1. Introduction; Scope of Pharmacology Routes of Drug Administration
Pharmacology I
BMS 242
Lecture I (Continued)
Introduction; Scope of Pharmacology Routes of Drug Administration
Dr. Aya M. Serry
2017

2. Parenteral Route

3. Routes of Drug Administration
Parenteral Route: Administering a drug by a needle or canula
 Parenteral administration is used for drugs that are poorly absorbed (e.g: Heparin) or that are unstable in the GI tract (e.g: Insulin)
Highest bioavailability ( Drug is not subject to first-pass metabolism or harsh GI environments)
Treatment of unconscious and emergency patients (Rapid action)
 Provides the most control over the actual dose of drug delivered to the body
However, these routes are irreversible and may cause pain, fear and infections

4. Routes of Drug Administration
 The three major parenteral routes are Intravenous(IV), Intramuscular (IM) and Subcutaneous (SC). Each route has it’s advantages and drawbacks;
Intravenous Injection (IV)
Advantages
Disadvantages
Rapid effect
Maximum control over the dose of the drug reaching the blood
Large quantities of drug can be injected
Injected drugs cannot be recalled by emesis or by binding to activated charcoal
IV injection may introduce bacteria through contamination at the site of injection
May also induce hemolysis or other adverse reactions due to too-rapid delivery of high concentrations of drug to the plasma and tissues (rate of infusion must be carefully controlled)

5. Routes of Drug Administration
B. Intramuscular Injection (IM)
Advantages
Disadvantages
Rapid effect
• Suitable for oily vehicles and certain irritating substances
• Preferable to intravenous if patient must self administer
Only up to 10 ml drug given
Local pain
Can cause intramuscular hemorrhage

6. Routes of Drug Administration
C. Subcutaneous Injection (SC)
Advantages
Disadvantages
Suitable for slow-release drugs (Insulin is the most famous example of SC injections)
Ideal for some poorly soluble suspensions
Pain and inflammation at site of injection
Injection site should be changed frequently to avoid tissue damage
Unsuitable for drugs administered in large volumes

7. Routes of Drug Administration
Advantages:
Other Routes:
Topical route
Used when a local effect of the drug is desired. Drug is applied directly to the skin or mucous membrane (e.g: Skin and eyes)

8. Routes of Drug Administration
Advantages:
Other Routes:
Transdermal route
This route achieves systemic effects by application of drugs to the skin via a transdermal patch
The rate of absorption varies depending on the physical characteristics of the skin
This route is most often used for the sustained delivery of drugs, such as the anti-anginal drug nitroglycerin and the once-a-week contraceptive patches

9. Routes of Drug Administration
Other Routes:
Oral Inhalation
Inhalation provides the rapid delivery of a drug across the large surface area of the mucous membranes of the respiratory system
Rapid effect (almost as rapidly as with IV injection)
Used for drugs that are gases or those that can be dispersed in an aerosol
This route is mainly effective for patients with respiratory complaints (as asthma)

10. Routes of Drug Administration
Advantages:
Other Routes:
Nasal Inhalation
This route involves administration of drugs directly into the nose. Agents include nasal decongestants such as the anti-inflammatory corticosteroids