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doxepin (doxepin, GenDerm / Zonalon / Xepicort)

✓ Approved

Takeda · HRH1 · Small Molecule

What is doxepin?

doxepin is a small molecule developed by Takeda. It is approved for therapeutic indications via topical.

Drug Profile

Brand Namesdoxepin, GenDerm, Zonalon, Xepicort
CompanyTakeda
Drug ClassSmall Molecule
Molecular TargetHRH1, HRH2, SLC6A2
RouteTopical
StatusApproved

Mechanism of Action

Molecular Targets

doxepin acts on 3 molecular targets:

HRH1histamine receptor H1 (HH1R, H1R)
HRH2histamine receptor H2 (HH2R, H2R)
SLC6A2solute carrier family 6 member 2 (SLC6A5, NAT1)
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Therapeutic Indications

doxepin is developed for 1 unique indication across 1 therapeutic area.

Therapeutic AreaConditionPhase
Skin and subcutaneous tissue disordersPruritus✓ Approved

Related Research Articles

PubMedCurrent neuropharmacology2026-10-14

Doxepin Attenuates Cognitive and Anxiety-like Behavioral Deficits Induced by Acute Kidney Injury in Rats.

Jaber Sanaa S, Alsmadi Mo'tasem M, Alzoubi Karem K, Khabour Omar O et al.

Acute kidney injury (AKI) is a systemic disorder with consequences extending beyond the kidney, including central nervous system dysfunction. Clinical and experimental evidence indicates that AKI is associated with cognitive impairment and neuropsychiatric disturbances. However, effective strategies to prevent or attenuate AKI-associated brain dysfunction are lacking. Doxepin, a tricyclic antidepressant, exhibits neuroprotective properties that may counteract key mechanisms implicated in AKI-induced neural injury. In this study, acute renal failure (ARF) was used as an experimental model of AKI. ARF was induced in male Wistar rats through glycerol injection. Animals were allocated into four experimental groups: Control, doxepin (DOX), ARF, or ARF-DOX. Doxepin was given orally at a dose of 5 mg/kg once daily over a 12-day period. Renal function was assessed using serum and urinary urea measurements. Anxiety-related behavior was assessed using the open field test and the elevated plus maze, whereas spatial learning and memory were evaluated with the radial arm water maze. Glycerol-induced ARF resulted in significant alterations in urinary parameters, including reduced urinary urea concentration and increased urine output and flow rate, while serum urea levels did not differ significantly among groups. ARF did not impair spatial learning acquisition but significantly disrupted short- and long-term memory retention. In addition, ARF induced specific anxiety-like behavioral alterations, including increased freezing behavior, reduced rearing activity, and decreased open-arm entries in anxiogenic environments. Doxepin treatment significantly attenuated memory impairments and partially normalized anxiety-related behaviors, without improving biochemical markers of renal dysfunction. These findings demonstrate that AKI induces selective cognitive and anxiety-like behavioral deficits and support the existence of a kidney-brain axis. Doxepin attenuated AKI-associated neurobehavioral impairments. This study supports the potential repurposing of doxepin, an established clinically used and brain-penetrant drug, as a therapeutic strategy for attenuating AKI-associated neurobehavioral dysfunction.

PubMedExpert opinion on pharmacotherapy2026-10-14

Current perspectives on the pharmacotherapeutic management of insomnia in Veterans.

Saliba Ranime R, Cercone Julia J, El-Solh Ali A AA

Insomnia is a highly prevalent sleep disorder among Veterans and frequently co-occurs with post-traumatic stress disorder (PTSD), depression, chronic pain, and substance use disorders. This review synthesizes the current evidence on pharmacological management of insomnia in Veterans with attention to guideline recommendations, veteran-specific safety considerations, and comorbidity-driven prescribing. We discuss the rationale for reducing long-term reliance on benzodiazepines and benzodiazepine receptor agonists (BZRAs) in favor of agents with more favorable long-term risk profiles. Concurrent prescribing of GABAergic hypnotics with opioids is addressed in the context of existing VA Opioid Safety Initiative policy, FDA labeling, and observational overdose data. Off-label agents such as trazodone and quetiapine continue to be widely used despite limited efficacy evidence for insomnia; their use is best reserved for cases in which better-supported options have failed. Contemporary guidance places cognitive behavioral therapy for insomnia as first-line treatment, while pharmacotherapy is reserved for patients who do not respond to, cannot access, or decline behavioral treatment. The 2025 VA/DoD guideline suggests several medications when pharmacotherapy is used, including daridorexant, doxepin, eszopiclone, lemborexant, suvorexant, zaleplon, and zolpidem, and recommends against antipsychotics, benzodiazepines, and trazodone for chronic insomnia disorder.

PubMedFrontiers in psychiatry2026-09-23

Pharmacological modulation of hyperarousal in insomnia associated with major depressive disorder: a narrative review of sedating antidepressants and orexin receptor antagonists.

Zhang Yiwei Y, Zhang Hua H, Tang Jingkai J, Wang Yibing Y et al.

