Adverse Drug Reactions Flashcards
what is the difference between an adverse effect and an an adverse drug reaction
AE= unwanted occurrence (cannot necessarily be attributed to the use of a drug)
ADR= negative/unwanted/undesiravle effect of a medicine that occurs during clinical used
what factors need to be taken into account when trying to establish whether or not an adverse reaction is due to a drug
T = timing (in relation to taking the drug)
R= recovery (do symptoms improve when drug is stopped)
I= independent evidence (is there a possible non-drug cause or are the symptoms caused by the underlying disease, does rechallenge cause the symptoms to re-appear if the drug is restarted)
P= predictability (are the characteristics of this AE consistent or inconsistent with the known pharmacology of the drug?, have similar events previously been reported with use of this drug )
What is an “A” type ADR
Give an example
Augmented
dose dependent, predicted from known pharmacology of the drug
e.g hypoglycaemia caused by insulin
What is an “B” type ADR
Give an example
Bizzarre
Unpredictable
Dose independent
Rare
Fatal
e.g anaphylactic reaction to penicillin
What is an “C” type ADR
Give an example
Chronic reaction
Due to prolonged treatment
e.g analgesic neuropathy
What is an “D” type ADR
Give an example
Delayed reaction
May not require long term use of drug but reaction is seen long time after drug exposure
ADR occurs after years after treatment has stopped
e.g. endometrial cancer associated with tamoxifen
or antipsychotic turdive dyskinesia
What is an “E” type ADR
Give an example
End of use
withdrawal effect
e.g. glucocorticoid withdrawal
what is the QT interval
QT Interval – time for depolarisation and repolarisation of ventricles
Repolarisation is due to the opening of K+ channels (hERG channel)
how do drugs cause prolongation of the QT interval
Both drugs block hERG channels
Increases QT interval
what can occur as a result of QT interval prolongation
Can lead to a life threatening arrhythmia known as torsades de pointes
how can aspirin induce neuropathy
Nephropathy due to chronic inhibition of vasodilatory prostaglandin synthesis by NSAID, leading to ischaemia and damage
what are the dangers of taking warfarin in pregnancy
skeletal deformities
(scoliosis- curved
spine
brachydactyly – loss
of fingers or toes)
nasal hypoplasia
absence of spleen
eye abnormalities
what are the dangers of taking lithium in pregnancy
Heart abnormality (Ebstein’s malformation) affecting right side of the heart
what are some side effects of antimuscarinic drugs
dru mouth
decreased GI motility
constipation
blurred vision
what ADR are cox-2 inhibitors associated with
Selective COX-2 inhibitors are associated with an increased risk of thrombotic events
