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Letrozole: Indications, Dosing, Side Effects and Interactions
Letrozole clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 3 min read
Letrozole: Indications, Dosing, Side Effects and Interactions
Letrozole clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**First-line treatment in postmenopausal women with hormone-dependent advanced breast cancer,Adjuvant treatment of oestrogen-receptor-positive invasive early breast cancer in postmenopausal women,Advanced breast cancer in postmenopausal women (naturally or artificially induced menopause) in whom other anti-oestrogen therapy has failed,Extended adjuvant treatment of hormone-dependent invasive breast cancer in postmenopausal women who have received standard adjuvant tamoxifen therapy**
- **Adult** (By Mouth): for 5 years, Neo-adjuvant treatment in postmenopausal women with localised hormone-receptor-positive, human epidermal growth factor-2 negative breast cancer where chemotherapy is not suitable and surgery not yet indicated 2.5 mg daily.
Cautions
Susceptibility to osteoporosis
Contraindications
Not indicated for premenopausal women
Side effects
Common or very common Alopecia; appetite abnormal; arthralgia; asthenia; bone fracture; bone pain; constipation; depression; diarrhoea; dizziness; gastrointestinal discomfort; headache; hot flush; hypercholesterolaemia; hyperhidrosis; hypertension; malaise; myalgia; nausea; oedema; osteoporosis; skin reactions; vaginal haemorrhage; vomiting; weight changes Uncommon Anxiety; arthritis; breast pain; cancer pain; carpal tunnel syndrome; cataract; cerebrovascular insufficiency; cough; drowsiness; dry mouth; dysaesthesia; dyspnoea; embolism and thrombosis; eye irritation; fever; insomnia; irritability; ischaemic heart disease; leucopenia; memory loss; mucosal dryness; myocardial infarction; palpitations; stomatitis; tachycardia; taste altered; thirst; urinary frequency increased; urinary tract infection; vision blurred; vulvovaginal disorders Frequency not known Angioedema; hepatitis; toxic epidermal necrolysis; trigger finger
Interactions
**Other interactions (8):**
- Metabolism of letrozole is partly mediated via CYP2A6 and CYP3A4.
- Cimetidine, a weak, unspecific inhibitor of CYP450 enzymes, did not affect the plasma concentrations of letrozole.
- There is no clinical experience to date on the use of Femara in combination with oestrogens or other anticancer agents, other than tamoxifen.
- Tamoxifen, other anti-oestrogens or oestrogen-containing therapies may diminish the pharmacological action of letrozole.
- In addition, co-administration of tamoxifen with letrozole has been shown to substantially decrease plasma concentrations of letrozole.
- Co-administration of letrozole with tamoxifen, other anti-oestrogens or oestrogens should be avoided.
Pregnancy
Avoid (isolated cases of birth defects reported).
Breast feeding
Manufacturer advises avoid.
Hepatic impairment
Manufacturer advises caution in severe impairment (increased exposure and half-life).
Renal impairment
Use with caution if creatinine clearance less than 10 mL/minute (limited information available), M see Prescribing in renal impairment .
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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