Various Route of drug administration.

1. Route of administration of
medications.
C A U V E R Y G R O U P O F I N S T U T I O N

2. Route of administration
• Enteral
a) Oral
b) Sublingual
c) Rectal ( use for both local effect and for systemic effect)
• Parental
a) Inhalation
b) Injection
I. Commonly used : IM, IV, SC
II. Used occasionally
Intradermal/ Intracutaneous, Intraperitoneal, Intrathecal and epidural, Intramedullary, Intraarterial.

3. III. Used for local effect
Intraarticular, Intracardiac, Subconjuctival and other ocular routes.
• Topical
Ocular, Ear, Nasal(local effect and systemic effect), Dermal, Urethral, Vaginal
Note: Drugs that are rubbed for better penetration and effect and the rubbing of drug on the
skin for better penetration is called innuction.

4. Enteral route
• It is the most common and acceptable route for drug administration. Dosage forms are
tablet, capsule, syrup, mixture etc. eg; paracetamol, omeprazole.
• Advantages: Safer, cheaper, painless, can be self administered, convenient for prolonged
use.
• Disadvantage:
It is not suitable for:
-Highly irritant drugs.
- Drugs that are destroyed by diagestive juices( eg insulin)

5. - Unconscious patient.
- Uncoperative and unreliable patients.
- Patients with severe vomiting and diarrhoea.
Not suitable for emergency as onset of action of orally administrated drugs is slow.

6. Sublingual Route:
• The preparation is kept under the tongue. The drug is absorbed throught the buccal
mucous membrance and entrers the systemic circulation directly, eg nitroglycerin for acute
anginal attack and buprenorphine for MI.
Advantages:
- Quick onset of action of the drugs.
- Action can be terminated by spitting out the tablets.
- Self administration is possible.

7. • Disadvantages:
- It sis not suitable for :
Irritant and lipid soluable drugs.
Drugs with bad taste.

8. Rectal route:
• Drugs can be given in the form of solid or liquid.
1. Suppository: It can be used for local or systemic effects eg; indomethacin for rheumatic
arthritis.
2.Enema: Retention enema can be used for local effect as well as systematic effect. The
drugs is absorbed through rectal mucous membrane and produces systemic effects, eg
diazepam for status epilepticus in children.

9. Parental route
• Routes of administration other than enteral route are called parental routes.
Advantage:
-Onset of action of drugs is faster , hence suitable for emergency.
- Useful in:
- Unconscious patient, uncooperative and unreliable patient, patient with vomiting and diarrhoea.
- Suitable for:
- Irritant drugs, drugs with high first pass metabolism, drugs not absorbed orally, drugs
destroyed by digestive juices.

10. • Disadvantage:
- Require aseptic condition.
- Preparation should be sterile and is expensive.
- Require invasive techniques, which are painful
- Cannot be usually self administered.
- Can cause local tissue injury to nerves, vessels,etc.

11. Inhalation
• Volatile liquids and gases are given by inhalation for systemic effects, eg. General
anaesthetics.
• Advantages:
- Quick onset of action.
- Dose required is very less, so systemic toxicity is minimized.
- Amount of drug administered can be regulated.
- Disadvantage:
- Local irritation may cause increased respiratory secretion and bronchospasm.

12. Injections
1) Intradermal route: The drugs is injected into the layers of the skin, eg. BCG vaccination
and drugs sensitivity test. It is painful and a small amount of the drug can be administered.
2) Subcutaneous route: The drug is injected into the subcutaneous tissues of the thigh,
abdomen, arm, eg. Adrenaline, insulin,etc.
Advantages:
-Self administration of drug is possible , eg insulin.
-Depot preparations can be inserted into the subcutaneous tissues ,eg norplant for contraception.

13. • Disadvantages:
- It is suitable only for non-irritant drugs.
- Drug absorption is slow, hence not suitable for emergency.
3. Intramuscular route: Drugs are injected into large muscles, such as deltoid, gluteus
maximus and vastus lateralis, eg paracetamol, diclofenac,etc. A volume of 5-10ml can be
given at a time.

14. • Advantages:
- Absorption is more rapid as compared to oral route.
- Mild irritants, depot injections soluble substances and suspension can be given by this
route.
 Disadvantages:
- Aseptic conditions are needed.
- Intramuscular injections are painful and may cause abscess.
- Self administration is not possible.
- There may be injury to nerves.

15. Intravenous route
• Drugs are injected directly into the blood stream through a vein. Drugs are administered
as:
1. Bolus: Single, relatively large dose of a drug injected rapidly or slowly into a vein, eg.
IV. Ranitidine in bleeding peptic ulcer.
2. Slow intravenous injection: for example, i.v morphine in myocardial infraction.
3. Inravenous infusion: For example dopamine infusion in cardiogenic shock; mannitol
infusion in cerebral oedema fluids infused intravenously in dehydration.

16. • Advantages:
- Bioavailablity is 100%.
- Quick onset of action, so it is the route of choice in emergency eg intravenous diazepam to
control convulsion in status epileticus.
- Large volume of fluid can be administered, eg. Intravenous fluids in patients with severe
dehydration.
- Highly irritant drugs, eg.anticancer drugs can be given because they get diluted in blood.
- Hypertonic solution can be infused by intravenous route, eg.20% mannitol in cerebral
oedema.
- By I.V infusion , a constant plasma level of the drug can be maintained, eg. Dopamine
infusion in cardiogenic shock.

17. • Disadvantages:
- Local irritation may cause phlebitis.
- Self administration is usually not possible.
- Strict aseptic conditions are needed.
- Extravasation of same drugs can cause injury, necrosis and sloughing of tissues.
- Depot preparations cannot be given by I.V route.
- Precaution:
- Drug should usually be injected slowly.
- Before injecting make sure that the tip of the needle is in the vein.

18. Intrathecal route
Drug is injected into the
subarachnoid space. Eg.
Lignocaine( spinal anaesthesia) ,
antibiotic (amphotericin)

19. Transdermal route
• The drug is administered in the form of a patch or oinment that delivers the drug into the
circulation for systemic effect. Eg. Nitroglycerin patch/oinment for prophylaxis of angina,
fentanyl patch for chronic pain.
• Advantage:
-Self administration is possible.
- Patient compliance is better.
- Duration of action is prolinged.
- Systemic side effects are reduced.

20. - Provides a constant plasma concentration of the drug.
- First pass metabolism is bypassed.
Disadvantages:
- Expensive.
- Local irritation may cause dermatitis and itching.
- Patch may fall off unnoticed.

22. Q and A