The document discusses the various routes of drug administration including oral, sublingual, buccal, rectal, parenteral, injection, inhalation, and others. The choice of route depends on factors like the drug properties, the organ or tissue to be treated, absorption rate, patient condition, and accuracy of dose required. Each route has advantages and disadvantages related to onset of action, convenience, side effects, and applicability based on the drug and patient.

1. Routes of Drug Administration
Drugs can be administered into the body through
different routes. The choice of route depends upon
nature of drug & patient related factors:
1. Physical & chemical properties of the drug e.g: solid,
liquid, gas (physical); pH, solubility, stability
(chemical)
2.Tissue or organ to be treated
3.Rate & extent of absorption of drugs and fates
4.Effect of digestive juices & first pass metabolism of
drug
5.Urgency of the situation
6.Accuracy of dose required
7.Patient condition e.g: unconsciousness, vomiting
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2. 2

3. 3

4. Systemic Routes
The drugs administered through systemic routes are
intended to enter blood circulation & distribute to the
body & target site. Examples: Oral tablet, capsules,
suspensions, injections, etc
Local Routes
The drugs administered through local routes act
locally to the applied areas. The drug concentration is
high at application site without exposing to the other
parts of the body. Examples: topical ointment, lotion,
cream, spray, drops, suppositories, pessaries, etc
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5. 5

6. 1. Oral or Enteral Route
1. Drugs are administered through the alimentary tract
(Enteron) known as Oral route.
2. This is the most common route of administration.
3. Only a few drugs are dissolved within the mouth
e.g:sublingual (under-the tongue) and buccal tablet
dosage forms.
4. The majority of drugs are intended to be swallowed.
5. The majority of these dosage forms are taken for their
systemic effects resulting after absorption from the
various surfaces along the gastrointestinal tract (GIT).
6. The types of dosage form are: tablets, capsules, solution,
syrups, elixirs, suspensions, powders etc.
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7. Advantages
Generally safest route of administration.
Convenient for patient.
Cheap than other form i.e. Economical
Complications of the parenteral therapy are avoided
Systemic distribution
No need for sterile equipment
Self-medication is easy
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8. Disadvantages
The onset of drug action is slow
Absorption may be variable
Irritant and unpalatable drugs cannot be administered by
this route
Gastric irritation may produce vomiting
The route may not be useful in the presence of vomiting
and diarrhea
Drugs likely to be destroyed by digestive juice cannot be
administered orally e.g: Insulin, Penicillin
Oral route is not useful in unconscious and uncooperative
patients
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9. 2. Sublingual or buccal route
The tablet or pellet containing the drug is placed
under the tongue or buccal mucosa. Only lipid
soluble & non-irritating drugs can be administered
through this route. Absorption is very rapid & action
can be produced in minutes. Examples: GTN,
buprenorphine
Advantages:
Rapid onset of action
No first pass metabolism
Systemic effects
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•Disadvantages:
•Inconvenient
•Chances of spitting of drug

10. 10
A. Sublingual
B. Buccal

11. 3. Rectal route
Drugs that causes irritation & have unpleasant taste
while taken by oral route can be place into rectum for
systemic effects. Example: suppository, enema. This
route can be used when patient is unconscious or
vomiting.
Disadvantages
•Inconvenient & embarrasing
•Absorption is slow &
irregular
•Chances of rectum mucosal
irritation inflammation
Advantages:
•Useful when patient is
unconscious or vomiting.
•Absorbed directly through
external & internal haemorrhoidal
veins.
•Systemic effects

