Routes of drug administration refer to the paths through which drugs can be delivered into the body. The main routes discussed are oral, parenteral (subcutaneous, intramuscular, intravenous), rectal, inhalation, and local application. Factors like drug properties, patient factors, and desired therapeutic effect determine the optimal route. The oral route is most common due to convenience but other routes are needed for unstable, irritant drugs or unconscious patients.
2. Introduction:
Routes of drug administration refer to the right path or the
required route through which a drug has to be administered
into the body to obtain maximum benefit.
Factors affecting the choice of route:
- Drug related
- Patient related (unconscious, uncooperative, vomiting)
- Therapeutic action desired (local, systemic)
3.
4. ORAL ROUTE:
Most common route of drug administration.
Drug which are absorbable and stable in GIT are given by this
route.
Drug which are not absorbable; which are destroyed in GIT;
Which are destroyed during portal circulation after absorption
(having high first pass metabolism)and drugs which are irritant
cannot given by this route.
Majority of drugs produce systemic effects, except a few which
are administered for local effect e.g. antacids and antidiarrhoeal
drugs like norfloxacin, streptomycin, phthlyl-sulfathiazole, pectin
and kaolin.
5. Oral Route: Advantages
Convenient
Economical
No complications of parenteral therapy
Dose adjustment is easy.
Self administration is possible.
6. Oral Route: Disadvantages
Slower onset of actions.
Highly polar drugs like Aminoglycosides- streptomycin or quaternary salts like d-tubocurarine
and suxamethonium : not absorbed.
Drugs like Penicillin-G, insulin, oxytocin and testosterone are destroyed by gastric juices.
Drugs with high first pass effect e.g. morphine, isoprenaline.
Palatability of drugs is essential.
Cannot be used in non-cooperative unconscious patients and patient having vomiting and
diarrhea.
7. SUBLINGUAL ROUTE:
Tablet is
placed under
tongue
Crosses
buccal
mucosa
Enters into
systemic
circulation
The tablet is kept underneath the tongue and drug is allowed to get absorbed.
8. SUBLINGUAL ROUTE:
Advantages Of Sublingual Route
Rapid onset of action
Quick termination on spitting
No degradation in stomach
No degradation in intestinal wall and liver.
9. SUBLINGUAL ROUTE:
Disadvantages Of Sublingual Route
Irritant drugs can not be given.
Drugs with high molecular weight can not be given e.g. insulin
Examples:
• Isosorbide dinitrate, nitroglycerine: angina
• Isoprenaline: asthma
• Nifedipine: hypertension
10. Buccal Route:
The drug is kept in the buccal cavity where it disintegrates and
absorption occurs in the mouth.
12. Advantages
No GI irritation
First pass
degradation is
largly bypassed.
Examples
Indomethacin in
rheumatoid
arthritis
Aminophylline
in bronchial
asthma
Diazepam in
status
epilepticus
Dulolax
suppositories
NSAIDS–
Suppository post
operative
Disadvantage
All patients
may not be
comfortable/
willing to do it.
15. 15
Intra-dermal Route
Site: drug is injected into the dermal layers of the skin
Demerits
Only small amount of
drug can be given.
0.1ml-adult
0.05ml-infants
Absorption is slow.
Examples
BCG vaccine
Penicillin sensitivity
testing
16. 16
Subcutaneous Route
Site: injection into the subcutaneous tissue
Merits
Demerits
Examples
Smooth but slower
absorption over
longer period
Only small volume can be given (max 2-3 ml)
Not suitable in shock as reduced peripheral circulation decreases rate of
absorption.
• Vaccines
• Local anaesthetics
for local action
• Insulin for systemic
action.
17. 17
Hypodermoclysis
It is a form of subcutaneous injection in which large amounts
of (500 to 1000 ml in adults) of fluids such as normal saline or 5
% dextrose is slowly administered in the patients
• Extremely beneficial for infants and children to treat dehydration.
• Precaution: prevent too rapid injections- circulatory overload.
e.g. normal saline,
hyalluronidase in treatment of
ganglions.
18. Site : deltoid muscle or gluteal mass of right or
left buttock, vastus muscle over lateral side of
thigh.
e.g. depot preparation of testosterone and
neuroleptics like haloperidol.
Intramuscular Route
18
19. Demerits
Merits
Absorption is more predictable
Depot injections can be given.
Aseptic conditions are required
Abscess formation
Nerve damage
Large volume can not be administered. (max 5-10 ml)
19
20. Site : through the lumen of the vein, mainly the antecubital vein.
Types:
◦ Bolus injection: initial large dose is given
E.g. corticosteroids
◦ Rapid i.v. injection
E.g. adenosine
◦ Slow i.v. injections: over 10-15 min
E.g. aminophylline
◦ I.V. infusions: 1-8 hrs or more
Dopamine, dobutamine.
Intravenous Route
20
21. Merits
Quick onset
of action
Useful in nausea
and vomiting
Lesser dose
required
Useful in
unconscious &
uncooperative pts.
