Route of drug administration

Drugs may be administered by various routes. The choice of the route for a given patient depends on the properties of the drug and the patient’s requirements. A knowledge of the advantages and disadvantages of the different routes of administration is essential. The routes can be broadly divided into:

•Enteral/oral/ peroral

•Parenteral

• Local.

ENTERAL ROUTE (ORAL INGESTION)

The enteral route is the most commonly used, oldest, and safest route of drug administration. The large surface area of the gastrointestinal tract, the mixing of its contents, and the differences in pH at different parts of the gut facilitate the effective absorption of the drugs given orally. However, the gut’s acid and enzymes, along with the biochemical activity of its bacterial flora, can destroy some drugs before they absorb them.

Advantages

1. Convenience: The oral route is easy and convenient for patients, as it does not require needles or invasive procedures. Patients can self-administer oral medications at home.

2. Patient Compliance: Patients are more likely to comply with their treatment regimens when taking medications orally because it is generally more acceptable and less intimidating than injections.

3. Variety of Dosage Forms: Oral medications come in various forms, including tablets, capsules, liquids, and powders, making it possible to accommodate patient preferences and special requirements.

4. Absorption Control: Oral administration allows for controlling the rate of drug absorption by adjusting the drug’s formulation. Formulations such as delayed-release and extended-release are designed to release the drug slowly over time, thereby providing prolonged therapeutic effects.

5. Cost-Effective: Oral medications are often more cost-effective than injectable forms, which require additional medical equipment and personnel for administration.

Disadvantages

1. Variable Absorption: Factors such as food, gastric pH, and individual patient variability can influence the absorption of oral medications. This can lead to variable drug levels in the bloodstream.

2. First-Pass Metabolism: After oral administration, drugs must pass through the liver before entering the systemic circulation. This can result in some drugs’ partial metabolism and inactivation, reducing their bioavailability.

3. Gastric Irritation: Some drugs can irritate the stomach lining, potentially leading to gastrointestinal side effects, such as nausea, vomiting, or gastritis.

4. Swallowing Difficulty: For individuals with difficulty swallowing, including children and the elderly, oral administration can be challenging. In such cases, alternative routes of administration may be necessary.

5. Potential for Non-Compliance: Patients may forget to take their medications, take them irregularly, or discontinue treatment prematurely. This can affect the effectiveness of the drug therapy.

6. Unsuitable for Nauseous or Unconscious Patients: Patients who are nauseous or unconscious may be unable to take medications orally. In these situations, alternative routes of administration, such as intravenous, may be required.

7. Delayed Onset of Action: Oral medications typically have a slower onset of action than intravenous administration, making them less suitable for emergencies or situations requiring rapid drug effects.