adverse drug reactions

Question 1

What ADR does one worry about in a patient with a newly started statin?

Answer 1

Rhabdomyolysis

Question 2

What factors an increase the liklihood of a rhabdomyolysis when starting a statin?

Answer 2

• genetic predisposition
• female sex
• acute or chronic kidney injury
• concurrent use of a CCB

Question 3

How does one treat rhabdomyolysis?

Answer 3

• stop the causative drug
• give IV fluids to reduce risk of kidney injury
• consider sodium bicarbonate to alkanilize the urine
• monitor potassium and correct when necessary

Question 4

What is the definition pf an adverse drug reaction?

Answer 4

• harmful or unpleasant response/relation to a drug
• predicts if happening again if the drug is still used
• that warrants change in dose or withdrawal of treatment
• can be related to overdose, misuse or administration error

Question 5

Adverse drug event vs reaction. What’s the dif?

Answer 5

• event is something negative that happens to the patient when they are using the drug
• reaction is something negative that happens to the patient and it’s suspected that the drug in question caused it.

Question 6

what is a Type A ADR?

Answer 6

-A for augmented reaction
-dose related
-predictable & common
-relating the the pharmacology of the drug
-unlikely to be fatal
(constipation with opiods, brusing with warfarin)

Question 7

What is a Type B ADR?

Answer 7

-B for bizzare reaction
-no dose related
-unpredictable and uncommon
-not related to pharmacology
-often fatal
(hypersensitivity, hepatitis, angioedema)

Question 8

What are Type C, D, E and F ADR?

Answer 8

C - Chronic - cumulative dose effect - HPA suppression in long term steroid use
D - Delayed - carcinogenesis later down the line
E - End of Treatment - withdrawal Sx on cessation of opioid Tx
F - Failure - no therapeutic action - OCP failure in presence of an enzyme inducer

Question 9

What’s the DoTS model of ADRs?

Answer 9

• Dose
• Timing
• Susceptibility

Question 10

What’s the dose breakdown of the DoTS model?

Answer 10

ADR can occur at three levels of dose

• Hypersensitivity reactions - occuring at subtherapeutic levels of dosing
• Collateral reactions - happens when the dose is in therapeutic range
• Toxicity reactions - happens when there is too much circulating drug in the system

Question 11

What is the Timing breakdown in the DoTS model?

Answer 11

Can be time dependent or independent
Time dependent
-rapid - ‘red man syndrome’ giving Vanc too fast
-early - nitrate induced headache
-first dose - hypotension in ACEi dose
-intermediate - slightly delayed allergic reaction
-late - withdrawal from long term steroids
-delayed - tetragenicity

Question 12

What needs to be taken into account for ADR susceptibilities?

Answer 12

• Age
• Sex
• ethnicity
• Genetics - specifically increase risk of ADR haemolytic anaemia in G6P deficiency