Routes of drug administration

1. ANSUMAN SAHU
ROUTES OF DRUG
ADMINISTRATION

2. Defination :
 The path taken by the drug to get into the body is
known as the route of drug administration.
• A drug may be in ionized or unionized form.
1.Enteral Route
2.Parenteral Route
3.Inhalation
4.Topical Route

3. CHANNELS OF
DRUG
ADMINISTRATION
ENTERAL PARENTERAL TOPICAL

4. ENTERAL
ORAL
RECTAL
BUCCAL
SUBLINGUAL

5. 1. ENTERAL ROUTE :
 Enteral Route is through the alimentary canal.
It may be
● Oral
● Sublingual
● Rectal

6. a. ORAL ROUTE :
 Oral route is the most common route of drug
administration.
 It is mostly used for the neutral drugs.
 It may be in theform of tablets,
capsules, syrups, emulsions or powders etc.
Advantages :
 It is convenient
 It is the cheapest available route
 It is easy to use
 It is safe and acceptable.
 Self administered

7.  Disadvantages :
 Less amount of drug reaches the target tissue.
 Some of the drug is destroyed by gastric juices e.g.
adrenaline, insulin, oxytocin
 Absorption has to take place which is slow, so is
not preferred during emergency.
 It might cause gastric irritation
 It might be objectionable in taste.
 It might cause discoloration of teeth e.g. iron
causes staining, tetracyclines below 14 cause
brown discoloration so are not advisable during
pregnancy.
 Undergoes Fast Pass Metabolism
 Delayed action

8. FIRST PASS EFFECT :
 The first-pass effect is the term used for the
hepatic metabolism of a pharmacological agent
when it is absorbed from the gut and delivered to
the liver via the portal circulation. The greater the
first-pass effect, the less the agent will reach the
systemic circulation when the agent is
administered orally
 Ex- imipramine, morphine, propranolol,
buprenorphine, diazepam, midazolam,
pethidine, tetrahydrocannabinol (THC),
ethanol (drinking alcohol),
cimetidine, lidocaine,
and nitroglycerin (GTN).

9. FIRST PASS EFFECT :

10. B. SUBLINGUAL ROUTE :
Sublingual route involves tablets placed under the tongue or between cheeks or
Gingiva. The drug should be lipid soluble and small.
Advantages:
 Rapid absorption takes place. Drug is
dissolved easily
 Drug enters the blood directly Less first
pass effect.
 Spitting out of the drug removes its effect
Disadvantages:
 This method is inconvenient.
 Irritation of the mucous membrane might occur Person may
swallow the drug
 Might be unpleasant in taste.
Ex - Nitroglycerin, isoprenaline and oxytocin. Nifedipine used for the
treatment of hypertension in emergency is given by sublingual route.

11. c. RECTAL ROUTE :
 Drugs in solid forms such as suppositories or in liquid
forms such as enema are given by this route. This route
is mostly used in old patients. Drugs may have local or
systemic actions after absorption.
Advantages:
• This route is preferred in unconscious or uncooperative
patients.
• This route avoids nausea or vomiting
• Drug cannot be destroyed by enzymes.
• This route is preferred if drug is irritant.
Disadvantages:
• This route is generally not acceptable by the patients.
Ex - Locally acting drugs include glycerin and
Bisacodyl suppository, Retention enema is
diagnostic and is used for finding the pathology of
lower intestines.

12. 2. PARENTERAL ROUTE :
Parenteral route includes: ( based on Site of release)
• Intra muscular
• Intra venous
• Intra-arterial
• Intra-cardiac
• Intra-thecal
• Intraosseous- into bone marrow
• Intrapleural
• Intraperitoneal
• Intra-articular
• Intradermal (Intracutaneous)
• Subcutaneous route (Hypodermic)

13.  Advantages:
 • Parenteral route is rapid.
 • It is useful for uncooperative patients
 • It is useful for unconscious patients
 • Inactivation by GIT enzymes is avoided
 • First pass effect is avoided
 • Bioavailability is 100%
 Disadvantages:
 • Skill is required
 • It is painful
 • This method is expensive
 • It is less safe.

14. a. Subcutaneous:
• Subcutaneous route might be used for the arm,
forearm, thigh.
• The volume used is 2 ml.
• Insoluble suspensions like insulin and solids might be
applied by this route.
Advantages:
• Absorption is slow and constant
• It is hygienic
Disadvantages:
• It might lead to abscess formation
• Absorption is limited by blood flow
Examples of drugs given by subcutaneous route
include insulin, adrenaline

15. b. Intramuscular route:
• Intramuscular route might be applied to the buttock,
thigh and deltoid.
• The volume used is 2-5 ml.
Advantages:
• Absorption is rapid than subcutaneous route.
• Oily preparations can be used.
• Irritative substances might be given
• Slow releasing drugs can be given by this route.
Disadvantages:
• Using this route might cause nerve or vein damage
• Trained person required

16. c. Intravenous injections:
• Intravenous injections might be applied to the cubital,
basilic and cephalic veins.
Advantages:
• Immediate action takes place
• This route is preferred in emergency situations
• This route is preferred for unconscious patients.
• Large volume of fluids might be injected by this route
• Diluted irritant might be injected
• Shows 100% bioavailability.
• No first pass effect takes place.
• Blood plasma or fluids might be injected.

