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INNOSC Theranostics and
Pharmacological Sciences TDM of imipramine: Correlation and case study

Table 1. Tricyclic antidepressants’ therapeutic range [31]
Drugs Therapeutic range Comments
Imipramine+Desipramine 150 – 240 μg/L Most clinicians prefer a wider range of 180 – 350 μg/L
Amitriptyline+Nortriptyline Not clearly established: 120 – 250 μg/L The concentration of >450 μg/L does not increase response
in patients who failed to develop a response at a lower
concentration but may develop anticholinergic side effects

and in those with certain cardiac disorders. Caution should In terms of special populations, pediatric patients have
also be exercised in patients with a history of seizures, a higher proportion of lean body mass than fatty tissues,
urinary retention, glaucoma, and liver or kidney disease [9,24] . leading to altered tissue stores and increased metabolism
due to increased hepatic area [27,28] . Geriatric patients, on
6. Discussion the other hand, have low hepatic blood flow, leading to
The TCA imipramine has been widely used for the decreased clearance and increased adverse drug reactions.
treatment of depression and other mood disorders since Patients with hepatic or renal impairment may also
its introduction in the 1950s. Over the years, extensive experience altered clearance and plasma concentrations of
research has been conducted on the pharmacokinetics imipramine [29-32] .
and pharmacodynamics of imipramine, as well as its Overall, the pharmacokinetics and pharmacodynamics of
contraindications and precautions. imipramine should be carefully considered when prescribing
Imipramine is highly lipophilic, with a rapid rate of this medication to patients. The contraindications and
absorption and maximum plasma concentration occurring precautions should be taken into account, and special
2 – 8 h after administration. Its distribution throughout the attention should be paid to patients with hepatic or renal
body is extensive, with a large volume of distribution, and impairment, as well as geriatric and pediatric patients.
it is mainly metabolized in the liver before being excreted. Patients should also be advised to avoid cigarette smoking
However, it is inadvisable for patients with a history of while taking imipramine.
TCAs hypersensitivity, recent myocardial infarction, and In conclusion, imipramine remains an important
certain cardiac disorders to use imipramine. Patients with medication for the treatment of depression and other
a history of seizures, urinary retention, glaucoma, and mood disorders, but it is important to understand its
liver or kidney disease should use imipramine with care. pharmacokinetics and pharmacodynamics, as well as its
The therapeutic range for imipramine in the treatment of contraindications and precautions, to ensure its safety and
depression is generally considered to be between 150 and effective use in patients. Further research may shed more
[25]
300 ng/mL . This range is consistent with previous light on the optimal dosing and management of patients
studies that have established a therapeutic threshold taking imipramine, particularly in special populations.
of 180 ng/mL . Imipramine concentrations below
[17]
150 ng/mL show no response, while concentrations above Acknowledgments
450 ng/mL can lead to toxicity, including anticholinergic None.
and cardiovascular side effects . The recommended
[18]
therapeutic range for imipramine and its active metabolite Funding
desipramine is between 150 and 240 µg/L, although some
clinicians prefer a wider range of 180 – 350 µg/L . It is None.
[25]
important to consider these therapeutic ranges during Conflict of interest
TDM of imipramine to ensure optimal treatment response
and minimize the risk of adverse effects (Table 1). The authors declare that they have no conflicts of interest.
A study by Leinonen et al. (1980) found that cigarette Author contributions
smoking can affect the metabolism of imipramine in
humans, suggesting that smoking should be avoided by Conceptualization: All authors
patients taking imipramine . In addition, imipramine has Writing – original draft: All authors
[26]
been found to have a therapeutic threshold of 180 ng/mL, Writing – review & editing: All authors
with no response found at concentrations below 150 ng/mL,
and toxicity including anticholinergic and cardiovascular Ethics approval and consent to participate
side effects occurring at concentrations above 450 ng/mL. Not Applicable.

Volume 6 Issue 2 (2023) 5 https://doi.org/10.36922/itps.0505