LESSON 1: Principles and Concepts of Pharmacology Flashcards
Why study pharmacology?
Healthcare workers need to have knowledge about the actions and effects of medications
What is pharmacology?
The study of drugs
What is a substance that brings about a change in biological function through its chemical actions
Drug
WHO defines a drug as _____
Something that gives benefit to the recipient
Drugs produce _____
A biologic effect
Sources of drugs
- Made from snthetic chemicals
- Extracted from plants or animals
- Products of genetic engineering
What is the preferred term by WHO for drugs with therapeutic use?
Medicine
What are the effects of drugs that are non-therapeutic and used as a recreation?
- Addictive
- Narcotic
- Mind-altering
Describes the drug’s chemical composition and molecular structure
Chemical name
Example: 2-(p-isobutylphenyl) propionic acid
Name given by the Unites States Adopted Name Council
Generic name (nonproprietary name)
Example: Ibuprofen
The drug has a registered trademark; use of the name restricted by the drug’s patent owener (usually the manufacturer)
Trade name (proprietary name)
Example:
Motrin (other countries),
Advil (Philippines)
How is drug classified?
Catergorize medications with similar characteristics by their class
Medication classification indicates:
* Effect on the body system
* Symptom it relieves
* Desired effect
Examples of classification based on body system
- Cardiac drug
- GI drug
- CNS drug
Examples of classification based on symptom the medication relieves
- Pain-reliever
Examples of classification based on the medicine’s desired effects
- Oral hypoglycemics
- Antihypertensive medications
True or False: A medication may also be part of more than one class
True
Example: Aspirin
* Analgesic: relieves pain
* Antipyretic: relieves fever
* Anti-inflammatory: relieves inflammation
* Anti-platelet: prevents stroke recurrence
True or False: Medications are available in a variety of forms and preparations
True
True or False: The form of the medication will determine its route of administration
True
The composition of medication is designed to _____
Enhance its absorption and metabolism
One can alter the characteristics of absorption and design a formulation that is easier to absorb
Enumerate the medication forms
- Tablet
- Capsule
- Elixir
- Enteric-coated
- Suppository
- Suspension
- Transdermal patch
Which of the medication forms: drug with alcohol as a base; usually sweet
Elixir
Which of the medication forms: prevents the dissolution of drugs in the stomach and absorbed later in the intestine
Enteric-coated
Which of the medication forms: placed in the anus
Suppository
Which of the medication forms: drugs that you mix with liquid
Suspension
Which of the medication forms: drug is absorbed through the skin
Transdermal patch
Example: Some anti-hypertensive medication, medication for dizziness
Concepts as to how drugs can reach the market
New Drug Development
Conducted in a regulatory facility after it has completed animal testing
Investigational new drug (IND) application
Must be obtained for all human test subjects
Informed consent
Can be completed only after approval
Investigational drug studies
A shortened process used for life-saving drugs
Medications must show early promise in Phases I and II
Expedited drug approval
Which clinical phase of investigational drug studies: A small number of healthy subjects are used
Phase I
Determing possible adverse effect
Which clinical phase of investigational drug studies: Small number of volunteer subjects who have illness
Phase II
Determine the possible dosing in a small number of patients
Which clinical phase of investigational drug studies: Large number of subjects are used
Phase III
Which clinical phase of investigational drug studies: Post-marketing
Phase IV
Determine drug reactions that are very rare
Concerned with the use of chemicals in the prevention, diagnosis, and treatment of disease
Medical Pharmacology
Concerned with the use of chemicals in the prevention, diagnosis, and treatment of disease
Medical Pharmacology
Concerned with undesirable effects of chemicals on living systems and deals with the adverse effects of drugs and poisonous effects of various chemicals
Toxicology
Scientific discipline that involves all aspects of the relationship between drugs and humans; involves both therapeutic and non-therapeutic use of drugs
Clinical Pharmacology
Scope of Pharmacology:
Deals with genetically mediated variations in drug responses; Involves the study of a population
Pharmacogenetics
Scope of Pharmacology:
The use of genetic information to guide the choice of drug therapy on an individual basis; Involves the study of the effect of a particular drug for** one particular person** given that we have knowledge about the genetic make-up of that particular person
Pharmacogenomics
Scope of Pharmacology:
Deals with the development of new drug delivery systems and new dosage forms
Biopharmaceutics
Scope of Pharmacology:
Study of drug effects at the population level; Helps in regulation of drugs
Pharmacoepidemiology
Scope of Pharmacology:
Deals with the use of chemotherapeutic agents to** inhibit or destroy invading microbes, parasites or cancer cells** with minimal effect on healthy living tissues
Chemotherapy
Scope of Pharmacology:
Branch of pharmacology that deals with identification, selection, preservation, combining, analyzing, standardization, preparing, compounding and dispensing of medicines for administration to the patient.
