JNTU Pharm. D II Year PHARMACOLOGY-I Previous Question Paper (August/September - 2022 - R08)

Routes of drug administration are broadly classified into two main categories: Enteral and Parenteral routes.

1. Enteral Routes

These involve the gastrointestinal tract.

• Oral: The most common route. Advantages: Safe, convenient, economical, and does not require sterile conditions. Disadvantages: Slow onset of action, potential for first-pass metabolism, may cause gastric irritation, and not suitable for unconscious patients or drugs destroyed by gastric acid.
• Sublingual/Buccal: Drug is placed under the tongue or in the cheek pouch. Advantages: Rapid absorption, bypasses first-pass metabolism, and can be terminated by spitting out the drug. Disadvantages: Limited to lipid-soluble drugs, may cause local irritation, and inconvenient for frequent use.
• Rectal: Used for localized or systemic effects. Advantages: Useful in vomiting, unconscious patients, or children. Disadvantages: Erratic absorption, potential for rectal mucosal irritation, and patient discomfort.

2. Parenteral Routes

These bypass the gastrointestinal tract and are typically invasive.

• Intravenous (IV): Drug injected directly into a vein. Advantages: Rapid onset, 100% bioavailability, suitable for large volumes and irritating substances. Disadvantages: Once injected, the drug cannot be retrieved, requires sterile technique, risk of infection, and potential for embolism.
• Intramuscular (IM): Injection into skeletal muscle. Advantages: Faster absorption than oral, suitable for oily vehicles or depot preparations. Disadvantages: Painful, risk of nerve damage, and limited volume.
• Subcutaneous (SC): Injection into the loose connective tissue under the skin. Advantages: Suitable for self-administration (e.g., insulin) and allows for slow, sustained absorption. Disadvantages: Not suitable for large volumes or irritating drugs.
• Inhalation: Administration via lungs. Advantages: Rapid absorption due to large surface area, localized action for respiratory diseases. Disadvantages: Requires specialized equipment and patient coordination.
• Topical: Application to skin or mucous membranes. Advantages: Localized effect with minimal systemic side effects. Disadvantages: Poor absorption through intact skin; systemic absorption may occur if the skin is damaged.