This document discusses routes of drug administration. It describes several factors that influence the choice of route, including the drug's properties, desired site of action, absorption rate, and patient condition. Systemic routes aim to distribute drugs through the bloodstream and include enteral (oral, sublingual, rectal) and parenteral (injections, inhalation, transdermal) routes. Local routes deliver high drug concentrations locally with minimal systemic absorption. Proper administration techniques are outlined for intramuscular and intravenous injections.

1. General PHARMACOLOGY
AMIT KUMAR
Assistant Prof.
Pharmacology

2. ROUTES OF DRUG ADMINISTRATION
 It is the path by which a drug is taken in to the body.
 Most drugs can be administered by more than one route
 Choice of route depends on drug as well as patient related factors

3. FACTORS GOVERNING CHOICE OF ROUTE
1. Physical & chemical properties of the drug
2. Site of desired action-localized/generalized
3. Rate & extent of absorption of drug by different routes
4. Effect on digestive juices & first pass metabolism on the drug
5. Rapidity with which response is desired ( routine treatment or
emergency )
6. Accuracy of dosage required
7. Condition of patient

4. ENTERAL
ROUTES
1. ORAL
2. SUBLINGUAL
3. RECTAL
PARENTERL
ROUTES
1. INJECTIONS
• I.M, I.V, S.C,
Intradermal,
Intraperitoneal,
Inthrathecal, Intra-
arterial.
1. INHALATIONAL
2. TRANSDREMAL
TOPICAL
ROUTES
1.TOPICAL
• Skin or dermal
• Conjunctival
• Nasal
• Auricular
• Uretheral
• Vaginal
• Intra-aerticular injections
SYSTEMIC ROUTE
ROUTES OF DRUG ADMINISTRATION

5. LOCAL ROUTES
 Used for localized lesions at accessible sites and for drugs whose
systemic absorption from these sites is minimal or absent.
 High concentration attained at the desired site without exposing
rest of the body

6. Topical
 External application of drugs (Skin & Mucus membrane
 Skin and dermal - application of the drug to the skin to treat local
disease (Powder, Cream, Ointment, Lotion, Paste, And Gels)

7.  Conjunctival – Many drugs are instilled in eye as eye drops.
 Desirable local effect within eye can be achieved without any systemic
side effect.
 e.g. Dorzolamide eye drop used as a eye drop in patients with
glaucoma.

8.  Nasal- drugs are instilled as nasal drops.
 e.g Xylometazoline nasal drop used in patients with common cold.

9.  Auricular - drugs are instilled into the ear canal
as ear drops.
 e.g. Ciprofloxacin ear drop used in otitis media.

10.  Urethral- urethral suppository is inserted directly into
the urethra.
 e.g. Alprostadil used in Erectile dysfunction as a urethral
suppository

11.  Vaginal- vaginal pessaries is inserted directly into the vagina.
 e.g.- Nystatin pessaries for vaginal candidiasis.

12.  Intra-articular Injection- Directly into joint space
 e.g . Hydrocortisone injection used for the treatment of
rheumatoid arthritis as intra-articular injection.

13. SYSTEMIC ROUTES
 Administered through systemic routes is intended to be absorbed
into the blood stream and distributed at the site of action through
circulation.
 Divided in to two parts
A. Enteral route
B. Paraenteral route

14. ENTERAL ROUTES
Oral- By mouth
 Advantages
• Can be self- administered, noninvasive, pain free, easy to take, does
not need assistance
• Absorption takes place along the whole length of the GI tract, both
solid & liquid dosage form can be given.
• Cheap compared to most other parenteral routes

15. Cont..
 Disadvantages
 Destruction of drugs by gastric acid and digestive juices
 Effect too slow for emergencies
 Unpalatable taste of some drugs
 May cause nausea & vomiting
 Unable to use in unconscious patient
 Absorption may be slow

16. SUBLINGUAL / BUCCAL ROUTE
 Some drugs placed under the tongue. E.g. GTN.
Advantages
 Quick onset of action due to rapid absorption
 Can be spilled out if effect observed
 Avoid first-pass effect, onset of action
Disadvantage
 Distasteful, irritant, lipid insoluble drugs cannot be given,
 Drugs with higher molecular weights are not well absorbed

17. RECTAL ROUTE
By ractum
Advantage
 Unconscious patients and children
 useful for gastric irritant drugs
 1st pass degradation is less, major portion of drug is absorbed from
external haemorrhoidal veins
Disadvantage
• Absorption may be variable
• Rectal inflammation can result from irritant drugs
• Diazepam, aminophylline, enemas

18. PARENTERAL ROUTES
 Advantage
 Administration of drug directly into the tissue fluid or blood.
 Drug action is faster
 Can be in unconscious patients
 Use in emergency
 Liver bypassed
Disadvantages
 Preparation has to be sterilized, so costly
 Invasive & painful
 Assistance of another person mostly needed

19. INTRAVENOUS ROUTE
Advantage
• Drug directly into the blood stream
• Bioavailability 100%
• Large volume of drug by this route
• Used in unconscious pt.
• Effects are produced immediately so used in emergency condition
• Highly irritant drug can be given
• Titration of the dose is possible
• Constant plasma level of drug can be maintained.

