routes of drug administration 1 / 49 Routes of Drug Administration Jul 31, 2014 • 1.08k likes • 2.81k Views Routes of Drug Administration. The “Right” ways of administering drugs. Right patient Right drug Right dose Right route Right time Right documentation. Significance of Drug Administration. Input of drug in the Human body. artery route dependent carrier system right time splanchnic blood flow gastric motility e g fully ionized sema sema + Follow Download Presentation Routes of Drug Administration An Image/Link below is provided (as is) to download presentation Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. During download, if you can't get a presentation, the file might be deleted by the publisher. E N D Presentation Transcript Routes of Drug Administration The “Right” ways of administering drugs • Right patient • Right drug • Right dose • Right route • Right time • Right documentation Significance of Drug Administration • Input of drug in the Human body. • Permits entry of the therapeutic agent either Directly or Indirectly into the Plasma. • A drug once taken in any form has to be then distributed, metabolized and finally eliminated from the body. How do we choose the right route of administration • The route of administration is determined primarily by the properties of the drug (such as water or lipid solubility, ionization, etc.) and by the therapeutic objectives • (for example, the desirability of a rapid onset of action or the need for long-term administration or restriction to a local site). • The route of administration (ROA) that is chosen may have a profound effect upon the speed and efficiency with which the drug acts. Enteral/paraentral Oral Buccal Rectal Sublingual Topical Transdermal Inhalant Ophthalmic Intranasal Otic Vaginal Intradermal Subcutaneous Intramuscular Intravenous Intraosseous Intrathecal Routes Enteral routes • Drug placed directly in the GI tract: • Oral - swallowing • Sublingual- placed under the tongue • Buccal route • Rectum- absorption through the rectum (suppositories, anemas) • GI tubes (e.g. nasogastric, gastrotomy) Oral Route Oral Route • Giving a drug by mouth is the most common route of administration but it is also the most variable , and requires the most complicated pathway to the tissues. • Little absorption occurs until the drug enters the small intestine. Drugs are absorbed by: • Passive Diffusion: • Determined by the lipophilcity of the drug compound • Ionized drugs are poorly absorbed (Strong bases of pKa 10 or higher are poorly absorbed, as are strong acids of pKa less than 3, because they are fully ionized) • Active Diffusion: • By carrier proteins • Example: ca+2 is carried by V.t-D dependent carrier system Why most of the drugs are absorbed from the small intestine? • Small intestine has a much larger surface area for absorption (~200 m2) as compared to the stomach (~1-3 m2). • ...............

1. Routes of Administration of drugs
By.
Dr.Abdul latif Mahesar

2. ROUTES OFADMINISTRATION
►Enteral (Alimentary)
► Par - enteral
( Other than Alimentary)

3. ROUTES OFADMINISTRATION
Enteral (Alimentary canal)
 Oral
 Buccal & Sublingual
 Rectal
 Nasogastric

4. Par - enteral ( Other than Alimentary)
 Par - enteral injections
Intravenous , intramuscular, intradermal,
Subcutaneous, intrarterial, intrarticular,
intraperitoneal, intrathecal
 Inhalation
 Topical

5. ORAL
MERITS
 Commonest, Safest
 Convenient ,
 No skill required, self medication
 Painless, & acceptable
 Cost effective
 No maximal/strict sterilization required

6. ORAL
 MERITS cont’d
 Due to slow rate of absorption adverse effects occurs less and
slowly as compared to
parenteral route
 Large volume (doses) can be given
 Systemic / local effects in G.I.T
For local effect
e.g.,
neomycin (an aminoglycoside),
anthelmintics
antiamoebic.

