Tubes containing gel (SST and PST) are NOT acceptable
Specimens should be collected when the patient is in steady state with the treatment, 10-14hours from the last dose in once daily dosing regime,or just before the morning dose for divided daily dosing schedules.
A trough level must be measured to avoid the high levels found during the absorption phase of the drug.
A morning sample is recommended both on once daily and twice daily regimes. The morning dose must be withheld until after sampling.
Therapeutic Range Nortriptyline: 70-170 ug/L
The serum concentration of Nortriptyline is the best guide to its clinical effect.
This therapeutic range has been derived from the 2011 AGNP Concensus Guidelines for TDM in Psychiatry and assumes trough sampling in patients in steady state.
Results within this range are most likely to give a clinical response without adverse effects.
Uncertainty of Measurement: 15%
Analysed weekly
The monitoring of tricyclic antidrepressant drug levels is to assist with the adjustment of dose to optimise clinical response in individual patients.
The therapeutic reference range is obtained from population data and represents levels which are most likely to achieve a therapeutic effect with minimal side effects. These levels account for the differences in drug metabolism between patients but they cannot account for different responses to the drug.
Hence some patients many achieve a favourable therapeutic outcome with levels outside this range.
Emails to chemicalpathologist@adhb.govt.nz will receive priority attention from the on-call chemical pathologist.
If the query concerns a specific patient please include the NHI number in your email.
If email is not a suitable option, please contact the on-call chemical pathologist via Lablink (Auckland City Hospital ext. 22000 or 09-3078995).
Individual chemical pathologists may be contacted but will not be available at all times.
After-hours : contact Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.
Dr Samarina Musaad (Clinical Lead) : SamarinaM@adhb.govt.nz ext. 22402
Dr Cam Kyle: CampbellK@adhb.govt.nz ext 22052
Dr Weldon Chiu: WeldonC@adhb.govt.nz ext. 23427
Dr Campbell Heron: CHeron@adhb.govt.nz ext. 23427
Dr Sakunthala Jayasinghe: Sakunthala@adhb.govt.nz ext. 23427
Centrifuge and separate blood as soon as possible after collection.
If sending within Auckland then sample can be sent refrigerated (2-8 degrees) or at ambient temperature (8-24 degrees).
If sending from outside Auckland then send sample refrigerated (2-8 degrees).
Note: If temperature during shipping is likely to exceed 24 degrees then results may not always be reliable.