Antidepressant Drugs (Cyclic): Amitriptyline, Nortriptyline, Protriptyline, Doxepin, Imipramine
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Cyclic antidepressants: amitriptyline (Elavil, Endep, Etrafon, Limbitrol, Triavil); nortriptyline (Allegron, Aventyl HCL, Nortrilen, Norval, Pamelor); protriptyline (Vivactil); doxepin (Adapin, Co-Dax, Novoxapin, Sinequan, Triadapin); imipramine (Berkomine, Dimipressin, Janimine, Pertofrane, Presamine, SK-Pramine, Tofranil PM).
To monitor subtherapeutic, therapeutic, or toxic drug levels in evaluation of effective treatment modalities.
Serum collected in a red-top tube.
|Drug||Route of Administration||Recommended Collection Time|
|Amitriptyline||Oral||Trough: immediately before next dose (at steady state)|
|Nortriptyline||Oral||Trough: immediately before next dose (at steady state)|
|Protriptyline||Oral||Trough: immediately before next dose (at steady state)|
|Doxepin||Oral||Trough: immediately before next dose (at steady state)|
|Imipramine||Oral||Trough: immediately before next dose (at steady state)|
(Method: Chromatography for amitriptyline, nortriptyline, protriptyline, and doxepin; immunoassay for imipramine)
|Drug||Therapeutic Range Conventional Units||Conversion to SI Units||Therapeutic Range SI Units||Half-Life (h)||Volume of Distribution (L/kg)||Protein Binding (%)||Excretion|
|Amitriptyline||125–250 ng/mL||SI units = Conventional units × 3.6||450–900 nmol/L||20–40||10–36||85–95||Hepatic|
|Nortriptyline||50–150 ng/mL||SI units = Conventional units × 3.8||190–570 nmol/L||20–60||15–23||90–95||Hepatic|
|Protriptyline||70–250 ng/mL||SI units = Conventional units × 3.8||266–950 nmol/L||60–90||15–31||91–93||Hepatic|
|Doxepin||110–250 ng/mL||SI units = Conventional units × 3.58||394–895 nmol/L||10–25||10–30||75–85||Hepatic|
|Imipramine||180–240 ng/mL||SI units = Conventional units × 3.57||643–857 nmol/L||6–18||9–23||60–95||Hepatic|