What to Do If You Miss More Than One Day of Hizentra
If you miss more than one day of Hizentra, administer your next scheduled dose as soon as you remember and continue with your regular weekly dosing schedule without attempting to "catch up" with double doses.
Immediate Action Steps
- Resume therapy immediately upon remembering the missed dose, administering your regular prescribed dose (typically 0.1-0.2 g/kg body weight) 1, 2
- Do not double up or attempt to compensate for missed doses by administering larger volumes 3
- Continue your regular weekly schedule after resuming treatment, maintaining the same dosing interval you were using before the interruption 3, 4
Clinical Context and Rationale
The pharmacokinetics of subcutaneous immunoglobulin therapy differ fundamentally from hormonal contraceptives (which comprised most of the provided evidence and are not applicable here):
- Hizentra maintains stable serum IgG levels through weekly subcutaneous administration, with mean trough levels typically around 8-9 g/L when dosed appropriately 2
- Missing doses will gradually lower your protective IgG levels, but this occurs over days to weeks rather than immediately, as IgG has a half-life of approximately 3-4 weeks 1, 4
- The risk of serious bacterial infections remains low even with occasional missed doses, with rates of 0.03-0.041 events per patient-year reported in clinical studies 4, 5
Important Monitoring Considerations
- Contact your healthcare provider if you've missed multiple consecutive doses (more than 2-3 weeks), as they may want to check your serum IgG trough levels 2
- Watch for signs of infection during the period when doses were missed, including fever, unusual fatigue, or recurrent infections 4
- Consider setting reminders (phone alarms, calendar alerts) to prevent future missed doses, as consistent weekly administration is crucial for maintaining protective antibody levels 3
Common Pitfall to Avoid
The most critical error is attempting to "make up" for missed doses by administering larger volumes or more frequent injections without medical guidance. This can increase the risk of local reactions (which occur at a rate of 0.001-0.592 per infusion) and does not provide additional clinical benefit 4. Simply resume your regular schedule and maintain consistent weekly dosing going forward 3.