Chapter 1 Information Sources Regulatory Agencies Drug Legislation and Prescription Writing What is Pharmacology Study of drugs and their effects on living organisms Why study pharmacology Knowledge about pharmacology is imperative in order for the dental professional to perform important ID: 778726
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Slide1
Pharmacology
Module #1
General Principles
Slide2Chapter 1
Information, Sources, Regulatory Agencies, Drug Legislation and Prescription Writing
Slide3What is Pharmacology?
Study of drugs and their effects on living organisms
Slide4Why study pharmacology?
Knowledge about pharmacology is imperative in order for the dental professional to perform important functions such as:
Obtaining health histories
Administering drugs in the office
Handling emergency situations
Planning appointments
Non-prescription medications
Discussing drugs
Slide5What are drugs?
Any substance taken by mouth, injected into a muscle, the skin, a blood vessel or cavity of the body, or applied topically to treat or prevent a disease or condition.
Chemical substances that act on biologic systems to produce an effect
stimulate or depress cells
Slide6Drug Names
Trade name
Registered trademark
Capitalized
generic name
U.S. Adopted Name Council
official name
lower caseChemical name
chemical structure
Slide7Which names are generic?
Calvin Klein
Denims
Gap
Levi’s
Silver
Jeans
Slide8Brand vs. Generic Drugs
Patients may want to know:
Are they the same?
Do they work equally as well?
Slide9Equivalency Laws
FDA requires that the active ingredients in generic products enter the bloodstream at the same rate as the brand name drug
To be sold in the US, generic drugs must be proven biologically and therapeutically equivalent to the brand name drug
Slide10Types of Equivalence
Chemical
equivalent
meet same chemical & physical standards
may not have same bioavailability
Biologic equivalent
similar concentrations in blood & tissues
Therapeutic equivalent
equal therapeutic effect
Slide11Video- Brand vs. Generic
You Tube
https://www.youtube.com/watch?v=27oUml96BlQ
Slide12Federal Regulatory Agencies
Food and Drug Administration (FDA)
Grants approval so that drugs can be marketed
Must be proven safe and effective
Quality control
Federal Trade Commission
Prohibits false advertising
Drug Enforcement Administration (DEA)Regulates substances that have potential for abuse
Slide13Clinical Evaluation of New Drugs
Animal studies
Phase 1
Small # of
h
ealthy volunteers- determine safety
Phase 2Larger #- determine effectivenessPhase 3
Sick patients- determine dosagePhase 4Post-marketing surveillance- toxicity?
Slide14Controlled Substances
5 schedules according to their abuse potential
Schedule 2 prescriptions:
Must be hand-written and signed
Cannot be called in to the pharmacy (patient must hand-deliver)
Never any refills (new Rx every time)
Schedule 3-5 prescriptions:
May be phoned in, no more than 5 refills
Slide15Schedule of Controlled Drugs
Slide16Prescription Writing
Dental practitioners need to be familiar with the basics of prescription writing for the following reasons:
If written correctly, it will save time
Carefully written prescriptions have fewer mistakes
Unusual prescriptions can be explained, saving the patient and pharmacist time
Slide17Prescription Basics
Metric system
Milliliters (ml)
1 tsp= 5ml
Milligrams (mg)
Slide18Common Abbreviations
See page
9
Table 1-5
Know:
a -
po
bid - prnc -q
d -qidh -statp
-
tid
Slide19Writing Prescriptions
Slide20Format
3 parts:
Heading
Body
Closing
Slide21Heading
Heading
Name*, address*, telephone number of prescriber (DDS)
Name*, address*, age, telephone number of patient
Date of prescription*
Slide22Body
Body
The symbol Rx*
Name and dose size or concentration of the drug*
Amount to be dispensed*
Directions to the patient
Slide23Closing
Closing
Prescribers signature* (DDS)
DEA number if required (controlled substances)
Refill instructions
Slide24Format cont.
NOTE:
* Required by law
Slide25Prescriptions from the DDS
Two criteria must be met:
Person for which the prescription is written must be a patient of record
Drug must be for a dental-related condition
Slide26Patient Education
Patient should know:
How long and when to take their medication
What precautions to observe
What the medication is for
Slide27Clinical Considerations
Keep prescription blanks in a secure place
DEA number should be hand-written only when needed
Slide28Let’s Try it!!!
