Different routes of drug administration, oral, parenteral, topical, their advantages and disadvantages

1. 1
Routes of Drug
Administration
By:
Dr. Faraza Javaid

2. Pharmacology
Derived from two Greek words:
Pharmakon (drugs) and Logos (science).
It is the study of the actions of drugs on living system.
It includes:
 Biochemical and Physiological effects,
 Mechanism of action
 Therapeutic uses
 Adverse effects of drugs.

3. As per WHO Scientific group
“Any Substance or product that is used and intended to
be used to modify or explore the physiological system or
pathological state for the benefit of the recipient “

7. Routes of Drug Administration
Methods by which a drug is given to a
person
Types:
A) Enteral
B) Parenteral
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8. A) Enteral Route
Administration of drugs through GIT
Types:
 Oral
 Sublingual
 Rectal
 Buccal
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9. 1) Oral Route
Drug is taken in mouth and swallowed by
water or other fluid
Advantages:
 Most commonly used
 Convenient
 Economical
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10. Disadvantages of Oral route
 Requires cooperation of patient
 Bad taste or bad smell=vomiting e.g., quinine
(bitter taste); castor oil (bad smell)
 Irritation on gastric mucosa
e.g., aspirin irritation of stomach
 Destruction of drug by digestive enzymes,
e.g., benzyl penicillin, insulin
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11.  Metabolism of drug during its absorption c/d
first pass effect or first pass metabolism
e.g. antiviral drugs.
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12. 2) Sublingual Route
Drugs kept under tongue  rapid absorption and
quick effect e.g., nitroglycerin
Advantages:
 Quick absorption= rapid effect
 No first pass effect
 Economical & no need of
other person
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13. Disadvantages of sublingual route
 Cant be used in vomiting
 Cant be used in unconscious person
 Irritation of oral mucosa with excessive saliva
formation = swallowing of drug
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14. 3) Rectal Route
 Solid drug administration into rectum=
Suppository,
 Liquid drug administration into rectum=
Enema
 For local or systemic effect, e.g. corticosteroids
(local), indomethacin (systemic)
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15. Advantages of Rectal route
 Used in unconscious
 Used in vomiting
 Uncooperative child
 For drug causing irritation of stomach e.g.,
indomethacin & aminophylline
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16. Disadvantages of rectal route
 Repeated use cause irritation & inflammation
of rectal mucosa
 Unpredictable absorption
 First pass hepatic metabolism (portal
circulation)
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17. 4)BUCCAL ROUTE
 Buccal
administration is
where the dosage
form is placed
between gums and
inner lining of the
cheek (buccal
pouch)

18. BUCCAL ROUTE
ADVANTAGES
–Avoid first pass effect
–Rapid absorption
–Drug stability
DISADVANTAGES
–Inconvenience
– advantages lost if
swallowed
–Small dose limit

19. B) Parenteral Route
Administration of drugs by routes other
than GIT
Types:
1) Injectables (most often)
2) Inhalations
3) Topical/Local
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20. 1) Injections
Administration of drug with special
instrument (syringe or infusion apparatus)
Types:
Intravenous (I.V.)
Intramuscular (I.M.)
Subcutaneous (S.C.)
Intrathecal (I.T.)
Intra-articular (I.A.)
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21. Intravenous route
 Injection of drug into peripheral vein
 Quick effect
 For short duration of drugs & for large
quantities of drugs (normal saline, dextrose sol.)
Methods:
a) Bolus injection (vein by syringe)
b) Infusion (apparatus)
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22. Advantages of Intravenous Route
 Use in emergency (rapid effect)
 Highly effective & reliable route
 Bioavailability =100%
 Rate of infusion of drug can be controlled
according to response of patient
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23. Disadvantages of intravenous route
 Requires help of technical person
 Proper aseptic precautions
 Serious adverse or toxic effect can occur
 Some drugs can cause irritation of vein wall
e.g., diazepam
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24. Intramuscular route
 Direct injection of drug into skin muscle by
syringe e.g. of muscles; Deltoid, gluteus
maximus.
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25. Advantages of IM route
 Reliable route
 Effect= 10-30 min
 Rate of abs. rapid than S.C.
 Depot preparation, prolonged period
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26. Disadvantages of IM route
 Trained person
 Proper aseptic precaution
 Irritation of skin muscles by some drugs e.g.,
penicillin
 Use of drug in limited amount
 No removal of drug from site of injection
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27. Subcutaneous route
Injection of drug beneath the skin
Slow abs. than I.M.
Advantages:
Self injection possible
Reliable route
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28. Disadvantages of S.C. Route
 Poor absorption
 Repeated injections
resulted in atrophy of SC
fat, hence, irregular
absorption e.g. insulin
 Irritation of subcutaneous
tissue
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30. Inhalation
Inhalation = lungs  alveoli  sys circ.
Types:
a) Gas Inhalation = GA (halothane, enflurane)
b) Aerosol Inhalation = Drug particles suspended in
gas (inhalers) e.g., salbutamol, terbutaline,
ipratropium, corticosteroids
c) Powder Inhalation = Fine powder of drug inhaled
by spinhaler, e.g., sodium chromoglycate
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32. Advantages
 Rapid absorption from lungs (GA) = controlled
administration
 Minimum systemic effects by aerosols &
powders
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33. Disadvantages of Inhalations
 Requirement of special apparatus for inhalation
 Improper handling of apparatus
 Obstruction of bronchial tree with mucous
 Irritation of bronchial tree
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34. Topical Route
External application of drug to surface for
localized action
E.g., skin, eye, ear, nose, oral cavity, vagina,
rectum & urinary bladder
Drug formulation = ointment, cream, lotion,
paste, powder e.g., Nitroglycerin (Patches on
skin)
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36. Advantages:
 High local conc. without systemic effect
 Patient can use easily
Disadvantages:
 Local allergic reaction e.g., antibiotics
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38.  intravenous
 intraosseous
 inhalation
 sublingual
 intramuscular
 subcutaneous
 rectal
 ingestion
 transdermal (topical)
30-60 seconds
30-60 seconds
2-3 minutes
3-5 minutes
10-20 minutes
15-30 minutes
5-30 minutes
30-90 minutes
variable (minutes to hours)
Route for administration
-Time until effect-

39. Intradermal Injection
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40. Intrathecal Injections
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41. Intraarticular Injection
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42. Intraosseous Injection
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43. Intraperitoneal Injections
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44. Intracardiac Injections
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45. Assignment??????
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