Narrow therapeutic range drugs Flashcards
What are the drugs with a narrow therapeutic range?
GWLDTMPIC Gentamycin/Vancomycin Warfrin Lithium Digoxin Theophylline Methothrexate Phenytoin Insulin Ciclosporin
What toxicity does Gnetamycin/Vancomycin cause? How should it be monitored?
It causes ototoxicity and renal failure
Should have levels every 1-3 days and adjust dosing accordingly
What toxicity does warfarin have and how should it be monitored?
Causes bleeding
Watch INR in anticoagulant clinic - interval depends on INR stability
Usually aim for 2-3
What toxicity is lithium monitored for? How is it monitored?
Causes Tremor, Coma and renal failure
Can look at blood lithium level, TFTs and LFTs
Initially check levels weekly then every 3 months
What toxicity does digoxin cause and how is it monitored? What is the loading and regular doseage?
It is cardiotoxic, it causes arrhythmias and GI disturbance
Measure the digoxin level, this does not require routine monitoring but check level if concerned
Loading dose of 500mcg then regular 65-250mcg OD
What toxicity does theophyline cause? How is it monitored?
Theophylline causes arhythmias and seizures
Monitored by checking levels 3 days after any dose changes and adjust dose accordingly
What toxicity does methotrexate cause and how is it monitored?
It causes myelosuppression, liver toxicity and renal failure
Should monitor FBC, LFT and U+Es
Should be done every 2 weeks until stabalised then every 2-3 months
What toxicity does phenytoin cause and how is it monitored?
Phenytoin causes arrhythmias and cerebellar syndrome (ataxia)
Can monitor phenytoin level if concerned but does not require regular monitoring
What toxicity does insulin cause and how is it monitored?
Causes hypoglycaemia, measured with capillary insulin
What toxicity does ciclosporin cause and how is it monitored?
Causes renal failure - weekly pre-dose levels are looked at in blood until stable then monthly
How should gentamycin dosing be adjusted with regards to monitoring?
Should measure serum concentrations an hour after the dose (peak) and before the next dose (trough)
If the peak is too high then need to decrease the dose
If the trough level is too high the interval between the doses should be increased