17. Disadvantages:
• There is no retreat
• This method is more risky
• Sepsis-Infection might occur
• Phlebitis(Inflammation of the blood vessel) might
occur
• Infiltration of surrounding tissues might result.
• This method is not suitable for oily preparations
• This method is not suitable for insoluble preparations

18. d. Intradermal route:
• This route is mostly used for diagnostic purposes
and is involved in:
1.Schick test for Diphtheria
2.Dick test for Scarlet fever
3.Vaccines include DBT, BCG and polio
4.Sensitivity is to penicillin

20. e. Intraarterial route:
• This method is used for chemotherapy in cases of
malignant tumors and in angiography.
f. Intracardiac route:
• Injection can be applied to the left ventricle in case of
cardiac arrest.
g. Intrathecal route:
• Intrathecal route involves the subarachnoid space.
Injection may be applied for the lumbar puncture, for
spinal anesthesia and for diagnostic purposes. This
technique requires special precautions.

21. h. Intra-articular route:
• Intra-articular route involves injection into
the joint cavity. Corticosteroids may be
injected by this route in acute arthritis.
i. Intraperitoneal route:
• Intraperitoneal route may be used for peritoneal
dialysis.
j. Intrapleural route:
• Penicillin may be injected in cases of lung empyma by
intrapleural route.
k. Injection into bone marrow
• This route may be used for diagnostic or therapeutic
purposes.

23. Hypospray/Jet Injection:
• This method is needleless and is subcutaneous done
by applying pressure over the skin.
• The drug solution is retained under pressure in a
container called ‘gun’.
• It is held with nozzle against the skin.
• Pressure on the nozzle allows a fine jet of solution to
emerge with great force.
• The solution can penetrate the skin and
subcutaneous tissue to a variable depth as
determined by the pressure.
• Mass inoculation is possible but the method is
expensive, definite skills are required and cuts might
result.

25. 3. INHALATION :
• Inhalation may be the route of choice to avoid the systemic
effects. In this way drugs can pass directly to the lungs.
• Drugs used involve volatile drugs and gases.
Examples include aerosols like salbutamol; steam
inhalations include tincture and Benzoin
Advantages:
• Rapid absorption
• Rapid onset of action
• This route has minimum side effects.
• No first pass effect
• This method is easy.
• Fewer doses is required.
Disadvantages:
• Special apparatus is required.
• Irritation of the respiratory tract may take place.
• Cooperation of the patient is required.

26. 4.TOPICAL ROUTE :
Drugs may be applied to the external surfaces, the skin
and the mucous membranes. Topical route includes:
a. Enepidermic route
• When the drug is applied to the outer skin, it is called
enepidermic route of drug administration. Examples
include poultices, plasters, creams and ointments.
b. Epidermic route (Innunition):
• When the drug is rubbed into the skin, it is known as
epidermic route. Examples include different oils.
c. Insufflations:
• When drug in finely powdered form is blown into the
body cavities or spaces with special nebulizer, the
method is known as insufflations.

27. d. Instillation
• Liquids may be poured into the body by a dropper
into the conjunctival sac, ear, nose and wounds.
Solids may also be administered.
e. Irrigation or Douching
• This method is used for washing a cavity e.g.
urinary bladder, uterus, vagina and urethra. It is
also used for application of antiseptic drugs.
f. Painting/Swabbing
• Drugs are simply applied in the form of lotion on
cutaneous or mucosal surfaces of of buccal, nasal
cavity and other internal organs.

28. Advantages :
 Local therapeutic effects
 Not well absorbed into the deeper layers of the
skin or mucous membrane
lower risk of side effects
 Transdermal route offers steady level of drug in
the system
 sprays for inhalation through the nose may
be for local or systemic effects

29. Transdermal Patches :
 absorption of drug through skin (systemic action)
i. stable blood levels
ii. no first pass metabolism
iii. drug must be potent or patch
becomes too large

30. Time of Action using Different Routes
of
Administration
 Route of Drug Administration Delay time for
Action
 Intravenous route 30-60
seconds
 Intraosseous route 30-60
seconds
 Endotracheal inhalation 2-3 minutes
 Sublingual route 3-5 minutes
 Intramuscular route 10-20 minutes
 Rectal route 5-30 minutes
 Ingestion 30-90 minutes

31. THANKS
TO
ALL