Letrozole
Indications
Letrozole is used for:
Breast cancer
Adult Dose
Oral
Advanced or locally advanced breast cancer ; Adjuvant therapy for postmenopausal women with hormone receptor positive early breast cancer
Adult: 2.5 mg once daily.
Hepatic impairment: Reduce dose by 50% in patients with cirrhosis and severe hepatic impairment; recommended dose: 2.5 mg on alternate days.
Child Dose
Renal Dose
Administration
May be taken with or without food.
Contra Indications
Premenopausal women and children; hypersensitivity.
Precautions
Severe renal impairment; severe hepatic impairment; osteoporosis. Caution when driving or operating machinery.
Lactation: not known if excreted in breast milk (for post-menopausal women)
Pregnancy-Lactation
Interactions
Plasma levels reduced by tamoxifen.
Adverse Effects
Side effects of Letrozole :
Hot flushes, arthralgia, nausea, vomiting, fatigue, dizziness, headache, dyspepsia, constipation, diarrhoea, anorexia, alopoecia, increased sweating, rash, peripheral oedema, osteoporosis, musculoskeletal pain, vaginal irritation.
Potentially Fatal: Thromboembolic events.
Mechanism of Action
Letrozole competitively binds to the heme group of aromatase, a cytochrome P450 enzyme which catalyzes conversion of androgen to oestrogen, leading to inhibition of the enzyme and a significant reduction in plasma oestrogen levels.