Pharmacology Flashcards
What is meant by ‘competitive binding’?
(1. ) Two drugs bind to the same receptor therefore must compete with each other for the receptor.
(2. ) This prevents one of the drugs from binding and therefore reducing its level and effects.
What is meant by ‘half-life’ when it relates to drugs and renal elimination
The elimination half life of a drug is defined as the time required for the serum concentration of the drug to decrease by 50%.
In what ways can a prescription be altered to mitigate the effects of reduced renal function?
(1. ) Prescriptions can be altered to mitigate the effects of renal impairment by either:
- reducing the dose
- or lengthening the dosing interval or both.
(2.) Some drugs will be less effective in renal impairment and so should be substituted if necessary
What is an agonist and antagonist?
(1. ) Agonist = ligand that binds to receptors and activate it
(2. ) Antagonist = ligand that interacts and blocks activity of receptor
What is drug specificity?
How much a drug will bind to one type of target
What is efficacy?
The maximal effect of drug, irrespective of dose. Antagonists will have zero efficacy.
What is potency?
(1. ) The amount of drug that is needed to elicit a response
(2. ) This can be a concentration (EC50) or dose (ED50) of a drug required to produce 50% of that drug’s maximal effect.
What is pharmacoDYNAMICS?
How drug acts on the body
What is pharmacoKINECTICS?
What the body does to a drug - absorption, distribution, metabolism, excretion [ADME]
What is first pass metabolism?
The idea that orally given drugs do not completely reach maximum dose in systemic circulation, they get modified and metabolised in the GI system/liver
What would be the bioavailability of IV drugs?
100% IV drug do not undergo first pass metabolism, so 100% of drug dose given is available to systemic circulation
Name something a drug may be designed to target
An enzyme, receptor, co-transporter, ion gate channel etc.
What is meant by bioavailability
Fraction of the drug administrated reached systemic circulation unaltered
What is meant by affinity?
(1. ) ‘Forward rate of association’ (backward rate would be disassociation)
(2. ) E.g. If a receptor has a high affinity for a drug, when they associate they will stay together and dissociation is slow
What are allosteric modulators?
Group of substances that bind to a receptor to change that receptor’s response to stimulus
