1. ROUTES OF DRUGROUTES OF DRUG
ADMINISTRATIONADMINISTRATION

2. Formal Definition of DrugFormal Definition of Drug
 “A drug is a chemical which is used for
diagnosis, prevention and cure of a disease”
Routes of Administration of Drugs
Dugs can be given by various routes. The
goal is to deliver the drug to target organ or
tissue, so that it can exert its maximum effect

3. Major Routes
Enteral
Oral
Sublingual
Rectal
Parenteral
IV
IM
Subcutaneous
Inhalation
Intranasal
Intrathecal
Topical
Transdermal

4. ENTERAL ROUTE OFENTERAL ROUTE OF
ADMINISTRATIONADMINISTRATION
Oral
Sublingual Rectal

5. ORAL ROUTE OFORAL ROUTE OF
ADMINISTRATIONADMINISTRATION
By Mouth
FOR SYSTEMIC EFFECT:
Advantage:
Convenient Method
Disadvantages:
 Absorption may be delayed or enhanced after food
intake.
 Presence of food in stomach delays gastric emptying.
So drugs like penicillin, insulin and oxytocin are
destroyed in stomach by acids

6. FOR EFFECT IN THE GUT:
Advantage:
Drug is placed at the site of action and local
concentration can be higher than would be safe in
blood, e.g., Neomycin, Anthelminthics.

7. Disadvantages:
 Drug distribution may be uneven and in some
diseases the whole thickness of gut wall is affected, e.g., in
severe bacillary dysentery, typhoid.
 Drug passes through stomach, intestinal wall and
then through liver before it is transported via blood
stream to target organ. The intestinal wall and liver
metabolizes drug thus decreasing amount of drug
reaching the blood stream.
 EXAMPLES: Anthelminthics, Neomycin,Metronidazole,
Omeprazole

8. SUBLINGUAL ROUTESUBLINGUAL ROUTE
Drug is placed below the tongue. It is usually employed for
rapid absorption of drug in cases of emergency.
Advantages:
 Quick effect is obtained as the drug bypasses liver and
intestine and diffuses directly into capillary network.
 Effect can be terminated by spitting out the tablet.
 Prevents the destruction of drug by low pH and
enzymes in stomach.
Disadvantage:
Irritation of mucous membrane can occur.
EXAMPLES : Nitroglycerine, Isosorbide(angesid),
Nifidepine(antihypertensive)

9. RECTAL ROUTE
Drug is administered through anal canal. e.g.,
suppositories are inserted into rectum, enema.
Advantages:
 Rectal mucosa has a rich blood supply so the
drug is readily absorbed.
 Drugs irritant to stomach can be given by
suppository, e.g. aminophylline, indomethacin
 It is used in vomiting, motion sickness, in
children, comatose patients and post operative
patients.

10. Disadvantages:Disadvantages:
 PsychologicalPsychological
 Rectal inflammation may occur.Rectal inflammation may occur.
 Absorption may be unreliable if rectum isAbsorption may be unreliable if rectum is
full of fecal materialfull of fecal material..
 Examples: Aminophylline,Examples: Aminophylline,
Indomethacin, GlycerinIndomethacin, Glycerin
suppositories,Prostaglandinssuppositories,Prostaglandins

11. PARENTERAL ROUTE OFPARENTERAL ROUTE OF
ADMINISTRATIONADMINISTRATION
((It involves drug administration via injectionIt involves drug administration via injection
into a blood vessel, soft tissue or bodyinto a blood vessel, soft tissue or body
cavitycavity))

12. ADVANTAGES
 Used for drugs that are unstable in GIT.
 Under conditions which require a rapid onset of
action.
 In treatment of unconscious patients.
 Used for drugs that are poorly absorbed from
GIT.
 Provides maximum control over actual drug
delivered to body.

13. DISADVANTAGES
 Need of a technical staff
 Care of sepsis.
 Pain at the site of injection.
 Fear of needle.
 No retreat once the drug is injected.

14. INTRAVASCULAR ROUTE
 Intravenous – more common
 Intra-arterial - less common. It is dangerous
and has specific indications for diagnosis and
treatment, e.g. coronary angiography and
anticancer drugs

15. AdvantagesAdvantages
 Bypasses GIT and First pass metabolismBypasses GIT and First pass metabolism
 Gives swift, effective and highly predictableGives swift, effective and highly predictable
blood concentration of drug.blood concentration of drug.
 Suitable for administration of drugs that are notSuitable for administration of drugs that are not
absorbed from gut or are irritant to GITabsorbed from gut or are irritant to GIT

16. Disadvantages
 Unlike drugs in GIT, those that are injected
cannot be recalled by strategies such as emesis
or binding with charcoal.
 May introduce bacteria through contamination
at the site of injection.
 May induce hemolysis or other adverse reactions
by two rapid delivery of high concentration of
drug to plasma and tissues.

17. INTRAMUSCULAR ROUTE
 Drugs administered IM can be aqueous
solutions or specialized depot preparations
 This route is suitable for moderate volume
drugs, oily vehicles and less irritating substances
 Injections are given deep into skeletal muscles.
Most common sites are deltoid and gluteus
muscles.
 Example : Antibiotics and Analgesics

18. Advantage
 Reliable and suitable for irritant drugs and depot
preparations e.g. penicillin, neurolepticis and
medroxyprogesterone.

19. Disadvantages
 Not acceptable for self
administration
 May be painful

20. SUBCUTANEOUS ROUTE
 In it needle is inserted deep into the fatty tissue
just beneath the skin to produce slow and even
absorption of drug for sustained effect.
 Example: Insulin and Heparin.

21. Advantages:
 Minimizes the risk associated with IV injection
 Reliable and acceptable for self administration
Disadvantages:
 Repeated injections at one site can cause
lipoatrophy.
 Poor absorption in peripheral circulatory failure.