MicRhoGAM Drug Interactions: What to Avoid and What to Tell Your Doctor

MicRhoGAM (Rho(D) immune globulin mini-dose) has a relatively limited drug interaction profile compared to many medications — it is a single-dose injection with a specific mechanism of action. However, there are important interactions with live vaccines and a few other considerations your provider should know about before you receive it.

The Most Important Interaction: Live Vaccines

The most clinically significant interaction with MicRhoGAM involves live attenuated vaccines. Because MicRhoGAM is an immunoglobulin containing pre-made antibodies, those antibodies can interfere with the body's immune response to live vaccines — potentially making the vaccines less effective or ineffective.

Live vaccines affected include:

MMR (measles-mumps-rubella vaccine)

Varicella (chickenpox) vaccine

Zoster (shingles) vaccine — live formulation

MMRV combination vaccine (measles-mumps-rubella-varicella)

Vaccine Timing Rules

Follow these timing rules carefully to protect your vaccine immunity:

After receiving MicRhoGAM: Wait at least 12 weeks before receiving live vaccines. The passive antibodies from MicRhoGAM can interfere with vaccine efficacy for up to this period.

After receiving a live vaccine: Wait at least 3 weeks before receiving MicRhoGAM unless clinically urgent (the 72-hour Rh sensitization window takes clinical priority over vaccine timing in emergency situations).

Note: If MicRhoGAM is given within 3 weeks of a live vaccine, the CDC recommends either revaccinating at 5 months or testing for immunity and revaccinating if seronegative. Your provider will guide this.

Inactivated vaccines (flu shot, COVID-19 vaccines, Tdap, hepatitis B, etc.) are NOT affected by MicRhoGAM. You can receive inactivated vaccines on any schedule relative to MicRhoGAM.

CAR-T Cell Therapies (Major Interaction)

MicRhoGAM has a major interaction with CAR-T cell immunotherapy products, including:

Axicabtagene ciloleucel (Yescarta)

Brexucabtagene autoleucel (Tecartus)

Ciltacabtagene autoleucel (Carvykti)

Idecabtagene vicleucel (Abecma)

The interaction involves immunosuppressive effects that increase the risk of infection. If you are receiving or have recently received CAR-T cell therapy, inform your provider before receiving MicRhoGAM. This combination should be avoided or used only when absolutely necessary.

IgA Deficiency Consideration

MicRhoGAM contains a small amount of IgA (less than 15 mcg per dose). While this quantity is very small, patients with IgA deficiency and antibodies against IgA may be at risk for hypersensitivity reactions. Your provider should weigh the risks and benefits in this specific population.

What to Tell Your Doctor Before Receiving MicRhoGAM

Before receiving MicRhoGAM, inform your provider if you:

Received any live vaccines within the past 3 weeks (MMR, varicella, shingles)

Have IgA deficiency or a known history of reactions to blood products or immune globulins

Are receiving or recently completed CAR-T cell therapy

Are Rh-positive (MicRhoGAM should not be given to Rh-positive individuals)

Are already Rh-sensitized (already have anti-D antibodies)

For information on MicRhoGAM side effects, read our MicRhoGAM side effects guide. If you're still looking for MicRhoGAM at a pharmacy near you, medfinder can help locate it quickly.