Prescribing Safety Assessment: Drug Monitoring & ADRs Flashcards
Which patients are statins associated with myopathy in?
Personal or family history of muscular disorders, previous history of muscular toxicity, renal impairment, high alcohol intake, hypothyroidism, elderly. Check CK at baseline in these patients only.
What monitoring level is done for phenytoin?
Pre-dose (trough)
Checking ALT when starting statin?
Should be done in all patients. If ALT/AST are 3* normal, statins are contraindicated (or if have active liver disease). Should be checked at 3 and 12 months after starting treatment.
Normal range for lithium?
0.4-0.8mmol/L
When to monitor lithium?
12 hours post dose
When should routine lithium monitoring be done?
Weekly after initiation, after each dose change until stable, and every 3 months thereafter
Sodium and lithium?
Sodium depletion is known to increase the risk of lithium toxicity and patients are advised to avoid making dietary changes that increase/decrease sodium intake
What parameters need monitoring for lithium?
Serum concentration, U&E, TFTs, ECG, BMI/weight
When to monitor methotrexate?
FBC regularly, but can be 2-3 months when established
Starting methotrexate if LFTs abnormal?
Should not be done!
Key parameter at baseline when starting APS?
Fasting blood glucose; ECG only indicated in those with CVD or RFs
Key parameter when starting COCP?
Cardiovascular e.g. blood pressure.
What thyroid bloods need monitoring for amiodarone?
Full panel e.g. T3/T4/TSH
Key baseline investigation in amiodarone?
CXR (risk of pulmonary toxicity), LFTs, U&E (K+), TFTs
Amiodarone and potassium?
Should be used with caution when hypokalaemic (risk of arrhythmia)
Which doses need checking for multiple daily dose regimen in gentamicin?
Pre-dose (trough) and peak dose
When is plasma digoxin concentration measured?
Not routinely done! Only if toxicity/ non-compliance or inadequate effect suspected
Key blood to monitor in digoxin?
U&E (renally excreted)
One advantage of digoxin over CCBs and B-blockers?
Does not cause hypotension so may be better for hypotensive patients
Monitoring valproate?
Should do baseline LFTs and regular monitoring, and FBC.
Clozapine dose if leukocyte and neutrophil counts drop below normal?
Should STOP it, not adjust it
Who needs to register with clozapine monitoring service?
All patients!
Type A and B drug reactions?
Type A = common, predictable, dose-related. Type B = idiosyncratic, bizarre, unexpected
ADRs of CCBs?
Hypotension, bradycardia, peripheral oedema, flushing
ADRs of diuretics?
Hypotension, electrolyte abnormalities, AKI, sub-class specific e.g. gynaecomastia
ADRs of B-blockers?
Hypotension, bradycardia, wheeze in asthmatics, worsens acute heart failure
ADRs of heparins?
Haemorrhage (especially if renal failure or <50kg), thrombocytopenia
ADRs of aspirin?
Haemorrhage, PUD, gastritis, tinnitus in large doses
ADRs of warfarin?
Haemorrhage, obviously. Initially pro-thrombotic hence why need LMWH alongside warfarin for the first few days
ADRs of digoxin?
Nausea, V&D, blurred vision, confusion, drowsiness, xanthopsia (yellow/green vision inc. ‘halo’ vision)
Digoxin and potassium?
As digoxin competes with K+ at Na+/K+ ATPase, low K+ augments digoxin effect
Amiodarone ADRs?
Pulmonary fibrosis, thyroid disease (hypo and hyper), skin greying, corneal deposits
Lithium ADRs?
Early = tremor, int. = tiredness, late = arrhythmias, seizures, coma, renal failure, diabetes insipidus
ADRs of haloperidol?
Dyskinesias e.g. acute dystonic reactions, drowsiness
ADRs of fludrocortisone?
Hypertension/sodium and water retention
ADRs of statins?
Myalgia, abdominal pain, increased ALT/AST, rhabdomyolysis (or just mildly increased CK)
Inhibition and induction time-scales?
Inhibition only takes hours-days, while inductions takes days-weeks
Drugs interacting with alcohol to cause GI bleeding?
NSAIDs
Drugs interacting with alcohol to cause increased anti-coagulation?
Warfarin (with acute alcohol due to its enzyme inhibition, while chronic alcohol excess causes enzyme induction thus reducing antiocoagulant effect)
Drugs interacting with alcohol to cause sweating, flushing, nausea and vomiting?
Metronidazole, disulfiram
Drugs interacting with alcohol to cause lactic acidosis?
Metformin!
Drugs interacting with alcohol to cause hypertensive crisis?
MAOIs
Drugs interacting with alcohol to cause sedation?
Barbiturates, opiods and benzos
Co-prescribing NSAIDs and ACEI?
Bad; NSAIDs constrict the afferent vessels, while ACEI dilate the efferent, leading to fall in renal perfusion and so the GFR tails off
What type of drug is amiloride?
K+ sparing diuretic
Key to finding which interactant is important?
Look for the “potentially serious interaction” (shown by black dot)
What is protamine used to treat?
Effects of heparin
Where should drug-induced hypoglycaemia be managed?
In hospital, as the effects can persist for hours
Why does metformin cause lactic acidosis?
Metformin inhibits hepatic gluconeogenesis. Normally, lactate is taken up in this process, so it can accumulate.
