Q&A

Is tamoxifen metabolized by CYP2D6?

Is tamoxifen metabolized by CYP2D6?

Tamoxifen is metabolized via CYP2D6 into endoxifen (4-OH-N-desmethyl-tamoxifen), its primary active metabolite. Multiple investigations have identified genetic variants of CYP2D6 that can affect its activity, which in turn affects the metabolism of tamoxifen.

Is tamoxifen a CYP2D6 inhibitor?

Let us briefly review the current status of the effect CYP2D6 inhibitors on tamoxifen pharmacokinetics and tamoxifen efficacy in breast cancer patients. First, there is general agreement that endoxifen is the primary active metabolite of tamoxifen, and that the formation of endoxifen is primarily via CYP2D6.

Is tamoxifen a CYP3A4 inhibitor?

Tamoxifen, N-desmethyltamoxifen, 4-hydroxytamoxifen and 3-hydroxytamoxifen also reversibly inhibited the activity of cDNA-expressed CYP3A4, CYP3A5 and CYP1B1.

How does tamoxifen affect gene expression?

The study found that tamoxifen regulates hTERT gene expression in a cell type-specific manner. Tamoxifen exerted an estrogen-antagonistic effect and inhibited E2-induced hTERT activation in breast cancer cells.

What is the purpose of genetic testing for tamoxifen?

These women have a version of a gene called Cytochrome P450 2D6, which reduces the effectiveness of tamoxifen and increases their chance of breast cancer recurrence. This test looks at a specific gene, called CYP2D6, to determine whether your body can fully metabolize tamoxifen to its active form, endoxifen.

Do you lose weight on tamoxifen?

Studies have shown that weight gain is not increased in women taking tamoxifen or anastrozole, but it is harder to study the effects of these drugs on a woman’s ability to lose weight. Regardless of the reasons for weight gain, weight loss requires calorie reduction.

Which antidepressants are safe with tamoxifen?

Antidepressants and Their Risk

Antidepressant Interaction With Tamoxifen
Antidepressant Degree of Interference
Paxil (paroxetine) Prozac (fluoxetine) Strong interference with antiestrogen benefit
Cymbalta (duloxetine) Wellbutrin (bupropion) Zoloft (sertraline) Moderate interference with antiestrogen benefit

Can I take berberine with tamoxifen?

The results indicated that berberine demonstrated dose‑ and time‑dependent anti‑proliferative activity in MCF‑7 and MCF‑7/TAM cells. Furthermore, the combination of berberine and tamoxifen induced cell growth inhibition more effectively than tamoxifen alone.

Does Celexa interfere with tamoxifen?

Using citalopram together with tamoxifen can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect.

Does tamoxifen change your DNA?

Although several studies have shown that long-term tamoxifen treatment can induce distinct global gene expression and promoter DNA methylation profiles in breast cancer cells [10], [20], it is unclear how this event might contribute to anti-hormone resistant cell proliferation.

Which genetic variation would cause problems with tamoxifen metabolism?

Therefore, genetic variations in the CYP2D6 gene can influence tamoxifen metabolism (19).

What enzymes metabolize tamoxifen?

Tamoxifen is metabolized to more active forms by various cytochrome P450 enzymes (CYP2D6, CYP3A4, CYP3A5, CYP2C9 and CYP2C19) (Figure 1) [7–11]. Each metabolite has its own specific binding affinity for the ER [12].