Transcript 100908 Gen Pharm History (pt1) 1801KB

GENERAL
PHARMACOLOGY
Better living through pharmacology, pharmokinetics,
and pharmodynamics,
P. Andrews
 CAREFUL AND JUDICIOUS USE OF
MEDICATIONS CAN TRULY MAKE A
DIFFERENCE
Things to know
about drugs
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Pharmokinetics
Pharmodynamics
Generic names
Trade names
Schedules of drugs
FDA approval process
The Harrison Narcotic
act of 1914
 Enteral drug
administration
 Parenteral drug
administration
 Mechanism of action
 Route of
administration
 Pure food and drug act
of 1906
Things to
know, cont.
 The Federal Food,
Drug and Cosmetic act
of 1938
 The DurhamHumphrey
Amendments to the
1938 Act
 The Controlled
Substance Act of 1970
 OTC medications
 Absorption
 Six rights of
medication
administration
 Bioavailability
 Biotransformation
 First-pass effect
More things
to know!
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Blood-brain barrier
Placental barrier
Oxidation
Hydrolysis
Elimination
Agonist
Antagonist
Agonist-antagonist
Extrapyramidal
symptoms
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Idiosyncratic response
Tolerence
Side effect
Cumulative effect
Synergism
Potentiation
Onset of action
Therapeutic index
Half-life
Minimum effective
concentration
Historical trends
 Ancient health care
 Herbs & minerals - 2,000 BC
 Pharmacology by end of Renaissance;
separate from medicine
 Vaccinations 1796 (Smallpox)
 Insulin, Penicillin early 20th century
 Modern health care
 Human insulin
 tPA
Pharmacology
 Chemical name
 Precise description chemical composition and
molecular structure
 Vecuronium Bromide:
 Chemical compound: piperidinum, 1-[(2, 3, 5,
16, 17)-3, 17-bis (acetyloxy)-2-(1piperidinyl)androstan-16yl]-1-methyl-, bromide.
 Molecular structure C34H57BrN2O4
 Generic name –
Non-proprietary name
 FDA approved
 First manufacturer
 vecuronium bromide
 Trade (Proprietary) name
 Registered to a specific manufacturer
 Marsam Pharmaceuticals, Inc.
 Vecuronium
TM
 Official name
 Assigned by USP
 Vecuronium Bromide USP
Drug Sources
 Plants
 Atropine – Deadly
nightshade plant
 Morphine – Opium
plant
 Digitalis – Foxglove
 Animals and Humans
 Insulin
 Glucagon
 Minerals
 Calcium chloride
 Sodium
Bicarbonate
 Magnesium Sulfate
 Synthetics
 Bretylium tosylate
 Lidocaine
 Procainamide
Drug Profiles
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Names
Classification
Mechanism of Action
Indications
Pharmacokinetics
Side effects/ adverse reactions
Routes of administration
Contraindications
Dosage
How supplied
Special considerations
Legal stuff
- Federal
 Protect the public
 Pure Food and Drug Act, 1906
 Improve quality and labeling of drugs
 Harrison Narcotic Act, 1914
 Regulating importation, manufacture, sale, use of
opium, cocaine, derivatives
 Federal Food, Drug, Cosmetic Act, 1938
 Empowers FDA to enforce, set premarket safety
standards
More Federal stuff
 Durham-Humphrey Amendments, 1951
 Prescription drug amendments, 1938 act; requires
written or verbal prescription from physician to
dispense some drugs
 Created OTC category
 Comprehensive Drug Abuse Prevention &
Control Act, 1970 (Controlled substance
act)
 Replaces Harrison Narcotic Act
 Establishes 5 schedules of drugs
 Prohibits refilling of Rx for Schedule II drugs, &
requires original Rx to be filled within 72 hours
Other regulations
 Prescription drugs
 Designated sufficiently dangerous to require
supervision
 OTC
 Available in small doses; present low risk
General issues
 Drugs must be secured
 State laws vary; generally set scope of
practice for EMS
 Medical directors can delegate authority to
paramedics
New Drug Development
You Are Responsible!
 Know precautions and
contraindications
 Practice proper technique
 Know how to observe and
document effects
 Establish and maintain
professional relationships
with other health care
providers
In disease, all systems are
affected
 The three systems can’t exist without each
other
 The actions of one impact the actions of the
others
 I.e., stress (nervous system) disrupts endocrine
system which may respond with glucocorticoid
production = suppressed immune response
Drug Class Examples
 Nitroglycerin
 Body system: “Cardiac drug”
 Action of the agent: “Anti-anginal”
 Mechanism of action: “Vasodilator”
 Indications for nitroglycerin
 Cardiac chest pain
 Pulmonary edema
 Hypertensive crisis
 Which drug class best describes this drug?
