Anastrozole

Indications

Anastrozole is used for: Breast cancer, Ovulation induction

Adult Dose

Oral Advanced or locally advanced breast cancer, Adjuvant treatment in early breast cancer Adult: In postmenopausal women: 1 mg daily. Adjuvant treatment may be continued for up to 5 yr. Hepatic Impairment Mild-to-moderate impairment or stable hepatic cirrhosis: Dose adjustment not necessary Severe hepatic impairment: Not studied

Child Dose

Renal Dose

Administration

May be taken with or without food.

Contra Indications

Pregnancy. Hypersensitivity, premenopausal women.

Precautions

Moderate or severe hepatic impairment, hyperlipidaemias. Laboratory test for menopause if status is doubtful. Bone mass density test should be conducted at the start of the therapy and at regular intervals thereafter. Lactation: Unknown whether drug is excreted in milk; not recommended given potential for serious adverse reactions in nursing infants

Pregnancy-Lactation

Pregnancy Based on findings from animal studies and mechanism of action, therapy may cause fetal harm when administered to pregnant woman; there are no studies on use in pregnant women Advise pregnant women and females of reproductive potential of potential risk to a fetus Verify pregnancy status of females of reproductive potential prior to initiation of therapy Based on animal studies, therapy can cause fetal harm when administered to a pregnant woman Advise females of reproductive potential to use effective contraception during treatment and for at least 3 weeks after last dose Based on studies in female animals, treatment may impair fertility in females of reproductive potential Animal data Anastrozole caused embryo-fetal toxicities in rats at maternal exposure that were 9 times the human clinical exposure, based on area under the curve (AUC); in rabbits, anastrozole caused pregnancy failure at doses equal to or greater than 16 times the recommended human dose on a mg/m2 basis Lactation There are no data on presence of drug or metabolites in human milk, or effects on breast-fed child or on milk production; because many drugs are excreted in human milk and because of tumorigenicity shown for anastrozole in animal studies, or potential for serious adverse reactions in breast-fed child from treatment, advise lactating women not to breastfeed during treatment and for 2 weeks after last dose

Interactions

Efficacy decreased by oestrogens. Plasma concentrations decreased by tamoxifen.

Adverse Effects

Side effects of Anastrozole : >10% Hot flashes (12-36%), Vasodilation (25-36%), Fatigue (19%), Mood disturbances (19%), Nausea and vomiting (19%), Weakness (16-19%), Arthritis (17%), Pain (17%), Arthralgia (2-15%), Pharyngitis (14%), Depression (13%), Hypertension (2-13%), Bone pain (11%), Increased cough (11%), Osteoporosis (11%), Rash (8-11%) 1-10% Accidental injury (10%), Back pain (10%), Fracture (10%), Headache (10%), Insomnia (10%), Peripheral edema (10%), Dyspnea (8-10%), Abdominal pain (9%), Infection (9%), Lymphedema (9%), Diarrhea (8-9%), Constipation (7-9%), Breast pain (8%), Dizziness (8%), Urinary tract infection (8%), Chest pain (7%), Dyspepsia (7%), Paresthesia (5-7%), Anxiety (6%), Cataracts (6%), Flu syndrome (6%), Sinusitis (6%), Vulvovaginitis (6%), Xerostomia (6%), Breast neoplasm (5%), Bronchitis (5%), Cyst (5%), Diaphoresis (5%), Neoplasm (5%), Vaginal bleeding (5%), Fractures of spine, hip, or wrist (4%), Ischemic cardiovascular disease (4%), Vaginal hemorrhage (4%), Vaginitis (4%), Leukorrhea (3-4%), Deep vein thrombosis (2%), Endometrial cancer (intact uterus at baseline) (2%), Ischemic cerebrovascular event (2%), Weight gain (2%), Lethargy (1%)

Mechanism of Action

Anastrozole prevents conversion of androstenedione to estrone and testosterone to oestradiol by inhibiting aromatase, thus leading to significantly reduced serum oestradiol concentrations.