AVOIDING DRUG INTERACTIONS WITH YOUR TKI

[D.ap]

Open for discussion :)


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Part 2

Any medication has the potential of interacting with other substances, such as foods, beverages, other prescription drugs, supplements and over-the-counter medicines. One reason is that these substances need to be broken down by specialized enzymes in the liver and intestine, and various substances can have different effects on these enzymes.

In Part 1, we looked at how fruit juices can interfere with how your body metabolizes your TKI (tyrosine kinase inhibitor) medication, which may have an impact on the effectiveness of treatment or the frequency of side effects (see The grapefruit effect: what you need to know, CML-IQ, July 17, 2014).

Now let’s look at some of the drug interactions that can occur with TKIs (Gleevec, Tasigna, Sprycel).“

http://www.cureasps.org/forum/viewtopic.php?f=3&t=1665

[D.ap]

Abstract
Sunitinib, a new vascular endothelial growth factor receptor inhibitor, has demonstrated high activity in renal cell carcinoma (RCC) and is now widely used for patients with metastatic disease. Although generally well tolerated and associated with a low incidence of common toxicity criteria grade 3 or 4 toxicities, sunitinib exhibits a distinct pattern of novel side effects that require monitoring and management. This article summarizes the most important side effects and proposes recommendations for their monitoring, prevention and treatment, based on the existing literature and on suggestions made by an expert group of Canadian oncologists. Fatigue, diarrhea, anorexia, oral changes, skin toxicity and hypertension seem to be the most clinically relevant toxicities of sunitinib. Fatigue may be partly related to the development of hypothyroidism during sunitinib therapy for which patients should be observed and, if necessary, treated. Hypertension can be treated with standard antihypertensive therapy and rarely requires treatment discontinuation. Neutropenia and thrombocytopenia usually do not require intervention, in particular no episodes of neutropenic fever have been reported to date. A decrease in left ventricular ejection fraction is a rare, but potentially life-threatening side effect. Because of its metabolism by cytochrome P450 3A4 a number of drugs can potentially interact with sunitinib. Clinical response and toxicity should be carefully observed when sunitinib is combined with either a cytochrome P450 3A4 inducer or inhibitor and doses adjusted as necessary. Knowledge about side effects, as well as the proactive assessment and consistent management of sunitinib-related side effects, is critical to ensure optimal benefit from sunitinib treatment.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2422945/

[D.ap]

https://www.drugs.com/drug-interactions/pazopanib.html

[D.ap]

Abstract
The introduction of small-molecule tyrosine kinase inhibitors (TKIs) in clinical oncology has transformed the treatment of certain forms of cancers. As of 31 March 2013, 18 such agents have been approved by the US Food and Drug Administration (FDA), 15 of these also by the European Medicines Agency (EMA), and a large number of others are in development or under regulatory review. Unexpectedly, however, their use has been found to be associated with serious toxic effects on a number of vital organs including the liver. Drug-induced hepatotoxicity has resulted in withdrawal from the market of many widely used drugs and is a major public health issue that continues to concern all the stakeholders. This review focuses on hepatotoxic potential of TKIs. The majority of TKIs approved to date are reported to induce hepatic injury. Five of these (lapatinib, pazopanib, ponatinib, regorafenib and sunitinib) are sufficiently potent in this respect as to require a boxed label warning. Onset of TKI-induced hepatotoxicity is usually within the first 2 months of initiating treatment, but may be delayed, and is usually reversible. Fatality from TKI-induced hepatotoxicity is uncommon compared to hepatotoxic drugs in other classes but may lead to long-term consequences such as cirrhosis. Patients should be carefully monitored for TKI-induced hepatotoxicity, the management of which requires individually tailored reappraisal of the risk/benefit. The risk is usually manageable by dose adjustment or a switch to a suitable alternative TKI. Confirmation of TKI-induced hepatotoxicity can present challenges in the presence of hepatic metastasis and potential drug interactions. Its diagnosis in a patient with TKI-sensitive cancer requires great care if therapy with the TKI suspected to be causal is to be modified or interrupted as a result. Post-marketing experience with drugs such as imatinib, lapatinib and sorafenib suggests that the hepatotoxic safety of all the TKIs requires diligent surveillance.

https://www.ncbi.nlm.nih.gov/m/pubmed/23620168