Introduction to Pharmacology Flashcards
How do drugs work?
Most drugs act on normal cells. They are chemicals which bind to molecules in cells which mimic, stimulate or block the action of endogenous molecules.
How do we make a drug work?
The drug molecule must bind specifically to sites on the endogenous molecules and affecting their action.
List some classes of drugs which are relevant to dentists
Adrenoreceptors (activate alpha receptors to cause vasoconstriction) Antiviral agents Benzodiazepines - muscle relaxants Drugs affecting haemostatsis Local anesthetics Anti - inflammatory drugs
What is the affinity (Kd) of a drug?
The concentration of drug required to occupy 50% of the receptors at equilibrium.
High affinity means low Kd as a lower concentration is needed.
What does the efficacy of a drug relate to?
Its ability to activate the receptor so a response is produced.
What shape is formed when receptors occupied is plotted against drug concentration?
Rectangular hyperbola
What will be required if there is a low affinity for a drug?
A lot more agonists needed
Answering yes or no and then high or low, what is the affinity and efficacy of a full agonist, a partial agonist and an antagonist?
Full agonist A = yes E = high Partial agonist A = yes E = low Antagonist A = yes E = no
Give details on reversible competitive antagonists
Produce a parallel shift of right on an agonist conc vs response curve.
Maximum response can still be met in the cell by releasing more drug
Give details on irreversible competitive antagonists
Cannot leave once they are bound. They produce a suppression of the maximum response. The degree of suppression is dependant on the concentration of the antagonist.
What is the meaning of drug potency?
How effective a drug is in small amounts.
It can be potent due to its high affinity to its receptor , or due to high efficacy or slow metabolic breakdown in the body.
Give definitions for pharmacodynamics and pharmocokinetics
- Describes what a drug does to an organism (includes side effects)
- Describes what an organism does to a drug (absorption, metabolism and excretion)
Why are uncharged molecules better at being absorbed?
Their lipid solubility is larger so they pass through the bilayer much easier.
Which of the 3 circulatory systems do drugs taken orally go to?
What is bioavailability?
Portal circulation
The proportion of drug reaching the circulation
What are the two ways in which drugs are eliminated from the body?
What is the difference between catabolic and synthetic reactions?
Metabolism and excretion.
Phase 1 = catabolic and this breaks the drug molecule down.
Phase 2 = synthetic and this involves the conjugation of chemical groups to the drug molecule.
