Exemestane


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Adjuvant therapy for postmenopausal women w/ hormone receptor positive early breast cancer 25 mg once daily for 5 yr of combined adjuvant hormonal therapy (following tamoxifen). Advanced breast cancer in postmenopausal women 25 mg once daily until evident tumour progression.
Dosage Details
Oral
Adjuvant therapy for postmenopausal women with hormone receptor positive early breast cancer
Adult: Following 2-3 yr initial adjuvant tamoxifen treatment, 25 mg once daily for a total of 5 yr of combined sequential adjuvant hormonal therapy; or earlier if tumour relapse occurs.

Oral
Advanced breast cancer in postmenopausal women
Adult: 25 mg once daily continued until evident tumour progression.
Special Patient Group
Patients on strong CYP3A4 enzyme inducers: 50 mg once daily.
Administration
Should be taken with food.
Contraindications
Premenopausal women. Pregnancy and lactation.
Special Precautions
Patient w/ uncontrolled HTN, osteoporosis and its potential causes (e.g. vit D deficiency, hyperthyroidism, hyperparathyroidism). Hepatic and renal impairment.
Adverse Reactions
Significant: Decrease in BMD.
Nervous: Headache, dizziness, depression, insomnia, anxiety, neuropathy, paraesthesia.
CV: HTN, peripheral oedema.
GI: Diarrhoea, nausea, abdominal pain, anorexia, constipation, vomiting.
Resp: Dyspnoea.
Musculoskeletal: Arthralgia, myalgia, carpal tunnel syndrome, osteoarthritis, osteoporosis.
Ophthalmologic: Visual disturbances.
Dermatologic: Hot flushes, alopecia, increased sweating, dermatitis, rash.
Others: Fatigue.
Patient Counseling Information
This drug may cause drowsiness, asthenia, and dizziness, if affected, do not drive or operate machinery.
MonitoringParameters
Monitor 25-hydroxy vit D level and BMD prior to therapy; and LFT. Assess for new or unusual bone pain or swelling of face, lips, or throat.
Drug Interactions
Decreased plasma levels of exemestane when used w/ strong CYP3A4 enzyme inducers (e.g. phenytoin, carbamazepine, rifampicin). Antagonised effect w/ oestrogens.
Food Interaction
Increased bioavailability w/ food. Decreased therapeutic effect w/ St John’s wort.
Action
Description: Exemestane is an irreversible, selective aromatase inhibitor which acts as a false substrate for the enzyme and forms an intermediate that binds to its active site. This leads to inactivation or suicide inhibition, thus preventing the conversion of androgens to oestrogens in peripheral tissues. It lowers circulating oestrogens in postmenopausal women w/ breast cancers where growth is oestrogen-dependent.
Pharmacokinetics:
Absorption: Rapidly absorbed from the GI tract. Time to peak plasma concentration: 1.2 hr.
Distribution: Extensively distributed into tissues; crosses the placenta. Plasma protein binding: 90%, primarily to albumin and α1-acid glycoprotein.
Metabolism: Metabolised via oxidation by CYP3A4 enzyme and via reduction by aldoketoreductase into inactive metabolites.
Excretion: Via urine (>1% as unchanged drug; 39-45% as metabolites); faeces (36-48%). Elimination half-life: Approx 24 hr.
Chemical Structure

Chemical Structure Image
Exemestane

Source: National Center for Biotechnology Information. PubChem Database. Exemestane, CID=60198, https://pubchem.ncbi.nlm.nih.gov/compound/Exemestane (accessed on Jan. 23, 2020)

Storage
Store between 20-25°C. 
ATC Classification
L02BG06 - exemestane ; Belongs to the class of enzyme inhibitors. Used in treatment of neoplastic diseases.
References
Anon. Exemestane. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 01/03/2017.

Buckingham R (ed). Exemestane. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 01/03/2017.

Exemestane Tablet, Film Coated (West-Ward Pharmaceuticals Corp). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 01/03/2017.

Joint Formulary Committee. Exemestane. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 01/03/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Exemestane. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 01/03/2017.

Disclaimer: This information is independently developed by MIMS based on Exemestane 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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