Flashcards in 2 -Pharmacodynamics Deck (30):
Effect of body on drugs
Binds to endogenous proteins and activates them
Bind to endogenous proteins, block and inhibit them
What is the difference between competitive and non competitive antagonists?
The site at which they bind
Competitive bind to the same site as the agonist and block the receptor
Non competitive bind to an alternate site and cause a conformational change in the receptor that prevent agonists from binding
What is a highly selective drug?
One that has minimal interaction with other targets, producing few side effects
What does it mean if a drug is highly specific?
Can be targeted to specific organs due to the receptors present
Which organs are B1 and B2 receptors found?
Tendency of a drug to bind to a specific receptor type, the higher the affinity the greater the tendency to bind
Ability of a drug to produce response as receptor is occupied, describes the max effect of a drug
Dose required to produce desired biological response, different doses of 2 drugs to produce same response
What is therapeutic index?
Relationship between concentrations for desired and adverse effects
Toxic dose / effective dose
Define therapeutic window
Range of doses that effectively treat while still remaining safe pm between lowest dose that still has a positive effect and highest dose before negative effects outweigh positive
Describe how paracetamol absorption changes with alcohol
Paracetamol with alcohol and food lower than just alcohol
How is the absorption of tetracycline altered with ferrous?
Concentration of tetracycline decreases with addition of ferrous (Fe 2+)
What types of drug are protein binding interactions important for?
Short half lives
Narrow therapeutic windows
Which CYP metabolises warfarin?
Which CYP metabolises codeine?
What effect does codeine have on alcohol absorption?
Codeine slows gastric emptying, so less alcohol absorbed
Give an example of agonist/antagonism at the same receptor
Beta blockers and B2 agonists
Give an example of agonism/antagonism at different receptors
Warfarin and aspirin
What receptors are activated by anti depressants?
What drugs can interact with digoxin to cause toxicity?
Loop diuretics, causing hypokalaemia
How does renal disease effect drug interactions?
Fall in GFR - reduced clearance
Disturbance of electrolytes predisposes to toxicity
Nephrotoxins allowed to build up, further damaging kidneys
How does hepatic disease affect drug interactions?
Reduced CYP 450 activity
Longer half lives
How does cardiac disease affect drug interactions?
Excessive response to hypotensive agents, drugs remain in subcutaneous tissue
Reduced organ perfusion, reduced blood flow to liver and kidneys, reduced clearance
Describe the effects of grapefruit juice on drug metabolism
Inhibits CYP 450 enzymes
Increased exposure to drugs
Describe the effect cranberry juice has on drug metabolism
Decreases metabolism of warfarin, increasing anticoagulative effects, increased risk of haemorrhage
Define an adverse drug reaction
Unwanted reaction occurring after administration of a drug
What increases the risk of an adverse drug reaction?
Extremities of age - altered pharmacokinetics
Narrow therapeutic indexes
Minimum effective dose prescription, risk of treatment failure if metabolism increases