Anastrozole


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Adjuvant therapy for postmenopausal women with hormone receptor-positive early breast cancer; Breast cancer in postmenopausal women As monotherapy in hormone receptor-positive advanced cases or in patients with disease progression following tamoxifen therapy: 1 mg once daily. Treatment may be continued up to 5 years for adjuvant therapy or until tumour progression for advanced breast cancer.
Dosage Details
Oral
Adjuvant therapy for postmenopausal women with hormone receptor positive early breast cancer, Breast cancer in postmenopausal women
Adult: As monotherapy in hormone receptor-positive advanced cases or in patients with disease progression following tamoxifen therapy: 1 mg once daily. Treatment may be continued up to 5 years for adjuvant therapy or until tumour progression for advanced breast cancer.
Special Patient Group
Pharmacogenomics:
Anastrozole is a selective nonsteroidal aromatase inhibitor. Aromatase enzyme is encoded by CYP19 gene that is responsible for the final step in the conversion of androgen and oestrogens. Oestrogen acts as a growth factor for hormone-dependent breast cancer cells. Genotyping for CYP19 rs4646 gene polymorphism may play an important role in breast cancer survival.

In a study conducted on 406 Chinese women with Stage I-II and operable Stage III breast cancer, the association between CYP19 rs4646 genotypes and disease-free survival (DFS) was evaluated. The study shows that polymorphism is related to DFS in early breast cancer and the prognosis may depend on the menopause status of the patient.

CYP19 rs4646 polymorphism carrier of AA allele
Patient may have increased treatment efficacy in pre-menopausal women and decreased treatment efficacy in postmenopausal women.

CYP19 rs4646 polymorphism carrier of AC or CC allele
Patient may have decreased treatment efficacy in pre-menopausal women and increased treatment efficacy in postmenopausal women.

However, the findings are novel, and if confirmed, rs4646 genotyping may be a potential tool in the management of breast cancer.
Renal Impairment
CrCl (mL/min) Dosage 
 <20 Contraindicated.
Administration
May be taken with or without food.
Contraindications
As monotherapy in pre-menopausal women with breast cancer. Severe renal impairment (CrCl <20 mL/min). Pregnancy and lactation.
Special Precautions
Patient with hyperlipidaemia; pre-existing osteopenia, ischaemic cardiac disease. Moderate to severe hepatic or mild to moderate renal impairment.
Adverse Reactions
Significant: Decreased BMD (e.g. osteoporosis), hypercholesterolaemia, hypersensitivity reactions (e.g. anaphylaxis, angioedema, urticaria), ischaemic heart disease.
Blood and lymphatic system disorders: Lymphoedema.
Cardiac disorders: Angina pectoris, dyspnoea, chest pain.
Eye disorders: Cataract.
Gastrointestinal disorders: Gastrointestinal distress, anorexia, nausea, vomiting, constipation, diarrhoea, abdominal pain, dyspepsia, gastrointestinal disease, xerostomia.
General disorders and administration site conditions: Fatigue, pain, weakness.
Injury, poisoning and procedural complications: Bone fracture, accidental injury.
Investigations: Weight gain.
Metabolism and nutrition disorders: Oedema.
Musculoskeletal and connective tissue disorders: Arthritis, myalgia, arthralgia, back pain, ostealgia.
Nervous system disorders: Headache, dizziness, paraesthesia, carpal tunnel syndrome.
Psychiatric disorders: Mood disorder, depression, insomnia, anxiety.
Renal and urinary disorders: UTI.
Reproductive system and breast disorders: Pelvic pain, mastalgia, vulvovaginitis, vaginal dryness or bleeding.
Respiratory, thoracic and mediastinal disorders: Pharyngitis, cough, flu-like symptoms, sinusitis.
Skin and subcutaneous tissue disorders: Rash.
Vascular disorders: Vasodilation, hypertension, hot flushes.
Patient Counseling Information
This drug may cause asthenia and somnolence, if affected, do not drive or operate machinery.
MonitoringParameters
Perform pregnancy test prior to initiation of treatment in women with child-bearing potential. Monitor BMD, total cholesterol, LDL, CNS changes, hypotension, thrombophlebitis, bone pain or fracture at regular intervals during therapy.
Drug Interactions
Diminished therapeutic effect with oestrogen derivatives. Decreased serum concentration with tamoxifen.
Food Interaction
Slightly decreases the rate of absorption with food.
Action
Description: Anastrozole, a potent and selective nonsteroidal aromatase inhibitor, inhibits aromatase enzyme by preventing the conversion of androstenedione to oestrone and testosterone to oestradiol, leading to decreased serum estradiol concentration, decreased tumour mass or delayed progression in patients with tumours responsive to hormones.
Onset: Estradiol reduction: 70% after 24 hours; 80% after 2 weeks.
Duration: Estradiol reduction: 6 days.
Pharmacokinetics:
Absorption: Rapidly and almost completely absorbed from the gastrointestinal tract. Slightly decreases the rate of absorption with food. Time to peak plasma concentration: Approx 2 hours.
Distribution: Plasma protein binding: 40%.
Metabolism: Extensively metabolised in the liver via N-dealkylation, hydroxylation and glucuronidation into primary inactive metabolite, triazole.
Excretion: Via faeces; urine as metabolites. Elimination half-life: Approx 40-50 hours.
Chemical Structure

Click on icon to see table/diagram/image
Storage
Store between 20-25°C. This is a cytotoxic drug. Follow applicable procedures for receiving, handling, admin, and disposal.
ATC Classification
L02BG03 - anastrozole ; Belongs to the class of enzyme inhibitors. Used in treatment of neoplastic diseases.
Disclaimer: This information is independently developed by MIMS based on Anastrozole from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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