Principles of Pharmacology Flashcards
Pharmocology
Study of how various substances interact with or alter the function of living organisms
Opium Expolsuion Act
In 1909 was created to stop import of opium
Food, Drug, and Cosmetic Act
In 1938 the US FDA was given enforcement authority for rules requiring that new drugs were safe and pure
FDA
Responsible for approving new drugs
Controlled Substances Act
Classifies certain medications into five categories with potential of abuse and addiction
Schedule 1
High Abuse potential:
May not be prescribed, dispensed, used or administered for medical use and has no recognized medical purpose
Ex: heroin, marijuana, lsd
Schedule 2
High Abuse Potential:
Has a medical purpose but is required t be under constant lock and key, records kept and proper storage
Ex: fentanyl, Ritalin, cocaine
Schedule 3
Lower Potential Abuse:
Must remain under lock and key with records kept and proper storage
Ex: hydrocodone, codeine, ketamine
Schedule 4
Lower Potential Abuse:
S/a 2-5
Ex: diazepam, lorazepam, midazolam
Schedule 5
Lower Potential Abuse:
S/a 2-5
Ex: narcotic cough drops
Synthetic
Made in a labratory
Sources of Medication exampls
Plant: atropine, aspirin, digoxin, morphine
Animal: heparin, antivenom, insulin
Microorganism: streptiknoase, antibiotics
Minerals: iron, magnesium, Sulfate, lithium
Medication Name
Given three different names
Chemical: very long name (sodium bicarbonate)
Generic Name: usually contain stem at the end of the name to link it to other medications lam, pine, lol, lal
Brand Name: Lasix, Tamiflu, Lopressor makes it easier to remember drug generic name
Pharmacodynamics
When a medication alters a function or process in the body
Pharmokinetics
The action of the body on a medication
Receptor Site with Medication
Either
1: ion passages may open or close
2: bio mechanical messenger becomes activated initiating other reactions in cell
3: normal cell function prevented
4: normal or abnormal function of cell begins
Exogenous
From outside of the body
Agonist Medications
Initiate or alter a cellular activity by attaching to receptor sites, prompting a cell response
Ex: opiates
Antagonist Medications
Prevent endogenous or exogenous agonist chemicals from reaching cell receptor sites and initiating or altering a particular cellularactivity
Ex: nalaxone
Affinity
Ability of a medication to bind with a particular receptor site
Medication Concentration and Affinity
Determine how many receptor sites are bound by that medication
-only certain amount of receptors and all receptors can be taken up
Minimum Concentration
Certain minimum of medication must be present to activate cellular activity
Threshold Level
When initiation or alteration of cellular activity begins
Potency
The concentration of a medication required to intpitiate a cellular response
-when potency is low, a higher concentration is needed
Efficacy
Ability to initiate or alter cellular activity in a therapeutic or desired manner
One-Response Curve
Relationship of medication dose or concentration and efficacy
-once threshold is reached increasing dose increases efficacy until maximum effect range is reached then increasing dose has no effect
Competitive Antagonists
Temporarily bind with cellular receptor sites, displacing agonist chemicals
-until wasted naturally by kidneys
Noncompetetive Antagonists
Premnently bind with receptor sites and prevent activation by agonist chemicals
-effects continue until new receptor sites are made or until new cells are made
-Ex:
Ketamine NCA of Glutamate of the CNS
Aspirin NCA of Cyclooxygenase causing antiplatelet effects
Partial Agonist
Attach to cellular receptor sites but do not cause as much change as other agonists
-effectively lower efficacy of other agonists
Chelating Agents
Bind with heavy metals such as lead, mercury, and arsenic in the body nod creating a compound that can be eliminated
Diuretic
Draws excess water from certain body tissues including the brain and the eyes while enhancing excretion of urine by the kidneys
Medication Distribution
Distribute into either water, lipids or fat, and protein
Water-Soluble medication
Higher weight based dosing must be administered to infants because they have a higher percentage of water compared to adults and elederly
Ex: digoxin
Fat and Lipid medication
Require higher weight based doses in elederly people because of a higher body fat percentage and increased fat distribution
Ex: benzodiazepines
Paradoxical Reaction
Clinical effects opposite from desired effect
Formula Ideal Body Weight
In KG
Men: 50 + (2.3 times patients height in inches over 5 feet)
Women: 45.5 + (2.3 times patients height in inches over 5 feet)
Temperature
Hyper and hypothermia can effect body absorption of medication
- fever causes tachycardia that increases hepatic blood flow increasing initial metabolism of drugs in the liver and decreasing amount of drug delivered to circulation
- hypothermia impairs acls Medications. Atropine and lidocaine generally seen as ineffective.
