Routes of Drug Administration
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Transcript Routes of Drug Administration
Routes of Drug Administration
Factors Deciding Choice of
Route
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
Drug Administration
Topical/Local
Administration
Mucus
Membrane
Skin
Inhalation
Systemic
Administration
Enteral
Parenteral
Systemic Routes
Enteral through GIT
Orally
Buccal or sublingual
Rectal
Parental
Intravenous (IV)
Intramuscular (IM)
Subcutaneous (SC)
Enteral Route
Oral Administration
Via mouth
Tablets, capsules, powder, syrup, mixture suspension or
emulsion
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
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
Cannot be used for unconscious patients
Cannot be use for patients who should keep nil by oral
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
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
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
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
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
Parenteral Administration
Parenteral Administration
Intravenous
Intramuscular
Subcutaneous
Intradermal
Intrathecal
Intraarterial
Intra articular
Intravenous Route
Drug administration directly to the vein
Direct injection
Bolus
Infusion
Advantages of Intravenous Route
Immediate effects
Valuable for emergency use
Suitable for large volume
Complete bioavailability
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
Difficulty of maintaining IV line
Complications of IV therapy – bleeding, infection and fluid
overload
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
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
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
Disadvantages: tissue damage, tissue necrosis and sterile abscess
formation
Only nonirritant drugs
Not suitable for large volume
Intraarterial Route
Direct injection into artery
Localization of effect in particular tissue or organ
Advantages: Diagnostics agents
Disadvantages: Reserved route for experts
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
Intradermal Route
Injection into skin layers
Uses: BCG, Small pox vaccination
Testing drug sensitivity- Penicillin's
Tuberculin test
Intraarticular Route
Drug administration directly to the joint
Usually local effect
Uses: Rheumatology disorders
Topical Application- Mucous
Membrane
Conjunctiva, nasopharynx, oropharynx, vagina, urethra,
urinary bladder, ear, nose, anal canal for local effects
Ointment, cream, drops, jelly, powder, tablet, suppository,
pessary, sprays, gargles
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
Advantages: Absorption rapid
Only local effect
Disadvantages: Toxicity by highly lipid soluble substances
Inhalation
Inhalation
Via inhaler
Via nebulizer
Medication directly to the respiratory system
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
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
If not clean properly nebulizers can be a source of infection
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