View source for Drug Level Sampling Times

 {| class="wikitable"
| '''Drug'''
|'''Ideal  Sampling Time<sup>1</sup>''' 
|'''Minimum  resampling interval<sup>2</sup>'''
|-
|'''AMINOGLYCOSIDES'''  (Gentamicin and Tobramycin)
|'''Conventional  Dosing (e.g. 3x day)'''

'''Trough:  <'''30 minutes before dose

'''Peak:     ''' 1 hour after IM injection or 1 hour after start  IV infusion
| 

1 day
|-
|
|'''Once  daily dosing (ODD)'''

'''Trough: ''' 18 hours after dose (or refer to specific ODD guidelines / contact Pharmacy for time of trough.)

'''Peak:     ''' 1 hour after start IV infusion
| 

A sample can be taken on the first dose.
|-
|'''CARBAMAZEPINE'''

(Tegretol)
|Immediately  before an oral dose
|Initiation of  therapy: 2-4 weeks.

Chronic  therapy:

4 days.
|-
|'''DIGOXIN''' 
|At least 6-8  hours after OR immediately before an IV or oral dose
|7 days
|-
|'''LITHIUM''' 
|At 12 hours  after dose
|Check weekly until stable, then 2-3 monthly.
|-
|'''PHENYTOIN'''

(Dilantin)
|> 6 hours  post dose OR immediately before an oral dose
|Dose dependent, 2-4 weeks.
|-
|'''THEOPHYLLINE'''

(Nuelin, Aminophylline)
|'''ORAL''' (slow release preparation) 4-8 hours after dose  OR Immediately before a dose

'''IV''' (continuous infusion) sample at 12 and 24 hours
|2 days
|-
|'''VALPROATE  SODIUM'''

(Epilim, Valproic acid)
|> 6 hours  post dose OR immediately before an oral dose
|3 days
|-
|'''VANCOMYCIN''' 
|'''Trough:'''  Immediately before an IV dose

'''Peak:    ''' Not necessary 
|1-2 days
|}
'''1.     Ideal Sampling Time:''' This should be adhered to wherever possible.  Drug levels taken at these times provide more meaningful information and this facilitates the interpretation of results.

'''2.     Minimum resampling intervals:'''  This is the earliest time a drug level should be measured following initiation of therapy or a change of dosage (unless therapeutic failure or toxicity is suspected). These times are based on the average time to steady state.


'''References:'''

'''''Abbott package insert.'''''

'''''Tietz, "Textbook of Clinical Chemistry and Molecular Diagnostics", 5th edition.'''''

'''''Medicine - Therapeutic Monitoring - IVTG002 HBDHB IV & Therapeutic Guidelines, July 2019.'''''