Ibrance and Atorvastatin

WOW! This is the first I'd heard of this, and I've been considering the COC Protocol. But now that you posted this, I also found the following:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC55118...

Very scary.

Yes, the statins are degraded in the bloodstream by the same Cyp3A4 enzyme that Ibrance uses. The blood pressure medicine amlodipine also uses the same enzyme. It means that the levels of statins and/or amlodipine in your body may be higher than normal while taking Ibrance, because all of these drugs are competing for the same enzyme to get turned over and flushed out of the system, There are significant studies showing that prolonged or high levels of statins can lead to muscle weakness and deterioration, even without Ibrance, but there are blood markers that indicate this, hopefully these are scrutinzed by our oncs.Higher levels of BP meds can only be followed by reading blood pressure.

Jack5ie, the interactions do not decrease the efficacy of Ibrance. But because there is (potentially) more Ibrance in the blood, there might be an increase in side effects.

Rosie, that's an important point to keep in mind. Atorvastatin (and other similar statins) have a potential for rhabdomyolysis on their own (rhabdomyolysis is what killed the poor patient in the article). It's rare (~1.5 in 100,000) and only <10% of the cases are lethal. But given the wide-spread use of statins, that is still ~800 cases every year, including 10-15 deaths.

The risk for rhabdomyolysis caused by statins is dose dependent, and the 40 mg dose has a 4-fold higher risk than the 10 mg dose. The 80 mg dose has an 11-fold higher risk (that's about 1.5 in 10,000) compared to the 10 mg dose. When you add Ibrance, as Curious explained above, the Ibrance and Atorvastatin compete for the same enzyme to be metabolized and eliminated from the body, and this can result in higher-than-normal concentrations in the blood for one or both drugs. So, for the patient in the article, it's possible that the Ibrance made the 40 mg dose "behave like" an 80 mg or even higher dose in terms of risk of rhabdomyolysis, and this person was unfortunate enough to develop a very rapid case that wasn't caught in time by blood tests and led to death.

I think it's good to raise awareness in the medical community of this drug-drug interaction, and perhaps doctors should consider lowering the statin dose on their Ibrance patients to see if perhaps a lower dose combined with Ibrance works as well as the higher dose without Ibrance. It's also good for the doctors (and patients) to know that they should take a look at the blood panels that most of us have done every month, to spot any abnormalities that could signal trouble.

But I don't think anyone should be panicking and stopping their medications - while terrible and tragic, this is still a very rare occurrence, and physicians can take simple steps to make it less life-threatening.