Genetic Factors
Primary Pulmonary Hypertension: may have acute decompensation when vasopressor medications are used
Aspirin: may precipitate hemolysis in patients with bleeding disorders
Sickle Cell: medications such as lasix (diuretics) or alpha 1 agonists may fatally worsen condition
Pregnancy
Hematocrit (percentage of RBC’s in plasma decrease due to increase in plasma)
Categories Desgined:
A- no risk to fetus
B- may have been effect in rates but none shown in women
C- are adverse effects on pregnancy. Drugs given only if benefit outweighs risk
D- fetal risk apparent.
X- fetal abnormalities. Contraindicated in pregnant women.
Placebo Effect
Fake medication given and still seen to cause change
Therapeutic (desired) Response
One that achieves a desired result by medication administration
Cumulative Action
Using multiple medications to achieve desired result
Adverse Medical Effects
untoward effects
Clinical changes, caused by medication, that are not desired and cause some degree of harm or discomfort to the patient
Ex: hypoglycemia after insulin administration, bradycardia after beta blocker, and allergic reaction
Stevens Johnsons Syndrome
Severe possible fatal medication administration reaction that mimics a burn
Idiosyncratic Reaction
Abnormal susceptibility to a medication due to genetic factors, dysfunction of metabolic enzyme, and peculiar to patient
Median Lethal Dose
LD50: weight based dose that caused death in 50% of animals tested
Median Toxic Dose
TD50: 50% of animals tested had toxic effect at or above weight based dose
Median Effect Dose
ED50: does not harm and achieves desired effect
Therapeutic Index
Relationship between ED and LD or TD
-If a large gap between lethal and effective it is relatively safe. If not, must be used very carefully
Medication Sensitivity
Adverse reaction not desired such as hives or allergic reaction
Tolerance
When a medication is constantly taken and causes the patient to have a decrease in efficacy
Down Regulation
When a patient builds a tolerance it decrease available cell receptors
Cross Tolerance
When using a certain medication in a class becomes tolerant to medications of the same class such as benzodiazepines
Tachyphylaxis
Repeated doses of medication within a short time frame rapidly causing tolerance making medication virtually ineffective
Ex: dobutamine, nitroglycerin
Stimulant
Increase in physical, mental and emotional performance
Ex: caffeine, cocaine, amphetamines
Increase HR and BP
Depressant
Decrease CNS causing section, reap depression, bradycardia, hypotension.
Ex: benzo’s, alcohol, opiods
Interference
When patients take other drugs that interfere with desired effect of given drug by paramedic
Onset
When medications begin to work
Peak
Medication is at max effectiveness
Duration of Action
How long medication causes effect on body
Bioavailability
Chosen route of administration determines percentage of unchanged medication that reaches circulation
Synergism
1+1=6
When two medications of similar effect combine to form a greater effect than sum of medications
Ex: benzodiazepines with opiod analgesics
Potentiation
Effect greatly enhanced by presence of another medication
Ex: phenegran given to increase effects of codeine or other antitussives
First Pass Metabolism
Drug travels from GI to portal vein to liver to be metabolized
-when liver is damaged, less first pass metabolism happens and the drug reaches systemic circulation with a greater bioavailability
IN
Intranasal
Close to 100% bioavailability
Good as an IV without attempting a line and has same effects almost
Ex: sublimaze, versed, nalaxone
IV
100% bioavailability
Sympathomimetic and electrolyte solutions scan cause severe tissue damage if infiltrated
IO
Any IV medication can be given IO
CAN BE LEFT IN PLACE FOR UP TO 24 hours
Contraindicated in bone fractures, bone diseases or skin infection over area
IM
Intramuscular
75-100% bioavailability
Absorption determined by perfusion to muscle and accuracy of administration
SC
Subcutaneous
Abdomen or skin overlaying tricep good landmarks
Rectal
Preferred over oral
Used in seizures, unconscious, vomiting or unable to swallow
Not usually subject to first pass metabolism
90-100% bioavailability
Suppository form, lubricated and entered into rectum ditspally preferred over proximal rectum
Rectal Dose often higher than oral or IV dose
Active Metabolites
Altering cell process or body function
Cytochrome P-450 System
Where most biotransformation occurs. System in the liver that uses a complex, enzyme based process to alter the chemical structure of a medication or other chemical.
