Femara Disease Interactions

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.

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.

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.