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tamoxifen and cbd

“We have to do some clinical studies to show in people that if you’re taking a specific drug and then you also smoke a marijuana cigarette that morning, you see higher or lower levels of that drug in your body,” Lazarus said.

That means there’s a risk that pot might dangerously amp up the effects of some prescription drugs, or cause other medications to flush through your system so quickly that they do you no good, said lead researcher Philip Lazarus.

“Generally,” Bednarczyk said, “CBD is thought to inhibit metabolic pathways, and THC is thought to induce metabolic pathways. THC can make your blood levels of other drugs fall, and CBD can make your blood levels rise.”

“Many of these patients are older and many of them may also be prescribed other medications. Were cannabinoids to be significantly contraindicated among this population, one would presume that there would be ample empirical evidence already available substantiating this concern,” Armentano said.

The investigators found that the major THC metabolites inhibited key CYP enzymes, including several that serve key roles in the liver.

Many people turn to marijuana or cannabidiol to ease their achy joints and help them, but a new study suggests that could wreak havoc with any other medications they’re taking.

In two lab reports published in the December issue of the journal Drug Metabolism and Disposition, Lazarus served as senior author. One study looked at a family of enzymes known as cytochrome P450s (CYPs), and the other analyzed the enzyme group UDP-glucuronosyltransferases (UGTs).

“We saw some significant inhibitions,” Lazarus said. “The concentrations we see in the lab are probably an indicator there is at least some inhibition of these enzymes in real-time.”

Why? Because the body uses the same set of enzymes to process them all, scientists report.

Case: A 58-year-old female with a history of bilateral breast carcinoma in remission, was treated with tamoxifen for breast cancer prevention for over 6 years. CBD was instituted to treat persistent postsurgical pain, inadequately managed by alternate analgesics. It was postulated that CBD may diminish tamoxifen metabolism by CYP3A4 and 2D6 to form active metabolite endoxifen, which exerts the anticancer benefits. Endoxifen, tamoxifen, N-desmetyltamoxifen and 4-hydroxytamoxifen levels were collected while the patient chronically received CBD 40 mg/day, and after a 60-day washout. Upon discontinuation of CBD 40 mg/day, it was observed that endoxifen levels increased by 18.75% and N-desmethyltamoxifen by 9.24%, while 4-hydroxytamoxifen remained unchanged.

Conclusion: CBD at a low dose of 40 mg/day resulted in the potential inhibition of CYP3A4 and/or CYP2D6. Patients receiving CBD and interacting chemotherapeutic drugs, such as tamoxifen, require monitoring to identify possible subtherapeutic response to treatment. Further pharmacokinetic studies are required to ascertain the dynamics of this drug interaction.

Background: Cannabidiol (CBD) serves as a promising medicine, with few known adverse effects apart from the potential of drug interactions with the cytochrome P450 system. It has been hypothesized drug interactions may occur with chemotherapeutic agents, but no supporting evidence has been published to date.

Keywords: CYP2D6; CYP3A4; cannabidiol; drug interaction; tamoxifen.

Tamoxifen and cbd

“New and emerging research from the past several years reveals that tamoxifen, and other Selective Estrogen Receptor Modulators, or SERMS, bind not only to estrogen receptors. They also bind with high affinity to one or both cannabinoid receptors, for CB1 and CB2,” said Wohlschlagel. “Tamoxifen apparently binds to both receptors, as what is called an ‘inverse agonist.’ The possible effects caused by that binding are just beginning to be explored.’”

Tamoxifen, Hormones, Receptors, and the Immune Response

Unlike most forms of cancer, “breast cancer” is actually a blanket term rather than a single diagnosis. It covers several distinct types of cancer that are further distinguished by diagnostic laboratory tests. The specific diagnosis drives individual considerations among patients and their medical teams regarding which treatments are most likely to produce the optimal outcomes for each patient.

Breast Cancer: Not Just One Disease

Perhaps the most common food-drug interaction that many people are already familiar with from warning labels and their own physicians is the grapefruit interaction; many pharmaceuticals come with specific warnings not to take them with grapefruit, because grapefruit contains enzymes that inhibit CYP450 metabolism. Tamoxifen is one of these drugs. And cannabinoids, like grapefruit, are known to inhibit CYP450 metabolism.