Introduction to Pharmacological Principles Flashcards
Functional Definition of a Drug
a chemical substance that produces a biological response
sources:
- small organic molecules
- proteins synthesized by bacteria, yeast, or mammalian cells
Legal Definition of a Drug
articles intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease in man or other animals
- articles (other than food) intended to affect the structure or any function of the body of man or other animals
Pharmacology
study of drugs and their interactions w/living systems
- the info used in decision making for drug use for pts comes from this
- focuses on chemical properties of a drug and its effects
a. biochemical effects: at the cellular level
b. physiologic effects: effects on body
*looks at therapeutic effects and adverse effects on body
Pharmacotherapy
the use of drugs to diagnose, prevent and treat disease
- what happens in clinical practice
- includes looking at four main things w/drugs:
1. Indication
2. Effectiveness
3. Safety
4. Convenience
Pharmacotherapy Indication (I)
why was this drug prescribed?
is it actually needed?
- if drug isn’t necessary, then should not be prescribed. asking this is important to assess in pts, especially those taking many drugs
Pharmacotherapy Effectiveness (E)
is it working?
is there a better option?
- looking at all drug options for a condition is important especially if pt is experiencing side effects or wants to return to a certain level after illness
Pharmacotherapy Safety (S)
are there adverse effects?
drug interactions?
what’s the therapeutic index?
- if drug is being prescribed at unsafe levels, can it be brought down? what are other options? good to know so that other options can be explored if drug is not safe
Pharmacotherapy Convenience (C)
does it work with the pt’s lifestyle?
is the pt willing to take it?
can the pt afford it?
- if pt cannot afford the drug or it doesn’t work with their lifestyle, then other options need to be looked at to ensure pt comfortability
Drug Safety in law
In the United States, new drugs weren’t regulated to be safe until 1940!! Before then, new drugs did not have to be proven to be safe to be on the market
Drug Classifications
- Therapeutic Category (“class”)
- Chemical Structure
- SubClass
- Target
- Generation
- Legal Restriction
Therapeutic Category Classification
also known as the class of a drug, based on what it is treating
- ex: antimicrobials
Chemical Structure Classification
based on the structure-activity relationship of a drug
- ex: Beta-lactams
Subclass Classification
further refinement of a specific category of drugs
- ex: cephalosporins (have SO MANY categories)
Target Classification
looks at the molecular mechanism that the drug is targeting
- ex: direct serine protease inhibitor
Generation Classification
when the drug was developed
- ex: 1-5 cephalosporins
Legal Restriction Classification
drugs are classified legally in “schedules” as to how dangerous they are:
1. Schedule I
2. Schedule II
3. Schedule III
4. Schedule IV
5. Schedule V
6. Legend Drug
7. OTC Drugs
Schedule I Drugs
no accepted medical use with high potential for abuse
Schedule II Drugs
high potential for abuse and psychological or physical dependence
Schedule III Drugs
moderate-low potential for abuse/dependence
Schedule IV Drugs
low potential for abuse/dependence
Schedule V Drugs
lower potential for abuse/dependence than schedule IV
- may contain small amounts of narcotics
Legen Drugs
prescription drugs
OTC Drugs
prescription not required and accessible at drug stores
Generic vs Brand Name Drugs
Generic drugs provide an effect within 10% (+/-) of the branded product
- however, there are some instances where the consistency of the manufacturer matters, whether brand or generic
Biologic Drugs
include blood, blood components, somatic cells, gene therapy, tissues, recombinant proteins, and vaccines
- typically derived from microorganisms, plants, animal or human cells
- composed of sugars, proteins, nucleic acids, or combinations of these
- complex, unique large mixtures not readily identifiable or easily duplicated
- sensitive to heat and vulnerable to microbial adulteration
- requires aseptic techniques from the initial manufacturing stages
Pharmacognosy
the science of drugs prepared from natural-sources including preparations from plants, animals and other organisms as well as minerals and other substances include in material medical
Pharmacokinetic Processes
- Absorption: drug being absorbed into the body and circulated where it needs to go
- Distribution: circulating drug and distributing it to targeted organ or tissue
- Metabolism: metabolized for removal from body but in some cases also activated through metabolism
- Excretion: leftovers excreted through urine, sweat, or other such excretions (created through enzymes in liver or kidneys)
Drug Transport over Membranes
MOST drugs can be diffused over membranes either through passive or facilitated diffusion
- in some cases they may need to be bound to an anion or cation if they have a charge themselves to get through an active transport channel
to get out of the cell, drugs are usually ejected using the P-glycoprotein channel
Two Compartment Model of Pharmacokinetic Processes
A. Central Compartment
B. Peripheral Compartment
Central Compartment of Pharmacokinetic Processing
systemic circulation + organs important to drug distribution and metabolism of drug
- includes: blood, heart, liver, lungs, kidney
Peripheral Compartment of Pharmacokinetic Processing
where drugs tend to stop after circulation for distribution into proper tissue to have effect
- can stop at organs but tends to stop at: adipose tissue, muscles, cerebrospinal fluid
Bioavailability (F)
the fraction of a dose that reaches systemic circulation around body
- oral dosage forms encounter barriers that reduce bioavailability
- if drug is given IV, F=1
Factors Affecting Absorption & Distribution
- Size: smaller molecules will diffuse more easily than larger molecules
- Lipid solubility: Lipophilic molecules cross membranes more easily
- Ionization/pH: polar (ionized) molecules have difficulty crossing membranes and pH varies in different body tissues
- Protein Binding: can range for 0-9% depending on the drug and needs to dissociate from protein to be active drug
Drug pH
lots of drugs are weak basics or acids to get where they need to go and absorb there
- acidic drugs are better absorbed in acidic fluid (stomach)
- basic drugs are better in basic fluids (gut)
Physiological Factors Affecting Rate of Absorption
- surface area
- blood flow
- gastric motility
- transporters
- pH
Drug Factors Affecting Rate of Absorption
- route of administration
- particle size
- rate of dissolution
- solubility
- pKa
- lipophilicity