Drug monitoring Flashcards
How are vancomycin and gentamicin excreted?
Renally.
What rare thing can vancomycin and gentamicin cause and when?
Neutropenia.
After a week of treatment.
(thrombocytopenia).
What should be assessed before starting vancomycin or gentamicin?
Renal function.
What do you do if a trough gentamicin dose is high?
Decrease the frequency of doses.
What do you do if a peak vancomycin dose is high?
Decrease the dosage.
How should vancomycin and gentamicin be administered?
IV intermittently with either dextrose/NaCl.
How are statins metabolised?
By the liver.
What can statins cause and in whom?
Myopathy, in patients with risk factors for it.
What should be checked in all patients before initiating statin treatment?
Liver function: all cholesterol and triglycerides.
TSH.
Renal function.
What should be checked in some patients before starting statins?
Creatinine kinase – in patients with risk factors for myopathy.
HbA1c/fasting glucose – in patients at high risk of diabetes.
What monitoring occurs during statin treatment?
At 3 months post treatment, then 12 months, then yearly unless evidence of toxicity.
Patients at risk of diabetes have checks every 4-6 months.
Normal reference range for phenytoin treatment.
40-80micromol/L (10-20mg/L)
Always consider in the context of the patient.
Contraindications for phenytoin treatment.
Acute porphyrias. Heart block (if giving IV).
Side effects of phenytoin.
Agranulocytosis.
Neurological symptoms: nystagmus–> ataxia and confusion–> coma.
What monitoring is required in Phenytoin treatment?
ECG if IV.
Blood counts.
Plasma concentrations.
Contraindications for amiodarone treatment.
Conductive disorders, unless treated with a pacemaker.
Side effects of amiodarone.
Arrhythmias.
Hepatic disorders.
Hyperthyroidism.
Respiratory disorders.
How long after stopping amiodarone can it continue to interact with other medications?
Up to 6 weeks.
Amiodarone has a long half life.
Monitoring during amiodarone treatment.
Thyroid function tests – 6 weeks after treatment initiation.
Liver function tests – 6 months after initiation.
Chest x-ray before treatment – risk of pulmonary toxicity.
How is digoxin excreted?
Renally.
When is plasma digoxin concentration indicated, and when should it be checked?
When signs of toxicity are present. Not regularly required.
6 hours after dose.
What is risk of digoxin toxicity increased by?
Electrolyte disturbance.
Contraindications for digoxin.
Other heart conditions – in particular heart block.
Side effects for digoxin.
Arrhythmias.
Cerebral impairment.
Dizziness.
Vision disorders.
