Parenteral Routes Overview

Parenteral Routes Overview

• Parenteral routes bypass the digestive system, allowing for direct entry into the systemic circulation; irreversible and may cause pain and risk of infections.
• Key types: intravascular, intramuscular, and subcutaneous, each with unique benefits and limitations.

Intravascular (IV) Route

• Most common parenteral route; drug is injected directly into a vein.
• Advantages:
  • Immediate action and precise control of drug levels in circulation.
  • Allows administration of large volumes through IV infusion.
• Disadvantages:
  • Risk of toxicity with rapid administration.
  • Only fluid solutions can be used.
  • Potential for local venous thrombosis and infection.

Subcutaneous (SC) Route

• Drug injected into the tissue just below the skin.
• Advantages:
  • Provides slow and controlled drug absorption.
  • Absorption rate can be modified by manipulating blood flow.
• Disadvantages:
  • Limited to small volumes per injection.
  • Repeated injections may cause lipoatrophy.

Intramuscular (IM) Route

• Drug injected into muscle mass.
• Advantages:
  • Faster absorption compared to subcutaneous injections.
  • Absorption rate can be altered by changes in blood flow.
• Disadvantages:
  • Risks include potential for infection or nerve damage.
  • May cause pain at the injection site.

Enteral Routes

• Simple and commonly used drug administration methods, primarily through oral intake.
• Oral Advantages:
  • Self-administered and does not require sterilization.
  • Overdoses can often be managed with antidotes.
  • Cost-effective relative to parenteral routes.
• Oral Disadvantages:
  • Ineffective absorption for some medications; first-pass metabolism can greatly reduce efficacy.
  • Not suitable for emergencies or individuals unable to swallow.

Sublingual Route

• Drug placed under the tongue for direct absorption into the bloodstream.
• Advantages:
  • Quick absorption; bypasses gastrointestinal metabolism.
  • Minimizes risk of local infection.
• Disadvantages:
  • Drug taste may be unpleasant.
  • Not suitable for long-term medication.

Other Administration Routes

• Inhalation: Rapid delivery through respiratory tract; effective for respiratory conditions.
• Intrathecal: Direct injection into cerebrospinal fluid, useful for central nervous system drugs.
• Intracardiac: Emergency injection directly into the heart; used in cardiac arrest.
• Topical: Local effects achieved through skin or mucous membrane application; minimizes systemic absorption.
• Rectal: Prevents drug degradation in the GI tract; useful when oral intake is not possible, but can irritate the rectal mucosa.

Injection Techniques

• Intramuscular: Inject at a 90° angle.
• Subcutaneous: Inject at a 45° angle.
• Intravenous: Inject at a 26° angle.
• Intradermal: Inject at a 10-15° angle.