Transcript Pharmacology 242 GBC - INAYA Medical College

Pharmacology I
BMS 242
Lecture I (Continued)
Introduction; Scope of Pharmacology
Routes of Drug Administration
Dr. Aya M. Serry
2016
II. Parenteral
Route
Routes of Drug Administration
II. 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
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;
A. Intravenous Injection (IV)
Advantages
• Rapid effect
• Maximum control over
the dose of the drug
reaching the blood
• Large quantities of drug
can be injected
Disadvantages
• 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)
Routes of Drug Administration
B. Intramuscular Injection (IM)
Advantages
• Rapid effect
Disadvantages
• Only up to 10 ml drug given
• Suitable for oily vehicles and certain irritating • Local pain
substances
• Can cause intramuscular hemorrhage
• Preferable to intravenous if patient must self
administer
Routes of Drug Administration
C. Subcutaneous Injection (SC)
Advantages
• Suitable for slow-release drugs
(Insulin is the most famous example
of SC injections)
• Ideal for some poorly soluble
suspensions
Disadvantages
• Pain and inflammation at site of injection
• Injection site should be changed frequently to avoid
tissue damage
• Unsuitable for drugs administered in large volumes
Routes of Drug Administration
•II. 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)
Routes of Drug Administration
•II. 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
Routes of Drug Administration
II. 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)
Routes of Drug Administration
•II. 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