Fundamental Pharmacology Flashcards
DRUG
is a chemical substance used for: Preventing, treating or diagnosing disease Preventing pregnancy Recreational or other forms of abuse
Pharmacology is the study of drugs and is divided into:
PHARMACODYNAMICS: what drugs do to the body
PHARMACOKINETICS: what the body does to drugs and how fast it does it (e.g. absorption, distribution, metabolism, excretion)
PHARMACOTHERAPEUTICS:
Treatment of disease by drugs.
- Palliative (most drugs)
- Curative (some drugs)
Pharmacy
is the profession responsible for dispensing drugs
Drugs that Prevent:
Vaccines
Anticoagulants
Antiseptics
Drugs that Diagnose:
Radiographic contrast media (e.g. barium)
Mydriatics for dilating pupil in ophthalmic exams
Drugs that Treat:
Palliative (most drugs): Nasal Decongestants Antihypertensives Anxiolytics Analgesics
Curative:
Antibiotics
Antineoplastics
PHARMACOKINETIC & PHARMACODYNAMIC STEPS
(Pharmacokinetic steps)
Administration Absorption Distribution
(pharmacodynamic steps)
Receptor Agonism or Receptor Antagonism
(pharmacokinetic steps)
Redistribution Metabolism Excretion
Most drugs have common characteristics.
Most drugs are organic compounds.
Most drugs originated from natural sources, but are synthesized for commercial purposes.
Most drugs have three names (Chemical name, Generic (official) name, Trade (proprietary) name)
All drugs have side effects
Formulations
Tablets Capsules Pills? Pearls Solutions Suspensions Ointments Tinctures Salves
Fact 3: There are multiple formulations and routes of administration
Routes of Administration
Enteral (Oral, Rectal)
Parenteral (Sublingual, Intramuscular, Intravenous, Subcutaneous, Intrathecal, Topical, Transdermal)
Fundamental Pharmacology Fact 4:
Drug absorption and Drug distribution are determined by:
- Drug molecular size.
- Drug solubility (non-polar/high lipid solubility = higher solubility)
- Conditions (i.e. blood flow, cell junctions, inflammation) at site of tissues to be penetrated by drug.
Drug absorption
passage of drug from site of administration into bloodstream
Drug distribution
passage of drug from bloodstream to site of action
Drug molecular size.
(Small molecules are absorbed and distributed more freely than large because they can squeeze between cells and pass through membrane pores.)
Drug solubility.
(Lipid soluble molecules are absorbed and distributed more freely than water soluble molecules because they can dissolve in the phospholipid layer of the cell membrane and filter through the protein layer. Highly lipid soluble drugs must often attach to water soluble plasma proteins to be transported in the aqueous blood stream.)
Conditions
(i.e. blood flow, cell junctions, inflammation) at site of tissues to be penetrated by drug. The blood-brain barrier provides an example of conditions that limit drug absorption and distribution.
Fundamental Pharmacology Fact 5:
Most drugs act on receptors and there are several descriptions of their actions.
Drugs that activate receptors are AGONISTS.
Drugs that block receptors are ANTAGONISTS.
Measures of desirable drug actions include:
- Potency: Dose required to produce minimum response.
- Efficacy: Maximum magnitude of response.
Measures of drug toxicity
- Margin of Safety: Difference between toxic & effective dose.
- Therapeutic Index: Ratio of toxic & effective dose.
Measures of drug longevity
- Duration of Action: Amount of time that drug acts.
- Half-life: Time required for ½ of drug to be eliminated.
Drug Efficacy, Potency and Toxicity
A drug is efficacious when it produces a large effect, potent when a small amount produces an effect and toxic when the effective dose and the lethal dose are similar.
Fundamental Pharmacology Fact 6: Drug actions are ended in three ways.
Redistribution
Metabolism
Excretion
Redistribution of a drug
The drug is carried away form the site of action, usually by blood flow.
Most often swept away by blood flow, but lymph, and other extracellular fluids may redistribute drugs from site of action.
Metabolism of a drug
The drug is modified to make it less active or more readily excreted.
The liver is the major organ of drug metabolism, but drugs are metabolized in almost all organs of the body including lungs, g.i. tract, synapses and blood stream. There are two phases of drug metabolism. Phase 1 uses oxidation and reduction and other reactions to produce a more polar metabolite. Phase 2 uses conjugation reactions to produce a metabolite that is larger.
Excretion of a drug
The drug is (or its metabolite) is removed from the body.
The kidney is the major organ for drug excretion, but the lungs, liver, sweat, saliva are also vehicles of excretion.
