1.10 : Routes of Drug Administration: Enteral

Medications can be administered through the enteral route using liquids, capsules, or tablets.

Enteral administration involves drug administration via the mouth in two ways: orally or sublingually.

Unlike sublingually drugs, drugs that are taken orally pass through the gastrointestinal (GI) tract and get metabolized by the liver. Once metabolized, the drug is absorbed into the systemic circulation, reaching different body parts via the bloodstream. However, while passing through the stomach, certain medications may be vulnerable to destruction by gastric secretions. Additionally, some drugs may irritate the gastric lining, leading to discomfort or side effects. Therefore, such sensitive drugs are often protected with an enteric coating, which shields the drug from stomach acid and only dissolves in the less acidic environment of the intestine.

Another method used to enhance drug delivery is the development of controlled-release preparations. These formulations are engineered to release the drug slowly and consistently, promoting uniform absorption of the drug over an extended period. This prolonged action is particularly beneficial for drugs with short half-lives, as it minimizes the need for frequent dosing and can also help reduce undesired side effects.

The sublingual route can be advantageous for certain drugs that are unstable in gastric secretions or quickly metabolized by the liver. The drug diffuses into the capillary network beneath the tongue and is directly absorbed into the systemic circulation, bypassing the GI tract and liver metabolism for more effective medication delivery to the body.