FoM:L1 - What is a Drug? Flashcards
What is a drug?
An active substance with a direct effect in the diagnosis, cure, mitigation, treatment or prevention of disease
What is a placebo?
An inactive substance administered as though it is a drug, but which has no therapeutic effect
What are the important attributes of drugs that need to be quantified?
- purity
- potency
- efficacy
- variability
- selectivity
- safety
- bioavailability
- cost
What is variability?
what proportion of patients have the desired response
How does a drug bind to a receptor?
reversibly
How do drugs interact with targets?
makes transient contact with a target
What is a agonist?
- endogenous substance or drug acting at a receptor
- activates receptor signalling to produce a response
What is an agonists affinity?
the extent to which a drug binds to a receptor at a given concentration
What is intrinsic activity?
efficacy
- the ability of a drug to illicit a pharmacological effect
What shape is produced when plotting a dose logarithmically?
sigmoid
What is the effective dose (EC50)?
50% of the response
What is therapeutic index?
Therapeutic dose / effective dose
What does a wide therapeutic index mean?
few people taking a therapeutic dose will experience toxic effects
What is pharmacovigilance?
monitoring the use of medicines in everyday practice to identify previously unrecognised. adverse effects or changes in the patterns of adverse effects.
Why would a drug be considered specific?
affinity and intrinsic activity for specific receptors
HOWEVER, may have low affinity for other receptors which leads to an unwanted response
