IPH - Hour 3 - Routes or Administration

Oral (PO)

The most common route of administration is the oral route , also known as the PO (per ostoma) route. Oral medications are swallowed, enter the stomach, then are absorbed in the small intestine.

The oral route is the least efficient route of administration. There are several reasons for this.

Time. It takes time for oral medications to be absorbed and distributed to the target cells. Typically, the effects of oral medications are not seen for 20 minutes to an hour or more. The 'onset of action' may take even longer in older persons.

Presence of Food. Food in the stomach delays the absorption of medications. In general, medications taken on an 'empty stomach,' achieve greater and more rapid results. However, medications taken on an 'empty stomach' cause more GI side effects such as nausea, vomiting, cramping, and diarrhea.

Gastric Secretions. The stomach secretes Hydrochloric Acid (HCl), enzymes, and other substances that break down medications. This degradation results in less medication being available for absorption. Some medications, such as insulin and nitroglycerine tablets are so completely destroyed, that they simply cannot be administered by the oral route.

First Pass Effect. Once medications are absorbed through the small intestine into the bloodstream, they are carried directly to the liver by the portal circulation. This pathway is designed so that ingested poisons and microbes can be removed from the bloodstream before they can cause damage to other tissues, organs, and systems. Even 'good drugs' are weakened by the 'first pass' through the liver.

Why, then, is the oral route the preferred method?

(1) Convenient. Pills and other oral forms of medications are quick and easy to administer. They require little or no privacy and cause little or no pain.

(2) Economical. Oral medications are fairly inexpensive to store and administer.

(3) Safe. If a mistake is made, measures can be taken before the medication becomes absorbed and is distributed throughout the system.

Adminstering Medications through a G-Tube or an NG-Tube

a G-Tube or an NG-Tube is a tube leading directly to the stomach. There are some special considerations when giving a medication through an enteral tube, but the general guidelines of orally administered medications remain the same.

Oral Medications

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