Drug monitoring

Question 1

Give 4 important drug monitoring points for Vancomycin

Answer 1

Clearance of vancomycin is reduced in renal impairment

Check renal function (serum creatinine BEFORE starting)

Is nephrotoxic and ototoxic

Can cause neutropenia (if taken >1 week)

Question 2

Give 3 important drug monitoring points for Simvastatin

Answer 2

Caution in liver disease (statins are metabolised by the liver)

Check ALT BEFORE starting and AGAIN at 3 and 12 months

Check Creatinine Kinase before starting in patients with persistent, generalised or unexplained muscle pain (risk of myopathy)

Question 3

Give 3 important drug monitoring points for Phenytoin

Answer 3

Has a Narrow Therapeutic Range

Pre-dose ‘trough’ phenytoin levels are measured to ensure it falls within normal range

If measurement is within the range, then the maintenance dose is appropriate.

Question 4

Give 4 important drug monitoring points for Lithium

Answer 4

Monitor Serum Lithium concentration throughout treatment

Levels should be measure 12 hours after a dose

Measure weekly during initiation and dose changes, then every 3 months once stabilised.

Serum concentrations above 1.5mmol/L can be toxic

Question 5

What is the normal range for Serum Lithium Concentration?

Answer 5

0.4-0.8mmol/L

Question 6

What can increase risk of lithium toxicity?

Answer 6

Sodium depletion (advise not to make drastic changes to diet whilst on lithium)

Question 7

Give 3 important drug monitoring points for Methotrexate

Answer 7

FBC, U&E and LFTs should be monitored every 1-2 weeks during initiation and following dost changes, then every 2-3 months once stabilised

Treatment should NOT be started if LFTs are abnormal (due to risk of liver cirrhosis)

Methotrexate MUST be STOPPED immediately during intercurrent illness (due to risk of neurtopenic sepsis)

Question 8

Give 4 important drug monitoring points for Olanzapine (atypical anti-psychotics)

Answer 8

Blood lipids and weight should be measured at baseline, at 3 months and then yearly

Fasting blood glucose should be measured at baseline, at 1 months, 4-6 months, then yearly

Prolactin levels should be measured at baseline, 6 months then yearly

Baseline ECG required for patients with significant cardiovascular risk factors

Question 9

Give 2 important drug monitoring points for COCP

Answer 9

BMI and Bloor Pressure should be checked annually

Check Hb if suspicion of anaemia

Question 10

Give 4 important drug monitoring points for Amiodarone

Answer 10

Baseline Chest X-ray required (due to risk of lung fibrosis)

LFTs required at baseline, then every 6 months (due to risk of liver dysfunction)

TFTs (T3/T4/TSH) measured at baseline, then every 6 months

Serum Potassium measured BEFORE treatment

Question 11

Give 1 important drug monitoring point for Carbimazole

Answer 11

Measure neutrophil count immediately in those presenting with sore throat (due to bone marrow suppression/agranulocytosis)