7. ORAL con’d
De-merits
 Absorption varies (delay, decrease, or
increase )
affected by ---- food or drugs that affect GI
motility
e.g. antimuscarinic, opioids )
 (Dose may not accurately be delivered)
 Irritation of gastric mucosa
 Patient compliance not ensured

8. ORAL cont’d
Demerits
 First pass metabolism ( First pass effect,
Presystemic elimination)
 Metabolism of drug (to inactive form)
after administration before it reaches the
systemic circulation Usually with orally
administered drugs

9. ORAL
De-merits cont’d
 First pass metabolism
- Orally administered drugs
- First pass effect in GIT
- Hepatic first pass metabolism
during its first passage thru liver
 Greater the first pass effect, lesser will be
the bioavailability

10. BIOAVAILABILITY
is the fraction of administered drug that
gain access to the systemic circulation
(after absorption) in a chemically
unchanged form

11. ORAL cont’d
Demerits cont’d
- Drugs with high first pass effect needs
to be given in high doses
- Variation in first pass effect
among individuals cause variation in
drug response

12. ORAL cont’d
Demerits cont’d
 Not suitable for :
Unconscious patients
Vomiting patients
Emergency --- (Slow onset of action)
 GIT diseases or abnormality may
affect the absorption of drug

13. ORAL cont’d
Demerits
- Following drugs can not be given by oral route:
- Drugs destroyed by Stomach pH
(some Penicillins e.g., benzyl penicillin)
- Drugs destroyed by Intestinal enzymes
(e.g., Insulin, oxytocin)
- Hydrophilic drugs which can not absorbed
(e.g., Aminoglycosides, but can be given for
local effect such as neomycin)

14. ORAL cont;d
Demerits cont’d
Uneven distribution (for local effect),
in some diseases of gut whole thickness of wall is
affected (e.g. severe bacillary dysentery, typhoid)
& effective blood concentrations ( as well as
luminal concentrations ) may be needed.
Drug interaction:
one drug can affect the absorption of other
drug e.g., antacids decrease the absorption of
tetracyclines.

15. SUBLINGUAL & BUCCAL
Merits
 Rapid onset of action
 useful in emergency
(glyceryl trinitrate, nifedipine & ergotamine),
especially if tablet is crushed, giving greater
surface area for solution
 Effect can be terminated by spitting out tablet

16. SUBLINGUAL & BUCCAL
Merits
 No sterilization required
 No skill
 first pass hepatic metabolism is avoided
 Increase in bioavailability
 Not affected by gastric acidity or intestinal enzymes

17. SUBLINGUAL & BUCCal
Demerits
 Inconvenient for frequent use
 Irritation of oral mucosa & excessive
salivation
 Promotes swallowing, so losing the advantage of
bypassing the first pass effect
 Patient compliance not ensured
 Not suitable for large doses and vomiting patients
 Bitter, irritant can not be given

18. RECTAL
 Dose requirement same or slightly greater than
oral route

19. RECTAL
Merits
 Can be used for producing both the systemic effects
and local effects
 Drugs that are irritant to stomach can be given by
suppository (aminophylline, indomethacin)
 Suitable in unconscious, vomiting , motion
sickness, migraine or when a patient can not swallow , &
when cooperation is lacking (sedation in children)

20. RECTAL
Merits
 No sterilization
 No skill
 Avoid 50% first pass hepatic metabolism (from
lower rectum)
 For local effect e.g. in proctitis or colitis

21. RECTAL
Demerits
 Psychological, patient may be embarrassed and dislike this
way
 Irritation of mucosa & inflammation may occur
with repeated use
 Emergency (slow onset of action)
 Absorption unreliable, especially if rectum is full of
feces

22. PAR-ENTERAL INJECTIONS
Dosage forms:
Solution,
Suspension

23. PAR-ENTERAL INJECTIONS
Intravenous ( I / V ),
Intramuscular ( I / M ),
Subcutaneous ( S / C )
Intra dermal
Intra articular
Intrathecal
Intraperitoneal

24. I / V INJECTIONS & INFUSIONS
Merits
 Rapid onset of action
 useful in emergency
 No first pass effect, 100% bioavailability,
 Dose more accurately delivered & give smooth
effective, & highly predictable blood
concentration
 Suitable in vomiting , motion sickness, migraine,
unconscious patients, or when a patient can not
swallow , & when cooperation is lacking
- Large volume (doses) of drug can be given

25. Intra venous and I.V infusions cont’d
Merits
 Suitable in vomiting , motion sickness, migraine,
unconscious patients, or when a patient can not
swallow , & when cooperation is lacking
 Large volume (doses) of drug can be given

