A Description for The Routes Available for Drug Adminstration

1. 05/27/1505/27/15 Dr. Medani A.B. ,2006Dr. Medani A.B. ,2006
Routes of DrugRoutes of Drug
AdministrationAdministration
*The route of drug administration (ROA)*The route of drug administration (ROA)
that is chosen may have a profound effectthat is chosen may have a profound effect
upon the speed and efficiency with whichupon the speed and efficiency with which
the drug acts .the drug acts .
*The possible routes of drug entry into the*The possible routes of drug entry into the
body may be divided into two classesbody may be divided into two classes
- Enteral- Enteral
- Parenteral .- Parenteral .

2. 05/27/15 Dr. Medani A.B. ,2006
** Enteral RouteEnteral Route
► - Drugs are placed directly in the GIT ,- Drugs are placed directly in the GIT ,
either by :either by :
► - Sublingual administration of drugs placed- Sublingual administration of drugs placed
under the tongue .under the tongue .
► - Orally swallowed drugs per os (p.o.) .- Orally swallowed drugs per os (p.o.) .
► - Rectal absorption through the rectum .- Rectal absorption through the rectum .

3. 05/27/15 Dr. Medani A.B. ,2006
** Sublingual / Buccal RouteSublingual / Buccal Route
► - Some drugs are taken as small tablets held- Some drugs are taken as small tablets held
under the tongue .under the tongue .
► - This will enhance rapid absorption and drug- This will enhance rapid absorption and drug
stability as well as achieve possibility of avoidingstability as well as achieve possibility of avoiding
the hepatic first pass effect ( Venus drainage ofthe hepatic first pass effect ( Venus drainage of
the mouth is to the superior vena cava ) .the mouth is to the superior vena cava ) .
► - It is disadvantageous in case of drugs with large- It is disadvantageous in case of drugs with large
doses and those with unpleasant taste .doses and those with unpleasant taste .

4. 05/27/15 Dr. Medani A.B. ,2006
** Oral RouteOral Route
► - It is a convenient ( self- administered + pain-free- It is a convenient ( self- administered + pain-free
+ possibility for absorption is available along the+ possibility for absorption is available along the
whole length of the GIT ) and cheap route drugwhole length of the GIT ) and cheap route drug
administration .administration .
► - It is some times irritating to the GIT , not fast in- It is some times irritating to the GIT , not fast in
case of emergencies ( first pass effect ) andcase of emergencies ( first pass effect ) and
inefficient ( only a part of the drug is absorbed , itinefficient ( only a part of the drug is absorbed , it
may be destructed by the gastric juices ormay be destructed by the gastric juices or
impossible to be used in case of unconsciousimpossible to be used in case of unconscious
patients ) . In addition drugs taken via this routepatients ) . In addition drugs taken via this route
may be unpleasant in taste .may be unpleasant in taste .

5. 05/27/15 Dr. Medani A.B. ,2006
** Rectal RouteRectal Route
►- It is useful in unconscious patients and- It is useful in unconscious patients and
kids , in case of nausea and vomiting , inkids , in case of nausea and vomiting , in
case of lower bowel – directed drugs atcase of lower bowel – directed drugs at
variable absorption rates ( laxatives ) and ifvariable absorption rates ( laxatives ) and if
exposure to the drug is to be terminated .exposure to the drug is to be terminated .
►- It is not suggested in case of irritating- It is not suggested in case of irritating
drugs .drugs .

6. 05/27/15 Dr. Medani A.B. ,2006
** Parenteral RouteParenteral Route
►-Either by :-Either by :
► > Intravascular ( the drug is injected> Intravascular ( the drug is injected
directly intravenously or intra-arterially ) .directly intravenously or intra-arterially ) .
► > Intramuscular ( the drug is injected into> Intramuscular ( the drug is injected into
skeletal muscles ) .skeletal muscles ) .
► > Subcutaneous ( the drug is administered> Subcutaneous ( the drug is administered
into the subcutaneous tissues ) .into the subcutaneous tissues ) .
► > Inhalation ( absorption is through the> Inhalation ( absorption is through the
lungs ).lungs ).

