Letrozole interactions
Full monograph for LetrozoleCheck it against another medicine
Medicines
335 documented
| Medicine | Severity | Mechanism | Effect | Sources |
|---|---|---|---|---|
| Citalopram Hydrobromide | Major | Metabolism | Coadministration with CYP450 2C19 inhibitors may increase the plasma concentrations of citalopram, which is partially metabolized by the isoenzyme. Cases of QT… | 9 sources — open the full entry |
| Drospirenone + Estetrol | Majorsource also lists Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Thalidomide | Major | Synergy | Coadministration of thalidomide with glucocorticoids and/or antineoplastic agents in the treatment of malignancy may potentiate the risk of thromboembolism… | 20 sources — open the full entry |
| Abametapir | Moderate | Metabolism | Based on in vitro inhibition data, a single topical application of abametapir lotion may increase plasma concentrations of drugs that are substrates of CYP450… | 1 sources — open the full entry |
| Apalutamide | Moderate | Absorption · Metabolism | Coadministration with apalutamide may decrease the plasma concentrations and therapeutic effects of drugs that are substrates of CYP450 3A4, 2C9, 2C19, breast… | 5 sources — open the full entry |
| Aprepitant | Moderate | Metabolism | Coadministration with aprepitant or its prodrug, fosaprepitant, may increase the plasma concentrations of drugs that are primarily metabolized by CYP450 3A4… | 2 sources — open the full entry |
| Asciminib | Moderate | Metabolism | Coadministration with asciminib may increase the plasma concentrations of drugs that are primarily metabolized by the CYP450 3A4 isoenzyme. The mechanism is… | 1 sources — open the full entry |
| Bosentan Monohydrate | Moderate | Metabolism | Coadministration with bosentan may decrease the plasma concentrations of drugs that are substrates of the CYP450 2C9 and/or 3A4 isoenzymes. The mechanism is… | 5 sources — open the full entry |
| Brigatinib | Moderate | Metabolism | Coadministration with brigatinib may decrease the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. Brigatinib has been shown in… | 6 sources — open the full entry |
| Cenobamate | Moderate | Metabolism | Coadministration with cenobamate may decrease the plasma concentrations and pharmacologic effects of CYP450 3A4 substrates. The proposed mechanism is… | 1 sources — open the full entry |
| Ceritinib | Moderate | Metabolism | Coadministration with ceritinib may increase the plasma concentration and the risk of adverse effects of drugs that are substrates of CYP450 2A6 and/or 2E1… | 8 sources — open the full entry |
| Cilostazol | Moderate | Metabolism | Coadministration with inhibitors of CYP450 3A4 and/or 2C19 may increase the plasma concentrations of cilostazol and or its pharmacologically active… | 11 sources — open the full entry |
| Clobazam | Moderate | Metabolism | Coadministration of clobazam with inhibitors of CYP450 2C19 may significantly increase the plasma concentrations of its active metabolite, N-desmethylclobazam… | 7 sources — open the full entry |
| Clopidogrel + Aspirin | Moderate | Metabolism · Unknown | Coadministration with inhibitors of CYP450 2C19 may reduce the efficacy of clopidogrel, whose antiplatelet effect is dependent in part on bioactivation by the…2 documented mechanisms | 21 sources — open the full entry |
| Clopidogrel Bisulphate | Moderate | Metabolism | Coadministration with inhibitors of CYP450 2C19 may reduce the efficacy of clopidogrel, whose antiplatelet effect is dependent in part on bioactivation by the… | 21 sources — open the full entry |
| Conjugated EstrogenCreamTablet | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Conjugated Estrogen + Bazedoxifene | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Cyproterone Acetate + Ethinyl Estradiol | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Dasatinib | Moderate | Metabolism | Coadministration with dasatinib may increase the plasma concentrations of drugs that are substrates of CYP450 3A4. The mechanism is decreased clearance due to… | 8 sources — open the full entry |
| Deferasirox | Moderate | Metabolism | Coadministration with deferasirox may decrease the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism may involve… | 3 sources — open the full entry |
| Dienogest + Estradiol Valerate | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Drospirenone + Estradiol | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Drospirenone + Ethinyl Estradiol0.02 mg0.03 mg | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Drospirenone + Ethinyl Estradiol + Levomefolate | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Efavirenz | Moderate | Metabolism | Coadministration with efavirenz may decrease the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism is accelerated… | 2 sources — open the full entry |
| Enzalutamide | Moderate | Metabolism | Coadministration with enzalutamide may decrease the plasma concentrations of drugs that are substrates of CYP450 3A4, 2C9, 2C19, and/or P-glycoprotein (P-gp)… | 4 sources — open the full entry |
