Finasteride and Tamoxifen Interaction

Avoid
Mechanism-based 75% confidence

Finasteride and Tamoxifen have a potentially harmful interaction with 75% confidence. Both Finasteride and Tamoxifen carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently. These compounds primarily affect different organ systems.

Compound Profiles

Finasteride

5-Alpha Reductase Inhibitor | DHT Blocker for Hair Loss & BPH

Finasteride competitively and selectively inhibits the Type II isoform of the enzyme 5-alpha reductase, which is predominantly found in hair follicles, the prostate, and the liver. This enzyme converts testosterone into dihydrotestosterone (DHT).

Half-life: 6-8 hours (DHT suppression persists ~24 hours) Typical dose: 1mg/day (hair loss) or 5mg/day (BPH) hair loss
5 alpha reductase estrogenichepatotoxicteratogenic
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Tamoxifen

Selective Estrogen Receptor Modulator | PCT & Breast Cancer Treatment

Tamoxifen competitively binds to estrogen receptors (primarily ERalpha) and exerts tissue-selective effects depending on the local coactivator and corepressor environment. In breast tissue and the hypothalamus, tamoxifen acts as an estrogen antagonist, blocking estradiol-mediated signaling.

Half-life: ~5-7 days Typical dose: 20-40mg oral daily pct
cyp3a4estrogen receptor anticoagulantcarcinogenic riskhepatotoxicpct agent
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Combined Organ Load

Skin
low
Gonads
low
Pituitary
low

Shared Safety Flags

2x 2 hepatotoxic compounds (Finasteride, Tamoxifen). Liver damage risk significantly increased. Include liver support (TUDCA/NAC) and monitor ALT/AST.
2x 2 compounds share the teratogenic safety flag (Finasteride, Tamoxifen). Monitor accordingly.

Frequently Asked Questions

Can I take Finasteride with Tamoxifen?

Combining Finasteride with Tamoxifen is not recommended. Both Finasteride and Tamoxifen carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently.

Is Finasteride and Tamoxifen safe together?

This combination carries significant risk. Both Finasteride and Tamoxifen carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently. Consult a healthcare professional before combining.

What are the interactions between Finasteride and Tamoxifen?

Both Finasteride and Tamoxifen carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently. This assessment has 75% confidence and is inferred from pharmacological mechanism analysis.

How should I time Finasteride and Tamoxifen?

Finasteride has a half-life of 6-8 hours (DHT suppression persists ~24 hours) and Tamoxifen has a half-life of ~5-7 days. No specific timing requirements identified for this combination, but separating administration can help monitor individual effects.

Check this pair in the full Interaction Checker Full comparison: Finasteride vs Tamoxifen

This interaction analysis is compiled from research literature and pharmacological mechanism data. This assessment is inferred from known mechanisms and may not reflect all real-world outcomes. Always consult a healthcare professional before combining compounds.