Get your prescription blanks
Write the following prescriptions
Make up any information that is not provided
Make sure you have everything included that is required by law
Slide29Write a Prescription for:
Peridex
for a 35 year old woman; with 3 refills
Chlorhexidine
gluconate
0.12%Dispense
16 oz. bottleRinse with 15 ml for 30 seconds bid after brushing & flossing; expectorate after rinsing
Slide30Write a Prescription for:
Sodium fluoride for a 3 year old child - birth date 5/23,
0.5
ppm
F in water
S
odium fluoride 0.25 mgD
ispense 30 tablets1 tab qd D
o not take with dairy products
Slide31Write a Prescription for:
Amoxicillin premedication for a 24 year old man for 2 appointments
A
moxicillin
500 mg
D
ispense 8 tabletsTake 4 tabs 1 h before appointment
Slide32Chapter 2
Drug Action and Handling
Slide33Log Dose Effect Curve
Slide34What does it tell us?
How strong or potent a drug is
How well it works
How safe it is
Slide35Potency
The
amount of drug needed to produce an
effect
Relative strength of the drug
Less
drug needed = more potentDetermined by the location of the curve on the x-axis
The closer to zero, the more potent the drug
Slide36Efficacy
The maximum effect of a drug regardless of dose
Relative effectiveness of the drug
More will not increase effect; may increase likelihood of an adverse reaction
Determined by the height of the curve on the y-axis
“Taller” curves have higher efficacy
Slide37Potency vs. Efficacy Example
Hard liquor and beer
Which is more potent?
Which is more effective?
Slide38Compare Efficacy & Potency
Slide39Look at the previous chart…
Which drug is the most potent?
Which drug has the highest efficacy?
Slide40Drug Safety
A log dose curve is also used to determine the:
ED
50
The dose that produces a response in one half of subjects
LD
50
The dose that kills one half of the subjects
Slide41Therapeutic Index
These values help to determine the Therapeutic index (TI) or relative safety of a drug
TI= LD
50
/
ED50TI should
be greater than 10 for a safe leeway between therapeutic dose and lethal dose
Slide42Therapeutic Index
Slide43Video- Log Dose Curve
You Tube
http://www.youtube.com/watch?v=UqCEADtuIgc
Slide44Mechanism of Action of Drugs
Drugs do not impart a new function to the organism, they either:
Amplify the cell’s function, or
Block it.
Slide45Nerve Transmission
Neurotransmitters are released at a synapse causing impulses (nerve action potential)
The neurotransmitter will bind to a receptor interact causing enzyme activation
See figure 2-7 page 15
Slide46Nerve Transmission Continued
Enzyme activation causes a channel to open- so that things can enter cell
See Figure 2-6 page 14
Example: sodium channel
This is how local anesthesia is achieved
Anesthetic blocks depolarization of nerve
Pain message cannot be sent to the brain
Slide47Video- Nerve Transmission
You Tube
https://www.youtube.com/watch?v=LT3VKAr4roo
Slide48Receptors
Drugs act by forming a chemical bond with specific receptor sites
Lock and key
The better the fit, the better the response
See Figure 2-8 on page 15
Slide49Agonist
Agonist
The drug has an affinity for a receptor
Combines with the receptor
Produces an effect
Slide50Antagonist
Antagonist - Counteracts the action of the agonist
Three types
Competitive
– combines with the same receptor & gives no response. Reduces effect of agonist.
Noncompetitive
– uses a different receptor & reduces maximal effect of agonist
Physiologic
– uses a different receptor & creates an opposite effect of agonist
Slide51Which is it?