7. 05/27/15 Dr. Medani A.B. ,2006
** Intravascular RouteIntravascular Route
►- Here the absorption phase is by-passed- Here the absorption phase is by-passed
( 100 % bioavailability ) ,precise and( 100 % bioavailability ) ,precise and
accurate dose size can be achieved ,accurate dose size can be achieved ,
immediate on- set of drug action isimmediate on- set of drug action is
manifested and large dose amounts can bemanifested and large dose amounts can be
given to the patient .given to the patient .
►- On the other hand there is a high risk of- On the other hand there is a high risk of
adverse effects and embolism .adverse effects and embolism .

8. 05/27/15 Dr. Medani A.B. ,2006
** Intramuscular RouteIntramuscular Route
►-It is a route that enhances rapid absorption-It is a route that enhances rapid absorption
of drugs in aqueous solutions used mostlyof drugs in aqueous solutions used mostly
for respiratory and slow- releasedfor respiratory and slow- released
preparations .preparations .
►-It may cause pain at the injection site .-It may cause pain at the injection site .

9. 05/27/15 Dr. Medani A.B. ,2006
** Subcutaneous RouteSubcutaneous Route
►- It is a slow route that enhances constant- It is a slow route that enhances constant
absorption of the drug .absorption of the drug .
►- This absorption is sometimes limitated by- This absorption is sometimes limitated by
factors that affect the blood flow likefactors that affect the blood flow like
circulatory problems and concurrentcirculatory problems and concurrent
administration of vasoconstrictors .administration of vasoconstrictors .

10. 05/27/15 Dr. Medani A.B. ,2006
** InhalationInhalation
► Used for volatile agents and aerosols to achieveUsed for volatile agents and aerosols to achieve
rapid onset of the drug .This rapid access to therapid onset of the drug .This rapid access to the
circulation is due to :circulation is due to :
A / The large pulmonary surface area .A / The large pulmonary surface area .
B / The thin membranes that separates theB / The thin membranes that separates the
alveoli from the circulation .alveoli from the circulation .
C / The high blood flow in the pulmonaryC / The high blood flow in the pulmonary
area .area .
► - It is an irreversible means in case of drug toxicity- It is an irreversible means in case of drug toxicity
and over dose .and over dose .

11. 05/27/15 Dr. Medani A.B. ,2006
** Topical RouteTopical Route
► - Drugs taken via this route are sited at :- Drugs taken via this route are sited at :
a/ The mucosal membranes ( nasal , vaginal , eyea/ The mucosal membranes ( nasal , vaginal , eye
drops , buccal ….etc) .drops , buccal ….etc) .
b/ The skin either by :b/ The skin either by :
i/ Dermal rubbing in ( inunctions or smeari/ Dermal rubbing in ( inunctions or smear
on ) of oil or ointment to give a local action .on ) of oil or ointment to give a local action .
ii/ Transdermal absorption through skin toii/ Transdermal absorption through skin to
achieve a systemic action .achieve a systemic action .
► -This will enhance a stable blood level of the drug and-This will enhance a stable blood level of the drug and
avoid the first pass effect .avoid the first pass effect .
► -It should be considered that drugs taken by this route-It should be considered that drugs taken by this route
should be non- allergic to the specific patient because ofshould be non- allergic to the specific patient because of
the difficulty of reversing their action .the difficulty of reversing their action .

12. 05/27/15 Dr. Medani A.B. ,2006
** Intrathecal RouteIntrathecal Route
►- This is used by injecting the drug ( e.g.- This is used by injecting the drug ( e.g.
antibiotics in meningitis and anathesia ) intoantibiotics in meningitis and anathesia ) into
the subarachnoid space via a lumberthe subarachnoid space via a lumber
puncture .puncture .

13. IntracavityIntracavity
This route is used for infections and painThis route is used for infections and pain
relief in cavity organs e.g haert.relief in cavity organs e.g haert.
05/27/1505/27/15 Dr. Medani A.B. ,2006Dr. Medani A.B. ,2006