20. Contd..
Disadvantage
• Local irritant drug cause Thrombophlebitis & necrosis.
• Only aqueous solutions can be injected, no depot preparations
or oily preparation.
• However, this is most risky route-vital organs like heart, brain
etc get exposed to high concentration of drug
• Self administration not possible
• Strict aseptic condition are needed.

21. INTRAMUSCULAR ROUTE
Advantage
 Absorption is rapid as compared to oral & SC
 Drug is injected in one of the large skeletal muscles
 Suitable for depot preparations or mild irritant
Disadvantage
 aseptic condition needed
 Self injection is not possible due to need of deep penetration
 Large volumes cannot be administered.
 Pain full
Antibiotics , antiemetics and depot injection of testosterone, haloparidole

22. SUBCUTANEOUS ROUTE
Advantage
 Drug deposited in loose connective tissue, richly supplied by nerves
 Less vascular, absorption slower
 Self injection possible
 Depot preparations can be injected for prolonged action
Disadvantage
 suitable for only small volumes of drugs.(maximum 1 ml)
 Irritant drugs cannot be administered
 Not suitable in states of shock as reduced peripheral circulation decreases the
rate of absorption

23.  Intradermal route : injected in to epidermis, most common site
inner aspect of forearm.
 Injection of BCG or skin sensitivity test.

25. INTRA – ARTERIAL
 Into the lumen of the desired artery
Advantage
 Greater concentration of the drug can be give
Disadvantage
 Expert hand needed
 Aseptic condition required
 High risk of systemic side effect and toxicity
 Painful
Eg. Coronary angiography , cerebral angiography

26. INTRATHECAL ROUTE
 Into the subarachnoid space.
Advantages
 Drug after diffusing from the lumber sac passes into the subarachnoid space,
bypassing the BBB.
Disadvantages
 Strict aseptic conditions are required & great expertise needed
 Painful & risky procedure
 Eg: Xylocaine injection for spinal anesthesia; antibiotics for infectious
meningitis.

27. Contd.
INTRACARDIAC INJECTION
 1 cm to the left of the xiphoid, needle may also be inserted in the left
fourth or fifth intercostal space
 Eg: adrenaline injection in cardiac arrest

28. EPIDURAL INJECTION
 Drug is injected Epidural space.
 Eg: Xylocaine injection to provide epidural nerve block

29. INHALATION
Advantages
 Rapid onset of action due to rapid access to circulation
a) large surface area of alveoli
b) high blood flow
 Controlled administration is possible with moment to moment adjustment
and can be self administered
Disadvantages
 Increase bronchial irritation can lead to increase bronchial secretion and
salivary secretion
Eg . Oxygen, general anaesthesia, metered dose inhaler , nebulizer.

30. Inhalation

31. TRANSDERMAL
 This route considered under parenteral route because the patches, though
applied topically and provide the systemic effects.
Advantages
 Highly lipid soluble drugs
 Adhesive patch applied to chest, upper abdomen or mastoid region
 Slow but sustained release of drug for several days
 Bypass 1st pass metabolism
Disadvantages
 Cause irritation at the site of application
E.g. . Nitroglycerine , scopolamine for motion sickness , clonidine for
hypertension

32. Transdermal therapeutic system
 Devices, adhesive patches, various shapes & sizes (5-20 cm2 )
 Deliver the contained drug at the skin surface by diffusion for
percutaneous absorption into circulation
 Rate of drug delivery is less than the slowest rate of absorption from
skin
 Offsets any variation in the rate of absorption from different sites
 Sites- chest, abdomen, upper arm, lower back, buttock or mastoid
region

34. Contd.
 GTN, fentanyl, nicotine, estradiol- available in India
 Isosorbide di nitrate, hyoscine, clonidine, not in India
 Constant & smooth plasma concentration for 1-7 days without
fluctuations
 Local irritation & erythema may occur
 Can be minimized by changing the sites

36. Steps of IM Injection
 Gather all needed supplies- needle and syringe with medication, alcohol pads, gauze,
bandages
 Wash your hands- Wash your hands with soap and warm water to prevent potential
infection. inject
 Load injection and remove bubble
 Select injection site- To isolate the muscle and target where you’ll place the injection
 Position and drape appropriately
 Gently tap to the muscle (To stimulate t he nerve ending and minimize pain)
 Clean injection site- Clean the site selected for injection with an alcohol swab by moving
in circle allow the skin to air dry.
 Put on gloves then gently stretch the skin
 Remove the needle seath
 Insert the needle in to muscle
 Check for blood
 Remove needle at same angle
 Apply gentle pressure to the site with the used alcohol swab
 Discard all equipment properly
 Wash your hands again

37. Steps for I.V.
 Gather all needed supplies- needle and syringe with medication, alcohol pads, gauze,
bandages
 Wash your hands- Wash your hands with soap and warm water to prevent potential
infection. inject
 Load injection and remove bubble
 Select vein
 Position and drape appropriately
 Apply a tourniquet
 Clean injection site- with alcohol swab by moving in circle allow the skin to air dry.
 Put on gloves
 Remove needle seath
 Insert the needle
 Check for blood
 Inject the medication
 Discard all equipment properly
 Wash your hands again


38. Thank you