Routes of drug administration
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Transcript of Routes of drug administration
ROUTES OF DRUG ADMINISTRATION
ADITHIYAN UDAYASANKAR
CONTENTS
O TYPES
O EXAMPLES
O FEW PICTURES
O ADVANTAGES
O DISADVANTAGES
O REFERENCE
DEFINITION OF DRUG
ODrug is any substance or
product that is used or is
intended to be used to
modify or explore
physiological systems or
pathological states for the
benefit of the recipient.
ROUTES OF ADMINISTRATION
OThe route of administration is
determined primarily by the properties
of the drug (for eg: water or lipid
solubility ,ionization) and by the
therapeutic objectives (eg: rapid onset
of action ,need for long term
treatment, or restriction of delivery to
a local site).
CLASSIFICATION OF ROUTES
LOCAL ACTION
SYSTEMIC ACTION
LOCAL ACTION
O Routes can be used for localized lesions
at accessible sites and for drugs whose
systemic absorption is minimal or absent.
O Thus high concentration are attained at
desired site without exposing the rest of
the body.
O E.g: glyceryl tri nitrate(GTN) applied on
the skin as ointment or transdermal patch.
TYPES
TOPICAL
DEEPER TISSUE
ARTERIAL SUPPLY
TOPICAL
O External application of the drug to the surface for localized action .
O It’s more convenient as well as encouraging to the patient.
O Drugs can be efficiently delivered to the localized lesions on skin, eyes, nasal mucosa in form of lotion, ointment, cream ,spray and lozengens.
O Clotrimazole is applied to skin in treatment of dermaphytosis.
DEEPER TISSUE
OCertain deep areas can be
approached by using a syringe and
needle , but the drug should be in a
form that systemic absorption is
slow.
OE.g: intra-articular injection i.e
hydrocortisone acetate in knee joint
, intrathecal injection ( lidocaine).
ARTERIAL SUPPLY
OIntra-arterial injection is used
for contrast media in
angiography .
OAnti cancer drugs can be
infused in femoral or brachial
artery to localise the effect for
limb malignancies.
SYSTEMIC ROUTES
The drug administered through systemic routes is intended to be absorbed into the blood stream and distributed all over, incl. the site of action.
Types
Systemic routes
oral
sublingual
Rectal
Cutaneous
Inhalation
Nasal
parenteral
ORAL
O Oldest and commonest mode of drug
administration.
O Solid dosage forms- powders , tablets,
capsules ,spansules .
O Liquid dosage forms – syrups, emulsions
and mixtures.
O 2 types
1. Enteric coated preparation
2. Extended release preparation
Enteric coated prepn.
OAn enteric coating is a
chemical envelope that
resists the action of the
fluids and enzymes in
stomach but dissolves in
u.i.t.
OE.g : omeprazole
Extended release prepn.
OExtended release medications have
special coatings or ingredients that
control how fast the drug is released
from the pill into the body.
OHaving a longer duration of action
may improve patient compliance
because the drug doesn’t have to
be taken often.
Oral-adv.&disadv.
Advantages
• Safest and most common , convenient, and economical route of administration
Disadvantages
• Limited absorption of some drugs.
• Food may affect absorption
• Drugs may be metabolized before systemic absorption
SUBLINGUAL
OTablet or pellet containing the
drug is placed under tongue or
crushed in the mouth and
spread over the buccal
mucosa.
ODrugs given sublingually are –
GTN, buprenorphrine ,
desamino-oxytocin.
S.L.-adv.&disadv.
Advantages
Bypasses first pass effect
Bypasses destruction by stomach acid
Disadvantages
Limited to certain types
of drugs
May lose part of the drug if swallowed
RECTAL
OCertain irritant & unpleasant
drugs can be put into rectum as
suppositories or retention
enema.
OE.g: diazepam ,indomethacin ,
paracetamol, ergotamine are
sometimes given rectally.
Rectal- adv.&disadv.
Advantages• Ideal if drug causes vomitting
• Ideal in patients who are comatose
Disadvantages• May irritate the rectal mucosa
• Not a well accepted route
INHALATION
OVolatile liquids and gases are given
by inhalation for systemic action.
OE.g: general anaesthetics and
coricosteroids such as fluticasone
OAbsorption takes place from the
vast of alveoli- action is very rapid.
Inhaln.-adv. & disadv.
Advantages
• Ideal for gases
• Dose can be titrated
• Fewer systemic side effects
Disadvantages
• Most addictive route
• Patient may have difficulty regulating dose
NASAL
OMucous membrane of the nose can readily absorb many drugs .
OE.g: desmopressin applied as a spray or nebulized solution have been used by this route.
ONasal decongestants such as oxymetazoline.
CUTANEOUS
O Highly lipid soluble can be applied over
the skin for slow and prolonged
absorption.
O The drug can be incorporated in an
ointment or in form of transdermal
therapeutic patches.
O Transdermal patches of GTN, fentanyl ,
nicotine and estradiol.
O TTS have designed to last for 1-3 days.
PARENTERAL
O It refers to administration by injection which takes the drug directly into the tissue fluid or blood without having to cross the enteral mucosa.
O Drug action is faster and surer .
O No gastric irritation or vommiting .
O Parenteral routes can be employed in unconsciousness , uncooperative .
O E.g: insulin injection
Parenteral- types
Par-beyond enteral-intestinal
Subcutaneous
Intramuscular
Intravenous
Intradermal injections
SUBCUTANEOUS
O The drug is deposited in the loose
connective tissue which is richly supplied
by nerves but is less vascular.
O 3 forms
1) Dermojet
2) Pellet implantation
3) Sialistic and biodegradable implants
Contd.O Dermojet : needle isn’t used. A high
velocity jet of drug soln. is projected from
a microfine orifice using a gun like
implement.
O Pellet implantation : drug is in the form of
a solid pellet is introduced with a trochar
and cannula. e.g: DOCA ,testosterone
O Sialistic & biodegradable implants:
crystalline drug is packed in tubes or
capsules made of suitable materials &
implanted under the skin. E.g; norplant
INTRAMUSCULAR
O The drug is injected in one of the large
skeletal muscles – deltoid , triceps
,gluteus maximus etc.
O E.g: Depot medroxyprogesterone,
haloperidol .
O Adv: suitable for oily vehicles and irritating
substances .
O Disadv: painful
Intra venous
OThe drug is injected as bolus or
infused slowly over hours in
one of the superficial veins.
OBioavailabity is 100%.
OMost common parenteral route
.
OE.g: sodium nitroprusside ,
atracurium
i.v- adv.& disadv.
Advantages
• Immediate effects
• Emergency situations
Disadvantages
• Bolus injection may result in adverse effects
• Strict aseptic techniques needed
INTRADERMAL
ODrug is injected into the
skin raising a bleb or
scarring puncture of the
epidermis through a drop of
the drug.
OE.g: BCG VACCINE,
sensitivity test.
REFERENCE