Routes of Drug Administration

1
Routes of Drug Administration
2
Factors Deciding Choice ofRoute

• Type of described effect, systemic or local
• Physiochemical properties, solid or insoluble
• Rapidity of effect
• Quality of effect
• Condition of patient, conscious or unconscious,
  vomiting

3
Drug Administration
Topical/Local Administration
Systemic Administration
Mucus Membrane
Enteral
Parenteral
Skin
Inhalation
4
Systemic Routes

• Enteral through GIT
• Orally
• Buccal or sublingual
• Rectal
• Parental
• Intravenous (IV)
• Intramuscular (IM)
• Subcutaneous (SC)

5
Enteral Route
6
Oral Administration

• Via mouth
• Tablets, capsules, powder, syrup, mixture
  suspension or emulsion

7
Advantages of oral route

• Convenience and patient comfort
• Safety, since medication can be retrieved in case
  of error or intentional overdose
• Economy, since there are few equipment cost

8
Disadvantages of oral route

• Slower onset of absorption and action
• Rate and degree of absorption vary with
  gastrointestinal contents and motility
• Some drugs destroyed by digestive fluids and must
  be administered by injection
• Cannot be used with nausea or vomiting
• Dangerous to use if patient has dysphagia, due to
  the possibility of aspiration

9

• Cannot be used for unconscious patients
• Cannot be use for patients who should keep nil by
  oral

10
Absorption from stomach and upper intestine is
affected by-

• Surface area
• Blood flow to site of absorption
• Physical state solid, solution, suspension
• Water solubility
• Concentration at the site of absorption
• Rate of dissolution
• Rate of disintegration
• Particle size

11
Via Nasogastric tube/Gastric tube

• For the patients unable to swallow
• Advantages ability to bypass mouth and pharynx
  when necessary , elimination of numerous
  injections
• Disadvantages discomfort specially for the
  conscious patients

12
Buccal or sublingual Route

• Buccal medication placed in the pouch between
  the cheek and the gum
• Sublingual under the tongue
• Advantages directly absorb to the circulation
  and rapid action
• Disadvantage misunderstanding of the way of use

13
Rectal Route

• For the patients having nausea and vomiting or
  patients who are unable to swallow
• Advantages bypassing the action of digestive
  enzymes
• Avoidance of irritation to the upper GI tract

14
Disadvantages of Rectal route

• Many medications are unavailable in suppository
  form
• Prolonged use of rectal suppositories can cause
  rectal irritation
• Absorption may be irregular or incomplete if
  feces are present
• Inconvenient embarrassing
• Rectal inflammation occurs

15
Parenteral Administration
16
Parenteral Administration

• Intravenous
• Intramuscular
• Subcutaneous
• Intradermal
• Intrathecal
• Intraarterial
• Intra articular

17
Intravenous Route

• Drug administration directly to the vein
• Direct injection
• Bolus
• Infusion

18
Advantages of Intravenous Route

• Immediate effects
• Valuable for emergency use
• Suitable for large volume
• Complete bioavailability

19
Disadvantages of Intravenous Route

• Not suitable for oily solutions insoluble
  substances
• Drug administered cannot be withdrawn
• Thrombophlebitis occurs at injection site
• Lack of sterility may cause viral hepatitis
• or AIDS
• Increased risk of adverse drug reactions
• Time and skill required for venipuncture

20

• Difficulty of maintaining IV line
• Complications of IV therapy bleeding, infection
  and fluid overload

21
Intramuscular Route ( IM)

• Injections of drugs into certain muscles
• Usually doses 3ml or less
• IM injection
• Depot preparation
• Absorption depends upon rate of blood flow to the
  injection site
• Rapid action compared to SC route
• Slow releasing compared to IV route

22

• Advantages can be use to administer solutions
  or suspensions
• Slow, sustained effect from depot preparation
• Disadvantages incorrect placement of the needle
  may damage blood vessels or nerves
• Pain
• Abscess formation
• Avoid during anticoagulant therapy

23
Subcutaneous Route (SC)

• Injection of drugs under the skin
• Use for highly soluble, non irritating, small
  volume of drug about 1ml or less
• Absorption is slower and the drug action is
  generally longer with SC injections than with IV
  or IM injections
• Advantages Slow absorption and distribution

24

• Disadvantages tissue damage, tissue necrosis and
  sterile abscess formation
• Only nonirritant drugs
• Not suitable for large volume

25
Intraarterial Route

• Direct injection into artery
• Localization of effect in particular tissue or
  organ
• Advantages Diagnostics agents
• Disadvantages Reserved route for experts

26
Intrathecal Route

• Injections into cerebrospinal fluid
• Blood Brain Barrier Blood CSF Barrier slow drug
  entry into CNS
• Used when local and rapid effects of drugs on
  the meninges or cerebrospinal axis desired

27
Intradermal Route

• Injection into skin layers
• Uses BCG, Small pox vaccination
• Testing drug sensitivity- Penicillin's
• Tuberculin test

28
Intraarticular Route

• Drug administration directly to the joint
• Usually local effect
• Uses Rheumatology disorders

29
Topical Application- MucousMembrane

• Conjunctiva, nasopharynx, oropharynx, vagina,
  urethra, urinary bladder, ear, nose, anal canal
  for local effects
• Ointment, cream, drops, jelly, powder, tablet,
  suppository, pessary, sprays, gargles

30
Topical Application- Skin

• Absorption depends on surface area of
  application, lipid solubility
• Few drugs readily penetrate skin
• Burned, denuded, abraded, inflammation increase
  systemic absorption
• Controlled- release topical patches

31

• Advantages Absorption rapid
• Only local effect
• Disadvantages Toxicity by highly lipid soluble
  substances

32
Inhalation
33
Inhalation

• Via inhaler
• Via nebulizer
• Medication directly to the respiratory system

34
Advantages of Inhalation

• Rapid action of the drug, with local effects with
  in the respiratory tract
• Potent drugs may be given in small amounts,
  minimizing the side effects
• Convenience and comfort of the patient

35
Disadvantages of Inhalation

• Requires cooperation of the patient in proper
  breathing techniques for effectiveness
• Adverse systemic side effects may result rapidly
  because of extensive absorption capacity of the
  lungs
• Improperly administered or too frequently
  administered, inhalation can lead to irritation
  of the trachea or bronchi or bronchospasm

36

• If not clean properly nebulizers can be a source
  of infection

37
Thank you.