Distinguish the terms parenteral and enteral modes of administration in pharmacology and toxicology.

Parenteral administration refers to the administration of drugs or substances through routes other than the digestive tract, such as intravenous, intramuscular, subcutaneous, or intradermal routes. This allows for rapid absorption and onset of action, as the drug bypasses the digestive system and is directly absorbed into the bloodstream.

Enteral administration, on the other hand, refers to the administration of drugs or substances through the digestive tract, such as oral or rectal routes. This route of administration is slower than parenteral administration, as the drug must be absorbed through the gastrointestinal tract before reaching the bloodstream.

In pharmacology and toxicology, the choice of administration route depends on factors such as the drug's properties, the desired onset of action, and the patient's condition. Parenteral administration is often used in emergency situations or when rapid onset of action is required, while enteral administration is more commonly used for chronic conditions or when the drug can be effectively absorbed through the digestive tract.

Parenteral Mode of Administration

- Administration of drugs directly into the body, bypassing the gastrointestinal (GI) tract.
- Methods:
- Intravenous (IV)
- Intramuscular (IM)
- Subcutaneous (SC)
- Intradermal (ID)
- Advantages:
- Rapid onset of action
- Consistent absorption
- Controlled dosage
- Disadvantages:
- Requires sterile technique and trained personnel
- Can cause pain, discomfort, or infection at the injection site

Enteral Mode of Administration

- Administration of drugs through the GI tract.
- Methods:
- Oral (PO)
- Sublingual (SL)
- Buccal (BK)
- Rectal (PR)
- Advantages:
- Convenient and cost-effective
- Can be self-administered
- Disadvantages:
- Slower onset of action
- Incomplete and variable absorption
- Can be affected by food, pH, and intestinal motility

Key Differences

| Feature | Parenteral | Enteral |
|---|---|---|
| Route of administration | Bypasses GI tract | Through GI tract |
| Onset of action | Rapid | Slower |
| Absorption | Consistent | Variable |
| Dosage control | Precise | Less precise |
| Convenience | Requires injections | Convenient and self-administered |
| Safety | Can cause pain or infection | Generally safer |

Choice of Administration Mode

The choice of administration mode depends on factors such as:

- Drug solubility and absorption
- Urgency and severity of the condition
- Patient preference and capabilities
- Availability of trained personnel