Is tamoxifen a CYP3A4 inhibitor?

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.

What drug is metabolized by CYP3A4?

Cytochrome P450 enzymes metabolize approximately 60% of prescribed drugs, with CYP3A4 responsible for about half of this metabolism; substrates include acetaminophen, codeine, ciclosporin (cyclosporin), diazepam, and erythromycin. The enzyme also metabolizes some steroids and carcinogens.

Is tamoxifen enzyme inducer or inhibitor?

Tamoxifen, endoxifen, and tamoxifen metabolites are substrates for enzymes and transporters that are susceptible to induction, such as uridine diphosphate-glucuronosyltransferases (UGTs), a family of enzymes that catalyse the covalent addition of glucuronyltransferases, CYP3A4, CYP2C9/CYP2C19, CYP2B6, and efflux …

How is tamoxifen absorbed?

(a) Humans. Tamoxifen is well absorbed after oral administration, and appears to be more than 99% bound to plasma proteins (mostly to albumin) (Lien et al., 1989).

What is a CYP3A4 inducer?

CYP3A4 inducers are drugs that increase the activity of CYP3A4. Note that the CYP3A4 enzyme is particularly susceptible to enzyme inducers, and marked reductions in the plasma concentrations of CYP3A4 substrates may occur.

How is tamoxifen eliminated?

Tamoxifen is extensively metabolized after oral administration. Studies in women receiving 20 mg of 14C tamoxifen have shown that approximately 65% of the administered dose is excreted from the body over a period of 2 weeks with fecal excretion the primary route of elimination.

What inhibits tamoxifen?

Tamoxifen is a potent inhibitor of cholesterol esterification and prevents the formation of foam cells.

What is contraindicated with tamoxifen?

For patients taking tamoxifen for breast cancer risk reduction at high risk for breast cancer or ductal carcinoma in situ, it should be avoided if the patient has a history of deep vein thrombosis (DVT) or pulmonary embolism (PE).

Can you take tamoxifen and levothyroxine together?

No interactions were found between Synthroid and tamoxifen. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.

What are CYP3A drugs?

CYP3A inducers include the glucocorticoids, rifampin, carbamazepine, phenobarbital, and phenytoin. Among the many significant CYP3A inhibitors are grapefruit juice, erythromycin, ketoconazole, clarithromycin, and verapamil.

What are CYP3A inhibitors or inducers?

What supplements interact with tamoxifen?

“There are supplements known to interfere with anti-hormonal agents used for breast cancer.” If you take tamoxifen, it’s best to avoid red clover, St. John’s wort, and black cohosh. Also skip DHEA, licorice, and red clover, because they may affect your hormone levels.

What drugs can you not take with tamoxifen?

Certain medications used to treat depression should be avoided by women taking tamoxifen. The antidepressants paroxetine (Paxil) and fluoxetine (Prozac) have been found to increase women’s risk of dying of cancer if they are taking tamoxifen.

What medications interact with tamoxifen?

Mild Interactions of tamoxifen include:

• aprepitant.
• artemether/lumefantrine.
• black cohosh.
• butalbital.
• divalproex sodium.
• eucalyptus.
• fluconazole.
• lapatinib.