 Understand pharmacokinetics,
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pharmacodynamics
Have current references available
Take careful drug histories
Evaluate compliance, dosage,
adverse reactions
Consult with medical direction when
appropriate
SIX RIGHTS OF MEDICATION
ADMINISTRATION
 Right medication
 Right dose
 Right time
 Right route
 Right patient
 Right documentation
 AND SEVEN – Right to refuse
Cells talk to each other
 Three distinct languages
 Nervous system
 neurotransmitters
 Endocrine system
 hormones
 Immune system
 cytokines
Another way to classify drugs
 Mechanism of Action
 Drugs in each category work on similar sites in the
body and will have similar specific effects/side effects
 Example: beta blocker actions and impacts
 Suppress the actions of the sympathetic nervous
system
 Prehospital administration of epinephrine may not
produce as dramatic effects with a patient taking a
drug in this class
Prehospital example:
Hyperglycemics
 Dextrose 50% and glucagon
 Both will raise blood glucose
 Mechanism of action
 Glucagon: hormone that works in the liver to convert
stored chains of carbohydrate to glucose
 Dextrose 50%: ready-made simple sugar that is ready
to enter into the cell
 Which drug is considered first-line for
hypoglycemia? Why?
 What are some limitations for glucagon in the
presence of severe hypoglycemia?
Sources of drug information
 On-line - be cautious of source
 Pharmacy.com
 Medline.com
 AMA Drug Evaluation
 Physician’s Desk Reference (PDR)
 Hospital Formulary
 Drug Inserts
 Other sources
Controlled
substances
 Schedule I. High potential for abuse; no
accepted medical indications
 Heroin, LSD, Crack, Marijuana
 Schedule II. High potential for abuse, but
have accepted medical indications
 Morphine, Fentanyl, meperidine, Dilaudid,
Oxycodone, Cocaine, Codeine, Opium,
Methadone
 Schedule III. Less potential for abuse, and
accepted medical indications
 Tylenol #3, Vicodin
 Schedule IV. Low potential for abuse, but
may cause physical or psychological
dependence.
 diazepam, midazolam, butorphanol, lorazepam,
Phenobarbital
 Schedule V. Low potential for abuse, but
have small quantities of narcotics
 Cough medicine (Vicks 44)
Standardization of Drugs
 A necessity
 Techniques for measuring a drug’s
strength and purity
 Assay
 Bioassay
 The United States Pharmacopeia
(USP)
 Official volumes of drug standards
Medical Control
 Medication administration is ALS skill
 Medical Director
 Actively involved in and ultimately responsible for
all clinical and patient care.
 We are extension of physician’s license
Special ConsiderationsPregnant patients
 Evaluate benefit vs. risk to fetus
 FDA has a scale (A,B,C,D,X) to
indicate drugs that may have
documented problems
 Many drugs are unknown to cause
problems
 Drugs may cross placental barrier or
through lactation
FDA Pregnancy Categories
A
B
Adequate studies have not
demonstrated a risk to the fetus
Animal studies have not demonstrated a
risk to the fetus; no adequate studies in
humans OR
Adequate studies in pregnant women
have not demonstrated a risk to fetus in
first and last trimester BUT animal
studies show adverse effects
FDA Pregnancy Categories, cont.
C
D
X
Animal studies have demonstrated
adverse effects, but there are no
adequate studies in pregnant woman
Fetal risk has been demonstrated; in
certain circumstances, benefits could
outweigh risks
Fetal risk has been demonstrated. This
risk outweighs any possible benefit to
mother. Avoid using in pregnant
patients.
Special Considerations –
Pediatric patients
 Based on weight or BSA
 Length-based resuscitation tape
(Broslow’s)
 Absorption of oral meds less due to
differences in gastric pH, emptying time,
low enzyme levels
Pediatrics, cont.
 Unexpected toxicity common in topically applied
meds
 Drugs that bind to protein have higher availability
 Neonates have much higher % of extracellular fluid
– may require higher doses
 Lower metabolic rate & hepatic system ; higher risk
for toxicity
Figure 6-1 ABroselow tape is useful for calculating drug dosages for pediatric patients.
Special Considerations Geriatric patients
 MULTIPLE MEDS A PROBLEM
 Physiological effects of aging can lead to altered
pharmacodynamics and pharmacokinetics.
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Absorb oral meds slower
Distribution altered
Lipid soluble drugs have greater deposition
Drug action delayed or prolonged
Pharmacology
 The study of drugs and their interactions with
the body
 Drugs do not confer any new properties on cells
or tissues – only modify or exploit existing
functions
 Given for local or systemic action
Pharmacokinetics
 The study of the basic processes that
determine duration and intensity of a drug’s
effect
Transport
 Active transport
 Requires energy to move a substance
 ATP ADP
 Sodium – potassium pump
 Facilitated diffusion
 Binds with carrier protein, configuration of cell
membrane changes, allows large molecule to enter
body
 I.e., Insulin increases glucose transport from 10-20
fold
Transport, cont
 Passive transport
movement of substance without energy
 Diffusion
 Movement of solute in solvent
 Osmosis
 Movement of solvent
 Filtration
 Molecules move across membrane down
pressure gradient
Absorption
 IM faster than SC
 Enteral administration; must survive digestive
process
 Enteric coating; dissolve in duodenum
 Many drugs ionize
 Ionized drugs don’t absorb across cell membranes
 Most drugs reach equilibrium
 pH affects ionization
 Concentration affects absorption
 Loading dose – maintenance dose
 Bioavailability
 Amount of drug still active after reaching target
tissue
Distribution
 Some drugs bind to proteins in blood and
remain for prolonged period
 Therapeutic effects due to unbound portion
of drug in blood
 Drug bound to plasma proteins can’t cross
membranes
 Changing blood pH can affect proteinbinding action of drug.
 TCA’s are strongly bound to plasma proteins.