Endoxifen in Child and Adolescent Psychiatry: Case Series Analysis

This set of flashcards covers a clinical case series regarding the off-label use of endoxifen in adolescents with treatment-resistant emotional and behavioral dysregulation, including its mechanism, regulatory status, and specific case outcomes.

What is the pharmacological classification and mechanism of action for endoxifen?

Endoxifen is an active metabolite of tamoxifen that functions as a protein kinase C (PKC) inhibitor and selective estrogen receptor modulator (SERM).

When did endoxifen receive regulatory approval in India, and for what specific conditions?

It was approved by the Drug Controller General of India (DCGI) in December 2023 for the treatment of manic and mixed episodes of bipolar affective disorder (BPAD) in adults.

According to the transcript, what is the role of Protein Kinase C (PKC) in psychiatric symptoms?

PKC is involved in intracellular signaling pathways related to affective instability, neuronal excitability, and aggression; its dysregulation is associated with manic states and impulsivity.

In Case 1, what were the primary diagnoses for the 16-year-old boy, and what was the final dosage of endoxifen administered?

The diagnoses were Oppositional Defiant Disorder (ODD) with Internet Addiction Disorder (IAD); endoxifen was initiated at $8\,mg/day$ and increased to a final dosage of $24\,mg/day$.

What clinical improvements were observed in Case 1 after four weeks of endoxifen treatment?

Caregivers noted a marked reduction in oppositional episodes, better mood, a voluntary decrease in screen usage (which previously exceeded $12\text{--}14$ hours daily), and increased frustration threshold.

In Case 2, involving a 15-year-old boy with Autism Spectrum Disorder (ASD), what were the specific targets of endoxifen treatment?

The treatment targeted frequent emotional meltdowns, self-injurious behavior (such as head banging and hand biting), and intense reactivity to environmental changes.

What was the dosage range for endoxifen used in Case 2, and what outcomes were reported?

Endoxifen was started at $8\,mg/day$ and doubled to $16\,mg/day$ within $2\text{--}4$ weeks, resulting in a significant drop in aggression, emotional lability, and impulsivity with normal liver function tests.

Describe the clinical profile and endoxifen dosage for Case 3.

A 16-year-old boy with Bipolar Affective Disorder (BPAD) and comorbid ADHD was treated with endoxifen starting at $8\,mg/day$ and increased to $16\,mg/day$, leading to improved affective control and reduced aggression.

Which study is cited to support the reduction of Young Mania Rating Scale (YMRS) scores using endoxifen in adults?

Ahmad et al. (2016) demonstrated significant reduction in YMRS scores in adult patients with mania.

According to the case series, what were the common functional gains observed beyond symptom control?

Clinical changes extended to functional gains in social, academic, and behavioral domains.

What specific side effects were notably absent across the three adolescent cases in this series?

The cases reported no sedation, weight changes, extrapyramidal symptoms, or metabolic side effects.

What work did Banerjee and Ray (2023) contribute regarding endoxifen?

They reported the efficacy of endoxifen in adults with borderline personality disorder and predominant impulsivity.