Certain pathways within the Cp-450 system are responsible for the metabolism of different medication groups
Kidneys, skin, lungs, GI tract
Other biotransformation occurs
-other words, biotransformation makes medications and chemicals more water soluble and easier for the kidneys and other organs to eliminate from the body
Medication Elimination
Primarily eliminated from the kidneys
And excreted into urine
Zero Order Metabolism
Fixed amount of substance is removed during a certain period, regardless of total amount in the body
Ex: alcohol, duration of intoxication is related to initial plasma levels
First-order Metabolism
Rate of elimination directly influenced by plasma levels of the substance
-quantified by medication half life
6 Rights
Patient Time Dose Medication Route Documentation
Benzodiazepines
Diazepam, Lorazepam, Midazolam
- antiseizure, anxiolytics, sedative properties
- high doses needed for airway sedation
- hypotension
- only administered to pregnant patients during life threatening situations; Class D
- Romazicon competitive benzodiazepines antagonist
Chemical Paralytic Agents
Provide muscle relaxation that facilitates airway placement
- Allow better visualization of cords compared to just sedatives
- Normal* nerve cells release acetylcholine which binds to nicotonic receptor sites on muscle cells causing contraction. Paralytic bind and antagonize nicotonic receptor sites preventing activation by Ach.
Succinycholine
Competitive depolarizing paralytic agent
- reaches nicotonic receptors and causes a brief activation known as fasiculations and prevents further Act of acetylcholine
- Rapid Onset 30-60 seconds and brief Duration 3-8 minutes
- Contraindicated: hyperkalmeia, Bradycardia, elevate intraocular pressure, malignant hyperthermia, burns, lumbi Indian
Fasiculations
Muscles twitch and move temporarily due to activation of nicotonic receptors
Malignant Hyperthermia
Causes a fast rise in body temperature and causes severe muscle contractions when given anasthetic and is passed down from families
Nondepolarizing paralytics
Compete with Ach at nicotonic receptor sites. They occupy but not activated receptor sites, preventing Ach activation
-Longer duration than depolarizing paralytic and less adverse reactions
Sedative Hypnotic Agents used in Airway
Etomidate and Ketamine are two ultra short acting sedative medications used to facilitate airway management
-Etomidate: imidazole derivative with minimal effect on BP. Onset is 30-60 seconds Duration is 5 minutes
No more than one dose given
-Ketamine: causes profound disassociation and general anesthesia. Maintains BP and HR but raises ICP so not good for head injury patients. Causes some degree of bronchodilator.
Beta Agonist Medications
Beta Adrenergic Medications remain primary treatment for acute bronchospasm with asthma, COPD, and others.
- walls of lower airways contain smooth muscle that contract or relax in response to biochemical changes and external irritants
- beta-2 receptor sites on bronchial smooth muscle cause muscle relaxation and bronchodilator effects
- nor Epi and Epi natural occurring beta 2 agonists
- beta agonists medications can be selective, or non selective, only targeting beta 1 or beta 2.
- Some beta 2 medications cause beta 1 effects such as Albuterol that causes tachycardia
- Albuterol can facilitate uptake of potassium
Mucokinetic and Bronchodilator
Atrovent
-Antagonizes muscarinic receptors causing bronchodilation and decrease mucus in upper and lower airways. Cardiovascular effects limited due to poor systemic absorption.