A key in the ignition that starts the car
A key broken in a locked car door
A child safety shield in an electrical outlet
A plug in an electrical outlet that provides energy for a light
Slide52Video- agonist vs. antagonist
You Tube
https://www.youtube.com/watch?v=oQlGSVH9tYE
Slide53Pharmacokinetics
Study of how a
drug:
enters the body
circulates within the
body
is changed by the bodyleaves the body
Slide54Pharmacokinetics
Absorption
Distribution
Metabolism or biotransformation
Excretion
Slide55Passage Across Membranes
Membranes are composed of lipids (fats) primarily
Lipophilic
= fat loving (water repelling)
Only allow lipid-soluble, non-ionized drugs to pass through
2 methods of transfer through a membrane:
Passive transport
Specialized transport
Slide56Passive Transfer
Movement of lipid-soluble substances across membranes
Simple diffusion
Movement from an area of high concentration to an area of low concentration
Slide57Passive Transfer
Slide58Specialized Transport
More complex than passive transfer
Involves carrier mechanisms
2 types:
Active transport
Facilitated diffusion
Slide59Video- Transport
You Tube
https://www.youtube.com/watch?v=c3SNtTHguCY
Slide60Absorption
The process by which drug molecules are transferred from the site of administration to the circulating blood
Requires passage through membranes
Oral dosing undergoes
Disruption
Disintegration
Dispersion
Dissolution
Slide61Distribution
The passage of drugs into various body fluid compartments
Drugs occur in 2 forms in the blood:
Bound to plasma proteins (storage of drug)
Free drug (exerts pharmacologic effect)
Slide62Distribution
Slide63Half-life
The amount of time that passes for the concentration of a drug to fall to one half of its blood level
Drugs with a short half-life are removed quickly from the body
Duration of action is short
Drugs with a long half-life are removed slowly from the body
Duration of action is long
Slide64Blood-brain Barrier
For drugs to act on the CNS, they must pass the blood-brain barrier
Protective feature
Drugs that can pass are:
Highly lipid-soluble
Non-ionized
Slide65Metabolism (Biotransformation)
The body’s way of changing a drug so that it can be more easily excreted by the kidneys
Many drugs undergo changes in the liver
Slide66First-pass effect
Enteral
(oral) administration
Concentration of a drug is greatly reduced by metabolism by the liver before it reaches systemic circulation
Can be avoided by other routes of administration- IV, suppository, sublingual,
ect
.
Slide67Metabolism Types
Oxidation
Hydrolysis
Reduction
Slide68Excretion
How a drug leaves the body
Routes of excretion include:
Renal
Kidneys- urine
Biliary
(bile)GI tract- feces
SalivaGingival crevicular fluid
Slide69Routes of Administration
Enteral
GI tract
Oral or rectal administration
Parenteral
Bypasses the GI tractInjection, inhalation, topical administration
Includes sublingual
Slide70Video- ADME
You Tube
https://www.youtube.com/watch?v=CtnKuLWFpQ4
Slide71Factors that Alter Drug Effects
Patient compliance
Psychological factors
Tolerance
Pathologic state
Slide72Psychological Factors
Attitude of prescriber and dental staff
Placebo effect
How well the patient thinks the drug will work effects how well it will actually work for them
Slide73Tolerance
The need for an increasingly larger dose of the drug to obtain the same effects as the original dose
When a patient becomes tolerant to one drug, tolerance to other drugs with similar pharmacologic actions occurs
Cross-tolerance
Slide74Chapter 3
Adverse Reactions
Slide75Why do they occur?
Drugs act on biologic systems to accomplish a desired effect
However, they lack absolute specificity and can act on many different organs or tissues
Slide76Drug Effects
Therapeutic
effect
Desirable action
Adverse
effect
Undesirable action
Slide77Types of Adverse Reactions
Slide78Side Effect
Predictable effects of a drug on sites other than the target
organ
Dose-related
The
effects become worse as the dose is
increasedExample: upset stomach from ibuprofen used for pain management
Slide79Toxic Reaction
This is an extension of the pharmacologic effect of the drug on the target organ or system.
CNS depression leading to respiratory arrest from a toxic dose of an
opioid
The effect becomes worse as the dose is increased.
Slide80Allergic Reaction
Immunologic reaction
First exposure
hapten
+ protein = antigen
antibodies are produced
Second exposure antigen reacts with antibodiesrelease of histamine,
bradykinin, prostaglandin
Slide81Types of Allergic Reactions
Not predicable
Not dose-related
Slide82Anaphylaxis
5-30 minutes after administration
Severe symptoms
hypotension
bronchospasm
laryngeal edema
cardiac arrhythmias
Slide83Teratogenic Effect
Effect on fetal development
FDA pregnancy categories
A, B, C, D, X
Slide84Drug Interactions
The effect of one drug on another drug
Can be beneficial
Can be harmful- toxicity or reduced effectiveness
Slide85Interference with Bodily Defenses
Some drugs reduce the body’s ability to fight infections
Get infections more easily
Harder to get rid of the infection
Slide86Questions???
Slide87Review
Your client tells you that 5 years ago she had penicillin and developed hives. She needs a prescription for antibiotic premed today. How will the above information affect your choice of drug?
Slide88Review
Pick the correct term in each of the following statements.
Absorption is improved if a drug is (lipid, water) soluble.
The movement of a drug to the site of action is called (absorption, distribution).
Most drug excretion is accomplished by the (kidney, liver).
Slide89Review
What government agency is responsible for the manufacture of most drugs?
What government agency is responsible for the distribution of opioids?