugs with food, or in combination with other drugs can influence absorption. The presence of food in the stomach delays gastric emptying, so drugs that are destroyed by acid (for example, penicillin) become unavailable for absorption
Sublingual: Placement under the tongue allows a drug to diffuse into the capillary network and, therefore, to enter the systemic circulation directly. Administration of an agent, sublingually, has several advantages including rapid absorption, convenience of administration, and low incidence of infection, avoidance of the harsh GI environment, and avoidance of first-pass metabolism.
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