12. 4. Parenteral Route
Route of administration other than the alimentary
tract (The Enteron) are called parenteral route.
This route eliminates the factor of absorption since
the absorption is injected directly into the circulation.
This route are divide into four classes:
Injection,
Inhalation
Transcutaneous and
Trans-mucosal
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13. Advantages of Parenteral Route
They can be administered to unconscious or
uncooperative patients
They can be administered in case of vomiting and
diarrhea, and the patient unable to swallow
Drug which might irritate the stomach or which are not
absorbed orally can be administered
They avoid drug modification by the alimentary juices and
liver enzymes
Rapid action and accuracy of dose are ensured
Liver is by-passed (No first pass metabolism)
Suitable for large volume
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14. Disadvantages of Parenteral
Route
Less safe because there is less time between
administration and absorption and extraction of
unabsorbed drug which may chance to produce toxic
effects.
More expensive
Inconvenient for use, self medication being difficult
Liable to cause infection if proper care is not exercised
Likely to injure important structures such as nerves and
arteries
Most dangerous route
Drugs must be in aqueous solution
Once injected, drug cannot be removed
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15. Injection
A drug administered parenterally is
one that is injected through the hollow
of a fine needle into the body at various
sites and to various depths.
The three primary routes are:
subcutaneous (SC, SubQ)
intramuscular (IM), and
intravenous (IV).
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17. Strict sterility requirements make this dosage
form more expensive and require competent
trained personnel for administrations.
Drugs destroyed or inactivated in the GI tract or
that are too poorly soluble to provide a
satisfactory response may be administered
parenterally.
Rapid absorption is essential in emergency
situations, when the patient is uncooperative,
unconscious, or otherwise unable to accept the
medication.
Injectable preparations are usually either sterile
suspensions or solutions of a drug in water or in a
suitable vegetable oil.
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18. Subcutaneous Administrations (SC)
The drug is deposited in the loose subcutaneous
tissue which is richly supplied by nerves but is less
vascular.
Subcutaneous injections are usually aqueous
solutions or suspensions administered in small
volumes of 2mL or less.
They are generally injected into subcutaneous tissue
of the fore arm, upper arm, thigh, or abdomen.
The site should be rotated if frequent injections are
to be given, to reduce tissue irritation, e.g: Insulin.
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Advantages Disadvantages
Self injection is possible
because deep penetration is
not needed.
Only small volumes(1-2ml)
can be injected.
Action is sustained &
uniform.
Not suitable for shock
patients.
High bioavailability & avoids
first pass effect.
Drug absorption is slower
than i.m. route.
Depot preparation can be
injected for prolong action.
Only non-irritant drugs can
be injected by this route.

20. Intramuscular Injections (IM)
Intramuscular injections are performed deep into
the skeletal muscles at the deltoid, triceps, gluteus
maximus, rectus femoris or lumbar muscles.
Aqueous or oleaginous solutions or suspensions
may be used with rapid effects.
Drugs that are irritating to subcutaneous tissue
are often administered intramuscularly with
volumes of 2 to 5 mL or more.
When a volume of 5 ml or more is to be injected it
should be in divided doses.
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21. 21
Advantages Disadvantages
Can be used for mild
irritants, suspensions &
colloids
Self injection is difficult as
deep penetration is required
Absorption is faster & rapid
onset of action
Not suitable for
anticoagulant treated
patients
High bioavailability & avoids
first pass effect.
Cause pain while injecting
Depot preparation can be
used.
Volume of injection should
not exceed 10 ml

22. Intravenous Injections (IV)
An aqueous solution is injected directly into a vein at a
rate of efficiency, safety, and comfort for the patient
with desired duration of the drug response.
The drug may be administered as a bolus or infused
slowly via a slow drip to maintain the blood level or to
provide nutrients and drugs after surgery.
The drug must be maintained in solution after
injection so that no precipitation occurs to produce
emboli (a clotting factor).
Injections with oleaginous bases are not given IV as
they might produce pulmonary embolisms.
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23. 23
Advantages Disadvantages
Can be given to
unconscious patients
No self administration
Immediate action &
response.
Local irritation can lead to
phebitis
Almost 100%
bioavailability.
Extravasation can lead to
thrombophlebitis
Avoids first pass effect Low chances of reversal

24. Intra-dermal Injections
These are administered into the skin layers of usually
in volumes of about a tenth of a milliliter (0.1 ml).
Common sites are the arm and back, where there is no
hair.
They are frequently done for diagnostic measures
(tuberculin and allergy testing).
Intra-arterial
Drug administration produce a sudden high
concentration in arterial blood and hence, may be
harmful locally or damaging to tissue supplied by the
artery.
Certain anti-malignancy compounds are administered
by this route
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25. Intrathecal
Administration of drugs into the subarachnoid space
of the spinal cord is known as intrathecal.
The drug acts directly on the CNS.
This route also is convenient for producing high level
concentration in the subarachnoid space, eg certain
antibiotics and anti-malignancy drugs.
Intraperitoneal
Administration of drug directly into the serum
membrane between viscera and lining the abdominal
cavity by injection is known as intraperitoneal.
This route has been sometime used in infants for
giving fluids like glucose, saline
It is also used for peritoneal dialysis. 25

26. Intramedullary
Administration of drug into the bone marrow is called
intramedullary.
This route is now rarely used.
Intrarticular route
Drug administration into the joint cavity directly for the
treatment of inflammatory joint condition.
Steroids are given into the joint cavity for inflammatory
joint condition.
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27. Inhalation
Drugs may be administered by this route using:
Pressurized meter dose aerosol. eg. Salbutamol
and beclomethasone in bronchial asthma
Oxygen or compressed air driven nebulised
solution. eg. Salbutamol in bronchial asthma
Dry powders from inhalers activated by patient's
inhalation. eg. Salbutamol
Drug given by this route are quickly absorbed and
produce rapid local and systemic effects.
Sometime local irritation may also results in an
increase in the respiratory tract secretions and
bronchospasms.
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Advantages Disadvantages
Self administration. Dose may cause irritation to
the mucosa respiratory tract.
Rapid onset of action. Difficulty in dose estimation.
Avoids first pass effect. Requires special knowledge on
delivering the drug.
Suitable for the controlled
delivery of drug to the
respiratory tract .
Expensive dosage form.

