[1] PRELIMS | INTRODUCTION TO PHARMACOLOGY Flashcards
Basic Principles of Pharmacology
The science concerned with history, sources, physical, and chemical properties of drugs, in ways in which drugs affect biological systems
Pharmacology
Basic Principles of Pharmacology
Chemical entities, both endogenous and foreign, that are capable of reacting with biological systems
Drug
Basic Principles of Pharmacology
Are chemicals that are introduced to cause some sort of change
Drugs
Basic Principles of Pharmacology
Science of preparing, compounding, and dispensing medicines
Pharmacy
Basic Principles of Pharmacology
Identification and preparation of crude drugs from natural sources
Pharmacognosy
Basic Principles of Pharmacology
Study of poisonous aspects of drugs
Toxicology
‘Toxic’ = ‘Posionous’
Branch of Pharmacology
Also known as clinical pharmacology
Uses drugs to treat, prevent, and diagnose diseases
Pharmacotherapeutics
Concerns of Pharmacotherpeutics
How the drugs are affected by the biological system
Pharmacokinetics
What the body does to the drug
Concerns of Pharmacotherapeutics
Effects of drugs in a biological system
Pharmacodynamics
What the drug does to the body
Drug Names
Chemical structure of the drug
Chemical name
Drug Names
Official nonproprietary name of drugs, universally accepted
Generic name/Official name
Ex. Diphenhydramine
Drug Names
Proprietary name, chosen by drug company
Brand name/Trade
Ex. Benedryl (Diphenhydramine)
A drug may have one generic name but many brand names
Sources of Drugs
- P___ Source
- M___ Source
- A___ Source
- S___ drug Source
- M___ Source
- Plant Source
- Mineral Source
- Animal Source
- Synthetic drug Source
- Microorganism Source
Drug Development
Tests to see if the drug is safe and its pharmocokinetics
20-100 subjects
Clinical Testing | Phase 1
3rd Stage
Drug Development
Where biologic products and chemical synthesis and optimization creates a lead compound
In Vitro Studies
1st Stage
Drug Development
Testing of the efficacy selectivity mechanism of the drug
Animal Testing
2nd Stage
Drug Development
Tests to see how if the drug works/effective in patients
100-200 patients
Clinical Testing | Phase 2
3rd Stage
Drug Development
Tests to see if the drug works double blind
1000-6000 patients
Clinical Testing | Phase 3
3rd Stage
Drug Development
Postmarketing surveillance of the drug which lasts for 10-20 years
Drug can be released to the market
Clinical Testing | Phase 4
4th Stage (Marketing)
Drug Development
Generics become available only after ____ years as the patent expires
20 years
Classification of Drugs
Need to be prescribed before acquired
Prescription Drugs
Ex. Antibiotics
Classification of Drugs
Medications that can buy without a prescription
Over the Counter Drugs (OTC)
Classification of Drugs
Drugs that are not yet known and are under clinical trials
Investigational Drugs (ID)
Classification of Drugs
Prohibited substances and should not be sold to the public
Ilicit or Street Drugs
Process of Pharmacokinetics
The entry of a drug into the systemic circulation from the site of administration
Absorption
Physical factors are to be considered prior to absorption
Physico-chemical Considerations For Drug Passage Across Barriers
- ____ of plasma membrane
- Presence of ____
- ____ of extracellular environment
- ____ of drugs
- Selectively permeability of plasma membrane
- Presence of membrane proteins
- pH of extracellular environment
- Ionization of drugs
Absorption
Where drugs administered orally are first exposed to the liver and may be extensively metabolized before reaching the rest of the body
First Pass Hepatic Metabolism
GI Tract -> Portal Circulation -> Systemic Circulation
Clinical Relevance of First Pass Hepatic Metabolism
Drugs with high first pass metabolism should be given in ____ to ensure that enough active drug reaches the desired site of action
doses sufficient enough
Absorption
The measure of the fraction of a dose that reaches the systemic circulation
Bioavailability
Bioavailability
By definition, ____ doses have 100% bioavailability
intravascular (IV)
Common Routes of Administration
- Bioavailability: 100
- Most rapid onset
Intravenous (IV)
Common Routes of Administration
- Bioavailability: 75 to < or = 100
- Large volumes often feasible, may be painful
Intramuscular (IM)
Common Routes of Administration
- Bioavailability: 75 to < or = 100
- Smaller volumes than IM, may be painful
Subcutaneous (SC)
Common Routes of Administration
- Bioavailability: 5 to <100
- Most convenient; first-pass effect may be important
Oral (PO)
Common Routes of Administration
- Bioavailability: 30 to <100
- Less first-pass effect than oral
Rectal (PR)
Common Routes of Administration
- Bioavailability: 5 to <100
- Often very rapid onset
Inhalation
Common Routes of Administration
- Bioavailability: 80 to < or = 100
- Usually very slow absorption, used for lack of first pass effect, prolonged duration of action
Transdermal
Process of Pharmacokinetics
Wherein drug reversibly leaves the bloodstream and enters the target organ
Distribution
Factors that influence Distribution
- S____
- B____
- S____
- P____
- Size of the organ
- Blood flow
- Solubility
- Protein binding
Distribution
Drug from ____ to ____
systemic circulation to organ and tissue
Distribution
Under physiologic condition, protein-binding capacity is (1) ____ than the drug concentration and the free fraction is (2) ____
(1) greater
(2) constant
Distribution
Plenty of drugs bind to plasma protein, (1) ____, with a balance (2) ____
(1) albumin
(2) between bound and free molecule
Distribution
- [1] ____ (active, free) -> [2] ____ (inactive, bound)
[1] Drug + Protein
[2] Complex
Distribution
Sulfonamides and bilirubin in (1) ____
-> (2) ____ -> (3) ____
Sulfonamides should not be given to pregnant mothers and babies
(1) neonates
(2) Hyperbilirubinemia
(3) Kernicterus
Kernicterus causes cerebral palsy and hearing loss in neonates
Distribution
Warfarin and sulfonamides -> (1) ____ -> (2) ____
Warfarin (drug) is an anti-coagulant, it is bound to albumin (protein) which makes it inactive
(1) displacement of warfarin
(2) increase free Warfarin
Free Warfarin = Active Warfarin, resulting in increase risk of bleeding
Unique Barriers to Distribution
Most low molecular weight medicines cross this barrier
Placental Barrier
Criteria for Safe Drugs in Pregnancy
- W____
- L____
- H____
- Water-soluble
- Large molecule
- Highly protein-bound
These drugs will not cross the placental barrier, deeming it safe
Unique Barriers to Distribution
Permeable only to lipid soluble or low molecular weight drugs
Ex. Lithium, Ethanol, Levodopa, Dopamine
Blood Brain Barrier
Distribution
Drugs that can redistribute into fat tissue prior to elimination
Lipid-soluble Drugs
Redistributing into the fat tissue, the drug can go back once again into systemic circulation and increase the effect of the drug
Redistribution
CNS Drugs: The duration of action an initial dose may depend more in the ____
Ex. Thiopental
redistribution rate than on the half-life
Process of Pharmacokinetics
Is the metabolic converion of drug to more water soluble metabolites that are more easily excreted
Metabolism / Biotransformation
Fates of Drug Metabolism
- Active drug -> ____
- Active drug -> ____
- Prodrug -> ____
*Prodrug is an inactivated drug
(1) Inactive drug
(2) Less active metabolite
(3) Active drug