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Letrozole / ribociclib Disease Interactions

There are 4 disease interactions with letrozole / ribociclib:


Letrozole (applies to letrozole/ribociclib) liver disease

Major Potential Hazard, Moderate plausibility.

Letrozole is extensively metabolized by the liver. The pharmacokinetic disposition of letrozole has not been assessed in patients with severe hepatic impairment. No dosage modification is recommended for patients with mild to moderate hepatic impairment, however, therapy with letrozole should be administered cautiously to patients with severe hepatic impairment.


  1. "Product Information. Femara (letrozole)." Novartis Pharmaceuticals, East Hanover, NJ.

Letrozole (applies to letrozole/ribociclib) cholesterol

Moderate Potential Hazard, Moderate plausibility. Applicable conditions: Hyperlipidemia

In an adjuvant clinical trial hypercholesterolemia was reported in 52.3% of letrozole patients and 28.6% of tamoxifen patients. CTC grade 3-4 hypercholesterolemia was reported in 0.4% of letrozole patients and 0.1% of tamoxifen patients. Also in the adjuvant setting, an increase of >=1.5 X ULN in total cholesterol (generally non-fasting) was observed in patients on monotherapy who had baseline total serum cholesterol within the normal range (i.e., <=1.5 X ULN) in 151/1843 (8.2%) on letrozole vs 57/1840 (3.2%). Caution is recommended when prescribing letrozole to these patients. Consideration should be given to monitoring serum cholesterol.


Letrozole (applies to letrozole/ribociclib) osteoporosis

Moderate Potential Hazard, Moderate plausibility.

Use of letrozole tablets may cause decreases in bone mineral density (BMD). Caution should exercise when prescribing this agent to patients with a risk of fractures, such as the elderly and patients with osteoporosis. Consider bone mineral density monitoring in patients treated with letrozole.


Multikinase inhibitors (applies to letrozole/ribociclib) lung toxicity

Moderate Potential Hazard, Moderate plausibility. Applicable conditions: Interstitial Pneumonitis, Pulmonary Impairment

The use of certain multikinase inhibitors has been associated with pulmonary toxicity. Serious cases of interstitial lung disease (ILD), including fatal cases and interstitial pneumonitis or pulmonary fibrosis have been reported. Caution is recommended when using these agents in patients with a history of interstitial pneumonitis or pulmonary fibrosis or those patients presenting with acute onset of new or progressive unexplained pulmonary symptoms such as dyspnea, cough, and fever pending diagnostic evaluation. If ILD is confirmed, permanently discontinue these agents and institute appropriate measures. Immediately withhold treatment in patients diagnosed with ILD/pneumonitis and permanently discontinue therapy if no other potential causes of ILD/pneumonitis have been identified.

Letrozole / ribociclib drug interactions

There are 640 drug interactions with letrozole / ribociclib

Letrozole / ribociclib alcohol/food interactions

There are 2 alcohol/food interactions with letrozole / ribociclib

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.