Basic Principles of Pharmacology Flashcards
Drug
Any chem that can affect the living processes
Pharmacology
Study of drugs & their interactions w/living sys
Therapeutics
The use of drugs to diagnose/prevent/treat disease or to prevent pregnancy
Objective of Drug Therapy
Provide max benefit w/ min harm
Properties of an Ideal Drug
Effectiveness, Safety, & Selectivity
Effective
Elicits response for which it is given
Safety
Cannot prod harmful effects
True or False (T/F): Not all drugs have the ability to cause harm.
F; ALL drugs have the ability to cause injury (especially for those w/increased doses/time infusing)
Selectivity
Elicits ONLY response for which it is given
Additional Properties of an Ideal Drug
- Reversible action
- Predictability
- Ease of administration
- Freedom from drug interactions
- Low cost
- Chemical stability
- Simple generic name
What should an ideal drug be able to do, in terms of, ease of administration?
Route of administration should be convenient & dose should be low
What are some advantages for a drug that has a convenient route of administration?
Can enhance patient adherence & decrease risk for adverse reactions
Does chemical instability increase or decrease a drug’s efficacy?
Decreases drug efficacy (can decrease if put in improper storage/put in a soln)
Factors that Determine the Intensity of Drug Responses
1) Administration (Dose, route, & time)
2) Pharmacokinetics (ADME)
3) Pharmacodynamics
4) Individual Variation (Drug interactions, physiologic variables, pathologic variables, genetic variables)
Steps in Preadministration Assessment
1) Collect baseline data (help eval therapeutic &adverse resp)
2) Identify High-Risk Patients via px hx, phys exam, lab data
3) Assess patient capacity for self care
Example of Preadministration Assessment
Measuring patient’s BP prior to administrating antihypertensive agents
Predisposing Factors for High-Risk Patients
1) Pathophysiology (liver & kidney impairment)
2) Genetic factors
3) Drug allergies
4) Lifespan considerations
Federal Pure Food and Drug Act
Set standards for drug quality & purity, in addition to strength
Food, Drug, & Cosmetic Act
All medications must be tested for safety, w/ results reviewed by FDA
Harris-Kefauver Agreements
Medications must be proven effective before marketing
Controlled Substance Act
Rules made for categorizing medications w/ potential for abuse
BPCA & PREA
Promote research in drug safety and efficacy in children w/ clinical trials
FDA Amendments Act
Include rigorous oversight of drug safety after approval
Schedule I Drugs
- High Potential for abuse
- No currently accepted medical use or treatment in US
- Lack of accepted safety
Schedule II Drugs
- High potential for abuse
- Currently accepted medical use in the U.S.
- Abuse may lead to severe psych/phys dependence
Schedule III Drugs
- Potential for abuse less than Schedule I & II drugs
- Currently accepted medical use in the U.S.
- Abuse may lead to mod/low physical dependence or high psych dependence
Schedule IV Drugs
- Lower potential for abuse < Schedule III Drugs
- Currently accepted medical use in the US
- Abuse may lead to lim phys/psychological dependence relative to schedule III substances
Schedule V Drugs
- Low potential for abuse rel to Schedule IV Drugs
- Currently accepted medical use in the U.S.
- Abuse may lead to limited phys/psych dependence rel to schedule IV drugs
- May be dispensed w/out medical reason
Random Controlled Trial (RCT)
Most reliable way to objectively assess drug therapies
3 Distinguishing Features of RCTs
1) Use of Controls
2) Randomization
3) Blinding
What is the purpose of using controls, randomization, and blinding in RCTs?
Minim the influence of personal bias on the results
In RCTs some subjects are given the ____ and others the ___.
new drug, standard treatment (placebo)
Control
Subject given the standard treatment/placebo
What is the purpose of randomization in RCTs?