Insomnia symptoms in major depressive disorder (MDD) are clinically heterogeneous, ranging from presleep rumination and prolonged sleep latency to repeated nocturnal awakenings and early-morning awakening. Their clinical significance and treatment implications may also differ between active MDD and residual insomnia symptoms during partial remission. This narrative review examines how these presentations may inform the use of sedating antidepressants and dual orexin receptor antagonists (DORAs). Sedating antidepressants, including mirtazapine, trazodone, doxepin, and other tricyclic antidepressants, differ in dose-dependent antidepressant activity, receptor profile, and adverse-effect burden. DORAs directly target orexin-mediated wake drive and have the strongest evidence for insomnia disorder, particularly sleep-maintenance outcomes, although evidence in active MDD remains limited. Because clinical presentations neither establish an underlying mechanism nor reliably predict treatment response, the proposed framework should be used as a hypothesis-generating aid rather than a validated treatment algorithm. Pharmacological selection should also consider suicide risk, substance-use history, comorbid sleep disorders, concomitant central nervous system depressants, and next-day functioning.

PubMedFrontiers in medicine2026-09-18

Case Report: A case of cutaneous collagenous vasculopathy.

Tang Chenjian C, Chen Liping L, Yu Jiangxiu J, Zhu Mei M

We report a case of a 62-year-old woman presenting with a 6-year history of purpuric patches and macules on the lower extremities, initially misdiagnosed as allergic purpura and treated with prednisone. Skin biopsy revealed dilated dermal vessels with perivascular collagen deposition, positive for collagen IV and diastase-periodic acid-Schiff (D-PAS) staining, consistent with cutaneous collagenous vasculopathy (CCV). Treatment included hydroxychloroquine, vitamin C, doxepin, and topical mucopolysaccharide polysulfate cream. Prednisone was tapered by one tablet every 3 days. After 4 weeks, the rash improved significantly with no new lesions. We would like to present a case of CCV.

PubMedJournal of psychopharmacology (Oxford, England)2026-08-04

A pharmacometric framework for norepinephrine transporter occupancy and dose equivalence across psychotropic medications.

Aboukaoud Mohammed M, Hoch Bosmat B, Amiaz Revital R

Norepinephrine transporter (NET) inhibition is a relevant mechanism across psychotropic medications, although prescribing classifications are largely based on drug class rather than quantitative target engagement. To facilitate cross-drug comparisons of noradrenergic activity, we developed a pharmacometric model to estimate NET occupancy for 26 psychotropic agents and their active metabolites. NET occupancy was estimated using National Institute of Mental Health Psychoactive Drug Screening Program Ki data, protein-binding-corrected plasma concentrations, a standard receptor occupancy model, and logit-derived ED50 values, and was compared with published positron emission tomography (PET) estimates. After protein-binding correction, desipramine, milnacipran, and maprotiline showed very high NET occupancy (⩾90%), nortriptyline, doxepin, and norquetiapine showed high occupancy (70%-90%), and hydroxybupropion and duloxetine showed moderate occupancy (50%-70%). Clomipramine, atomoxetine, and reboxetine demonstrated moderate-low occupancy (30%-50%), whereas venlafaxine showed low occupancy (~28%). Hydroxybupropion exhibited substantially greater NET engagement (~68%) than bupropion (~2%), and most Selective serotonin reuptake inhibitors showed minimal occupancy (<10%). Estimated ED50 values ranged from 6.6 mg (desipramine) to ⩾63 mg (duloxetine), and predicted occupancies correlated moderately with PET data (r = 0.76, p = 0.028, R² = 0.58). These findings suggest that variability in NET engagement across psychotropic medications may not be fully captured by conventional class-based classifications. The proposed framework offers a mechanism-informed approach to comparative pharmacological analysis and introduces a conceptual noradrenergic activity index. This approach may be useful for hypothesis generation in future studies integrating pharmacokinetic-pharmacodynamic modeling with in vivo imaging and clinical outcomes.

PubMedZhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases2026-07-31

[Determination of doxepin and nordoxepin in plasma by solid-phase extraction coupled with liquid chromatography-mass spectrometry (PRiME MCX-UPLC-HRMS)].

Chen X D XD, Wang Q Q QQ, Cai J J JJ, Pan S D SD

Objective: To establish a rapid method for the determination of doxepin and its metabolite nordoxepin residues in plasma samples by PRiME mixed cation-exchange solid-phase extraction coupled with ultra-performance liquid chromatography-high resolution mass spectrometry (PRiME MCX-UPLC-HRMS) . Methods: Plasma samples were extracted with 2% (V/V) aqueous phosphoric acid and purified by a PRiME MCX SPE cartridge. The target compounds were separated on an aurorasil MMP-G column (100 mm×2.1 mm, 3 μm) and gradient elution was performed with the mobile phases 5.0 mmol/L ammonium formate -0.1% (V/V) aqueous formic acid and methanol, and were determined in electrospray positive ionization mode (ESI(+)) and full mass scan-data dependent ms(2) scan (Full mass-ddMS(2)) mode, and the internal standard method was used for quantification. The limits of detection (LODs) and limits of quantification (LOQs) were calculated at signal-to-noise ratios of 3 and 10, respectively. Results: The linear ranges of doxepin and its metabolite nordoxepin were 1.0-100.0 ng/ml with correlation coefficients of 0.9988-0.9999. The LODs and LOQs for doxepin and its metabolite nordoxepin were determined to be 0.18-0.22 ng/ml and 0.54-0.66 ng/ml, respectively. The spiked recoveries of doxepin and its metabolite nordoxepin in plasma at the four concentration levels of 1.0 ng/ml, 10.0 ng/ml, 50.0 ng/ml and 80 ng/ml ranged from 90.8% to 105%, with relative standard deviations (RSDs) of 1.31%-4.59%. Conclusion: The method was rapid, sensitive and accurate and was suitable for the monitoring and analysis of doxepin and its metabolite nordoxepin in plasma samples from clinical patients.

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