Short answer: The Arimidex label gives a single dose with no titration: one 1 mg tablet once a day, with or without food. For advanced breast cancer it is continued until the tumor progresses. For early breast cancer after surgery the best length is unknown; in the ATAC trial it was given for five years. No dose change is needed for kidney problems, older age or mild-to-moderate liver problems.
This is what the FDA label says. Follow your prescriber. Your prescriber may use a different dose or pace than the label's standard schedule.
What Arimidex is approved for: Arimidex is approved for postmenopausal women with breast cancer: as adjuvant (after-surgery) treatment of hormone receptor-positive early breast cancer, as first treatment of hormone receptor-positive or unknown advanced or metastatic breast cancer, and for advanced breast cancer that progressed after tamoxifen (section 1).
Source
ARIMIDEX (anastrozole) tablet, for oral use, prescribing information and Patient Information. ANI Pharmaceuticals. DailyMed, version published March 5, 2026. DailyMed setid acbfaaa9-503c-4691-9828-76a7146ed6de
Arimidex is one 1 mg tablet taken by mouth once a day, with or without food (section 2.1).
The Patient Information says to continue taking it until your healthcare provider says to stop.
The table below is the label's schedule, from the Dosage and Administration section. Numbers are copied exactly; the section is in brackets.
| Use | Dose | How long |
|---|---|---|
| Adjuvant treatment of early breast cancer | 1 mg once a day | Optimal duration unknown; five years in the ATAC trial |
| Advanced breast cancer (first-line or second-line) | 1 mg once a day | Continued until tumor progression |
| Kidney impairment or elderly patients | 1 mg once a day | No dosage adjustment necessary |
| Mild-to-moderate liver impairment | 1 mg once a day | No change recommended; not studied in severe liver impairment |
The dose is one 1 mg tablet once a day for every approved use; the label has no titration or higher dose.
For adjuvant treatment of early breast cancer, the optimal length of therapy is unknown. In the ATAC trial, Arimidex was given for five years.
No dose change is recommended for mild-to-moderate liver impairment. Arimidex has not been studied in severe liver impairment.
Patients are advised not to take Arimidex with tamoxifen. The Patient Information says tamoxifen may lower the amount of Arimidex in the blood.
The Patient Information says Arimidex may not work if taken with estrogen-containing medicines such as hormone replacement therapy, birth control pills, estrogen creams, vaginal rings or vaginal suppositories.
Bone mineral density monitoring is considered during treatment; the Patient Information says a bone density test may be done before starting and during treatment.
Females who can become pregnant have a pregnancy test before starting and use effective birth control during treatment and for at least 3 weeks after the last dose; breastfeeding is avoided during treatment and for 2 weeks after the last dose (Patient Information).
If a dose is missed, take it as soon as you remember. If it is almost time for the next dose, skip the missed dose and take the next regularly scheduled dose. Do not take two doses at the same time.
More on this: missed a dose of Arimidex.
Arimidex is approved for advanced breast cancer that progressed after tamoxifen. The label says patients with ER-negative disease and those who did not respond to earlier tamoxifen rarely responded to Arimidex.
In Dose Track you set up Arimidex as a protocol with the dose and schedule your prescriber gave you. A protocol can hold dose steps, each with its own dose and length in days or weeks, so a step-up plan like the one on the label can be entered once and the app moves to the next step on its own. Reminders follow the schedule, and every dose is logged with the date and time, so you can see which step you are on and when your last dose was. The app follows what you enter; it does not choose or change a dose.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.