1. Introduction
Anastrozole, commonly marketed under the brand name Arimidex, is a nonsteroidal aromatase inhibitor used primarily in the treatment of hormone receptor-positive breast cancer. It works by lowering oestrogen levels in postmenopausal women, thereby slowing the growth of hormone-sensitive tumours.
2. Indications
- Approved Indications:
- Treatment of hormone receptor-positive early breast cancer in postmenopausal women.
- First-line treatment of hormone receptor-positive or hormone receptor-unknown advanced breast cancer in postmenopausal women.
- Treatment of advanced breast cancer in postmenopausal women after tamoxifen failure.
- Off-Label Uses:
- Ovulation induction in women with infertility.
3. Dosage
- Standard Dose: 1 mg once daily.
- No dosage adjustment is required for elderly patients or those with mild-to-moderate renal or hepatic impairment.
4. Administration
- Administer orally once daily, with or without food.
- Swallow the tablet whole with water.
5. Forms Available
- Tablets: 1 mg.
6. Side Effects
6.1. Common Side Effects
- Hot flushes.
- Nausea.
- Arthralgia (joint pain).
- Fatigue.
- Headache.
6.2. Less Common Side Effects
- Bone pain.
- Hair thinning or alopecia.
- Rash.
6.3. Rare but Serious Side Effects
- Osteoporosis or fractures.
- Increased cholesterol levels.
- Hepatotoxicity.
7. Warnings
- Contraindicated in premenopausal women and in patients with known hypersensitivity to anastrozole.
- Avoid use during pregnancy and lactation due to risk of foetal harm.
- Increased risk of bone fractures due to decreased bone mineral density.
8. Precautions
- Monitor bone health regularly, especially in patients with osteoporosis or risk factors for fractures.
- Use with caution in patients with severe hepatic impairment.
- Monitor lipid levels periodically in patients with hypercholesterolaemia.
9. Interactions
- Drug-Drug Interactions:
- Avoid concomitant use with tamoxifen, as it may reduce the efficacy of anastrozole.
- Drug-Food Interactions:
- No significant food interactions.
10. Monitoring Parameters
- Bone mineral density (BMD) at baseline and periodically.
- Lipid profile during treatment.
- Liver function tests (if clinically indicated).
11. Use in Children
- Safety and efficacy have not been established in paediatric populations.
12. Use in Pregnancy
- Contraindicated (Category X).
- Anastrozole may cause foetal harm; not to be used in women of reproductive potential who are not using contraception.
13. Use in Elderly
- No dosage adjustment required.
- Regular monitoring of bone health is essential due to increased fracture risk.
14. Use in Kidney Disease
- No dosage adjustment required in mild-to-moderate renal impairment (creatinine clearance ≥20 mL/min).
- Use with caution in severe renal impairment.
15. Use in Liver Disease
- No dosage adjustment required for mild-to-moderate hepatic impairment.
- Use with caution in severe hepatic impairment, and monitor liver function.
16. Patient Counselling Points
- Inform patients about the risk of osteoporosis and the importance of regular bone health monitoring.
- Advise on potential side effects like hot flushes and joint pain.
- Highlight the importance of adhering to the prescribed dosage and reporting unusual symptoms (e.g., persistent bone pain).
- Emphasise that the medication is not suitable for premenopausal women or during pregnancy.
17. Table of Brand Names, Manufacturers, and Prices
Brand Name | Manufacturer | Price (USD) |
---|---|---|
Arimidex | AstraZeneca | $150 (30 tablets, 1 mg) |
Generic Options | Various | $30–50 (30 tablets, 1 mg) |
18. FAQs (15 Questions)
- What is anastrozole used for?
Anastrozole is used to treat hormone receptor-positive breast cancer in postmenopausal women. - How does anastrozole work?
It inhibits the aromatase enzyme, reducing oestrogen levels and slowing tumour growth. - Can anastrozole be taken with food?
Yes, it can be taken with or without food. - What are the common side effects of anastrozole?
Hot flushes, joint pain, and fatigue are common side effects. - Are there any serious side effects?
Yes, osteoporosis, fractures, and increased cholesterol levels are possible. - Can premenopausal women take anastrozole?
No, it is not suitable for premenopausal women. - Can anastrozole be used during pregnancy?
No, it is contraindicated due to the risk of foetal harm. - How should anastrozole be stored?
Store at room temperature, away from moisture and heat. - What happens if I miss a dose?
Take it as soon as you remember, but skip it if it’s near the next dose. Do not double the dose. - Can I drink alcohol while taking anastrozole?
Alcohol does not directly interact with anastrozole, but it may exacerbate side effects like fatigue. - Does anastrozole cause hair loss?
Hair thinning is a possible but uncommon side effect. - Is anastrozole safe for elderly patients?
Yes, but bone health monitoring is particularly important. - Does anastrozole affect bone health?
Yes, it can decrease bone mineral density, increasing the risk of fractures. - Can anastrozole interact with tamoxifen?
Yes, tamoxifen may reduce the effectiveness of anastrozole. - Do I need regular tests while taking anastrozole?
Yes, bone density and lipid profile should be monitored periodically.