What to Do If You Missed Two Doses of ZyTiga (Abiraterone)
Do not double up or take extra doses to make up for the two missed doses—simply resume your regular dosing schedule with the next scheduled dose.
Immediate Action
When you realize you've missed two doses of abiraterone:
- Take your next dose at the regularly scheduled time
- Do not attempt to "catch up" by taking multiple doses at once
- Do not take extra doses over the following days
The principle here is straightforward: abiraterone has a relatively long half-life in the context of prostate cancer treatment, and the drug accumulates to steady-state levels over time. Taking double or triple doses creates unnecessary risk of adverse events without meaningful clinical benefit.
Why Not Double Up?
While some theoretical pharmacokinetic models suggest doubling doses after missed doses might be appropriate for drugs with long half-lives 1, this approach is not recommended for abiraterone because:
- Abiraterone has significant dose-dependent toxicities, particularly hypertension, cardiac disorders, and hepatotoxicity, which occurred in 10% and 7% of patients respectively in clinical trials 2
- The drug requires careful monitoring of blood pressure and hepatic function 2
- Grade 3-5 adverse events are already substantial at standard dosing (47% in patients ≥70 years) 2
Clinical Context
Missing two doses in the context of metastatic castration-sensitive prostate cancer (mCSPC) or metastatic castration-resistant prostate cancer (mCRPC) treatment is concerning but not catastrophic:
- Abiraterone is typically given continuously for months to years 2, 3
- The drug works by sustained androgen suppression, not by achieving specific peak concentrations
- Two missed doses represent a small fraction of the total treatment duration
- The combination with ADT (androgen deprivation therapy) provides ongoing disease control even during the brief interruption
Important Follow-Up Steps
After resuming your regular schedule:
- Contact your oncology team to inform them of the missed doses
- Ensure you understand your dosing schedule going forward
- Consider setting up reminders (phone alarms, pill organizers) to prevent future missed doses 4
- Do not skip your next monitoring appointments for blood pressure, liver function, and PSA levels
Common Pitfall to Avoid
The most dangerous response would be taking multiple doses at once to "make up" for missed doses. This significantly increases your risk of:
- Severe hypertension
- Cardiac events
- Hepatotoxicity
- Other grade 3-5 adverse events
These risks far outweigh any theoretical benefit from attempting to restore drug levels more quickly.