Hypertonic solutions
and GIT irritant drugs
can be given
Large volume –
uniform rate
Amount –
controlled
21
22. Site : into the peritoneal space.
Intraperitoneal Route
Merits
Demerits
22
Rapid absorption due to larger
surface area
Risky – chances of adhesions and infections (peritonitis)
Examples
Anti- rabies serum
Peritoneal dialysis
23. Site : into the Subarachnoid space(L3-L4).
23
Intrathecal (intraspinal) Route
Bypasses Blood-brain and
blood-CSF barrier
Merits
Demerits
Strict aseptic conditions required
• Radiopaque contrast
media for myelography
• Xylocaine injection for
spinal anasthesia
Examples
Chances of infection: Meningitis
Post-spinal headache, nausea ,vomitting
C/I Raised ICT
24. 24
Intramedullary Route
Site: injection into the tibial or sternal bone marrow
Merits
Demerits
Examples
Very fast onset of action
Very painful
• Bone marrow
transplantation
• Blood transfusion in
children
25. 25
Intra-arterial Route
Merits
Demerits
Examples
Site: into the lumen of desired artery
Greater concentration of drug can be
administered
• Radiopaque contrast
media for contrast
angiography & cerebral
angiography.
• Anticancer drugs like
nitrogen mustard can be
perfused to treat the
malignancy involving
limbs.
Strict aseptic conditions required
Chances of spread of infection
directly into bloodstream.
26. 26
Intra-articular Route
Site: injection directly into the joint space
Merits
Demerits
Ensures higher concentration of
drug into localized area
Damage to joint due to repeated
injections
Examples
• Rheumatoid arthritis :
Hydrocortisone and gold
chloride
27. 27
Inhalatational Route
Site: inspiration through nose or mouth
Merits
Demerits
Examples
• Larger surface area of alveoli
Faster absorption quick
onset of action
• Self administration possible.
Bronchial irritation increased bronchial
and salivary secretion
• Metered aerosol
preparation of salbutamol:
treatment Bronchial asthma
• Sodium chromoglycate :
prophylaxis of Bronchial
asthma (local effect)
• Oxygen and general anesthetics
( systemic effect)
29. 29
Intra-cardiac Route
The injection is given by a long needle into the heart
through the left 4th ICS in midclavicular line.
Adrenaline : in cardiac arrest
30. 30
Epidural Route
Site: through a vertebral interspace between the dura of the
spinal cord and the lining of the spinal canal.
Xylocaine: epidural nerve block
31. DR RUSHIKESH DESHPANDE, DR V M MOTGHARE 31
Topical Routes
• Transdermal patches
• Conjunctival
• Vaginal & Urethral
• Inunction
32. DR RUSHIKESH DESHPANDE, DR V M MOTGHARE 32
Trans-dermal Route
Site: adhesive matrix (patch)
containing the drug applied to chest,
upper abdomen or mastoid region.
Merits
Slow but sustained release of
drug over a period of days
Examples
Nitroglycerine : angina
Scopolamine : motion sickness
Clonidine: hypertension
Estradiol: menopausal syndrome
33. 33
Conjunctival Route
Site: drugs are instilled onto the conjunctiva.
Examples
Sulfacetamide
Chloramphenicol
Gentamicin
Ciprofloxacin
Occuserts Lacriserts
34. 34
Vaginal & Urethral Route
Solutions, ointments, emulsion, foams, tablets,
suppositories and pessaries are used for this route
Examples
Antifungal drugs
Metronidazole
•Pessary
Solid medicated preparation designed for
insertion into the vagina.
Solid medicated preparation designed
for insertion into the rectum.
• Suppository
• Bougie
Solid medicated preparation designed for insertion into
the urethra.
36. DR RUSHIKESH DESHPANDE, DR V M MOTGHARE 36
Inunction (Rubbing)
Site: rubbing the drug preparation onto the surface of skin.
Merits
Demerits
Safe and convenient
Difficulty in ascertaining the amount of drug given
Systemic absorption can take place
Examples
Turpentine liniment
38. Advantages of local route
Fast onset of
action
Better
concentration
at site of
action
Less quantity
is required.
Less systemic
ADR.
Disadvantages of local
route
Not always
possible to
apply a drug
locally
Local
irritation
Sometimes
systemic
absorption
and toxicity
can occur
39. ENEMA
EVACUANT ENEMA
•For evacuation of large bowel.
•Warm water, soap solutions, glycerin can be
given.
•Amount ~ 600 ml.
•Used for
– Constipation
– Pre-op preperation
– Before radiological examination.
RETENTION ENEMA
•Local action
– Steroids in ulcerative colitis.
•Systemic action
– Diazepam in status epilepticus
– Indomethacin in RA.
•Amount ~ 100-120 ml.
Causes
evacuation
Should be
retained
for action
40. Same drug different route different actiondifferent
therapeutic indications.
E.g magnesium sulphate, N acetyl cysteine, absolute alcohol.
Action of Magnesium Sulphate.
Oral Saline laxative
Rectally Reduces Intra cranial
tension
Injection
I.M. I.V.
Anticonvulsant Tocolytic
Topical Hygroscopic ,reduces
LOCAL edema
41. INTRAVENOUS INJECTION:
Introduction of drug directly into the bloodstream is called intravenous injection
Common Sites for IV Injection:
Ventral aspect of elbow or forearm median cubical, basilica or cephalic veins
Doral aspect of hand – branchial, cephalic or metacarpal veins
Editor's Notes
Peculiar route for the drugs undergoing high first pass metabolism.
Vaccines prefered by this route as the active protein reaches the lymphatic tissue directly.
Very fast onset of action due as the vascular spaces of bone marrow communicate directly with large veins.
