Anastrozole and Letrozole are both used for hormone receptor positive breast cancer in postmenopausal women, but they differ on onset, duration and tolerability. Here is the practical comparison.
Anastrozole vs Letrozole
| Factor | Anastrozole | Letrozole |
|---|---|---|
| Class | aromatase inhibitor | Same therapeutic goal, different pharmacokinetics |
| Onset | oestrogen suppression within days; clinical benefit over years | Comparable or slower depending on formulation |
| Duration | 24-hour dosing | Differs: the main reason clinicians switch |
| Strengths | 1 mg | Separate titration ladder |
| Typical tolerability issue | hot flushes | Class-typical, usually mild |
| Generic availability | Widely available from GMP manufacturers | Widely available |
Key takeaways
- Choose Anastrozole when the priority is steady, sustained cover.
- Choose Letrozole when tolerability or dosing convenience matters more.
- Both are available as quality generics, so cost is rarely the deciding factor.
- Switching within class does not usually require a washout period.
Which patient suits which
Patients who want on-demand control and a short exposure window generally do better on Anastrozole. Those who prefer fewer decision points, or who did not tolerate the first option, usually move to Letrozole. Both are prescribed for hormone receptor positive breast cancer in postmenopausal women and both need the same contraindication check: premenopausal women and pregnancy.
Supply-side view
For pharmacies and telehealth platforms, stocking both gives prescribers a switch option without a re-order delay. ShiningRX ships Anastrozole and Letrozole together on one consignment to reduce freight cost per unit.
Anastrozole at a glance
| Attribute | Detail |
|---|---|
| Drug class | aromatase inhibitor |
| Common brand | Arimidex |
| Licensed use | hormone receptor positive breast cancer in postmenopausal women |
| Available strengths | 1 mg |
| Dosage form | film-coated tablet |
| Typical onset | oestrogen suppression within days; clinical benefit over years |
| Duration / dosing interval | 24-hour dosing |
| Storage | below 30 °C |