Adverse Drug Effects Flashcards
What is a type A adverse drug reaction?
an exaggeration of a drug’s normal pharmacological action when given at the therapeutic dose
What is a type B adverse drug reaction?
idiosyncratic responses that cannot be predicted from the known pharmacology of the drug
What does a black triangle on drug packaging indicate?
the drug is new or is intensely monitored for side effects
What report system is used for pharmacological side effects?
Yellow Card Report
Give 3 common features of adverse drug reactions:
1) skin reactions
2) acute dystonia
3) blood dyscrasias
What is dystonia?
Involuntary sustained muscle contractions, producing twisting or squeezing movement and abnormal postures
What is blood dyscrasias?
disorders of the blood, bone marrow, lymph tissue or clotting factors
Give two examples of skin reactions associated with adverse drug reactions:
1) Stevens-Johnson Syndrome
2) Toxic epidermal necrolysis
What drug reduces the absorption of tetracycline antibiotics?
oral iron
Considering that oral iron reduces the absorption of tetracycline antibiotics by 90%, how should these drugs be taken together?
iron should be given 3 hours before/ after tetracycline
What drug group can displace warfarin from plasma protein binding sites?
NSAIDs
What drug reduces the effect of desogestrel contraception?
phenytoin
Describe the drug interaction between phenytoin and desogestrel:
phenytoin induces the metabolism of desogestrel which reduces its effect and allows for ovulation to occur
What drug interacts with simvastatin to cause myopathies and rhabdomyolysis?
clarithromycin
Describe the drug interaction between clarithromycin and simvastatin:
clarithromycin induces the CYP3A4 enzyme responsible for metabolising simvastatin, thus activating more simvastatin, resulting in toxicity
Give two clinical features of a clarithromycin/simvastatin drug interaction:
1) myopathy
2) rhabdomyolysis
What two blood thinners should not be prescribed together?
enoxaparin and apixaban (heparin and DOAC)
Why is prescription of both enoxaparin and apixaban contraindicated?
they both act on factor Xa, increasing the risk of bleeding
What drug can decrease the antiplatelet effects of clopidogrel?
omeprazole
What two drugs when given together carry a high risk of bone marrow suppression?
methotrexate and trimethoprim
What is the effect of the interaction between methotrexate and trimethoprim?
bone marrow suppression and subsequent pancytopenia
What two cardiac drugs when taken together can cause cardiac depression?
verapamil and beta blockers
Give 3 effects of taking both verapamil and beta blockers?
1) bradycardia
2) asystole
3) sinus arrest
What is the effect of enzyme inducer drugs on other drugs?
reduced drug concentration and reduced pharmacological effect
