CHAPTER 2 PHARMACOLOGIC PRINCIPLES
 Drug – any chemical that affects the physiologic processes of a living organism.
 Pharmacology – the study or science of drugs; enables the nurse to better understand
how drugs affect humans.
 Absorption
 Biochemical effects
 Biotransformation (metabolism)
 Distribution
 Drug history
 Drug origin
 Excretion
 Mechanisms of action
 Physical and chemical properties
 Physical effects
 Drug receptor mechanisms
 Therapeutic (beneficial) effects
 Toxic (harmful) effects.
Chemical name – describe the chemical composition and molecular structure.
Generic name – used in most official drug compendiums to list drugs.
Trade name – proprietary name is the drug’s registered trademark and indicates commercial
use is restricted to the owner of the patent for the drug.
Patient life – length of time from patent approval until patent expiration
- Of a newly discovered drug molecule is normally 17 years.
- The research processes for new drug development normally require about 10 years, and
the manufacturer generally has the remaining 7 years for sales profits before patent
expiration.
Therapeutic equivalence – drug in a class of several drugs is chosen as the preferred agent,
even though the drugs do not have the same active ingredient.
Biosimilar- Biosimilar, by definition, is a copy version of an already authorized biological
product.

Drug classifications can be classified by:
-
Structure (beta- adrenergic blockers)
Therapeutic use (antibiotics, antihypertensives, antidepressants)
Each class may have subclasses (penicillin are a subclass within the grp. Of antibiotics, and betaadrenergic blockers are a subclass within the group of antihypertensives.
Prototypical drugs – first drug in a class of drugs and are noted as key drugs throughout this
textbook.

3 basic areas of pharmacology
1. Pharmaceutics
-
study of how various dosage forms influence the way in which the drug affects the body.
Clinical use of drugs to prevent and treat diseases.
o Enteral Route
-
Oral
Sublingual
Buccal
Rectal (can also be topical)
o Parenteral Route
-
IV (fasted delivery into the blood circulation)
Intramuscular
Subcutaneous
Intradermal
Intraarterial
Intrathecal
Intraarticular
o Topical Route
-
Skin (transdermal patches)
-
Eyes
Ears
Nose
Lungs
Rectum
Vagina
2. Pharmacokinetics
-
-
study of what the body does to the drug. Involves absorption: Bioavailability is the term
used to express the extent of drug absorption, distribution, metabolism, and effect,
excretion. (ADMEE)
first pass effect and bioavailability
routes of administration
rate of drug absorption
half- life, onset, peak, and duration
3. Pharmacodynamics
-
study of what the drug does to the body. Involves drug receptor relationships.
Mechanisms of action (MOA)
Drug receptor interactions:





Agonist – drug binds to receptor = response
Partial agonist – drug binds to receptor = response is diminished compared with that
elicited by an agonist
Antagonist – drug binds to receptor = no response. Drug prevents binding of agonist.
Competitive antagonist – drug competes with the agonist for binding to the receptor. If
it binds = no response
Non competitive antagonist – drug combines with different parts of the receptor and
inactivates it, agonist then has no effect.
Pharmacogenomics
-
genetic considerations
Targeted drugs
Pharmacotherapeutics (Therapeutics)
-
Focuses on the clinical use of drugs to prevent and treat diseases. It defines the
principles of drug actions.
Drugs are categorized into pharmacologic classes according to:
-
Physiologic functions (beta adrenergic blockers)
Primary disease states treated (anticonvulsants, anti-infective)
Off – label prescribing (prescribers may choose to use one of these)
-
Non- FDA approved indications, but often gets approved indications for a given drug.
Toxicology
-
Study of adverse effects of drugs and other chemicals on living systems.
Toxic effects are often an extension of a drug’s therapeutic action.
Pharmacognosy
-
Study of natural (versus synthetic) drug sources (plants, animals, minerals)
Pharma economics
-
Focuses on the economic aspects of drug therapy.