Corticosteroids
Administered to reduce airway inflammation to improve oxygenation and ventilation
- Methylprednisolone and Decadron
- Have immunosupressant properties and can alter Endocrine functions
Cardiovascular Medications
Antidysrhytmic Meds specifically target cells within the heart to resolve a dysrhytmia or suppress ectopic focci (sites conducting other than primary pacemaker)
Vaughan Williams classification Scheme
The classification of dysrhythmia Medications based upon mechanism of action rather than specific groups
Cardiac Cycle
0-4 phases
Cycle begins at 4
Phase 4
Cardiac cells are at rest waiting for generation of spontaneous impulse from within (automaticity)
-coincides with diastole of the heart
Phase 0
Begins with rapid influx of sodium ions through channels in the cardiac cell and
Potassium ions slowly begin to exit the cell and depolarization occurs
Phase 1
Sodium influx decreases while potassium continues to leave the cell
Phase 2
Movement of calcium into the cardiac cell
While potassium continues to leave
Phase 3
Calcium movement ceases with continued outflow of potassium
-Phases 2-3 repolarization and myocardial contraction occur
Absolute Refractory Period
During phases 0-3 no additional depolarization may occur because of external stimuli
-ensures that a certain amount of time passes between myocardial contractions
Relative Refractory Period
Immediately follows absolute Refractory Period which is a brief window to initiate depolarization
Phases
\_\_\_\_\_|'''---,,,,,\_\_\_\_ \_\_\_= phase 4 | = phase 0 ''' = phase 1 --- = phase 2 ,,,, = phase 3
Class I Antidysrhytmics
Slow movement of sodium through channels in certain cardiac cells
- Procainamide and Lidocaine
- Lidocaine blocks sodium channels through purkinje fibers and ventricle, effectively resolving various ventricular dysrhtymias and suppressing ectopic foci
Class II Antidysrhytmics
Beta Blockers
- Directly inhibit catecholaimnes (Epi nor Epi)
- metoprolol and lebatolol
- Metoprolol beta blocker used to reduce heart rate during MI and in certain atrial tachycardias. Reduces heart rate with reduction in BP
Class III Antidysrhytmics
Increase duration of phases 1, 2, and 3
By extending cellular action potential, these medications prolong the absolute Refractory Period treating atrial or ventricular tachycardias
-Amiodarone: atrial and ventricular tachycardia by blocking sodium potassium channels
Class IV Antidysrhytmics
Calcium Channel Blockers
Used for reducing BP or heart rate
Anatagnize certain calcium receptor sites which slow conduction through av node, decrease automaticity of ectopic focci, and decrease dromotropic effects of cardiac conduction
-Cardiazem and Verapamil : used for control of heart rate in patients with a fib or a flutter. Cardiazem has less effect on BP
-Antidote is Calcium Gluconate or Chloride
Adenosine
Member of fifth and unnamed antidysrhythmic
Treats PSVT or SVT
-Decreases cardiac conduction dromotropic effects and prolongs relative absolute Refractory Period producing several second pause. Half life less than 10 seconds.
ACE Inhibitors
Antagonize the system that causes vasoconstriction and fluid retention in response to hypotension or hypoperfusion
- decrease blood pressure and cardiac afrerload
- treats hypertension, myopathy, CHF
- angiodema may occur when taking ACE inhibitors
Anticholinergics
Vagus Nerve is biggest parasympathetic Nerve in body responsible for heart lungs and digestive tract
- vagus nerve release aCH that acts on muscarinic 2 receptors in the heart to decrease heart rate and can cause activation of fluid mucus to accumulate
- Atropine: competitive muscarinic receptor antagonist that decreases effect of acetylcholine on heart effectively raising heart rate. Used when suspected vagus nerve is the problem such as patient strains, mechanical pressure applied to neck, and is ineffective in high degree heart blocks
- used before airway manipulation that may stimulate vagus nerve
- low dose < .1-.2 mg can cause paradoxical bradycardia
Catecholamines
Naturally occurring chemicals in the body that stimulate receptor sites in sympathetic nervous system
Epi, nor Epi, dopamine
Sympathomimetics
Not naturally found within the body. Mimic naturally occurring sympathetic.
Dopamine
Different affects at different doses due to different sites that the affinity of the medication begins to work on
-Dopaminergic Receptor Sites worked on at
2-5mcg/kg/min causing renal and mesenteric artery vasodilation
-Beta 1 Receptor sites activated at 5-10mcg/kg/min causing increased heart rate and increased contractility
-Alpha Receptor sites activated at 10-20 mcg/kg/min causing profound vasoconstriction
Vasodilators
Used for hypertension, CHF, mi, cardiogenic Shock
Nitroglycerin: vasodilator that primarily dilates veins and coronary arteries decrease cardiac preload, reducing oxygen demand, and improving circulation
Nitroprusside is potent IV vasodilator affecting smooth muscle of the veins and arteries. Used for malignant hypertension.
