Pharmacology
& the certified athletic trainer
ATC and Drugs
Study findings
Health advisor
Watch dog for
abuse
Terms
Drug vs Medicine
Pharmacology
– Pharmacokinetics
– Pharmacodynamics
Dosing
– Standard
– Pediatric
– Loading
Potency
Pharmacology
Pharmacotherapeutics Toxicology
Pharmacokinetics Pharmacodynamics
•Drug Absorption / Distribution •Cellular Effects
•Drug Metabolism / Excretion •Systemic Effects
Routes of Administration
Enteral vs Parenteral
Systemic Effects
– Oral (Ingestion) – liquid, tablets, capsules
Pros and Cons
Enteric coated pills
Sustained release tablets/capsules
– Injection (Parenteral) – subcutaneous,
intravenous, intramuscular
Pros and Cons
– Other – intranasal, inhalation, sublingual, buccal,
rectal, transdermal
Pros and Cons
Routes of Administration
Local Effects
– Topical – applied to the skin to treat skin
conditions
– Otic
– Opthalmic
Pharmacokinetics
Refers to movement of drugs across
body membranes to reach the target
organ
4 phases (ADME)
– Absorption
– Distribution
– Metabolism
– Elimination
Pharmacokinetics (phase 1)
Absorption
– from GI tract to bloodstream – ingestion
– All other methods go directly into blood
– Some drug binds to blood protein, some free
floating
Bioavailability – amount of drug available
to use following digestion
Exercise’s effect on Absorption
– Rate of dissolution
– Surface Area
– Lipid solubility
Pharmacokinetics (phase 2)
Distribution – movement from circulation
into tissues
– Delivered to target areas
– Exercise increases distribution
– Affected by poor circulation
How does a drug exert it’s effect?
– Lipid solubility of drug
– Receptor
– Physical or Chemical means
Drug Actions
Activation (Stimulation) – increase the rate of
functional activity
Inactivation (Depression) – decrease the rate of
functional activity
Blocking – prevents an action or response
Inhibition – changes cell functioning
Substitutive (Replacement) – substitute an
equivalent substance to restore optimal condition
Curative – destruction or prevention of growth
Irritation – abnormal excitation of function
Drugs in the Body
Example
Site of action (Target organ) - Neuron
– Synapses – space between axon and dendrites
In central and peripheral nervous system
– Dendrite – receive impulse from adjacent neuron
– Cell body – processes incoming information;
formulate action potential
– Axon – transmits action potential
– Neurotransmitter – protein chemical messenger
that carries an AP across synapse
Site of Action
Effects on Synapses – either excitatory
or inhibitory
Receptors – protein molecules on a cell
membrane that can interact with drugs
Dendrite
Axon
Neurotransmitter
Dendrite
Axon
Dendrite
Axon
Drug binds to presynaptic receptor
Dendrite
Axon
Drug binds to postsynaptic receptor
Dendrite
Axon
Drug mimics neurotransmitter
Dendrite
Axon
Drug destroys enzyme that should destroy neurotransmitter
Agonist
+
Agonist
-
Antagonist
Factors Affecting Drug
Actions
Age – infants and elderly more sensitive
Gender – affects women differently
– Hormones, % body fat, less H2O
Mindset –
Dosage –
Potency –
Purity –
Tolerance –
Pharmacokinetics
Metabolism (phase 3) – clearing of drugs
from the body
– Liver
– “First pass effect”
– Makes drug inactivative
– Exercise slows metabolism
– Liver illness slows metabolism – causes a buildup
of unmetabolized drug
Excretion (phase 4) – removal of drug from
the body
– Exercise slows excretion
– Kidney illness slows excretion
Example of Pharmacokinetic
Process (Aspirin)
Orally administered
Absorbed in Stomach and SI
80-90% binds to protein, so 10-20% exits
blood and has therapeutic effect
– Compared with 20-50% binding w/ Tylenol
Metabolism begins in blood and ends in liver
– changes to salicylic acid
Excreted by kidney
Pharmacokinectic Terms
Half-life
Duration of Action
MEC
Toxic Concentration
Therapeutic Range
Maximal Efficacy
Drug Interactions
Definition
Depends on many factors…..
2 Types of Interactions
– Pharmacokinetic Interactions
– Pharmacodynamic Interactions
Additive Effect 2+2=4
Synergistic Effect 2+3=5
Antagonistic Effect 2+2=1
Drug Interactions (con’t)
Alcohol and Foods
Preventive Methods
– Label
– Computerized record keeping
Adverse Drug Reactions (ADR)
– Allergies
– Negative side effects
– Minor or severe
– Local or systemic
– Seek Tx and requires discontinuation of drug
Guidelines for ATC’s
Read label for appropriate dosage
Consider possible interactions
Recognize adverse reactions and act quickly
IV and those absorbed thru thin most
mucus membrane take effect quicker than
oral administration
Drug effects are maximal at peak
concentration level, but ADME can all be
affected by a variety of factors
Be aware of all meds an athlete is taking