Flashcards in pharmacodynamics Deck (107)
Loading flashcards...
1
drug interaction
1 + 1 = 2
Response elicited by combined drugs is equal to the combined response of the individual drugs
Sedative(chlorpheniramine maleate found in decongestants like Neozep + ethanol)
1. ADDITIVE
2
drug interaction
1 + 1 = 3
Response elicited by combined drugs is greater than the combined responses of each individual
Penicillin G (antibiotic) removes the cell wall of the organism
Gentamicin (aminoglycoside antibiotic) inhibits protein synthesis in the organism
2. SYNERGISTIC
3
drug interaction
0 + 1 = 2
Drug which has no effect enhances the effect of the second drug
Cimetidine + heparin (anticoagulant
(Cimetidine enhances the anticoagulation)
3. POTENTIATION
4
drug interaction
1 + 1 = 0
Drug inhibits the effect of another drug
Heparin + protamine
4. ANTAGONISM
5
study of detailed mechanism of action by which drug produce their pharmacologic effects
-provides a scientific basis for the selection and use of drugs
PHARMACODYNAMICS –
6
– specific cell molecules by which drugs interact to produce their effects
-most ligands (drugs or neurotransmitters) bind to protein molecules
-Determine the quantitative relations between dose or concentration of drug and pharmacologic effects
RECEPTORS
7
– largest family of receptors for pharmaceutical agents
G protein-coupled receptors (GPCRs)
8
CLASSIFICATION OF RECEPTORS
• Best characterized drug receptors
• Mediates the action of endogenous chemical signals like neurotransmitters, autacoids and hormones
• Mediates the effects of the most useful therapeutic agents
1. REGULATORY PROTEIN
9
CLASSIFICATION OF RECEPTORS
• Inhibited (or less commonly, activated) by binding a drug
• Eg, dihydrofolate reductase, the receptor for methotrexate
2. ENZYMES
10
CLASSIFICATION OF RECEPTORS
• Eg, tubulin, the receptor for colchicine, an anti-inflammatory drug
4. STRUCTURAL PROTEINS
11
CLASSIFICATION OF RECEPTORS
• Eg, Na+/K+ ATPase, the membrane receptor for digitalis
3. TRANSPORT PROTEINS
12
• Specific binding region of the macromolecule
• High and selective affinity to the drug molecule
• Interaction between the drug and the receptor is the fundamental event that initiates the action of the drug
RECEPTOR SITE/RECOGNITION SITE
13
• Same site as the endogenous ligand
• Drugs directly compete for the receptor site
ORTHOSTERIC SITE
14
• Different site
• Alters the response of the endogenous ligand binding to the ligand-gated ion channel and increase or decrease the flow of ions
ALLOSTERIC SITE
15
• Non-regulatory molecules of the body
• Binding with these molecules will result to no detectable change in the function of the biologic system
• Buffers the concentration of the drug
• Bound drugs do not contribute directly to the concentration gradient that drives diffusion
• Eg, albumin
INERT BINDING SITES
16
• Receptor-like proteins predicted from the human genome for which an endogenous ligand is not identified
• Target for the development of new drugs
ORPHAN RECEPTORS
17
In most cases, drugs bind to their receptor by forming (what kinds of bonds) bonds with a receptor site.
hydrogen, ionic, or hydrophobic (van der Waals)
18
• weak bonds
• reversible and enable the drug to dissociate from the receptor as the tissue concentration of the drug declines
HYDROGEN, IONIC, OR HYDROPHOBIC (VAN DER WAALS) BONDS
19
• Drug must bind to one stereoisomer only
STEREOSPECIFICITY
20
• A substance that can exist in the L or D form
• L may be the better drug
ENANTIOMER
21
• Drug having both the L & D form; cannot be separated
• Patient will experience both the therapeutic and toxic effects.
RACEMIC MIXTURE
22
• Binding is permanent, irreversible
• Prolonged duration of effect
COVALENT BOND
23
The weaker the bond, the more _____ it becomes.
selective
24
• Tendency of a drug to combine with its receptor is
• A measure of the strength of the drug-receptor complex
•
AFFINITY
25
↑ affinity, __ binding
↓
26
• Describes the pathway from ligand binding to conformational changes in the receptor, receptor interaction with an effector molecule (if present), and other downstream molecules called second messengers.
• This cascade of receptor-mediated biochemical events ultimately leads to a physiologic effect.
• Pathway for drug to enter the cell
SIGNAL TRANSDUCTION
27
• Ability of a drug to initiate a cellular effect
• Efficacy is not directly related to receptor affinity and differs among various drugs that bind to a receptor and start the signal transduction pathway.
EFFICACY OR INTRINSIC ACTIVITY
28
• Binds to the receptor and directly or indirectly bring about an effect
• Full activation of the effector system
•
• Both agonists and antagonists have common components sufficient for receptor affinity, but only agonists have the structure required for efficacy.
AGONIST
29
Drugs that have both receptor affinity and efficacy
AGONIST
30