Diuretics
Correct volume overload such as CHF and pulmonary edema to improve respiration.
- Furosemide causes renal artery dialation and promotes urinary excretion working on distal loop of henle
- Mannitol osmotic diuretic that is used to decrease ICP. Osmotic Diuretics can target specific tissues decreasing pressure in the brain and eyes
Plasma
Increases clotting factors in body 225-250ml of plasma just like blood
RBC’s
Correct anemia in hypovolemia patients
-come packaged in 225-250 ml of RBC’s
Platelets
Administered to correct thrombocytopenia
Or a low platelet level causes by trauma, hemmorage, and anticoagulant medications
-must be blood type and Rh compatible
Anticoagulants
Impair the function of clotting or coagulation chemicals in bloodstream
- Enhance the function of substances in the blood that inhibit clot formation and prevent formation of new clots and the growth of existing clots but they do NOT dissolve existing blood clots
- Heparin : enhance antithromib III to inhibit blood coagulation
Antiplatelets
Reduces clumping of platelets preventing new thrombus or extension of new clot
- Aspirin : prevent thrombus formation
- Plavix and Ticlid also antiplatelets
Fibrinolytics
Dissolve blood clots in arteries and veins
Analgesics
Stimulate opiod receptors in body to relive pain
Medications act on Mu opiod receptors causing respiratory depression, hypotension
-Demerol, Dilaudid, Morphine, Fentanyl,
-Morphine cause nausea/vomiting in 30% of patients and may also cause histamine release causing itching
Phenytoin and Fosphenytoin
Dilantin and Cerebyx used to prevent seizure activity
Histamine 2 Receptor Antagonists
Decrease acid in stomach, protecting against ulcers or other GI issues
-Zantac, Tagamet, Pepcid (famatodine)
Antiemetics
The ‘zine’
Phenegran is an antiemetic to help with nausea and vomiting
Activate dopaminergic receptors in brain that inhibit emesis
-Ondansetron and ‘trons’ are 5-HT3 Receptor Antagonists and may cause potential QT prolongation
-5-HT3 are receptors present in brain that prdouce some reasons for vomiting
Acetaminophen
Tylenol is an antipyretic and analgesic
Elevated levels can cause liver damage
Calcium Preperations
Used for:
- Antidote to ca channel blocker OD
- Mag Sulfate toxicity
- Dysrhythmia prevention with hyperkalemia
- Hypocalcemia
- Calcium restoration after HFl acid burn
- Prevent hypotension with verapamil
Diphenhydramine
Benadryl is a competitive histamine 1 receptor Antagonists preventing recptor activation of histamine release
- Anaphylaxis
- Allergic Reaction
- Sedative
- Anitussive
- Dystonic Reaction
- Pruritus
- Rinorrhea dries mucous membranes
Glucagon
Converts glycogen stores in liver into glucose for hypoglycemia
- Beta Blocker overdose by producing chronotropic and inotropic effects but require a lot
- Upper Airway Obstruction by relaxing smooth muscle in the GI tract possibly allowing object to pass into stomach for disgestion
Ketorolac
Toradol, non steroidal antiinflammatory that inhibits prostaglandin synthesis, treating both pain and inflammation.
-Avoid with GI bleed or similar disorder
Mag Sulfate
IV electrolyte that treats:
- Torsades
- Hypomagnesia, common in malnourished patients from alcoholism
- Seizures in pregnant patients with pre or eclampsia
- Bronchodilators for Refractory asthma
Sodium BiCarb
Alkilizing agent that is used for metabolic acidosis
-Raised blood pH
-Stabilize profound hyperkalemia
-Tricylic Antidepressnt OD
-Promote urinary secretion of certain tissue waste products
-Use din crush injuries for built up of lactic Acid
Wipes out catecholamines delivered since catecholamines are acidic.
Thiamine
Vitamins B1 an corrects B1 deficiency in malnourished or chronic alcoholic patients
-deficiency in thiamine can cause wernicke encephalopathy, neurological disorder exacerbated by lack of thiamine and use of dextrose
