Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

3 weeks of treatment are required before therapeutic effectiveness becomes apparent. The most frequent
side effects are those attributable to anticholinergic effects; dry mouth, constipation, dizziness,
tachycardia, palpitations, blurred vision, and urinary retention. These occur at blood concentrations in
excess of 300 ng/mL, although they may occur at therapeutic concentrations in the early stage of
therapy. Cardiac toxicity (first-degree heart block) is usually associated with blood concentrations in
excess of 300 ng/mL. Doxepin Doxepin is recommended for the treatment of psychoneurotic patients
with depression or anxiety, and depression or anxiety associated with alcoholism or organic disease.
Nordoxepin (N-desmethyldoxepin) is the major metabolite and is usually present at concentrations
equal to doxepin. Optimal efficacy occurs at combined serum concentrations between 50 ng/mL and
150 ng/mL. Like other TCA, the major toxicity of doxepin is expressed as cardiac dysrhythmias, which
occur at concentrations in excess of 300 ng/mL. Other side effects include nausea, hypotension, and dry
mouth.
Useful For: Monitoring serum concentration during therapy Evaluating potential toxicity Evaluating
patient compliance
Interpretation: Therapeutic ranges are based on specimens drawn at trough (ie, immediately before
the next dose). Amitriptyline and Nortriptyline Most individuals display optimal response to amitriptyline
when combined serum levels of amitriptyline and nortriptyline are between 80 ng/mL and 200 ng/mL.
Risk of toxicity is increased with combined levels > or =300 ng/mL. Most individuals display optimal
response to nortriptyline with serum levels between 70 ng/mL and 170 ng/mL. Risk of toxicity is
increased with nortriptyline levels > or =300 ng/mL. Some individuals may respond well outside of these
ranges, or may display toxicity within the therapeutic range, thus interpretation should include clinical
evaluation. Imipramine Most individuals display optimal response to imipramine when combined serum
levels of imipramine and desipramine are between 175 ng/mL and 300 ng/mL. Risk of toxicity is
increased with levels > or =300 ng/mL. Despramine Most individuals display optimal response to
desipramine with serum levels of 100 to 300 ng/mL. Risk of toxicity is increased with desipramine levels
> or =300 ng/mL. Some individuals may respond well outside of these ranges, or may display toxicity
within the therapeutic range, thus interpretation should include clinical evaluation. Doxepin Most
individuals display optimal response to doxepin when combined serum levels of doxepin and nordoxepin
are between 50 ng/mL and 150 ng/mL. Some individuals may respond well outside of this range, or may
display toxicity within the therapeutic range; thus, interpretation should include clinical evaluation. Risk
of toxicity is increased with combined levels > or =300 ng/mL.
Reference Values:
AMITRIPTYLINE AND NORTRIPTYLINE
Therapeutic concentration: 80-200 ng/mL
Toxic concentration: > or =300 ng/mL
NORTRIPTYLINE
Therapeutic concentration: 70-170 ng/mL
Toxic concentration: > or =300 ng/mL
IMIPRAMINE AND DESIPRAMINE
Therapeutic concentration: 175-300 ng/mL
Toxic concentration: > or =300 ng/mL
DESIPRAMINE
Therapeutic concentration: 100-300 ng/mL
Toxic concentration: > or =300 ng/mL
DOXEPIN AND NORDOXEPIN
Therapeutic concentration: 50-150 ng/mL
Toxic concentration: > or =300 ng/mL
Clinical References: 1. Wille SM, Cooreman SG, Neels HM, Lambert WE: Relevant issues in the
monitoring and the toxicology of antidepressants. Crit Rev Clin Lab Sci 2008;45(1):25-89 2. Thanacoody
HK, Thomas SH: Antidepressant poisoning. Clin Med 2003;3(2):114-118 3. Baumann P, Hiemke C,
Ulrich S, et al: The AGNP-TDM expert group consensus guidelines: therapeutic drug monitoring in
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