This document discusses various routes of drug administration including enteral, parenteral, and local application routes. The enteral route involves placing drugs directly in the gastrointestinal tract, with oral and sublingual administration being examples. The parenteral route involves injection of drugs directly into tissues or blood, bypassing the gastrointestinal tract. Examples of parenteral routes discussed are intravenous, intramuscular, subcutaneous, and intraperitoneal. Local application routes place drugs directly on body surfaces, such as topical administration to the skin or mucous membranes. Advantages and disadvantages of different routes are provided.

1. Routes of drug administration
Ms. Gunjan verma
(Lecturer)

2. Routes of drug administration
Enteral Parenteral
Local
applicatio
n
Oral
Sublingua
l
Inhalation
Vaginal
Rectal
Intradermal
Intravenous
Intramuscular
Subcutaneous
Intraperitoneal
Intramedullary
Topica
l

3. Enteral route
The term ‘Enteron’ means ‘intestine’
The drug is directly place in GIT.
Oral route (by mouth)
In this type the drug weather liquid or solid preparation
placed directly in mouth cavity and then swallowed with
drinks such as milk, water etc.
Advantages
1. Safest route
2. Most convenient
3. Most economical
4. Drugs can be self-administered
5. Non-invasive route.
Disadvantages 1. Onset of action is slower as absorption
needs time.
2. Irritant and unpalatable drugs cannot be administered.
3. Irritation to the gastrointestinal tract may lead to
vomiting.

4. Sublingual or buccal : The tablet or pellet containing the
drug is placed under the tongue or crushed in the mouth
and spread over the buccal mucosa.
e.g. nitroglycerine tablet used in disease angina pectoris.
Advantages:
1) onset of action is quick.
2) The overdose of drug is avoided.
3) The drug is not destroyed by stomach enzymes.
Inhalation: Volatile liquids and gases are given by
inhalation, e.g. general anaesthetics or nasal drops.
Rectal :Certain irritant and unpleasant drugs can be put
into rectum as suppositories for systemic effect. This route
can also be used when the patient is having recurrent
vomiting or is unconscious.

5. Vaginal: the drug is introduce through vagina to produce
local or systemic effect.
Parenteral route:
(Par—beyond, enteral—intestinal)
parenteral refers to administration by injection which takes
the drug directly into the tissue fluid or blood without having
to cross the enteral mucosa.
Advantages
• Action is more rapid.
• These routes can be employed in an unconscious or
uncooperative patient.
• Gastric irritants can be given parenterally and therefore
irritation to the gastrointestinal tract can be avoided.
• It can be used in patients with vomiting or those unable to
swallow.

6. Disadvantages
• Injections may be painful.
• More expensive, less safe and inconvenient.
• Injury to nerves and other tissues may occur.
Subcutaneous (SC) :
Here the drug is deposited in the SC tissue, e.g. insulin,
heparin. As this tissue is less vascular, absorption is slow
and largely uniform making the drug long-acting.
Intramuscular (i.m.):
The drug is injected in one of the large skeletal muscles—
deltoid, triceps, gluteus maximus, rectus femoris etc.
Muscle is less richly supplied with sensory nerves (mild
irritants can be injected) and is more vascular (absorption
of drugs in aqueous solution is faster). It is less painful.

7. Intradermal :
The drug is injected into the layers of the skin(e.g. BCG
vaccine, tests for allergy)
Intravenous (IV):
Here, the drug is injected into one of the superficial veins
so that it directly reaches the circulation and is immediately
available for action.
Advantages
• Most useful route in emergencies because the drug is
immediately available for action.
• 100% bioavailability.
• Large volumes of solutions can be given.
• Irritants can be given by this route as they get quickly
diluted in blood.

8. Intraperitoneal:
Peritoneum offers a large surface area for absorption.The
drug is injected in peritoneal cavity. The drug absorbed then
enter into the blood circulation.
Intra-articular: Drugs are injected directly into a joint for the
treatment of arthritis and other diseases of the joints, e.g.
hydrocortisone is injected into the affected joint in
rheumatoid arthritis.
Topical:
Drugs may be applied on the skin for local action as
ointment, cream, gel, powder, paste, etc. Drugs may also be
applied on the mucous membrane as in the eyes, ears and
nose as ointment, drops and sprays.

9. Questions
1. Define the term route of administration.
2. Explain the oral route of administration
of drug.
3. Explain the intravenous route of
administration of drug.
4. Give advantages and disadvantages of
parenteral route of administration of drug.

10. Thank you