| Escitalopram Oxalate | Moderate | Metabolism | Coadministration with inhibitors of CYP450 2C19 may increase the plasma concentrations of escitalopram, which is primarily metabolized by the isoenzyme. High… | 18 sources — open the full entry |
| Estradiolbasevaginal cream | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Estradiol + Dydrogesterone | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Estradiol Hemihydrate + Progesterone Micronized | Moderate | Antagonism · Unknown | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer…2 documented mechanisms | 3 sources — open the full entry |
| Estradiol Valerate | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Ethinyl Estradiol + Desogestrel0.02 mg0.03 mg | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Ethinyl Estradiol + Gestodene | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Ethinyl Estradiol + Levonorgestrel + Ferrous Fumarate | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Ethinyl Estradiol + Lynestrenol0.0375 mg0.05 mg | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Fenofibrate | Moderate | Metabolism | Coadministration with fenofibrate may increase the plasma concentrations and risk of adverse effects of drugs that are substrates of CYP450 2C19, 2A6, and 2C9… | 37 sources — open the full entry |
| Flibanserin | Moderate | Metabolism | Coadministration with inhibitors of CYP450 2C19 may increase the plasma concentrations of flibanserin, which is partially metabolized by the isoenzyme. High… | 6 sources — open the full entry |
| Hydroxyprogesterone Caproate | Moderate | Metabolism | Coadministration with hydroxyprogesterone may decrease the plasma concentrations of drugs that are metabolized by CYP450 1A2, 2A6, and/or 2B6. | 1 sources — open the full entry |
| Lamivudine + Zidovudine + Nevirapine | Moderate | Metabolism | Coadministration with nevirapine may decrease the plasma concentrations and therapeutic efficacy of drugs that are substrates of CYP450 3A4. The proposed… | 4 sources — open the full entry |
| Lapatinib | Moderate | Metabolism | Coadministration with lapatinib may increase the plasma concentrations of drugs that are substrates of the CYP450 2C8 isoenzyme, CYP450 3A4 isoenzyme, and/or… | 6 sources — open the full entry |
| Larotrectinib | Moderate | Metabolism | Coadministration with larotrectinib may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. | 4 sources — open the full entry |
| Lefamulin Acetate | Moderate | Metabolism | When administered orally, lefamulin may increase the plasma concentrations of drugs that are primarily metabolized by CYP450 3A4. Based on interaction with… | 6 sources — open the full entry |
| Lorlatinib | Moderate | Metabolism | Coadministration with lorlatinib may decrease the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The proposed mechanism is… | 3 sources — open the full entry |
| Mavacamten | Moderate | Metabolism | Coadministration with mavacamten may decrease the plasma concentrations of drugs that are primarily metabolized by CYP450 3A4, 2C9, and/or 2C19. The proposed… | 1 sources — open the full entry |
| Medroxyprogesterone AcetateInjectionTablet | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Mifepristone | Moderate | Metabolism | Based on in vitro inhibition data, coadministration with mifepristone may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4… | 10 sources — open the full entry |
| Mifepristone + Misoprostol | Moderate | Metabolism | Based on in vitro inhibition data, coadministration with mifepristone may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4… | 10 sources — open the full entry |
| Nilotinib | Moderate | Metabolism | Based on in vitro inhibition data, coadministration with nilotinib may increase the plasma concentrations of drugs that are substrates of the P-glycoprotein… | 6 sources — open the full entry |
| Norgestrel + Ethinyl Estradiol + Ferrous Fumarate | Moderate | Antagonism | Theoretically, estrogen-containing drugs may negate the pharmacologic effects of aromatase inhibitors in the treatment of hormone-dependent breast cancer… | 3 sources — open the full entry |
| Oxcarbazepine | Moderate | Metabolism | Coadministration with oxcarbazepine may decrease the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism is… | 9 sources — open the full entry |
Conditions
Conditions in which Letrozole needs care, as documented in this source.
Liver Diseases
MajorLetrozole 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 source
- "Product Information. Femara (letrozole)." Novartis Pharmaceuticals (2001):
Hypercholesterolemia
ModerateIn 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.
1 source
- "Product Information. Femara (letrozole)." Novartis Pharmaceuticals (2001):
Osteoporosis
ModerateUse 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.
1 source
- "Product Information. Femara (letrozole)." Novartis Pharmaceuticals (2001):