Pharmacy
Pharmacist prepares compounds and dispenses medicines upon written order
Scope of Pharmacology:
Branch of pharmacology that deals with the source of drugs derived from plants and animals; Study of physical and chemical properties of such substances
Pharmacognosy
Pharmacologic Principles
How various drug forms influence pharmacokinetic and pharmacodynamic activities
Examines the difference between injectable medications, oral formulations such as capsules and tablets, and control-release medications
Pharmaceutics
Pharmacologic Principles
The study of what the body does to the drug
* Absorption
* Distribution
* Metabolism
* Excretion
* Relationship of dose and concentration
Involves the study of the drug dose and drug levels
Involves the study of the drug and what happens to the drugs before it gets to its are of action
Pharmacokinetics
Pharmacologic Principles
The study of what the drug does to the body
* Actions of the drug on the body
* Mechanism of drug actions in living tissues
* Relationship between drug concentration and pharmacological response
Involves the study of the drug concentration and pharmacological response
Involves the study of what would happen if a drug binds to a receptor
Pharmacodynamics
Pharmacologic Principles
The use of drugs and the clinical indications for drugs to prevent and treat diseases
Pharmacotherapeutics
Pharmacologic Principles
The study of natural (plant and animal) drug sources
Pharmacognosy
Pharmacokinetics
Movement of drug from the site of administration to the systemic circulation (intravascular)
Absorption
Measures the extent to which drug is absorbed
Bioavailability
It means that the drug has the same bioavailability in the same concentration of the agent when given to a person.
Bioequivalent
Factors that affect absorption
- Administration route of the drug
- Ability of medication to dissolve
- Food or fluids administered with the drug
- Body surface area
- Status of the absorptive surface
- Rate of blood flow to the small intestine
- Lipid solubility of medication
- Status of GI motility
True or False: A drug’s route of administration affects the rate and extent of absorption of that drug
True
Route of Administration:
Drug is absorbed into the systemic circulation through the oral or gastric mucosa, the small intestine, or rectum
Enteral Route (GI Tract)
A drug given orally may be extensively metabolized by the liver before reaching the systemic circulation
First Pass Effect
First-Pass Routes
- Hepatic artery
- Oral
- Portal Vein
- Rectal
Non First-Pass Routes
- Aural
- Buccal
- Inhalation
- Rectal
- Intraarteria
- Intramuscula
- Intranasal
- Intraocular
- Intravaginal
- Intravenous
- Subcutaneous
- Sublingual
- Transdermal
Route of Administration:
Provides peak concentration because it immediately reaches the bloodstream
Parenteral
Fastest delivery into the blood circulation
Intravenous
Route of Administration:
Used only if you want the effect to be local and not diffuse
If the drug needs to be continuously released in the body without
taking them per orem
Topical
The transport of a drug in the body by the bloodstream to its site of action
Distribution
Factors that affect distribution
- Protein binding
- Water soluble vs. fat soluble
- Blood-brain barrier
- Areas of rapid distribution: heart,liver, kidneys, brain
- Areas of slow distribution: muscle, skin, fat
The biologic transformation of a drug into an inactive metabolite, a more soluble compound, or a more potent metabolite
Metabolism
Liver (main organ), kidneys, lungs, plasma, intestinal mucosa
Delayed drug metabolism causes _____
- Accumulation of drugs
- Prolonged action of drugs
Stimulating drug metabolism causes _____
- Enhancement in metabolism
- Inhibition of metabolism
Mediated by cytochrome P450 enzymes (e.g. CYP1A2, CYP2D6, CYP3A4)
* Oxidation, deamination, desulfuration, reduction, hydrolysis
* These enzymes are largely targeted against lipid-soluble and non-polar (no charge) drugs which are difficult to eliminate
Majority of medications are lipid soluble and non polar
Phase I Reaction
Metabolizes 50% of drugs metabolized in the liver
CYP34A
Usually renders drug polar and excretable in kidneys
* Conjugation, glucuronidation, acetylation, sulfation
Phase II Reaction