Prevent allocation bias where subjects in the experimental group are different fro those in the control group
Blinded study
Clinical trial in which the patient (single-blind) or patient and investigator (double-blind) are unaware of which treatment the patient receives
Stages of New Drug Development
1) Preclinical testing
2) Clinical testing
-Phase II
-Phase III
3) Phase IV: Postmarketing Surveillance
Preclinical Testing Phase
Drugs eval for toxicities, pharmacokinetic prop, & potentially useful bio effects (takes 1-5 yrs)
-Tested on animals
Sufficient data obtained-> request FDA for permission to test in humans
-If granted-> get Investigational New Drug (IND) status
Clinical Testing Phase I
Can begin testing in healthy volunteers
Tests: Metabolism, pharmacokinetics, & biologic effects
Clinical Testing Phase II
Can begin testing in patients (500-5,000 receive it)
Tests for therapeutic utility & dosage range
Clinical Testing Phase III
Continue testing in patients
Tests for safety & efficacy
Upon completion-> applies to FDA for conditional approval of New Drug Application
Clinical Testing Phase IV: Postmarketing Surveillance
New drug is rel for gen use
Permits observation in large pop
Limitations in Testing Procedure for New Drug Development
1) Very limit info on med safety in women & children
2) Possibility of undetected adverse effects after going into the market
Medication Chemical Name
Describes med using chem nomenclature
Example of Med Chemical Name for Acetominophen
N-acetyl-para-aminophenol
Medication Generic Name
Name of drug assigned by US Adopted Names Council that is less complex than chemical name
Example of Medication Generic Name
Acetaminophen
Medication Trade Name
Name under which a drug is marketed under for ease of use and recall
Example of Med Trade Name for Acetominophen
Tylenol, Ofirmev, & APAP
Pharmacokinetics (ADME)
What the body does to the drug
Pharmacokinetics: Absorption
Movement from site of administration to bloodstream
What does the rate of absorption determine?
How soon effects will begin
What does the amount of absorption determine?
How intense the drug effects will be
What does the route of administration affect?
Rate & amnt of absorption
What are factors that can affect absorption?
1) Rate of dissolution
2) Surface Area
3) Lipid solubility
4) pH partitioning
Oral Med Administration (Capsules, Tablets) Barriers
Epithel lining of GI tract & capillary wall-> absorption is slow & variable
Advantages of Oral Med Administration
Easy & convenient to administer
Inexpensive & ideal for self-medication
Potentially reversible
Disadvantages of Oral Med Admin
Variability
Inactiv by gastric acid & digestive enzymes (possible N/V)
Patient must be conscious & cooperative
Sublingual & Buccal Med Administration Barriers & Absorption Pattern
Swallowing before dissoln allows gastric pH to inactiv med
Absorption pattern: Quick absorption syst via increased vascular membranes
Other Mucous Membrane Meds (Rectal/Vaginal) Barriers & Absorption Pattern
Barriers to absorption: Presc of stool in the rectum in the vagina limits tiss contract
Absorption pattern: Easy absorption w/ both local & systemic effects
Inhalation Med Barriers & Patterns of Absorption
Barriers to absorption: Inspiratory effort
Absorption pattern: Rapid absorption via alveolar capillary networks
IM & SQ Med Absorption Barriers & Pattern
Only barrier is capillary wall
Rapid absorption w/H2O sol drugs
IM & SQ Med Admin Advantages
Permits use of poorly soluble drugs & depot prep
IM & SQ Med Admin Disadvantages
Uncomfortable/possib painful
Inconvenient w/potential for injury
IV Med Absorption
Instantaneous absorption w/no barriers
IV Med Admin Advantages
Rapid onset
Permits use of large vol & irritant drugs
IV Med Admin Disadvantages
Irrev, inconvenient, & expensive
Not suited for self admin
Risk for fluid overload, infection, & embolism
Drugs must be H2O soluble
Pharmacokinetics: Distribution
Mvmnt of drugs into cells
Factors that Affect Distribution
1) Circulation
2) Cell membrane permeability
3) Plasma-protein binding
How does circulation affect distribution?
Conditions that inhibit blood flow delay med distribution
How does cell membrane permeability affect distribution?
Meds must be able to pass via tiss & membrane to reach target area
How does plasma-protein binding affect distribution?
The ability of a med to bind to a protein can affect how much the med will leave & travel to target tissues
Malnourishment & liver pathology can (increase/decrease) albumin stores?
They can decrease albumin stores
