ADRs Flashcards
4 types of ADR
Type 1 - identify adverse effects of common drugs
Type 2 - recognising common rtns
Type 3 - identify clinically important drug interactions
Type 4 - recognise + manage ADR - anaphylaxis, xs anticoag, drug induced hypoglycaemia, diuretic induced dehydration
Drugs with narrow TI
warfarin digoxin theophylline phenytoin lithium
Drugs that require careful titration of dose according to effect
+antihypertensives
+anti-diabetic drugs
-bodies handling of these drugs may be affected by addition of other drugs ie. radiological contrast –> AKI – > metformin induced lactic acidosis in T2DM
how long does it take drugs to be affected by CYP450 enzyme system (both induction + inhibition)
enzyme induction takes DAYS-WEEKS to establish
enzyme INHIBITION only takes HRS-DAYS
enzyme inducers
Phenytoin Carbamazepine Barbs Rifampicin Alcohol (chronic xs) Sulphonylurea
enzyme inhibitor
Zoles (omep, ketoconazole, fluconazole) Allopurinol Grapefruit juice Disulfiram Erythromycin Valproate Isoniazid Cipro Ethanol (acute xs) Sulphonamides)
digoxin SEs
N&V, blurred vision, xanthopsia (distrubed yellow/green vision incl halo vision)
digoxin MoA
antagonises K+ at myocyte Na+/K- ATPase limiting Na+ influx –> Ca2+ accumulates inside the cell, prolonging the AP –> lowering HR
what is the effect of LOW K+ on digoxin
ENHANCES digoxin effect
what is the effect of HIGH K+ on digoxin
REDUCES digoxin effect
what element is AmIODarone related to
IODINE
Amiodarone SEs
Hyper/hypothyroid, skin GREYING, corneal deposits, pulm fibrosis
What to do if amiodarone causes thyrotoxicity
HOLD the amiodarone
BB+ Verapamil
Profound hypotension + asystole due to complete heart block
Lithium SEs
Tremor –> tired –> arryhtmias, seizures, coma, AKI/CRF, DI