The elimination of drugs from the body by making it water soluble
Excretion
Kidneys (main organ), liver, bowel
Study of the mechanism of drug actions in living tissues
* Drug-induced alterations to normal physiologic function
* Goal of therapy: Therapeutic effect
Pharmacodynamics
Ways in which a drug can produce a therapeutic effect
Mechanism of action
True or false: The effect of a particular drug depends on the cell or organ targeted by the drug
True
Once the drug binds to its “site of action” it can modify the rate at which a cell or tissue functions
Drug binds to a receptor and induce an effect
Receptor interaction
Degree to which a drug binds with a receptor
Affinity
True or false: The drug with the best “fit” or affinity will elicit the best response
True
Drug binds to receptor → there is a response
Agonist
Example: Adrenergic agents such as Epinephrine
Drug binds to receptor → there is no response; prevents binding of agonists
Antagonist
Examples:
Alpha blockers (propanolol and atenolol)
Beta blockers
Drug can inhibit or facilitate the action of a particular enzyme
Enzyme interaction
Drugs will physically interfere with or chemically alter cell process → final product is altered causing cell defect or cell death
Non-specific Interaction
Disintegration of dosage form and dissolution of drugs depending on the form of drug and where it is given
Pharmaceutical phase
Drugs will be absorbed, distributed, metabolized, and excreted even before it reaches the drug receptor
Pharmacokinetic phase
Drug-receptor interaction
Pharmacodynamic phase
Sites of drug actions
- Action potential in nerve presynaptic nerve fiber
- Synthesis of transmitter
- Storage
- Metabolism
- Release
- Reuptake
- Degradation
- Receptor of transmitter
- Receptor-induced increase or decrease in ionic conductance
Types of medication action
- Therapeutic Effect
- Side Effects
- Adverse Effects
- Toxic Effect
- Idiosyncratic Reactions
- Allergic Reaction
- Medication Interactions
- Iatrogenic Response
Unintended secondary effects a medication predictably will cause
Side Effects
The expected or predictable physiological response a medication causes
Therapeutic Effects
Undesirable response of a medication; Unexpected effects of drug not related to therapeutic effect; Must be reported to FDA; Can be a side effect or a harmful effect
Adverse effects
A category of adverse effects: which is the extension of therapeutic effect
Pharmacologic
A category of adverse effects: which is specific only to a particular patient
Idiosyncratic
A category of adverse effects: which is an allergic reaction
Hypersensitivity
It is a type of ADE. Defined as any response to a medication that is ‘noxious or unintended and occurs at normal doses’ in patients for whom the drug has been properly prescribed and administered.
Adverse Drug Reactions (ADE) ADR
May develop after prolonged intake or when a medication accumulates in the blood because of impaired metabolism or excretion, or excessive amount taken
Toxic Effects
Toxic levels of opioids can cause ______
respiratory depression
Antidotes available to reverse effects such as____
Naloxone
Unpredictable effects-overreacts or under reacts to a medication or has a reaction different from normal
IDIOSYNCRATIC REACTIONS
Idiosyncratic drug reactions are usually caused by abnormal levels of drug-metabolizing enzymes. ______ leads to toxicity, _____leads to not getting its therapeutic effect
Overabundance; Deficiency
Unpredictable response to a medication. Makes up greater than 10% of all medication reactions
Allergic reaction
Severe allergic reactions
Anaphylactic reaction
Mild allergic reactions
hives, rash, pruritus
Other types of drug reactions: Structural effect in unborn fetus (thalidomide)Fetus doesn’t develop limbs properly
Teratogenic
Other types of drug reactions: Causes cancer
Carcinogenic
Other types of drug reactions: Changes genetic composition (radiation, Chemicals)
Mutagenic
Occurs when one medication modifies the action of another; Common in people taking several medications at once
Drug interactions
Unintentional adverse effects that occur during therapy
Iatrogenic responses
Drug interaction that is beneficial (sometimes can be bad). Effect of 2 meds combined is greater than the meds given separately.