29. Transcutaneous
Inuction:
Certain drugs when rubbed into the skin can get
absorbed and produce systemic effects. Eg.
Nitroglycerine Ointment in angina pectoris (chest
pain)
Jet Injection (Dermojet):
This method involves the transcutaneous
introduction of a drug by means of high velocity jet
produced through a micro-fine orifice. This method
does not require the use of needle and therefore29

30. Trans-mucosal
Sublingual administration:
A tablet containing medicament is placed under the
tongue and is allowed to dissolve in the mouth.
The active agents thus get absorbed through the
buccal mucous membrane directly into the systemic
circulation.
Trans-nasal route:
D-arginine vasopressin monoacetate (dDAVP), an
antidiuretic hormone of the posterior pituitary gland
are examples of drugs administered by this route.
It is important that no poisonous substance be
administered by this route, as it may reach the brain
along with lymphatic channels.
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31. Trans-rectal route:
Rectal administration of drugs may be preferred for
those drugs that are destroyed or inactivated by the
stomach or intestines.
The rectal route is also preferred when the oral route is
precluded due to vomiting or when the patient is
unconscious or incapable of swallowing drugs safely.
Drugs absorbed rectally do not pass through the liver
before entering the systemic circulation.
Endotracheal route:
The drug is given by endotrachial tube,
The drug is diluted in 5-10 ml of isotonic saline before
administration.
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32. 5. Local Application
Drugs applied locally for their actions at the site of
application are known as Local application route.
In this types dusting powder, paste, lotion, drops,
ointment or plastering are used for its action.
Drugs may also be administered locally in the form of
bougie for urethra, pessary for vagina and suppository for
the vagina and rectum.
Drugs used in the form of watery solutions for effects on
mucus membranes are sometimes likely to be absorbed
and may produce adverse systemic effects.
In case of corneal application, the drug may penetrate in
to the anterior chamber and affect the cilliary muscles, eg.
Cocaine
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33. Topical route: Drugs that are applied to a particular place on
or in the body. Most often topical administration means
application to body surfaces such as the skin or mucous
membranes. Many topical medications are epicutaneous,
meaning that they are applied directly to the skin. Topical
medications may also be applied to the surface of tissues
other than the skin, such as eye drops applied to
the conjunctiva, or ear drops placed in the ear, or medications
applied to the surface of a tooth.
Ocular route: Drugs used to treat eye disorders (such as
glaucoma, conjunctivitis, and injuries) in form of liquid, gel,
or ointment can be applied to the eye. Liquid eye drops are
relatively easy to use but may run off the eye too quickly to be
absorbed well. e.g: artificial tears, acetazolamide (glaucoma),
phenylephrine ( mydriatics/pupil dilation), ciprofloxacin
(antibiotic), ocuserts 33

34. Otic route: Drugs used to treat ear inflammation and
infection can be applied directly to the affected ears. Ear
drops containing solutions or suspensions are typically
applied only to the outer ear canal. Drugs that can be given
by the otic route include hydrocortisone (to relieve
inflammation), ciprofloxacin (to treat infection),
and benzocaine (to numb the ear)
Nasal route: This route involves administration of drugs
directly into the nose. Drugs are used to treat nasal
decongestants for cold and allergy treatment. It is also used
to treat irritation and inflammation of nasal cavity. e.g: nasal
sprays, nasal drops
Vaginal route: Some drugs may be administered vaginally
to women as a solution, tablet, cream, gel, suppository, or
ring. The drug is slowly absorbed through the vaginal wall.
This route is often used to give estrogen to women during
menopause to relieve vaginal symptoms such as dryness,
soreness, and redness. 34

35. 35
Nasal drops

36. Enema
Administration of a medicament in liquid form into the
rectum is called enema. There are two types of enema:
Evacuant Enema: Example is soap water enema. It is used
to remove the faecal matter and the flatus. The water
stimulates the rectum by distension while, soap acts as a
lubricant. The quantity of fluid administered is about 600
ml. An enema is useful in treating selective cases of
constipation.
Retention Enema: The fluid containing the drug is
retained in the rectum for local action as with
prednisolone enema for ulceration colitis. Usually the
quantity of fluid is about 100-120 ml.
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Route of Administration Primary Dosage Forms