Advantage And Disadvantage Of Oral Route Of Drug Administration

Oral administration of medication is a convenient, cost-effective, and most commonly used medication administration route. It is abbreviated as p.o or PO which is a Latin word per os meaning through the mouth. A few drugs taken orally are intended to be dissolved in the mouth. Other drugs taken orally are swallowed with large amounts of water.

Advantage and disdavntage of oral drug

Few drugs require local action without absorption such as antacids. For the others, the primary site of drug absorption is usually the small intestine, and the bioavailability of the medication is influenced by the amount of drug absorbed across the intestinal epithelium. The first-pass effect is an important consideration for orally administered medications. It refers to the drug metabolism whereby the drug concentration is significantly diminished before it reaches the systemic circulation, often due to the metabolism at the liver.

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Advantage Of Oral Route Of Drug Administration

Oral medications are convenient and are indicated for patients who can ingest and tolerate an oral form of medications. Some medications with short half-lives are administered orally as timed-release or sustained-release forms that get absorbed over several hours.

For patients, their main advantage is that doses usually only need to be taken once or twice daily. 

Solid dose forms such as tablets and capsules have a high degree of drug stability and provide accurate dosage.

1. Patient compliance

2. convenience of drug administration

3. cost-effectiveness

4. ease of large-scale manufacturing

5. Patient preference

6. Self administration possible

7. Painless

8. Ready to use form

9. No skill required

10. No sterile precautions needed

Disadvantage Of Oral Route Of Drug Administration

An oral medication route is contraindicated for patients who cannot tolerate oral drugs, such as those who have altered mental status or have nausea or vomiting that hinder them from safely ingesting the drug orally.

Difficulties frequently arise with patients who are prescribed modified-release preparations as these must not be crushed or broken at the point of administration. Modified-release formulations can delay, prolong or target drug delivery. The aim is to maintain plasma drug concentrations for extended periods above the minimum effective concentration. Damage to the release controlling mechanism, for example by chewing or crushing, can result in the full dose of drug being released at once rather than over a number of hours. This may then be absorbed leading to toxicity or may not be absorbed at all leading to suboptimal treatment.

The oral route is nevertheless problematic because of the unpredictable nature of gastro-intestinal drug absorption. For example the presence of food in the gastrointestinal tract may alter the gut pH, gastric motility and emptying time, as well as the rate and extent of drug absorption.

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The extent to which patients can tolerate solid dose forms also varies, particularly in very young and older patients. In such cases the use of liquids or soluble formulations may be helpful. Many drugs, however, are not stable in solution for liquid formulation and in such cases careful consideration should be given to the option of switching to alternative drug treatment.

1. Food can influence the absorption of drugs: it can decrease, increase, delay, or accelerate drug absorption

2. Drug action is slower, not for emergencies.

3. Not for unconscious patients and uncooperative patients

4. Bioavailability is not 100% because of first pass effect

5. Digestive enzymes act on drugs

6. Not suitable for highly irritant, bitter tasting drugs and drugs unstable to any gastrointestinal tract chemicals

7. Not suitable for unabsorbable drugs