Synergistic effects
Alcohol & Antihistamines, antidepressants, barbiturates, narcotics; All can depress _____, should not be given to sleeping patient
Sensorium
_____ are required to achieve a constant therapeutic concentration of a medication because a portion of medication is always being excreted
Repeated doses
Time it takes for excretion processes to lower the serum medication concentration by 1⁄2
Serum Half-life
Usually done for drugs with a very narrow therapeutic range
Therapeutic drug monitoring
The time it takes for one half of the original amount of a drug in the body to be removed
Half life
Number of half lives that is considered as steady state
4-5 Half lives
The time it takes for the drug to elicit a therapeutic response
Onset
The time it takes for a drug to reach its maximum therapeutic response
Peak
The time a drug concentration is sufficient to elicit a therapeutic response
Duration
Type of therapy: Give the drug once to relieve pain
Acute therapy
Type of therapy: Taken regularly to control the blood pressure, or blood levels
Maintenance therapy
Type of therapy: Replace something that the patient does not have (ex. Insulin)
Supplemental therapy
Type of therapy: Maintain comfort for the patient, not treating the condition anymore
Palliative therapy
Type of therapy:Supports and maintains body functions, but not necessarily treat the condition
Supportive therapy
Type of therapy: Drugs given so that certain conditions would not recur
Prophylactic therapy
Type of therapy: Drugs used based on actions, rather than scientific evidence.
Empiric therapy
The ratio between a drug’s therapeutic benefits and its toxic effects
Therapeutic index
The ratio between a drug’s therapeutic benefits and its toxic effects
Therapeutic index
A decreasing response to repetitive drug doses
Tolerance
A physiologic or psychological need for a drug
Dependence
Drug interactions: the alteration of action of a drug by:
- Other prescribed drugs
- Over-the-counter medications
- Herbal Therapies
Drug interactions:
Additive effect
Synergistic effect
Antagonistic effect
Incompatibility
What are the Five Rights of Medication Administration?
○ Right drug
○ Right dose
○ Right time
○ Right route
○ Right patient
Always_____ the entire “system” of medication administration. This involves ordering, dispensing, preparing, administering, documenting
double check
Other “rights” : (familiarize)
● Proper drug storage
● Proper documentation
● Accurate dosage calculation
● Accurate dosage preparation
● Careful checking of transcription of orders
● Patient safety
● Close consideration of special situations
● Prevention and reporting of medication errors
● Patient teaching
● Monitoring for therapeutic effects, side effects, toxic effects
● Refusal of medication
What is the relevance of medication shapes?
It’s just that it can help differentiate your drug from other manufacturers’ drugs. (For tablets taken orally)
What are the drugs that are commonly enteric coated?
Aspirin
How long does a medication need to be taken before it acquires a toxic effect?
It becomes toxic, for example, if it exceeds the patient’s ability to metabolize the drug
What if the dose you take is much more than what can be handled by the liver?
you saturate the enzymes that act to break it down, then you’re going to have toxicity.
What happens if we crush the tablet and mix it with water or milk? Will it still remain effective or still have the same effects?
There are certain drugs that you cannot mix with certain foods. Most likely, marami pwede pero ‘di lahat.
What is the reason why enteric-coated drugs are given?
to prevent gastric irritation
Is there an effect whether the drug is synthetically produced or naturally based?
if they have the same chemical structure, there will be no difference in the degree of effectivity.
