Pharmacodynamics, Drug Interaction And Toxcity Flashcards
(22 cards)
What are the advantages of drug selectivity?
The more selective a drug is, the lesser the chance it will interact with different receptors and therefore the lesser chance of undesirable effects
What does drug specficity mean?
Targeting a receptor subtype that allows the treatments to be targeted to a particular organ
What is the efficacy of a drug?
The ability of a drug to produce a response
What is a drugs potency?
The dose required to poduce the desired biological response
Describe agonist potency?
Defined by the drug concentration at which 50% of the maximal response is obtained
Describe antagonist potency?
the concentration that reduces the maximal reaction bu 50%
How is potency affected by competitive antagonism?
Agonist efficacy can be restored by increasing the agonist, and so the EC50 changes but the maximal effect stays the same
What is the thearpeutic index
The relationship between the concetration causing adverse effects and the concentration causing the desired effects
What is the therapeutic window?
The range of doses that can effectively treat a condition whilst remaining safe
What are some of the different types of pharmaockientic drug drug interactions?
Absorbtion, metabolism and hepatic effects, drug food interactions
What are some of the ways that drug drug interactions can effect absorption?
Changes in gut motility
Changes in volume of distrubtion.
How can drugs effect the gut motlitly and therefore absorption of other drugs?
Opiates and atrophine slow the gut which decreases the absorbtion of drugs, whereas meloclomprimide increases the speed of the gut and therefore increases absorption of drugs
How can drugs effect the volume of distrubtion of other drugs?
Interactions between drugs affecting the protein binding of different drugs
What are some of the ways that drugs can have metabolism or hepatic effects on other drugs?
Drugs can be inhibitors or inducers of cyp 450 enzymes
Inhibition causes decreased metabolism of drugs and possible ADR whereas induction causes increased metabolism of drugs and therefore a reduction in effect
Give an example of how drugs and food can interact?
Grapefruit juice can inhibit cYP450 enzymes and therefore cause decreased metabolism of a drug
Name some drugs that are CYP450 inducers
Phenytonin, Carbamazepine, Alchol, Rifampicin, Barbiutates and sulphonureas
Name some drugs that are CYP450 inhibitors?
Omeprazole, disulfram, erythromycin, valporate, isonzid, ciemtadine and ciprofloxin, ethanol and suplonamides
What are some of the classes of drug that commonly cause drug durg interactions?
Antibiotics such as rifampicin and quionlones
Anticonvuslants such as carbamazepine and phenytonin
Anticogulants such as warafrin
Antiarrythmics such as amidarone
Antidepressants
How can renal disease interact with drugs?
Causes a falling gfr which results in reduced clearnace, and can cause a disturbamce of electrolytes that predisposes to toxicity, and then nephrotoxins can futher disrput kidney function
How can hepatic disease interact with drugs?
Reduced clearnace of hepactically metabolised drugs, reduced cyp450 activity and longer half lives, and can cause hypoalbuminea reducing the binding of drugs and therefore leading to an increased excretion
How can cardaic disease interact with drugs?
Falling cardiovascular output can lead to a excessive response ot hypotensive agents, can caused reduced organ perfusion and therefore reduced perfusion of the liver and kidneys
How can drug drug interactions result from excretion?
Can cause changes in tubular flow ph, as well as changes in protein binding, for example NSAIDs inhbit tubluar secretion and therefore cause increased levels of a drug
