This drug may cause fatigue, somnolence and dizziness, if affected, do not drive or operate machinery.
Monitor BP, CBC, thyroid function test, BMD level, serum electrolytes, cholesterol, transaminases, and creatinine periodically.
Tamoxifen, anti-oestrogen agent, oestrogen-containing drugs may diminish the pharmacological action of letrozole. Decreased plasma concentration w/ strong CYP3A4 inducers (e.g. rifampicin).
Description: Letrozole is a non-steroidal aromatase enzyme inhibitor which competitively binds to the haem of the CYP enzyme, blocking the conversion of androstenedione and testosterone into oestriol and oestradiol respectively, thus, leading to significantly reduced serum oestrogen concentration. Pharmacokinetics: Absorption: Rapidly and completely absorbed from the GI tract. Distribution: Rapidly and extensively distributed to tissues. Volume of distribution: Approx 1.9 L/kg. Plasma protein binding: Approx 60%, mainly albumin. Metabolism: Metabolised in the liver by CYP3A4 and CYP2A6 enzymes into an inactive carbinol metabolite. Excretion: Mainly via urine (6% as unchanged drug, 75% as glucoronide carbinol metabolite, 9% as unidentified metabolites). Terminal elimination half-life: Approx 2 days.
Store at 25°C. Protect from moisture.
This is a cytotoxic drug. Follow applicable procedures for receiving, handling, admin, and disposal.
L02BG04 - letrozole ; Belongs to the class of enzyme inhibitors. Used in treatment of neoplastic diseases.
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