26. Intra venous and I.V infusions cont’d
 Following drugs which can not be given by
oral route, are given intravenously
 Drugs destroyed by stomach pH
(some Penicillins e.g., benzyl penicillin)
 Drugs destroyed by intestinal enzymes
(e.g., Insulin)
 Hydrophilic drugs which can not absorbed
(e.g., Aminoglycosides)

27. Intra venous and I.V infusions cont’d
Merits
- Drugs that are too irritant (anticancer agents) to be
given by other routes
- In I.V. infusion ----Rapid modification of dose and
immediate cessation of administration if unwanted
effects occur

28. I / V INJECTIONS & INFUSIONS
De-merits
 Costly
 Inconvenient
 More chances of adverse effects, most
dangerous
 Maximal Sterilization, chances of infection
Skill, no self medication
 Local irritation at site of administration

29. I / V INJECTIONS & INFUSIONS
Demerits
 Local venous thrombosis with:
prolonged infusion
irritant formulations
microparticulate components of infusion
fluids, especially if small veins are used
Infection of intravenous catheter and small
thrombi on its tip during prolonged infusions

30. PARENTERAL : I / M INJECTIONS
Merits
 Reliable and suitable for irritant drugs and
depot preparations (penicillins , neuroleptics,
medroxyprogesterone) can be used at monthly
or longer intervals
 Absorption is more rapid than following
subcutaneous injection or oral route
(soluble preparations are absorbed within 10 – 30 mins.)

31. : I / M INJECTIONS
De-merits
 Inconvenient
 Painful especially for frequent use
 More chances of adverse effects than oral
Sterilization,
 Chances of infection
 Skill required
 Local irritation at site of administration

32. I / M INJECTIONS
De-merits
Not acceptable for self administration
If any adverse effect occur tha can not be
removed.

33. S / C INJECTIONS
Merits
 Can be used for local and systemic effects both
 Reliable and acceptable for self administration
(e.g. diabetic patients taking Insulin)
For local effect --- e.g. local anesthetics

34. S / C INJECTIONS
De-merits
 Poor absorption in peripheral circulatory
failure
 repeated injections at one site can cause
lipodystrophy, resulting in erratic
absorption (insulin)

35. INHALATION
 Can be used for local & systemic effects both
As a gas, --- e.g. ---- General anaesthetics
As an aerosol,--- e.g. ---- β2 –adrenoceptor agonist
bronchodilators
As a powder, e.g. sodium chromoglycate

36. INHALATION
Merits
 Drugs as gases can be rapidly taken up or eliminated,
giving the close control that has marked the use of
this route in general anesthesia
 Self administration is practicable
 Aerosols & powders provide high local concentration
for action on bronchi, minimizing systemic effects
 Aerosols can also be used for systemic effect, e.g
ergotamine for migraine

37. INHALATION
De-merits
 Special apparatus is needed
 Drug must be nonirritant.
 If the patient is unconscious
Obstructed bronchi (mucus plugs in asthma)
may
cause therapy to fail

38. TOPICAL application
For local effect
 Skin
 Mucous membrane (eye, nose , ear , lungs,
anal canal, rectum, urethra, vagina, etc. )
For systemic effect ----- Transdermal

39. TOPICALAPPLICATION: FOR LOCAL EFFECT
Dosage forms
Ointment, lotion, cream, etc
Merits
usually high local concentration can be used
without systemic effect

40. TOPICAL APPLICATION: FOR LOCAL EFFECT
Demerits
systemic effects can occur especially when there is
tissue destruction e.g.,
adrenal steroids & neomycin --- to ---- skin,
atropine & β-adrenoceptor blocker --- to --- eye

41. TOPICALAPPLICATION: FOR SYSTEMIC EFFECT:
TRANSDERMAL DELIVERY SYSTEM (TDS)
Dosage form:
 Patches, ointment
as a sticking plaster (Patch) attached to skin or
as an ointment
glyceryl trinitrate
postmenopausal hormone replacement

42. TOPICALAPPLICATION: FOR SYSTEMIC EFFECT
Merits:
 Used for slow continuous administration for long
duration
 Fluctuations in plasma concentration are largely
avoided
 Usually No first pass effect
 Drug can be removed if required

43. TOPICALAPPLICATION: FOR SYSTEMIC EFFECT:
Demerits:
 Only small number of drugs can be used by
this route
 Slow onset of action
 Local reactions