What not to take with rituximab?

October 12, 2025 •

4 min read

In a 2020 study, off-label use of rituximab accounted for nearly 30% of prescriptions for non-oncology conditions [1.7.3]. Understanding what not to take with rituximab is vital for preventing severe adverse reactions across all its applications.

Quick Summary

This overview details the crucial medications, supplements, and vaccines to avoid when undergoing treatment with rituximab. Key interactions that pose significant health risks, such as with live vaccines and cisplatin, are highlighted for patient safety.

Key Points

Live Vaccines: It is absolutely contraindicated to receive live vaccines like MMR, chickenpox, and yellow fever while on rituximab as they can cause severe illness [1.2.3].
Cisplatin: Do not take the chemotherapy drug cisplatin with rituximab, as the combination is not approved and carries a high risk of fatal kidney damage [1.3.1, 1.4.4].
Blood Pressure Meds: Your doctor may instruct you to skip your blood pressure medication for 12-24 hours before an infusion to prevent a sharp drop in blood pressure [1.5.2].
Other Immunosuppressants: Using rituximab with other immune-suppressing drugs, like TNF inhibitors, increases the risk of serious infections and requires close monitoring [1.4.4, 1.6.2].
Vaccination Timing: If you need any live vaccines, they should be administered at least four weeks before you begin your rituximab treatment course [1.4.1].
Patient Disclosure: You must inform your healthcare provider about every prescription, over-the-counter medicine, vitamin, and herbal supplement you are taking [1.2.5, 1.4.5].
Herbal Supplements: Avoid immune-stimulating herbs like echinacea and metabolism-altering ones like St. John's Wort unless cleared by your doctor [1.9.1, 1.9.5].

Understanding Rituximab's Mechanism

Rituximab is a powerful monoclonal antibody designed to target and bind to the CD20 protein found on the surface of specific white blood cells called B-lymphocytes [1.8.4]. Once bound, rituximab triggers the body's immune system to destroy these B-cells. This process involves several pathways, including complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), and the induction of apoptosis (programmed cell death) [1.8.4, 1.8.5]. By depleting B-cells, rituximab can halt the progression of certain B-cell cancers like non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL). In autoimmune diseases such as rheumatoid arthritis (RA), it reduces the autoimmune response responsible for inflammation and tissue damage [1.8.1]. This profound effect on the immune system is why managing concurrent medications is so critical.

The Absolute Contraindication: Live Vaccines

The most critical rule for patients on rituximab is to avoid all live attenuated vaccines [1.2.3]. Because rituximab significantly suppresses a key part of the immune system, administering a vaccine containing a live (though weakened) virus or bacterium can lead to a full-blown infection [1.2.2]. The body is unable to mount a normal immune response to control the vaccine's organism, creating a serious and potentially life-threatening health risk [1.4.4].

Vaccines to Avoid:

Measles, Mumps, Rubella (MMR) [1.2.1]
Varicella (chickenpox) [1.2.1]
Yellow Fever [1.2.1]
Intranasal flu vaccine (the flu shot is an inactivated vaccine and generally safe) [1.2.1]
Rotavirus [1.2.1]
Typhoid (oral version) [1.2.1]
Bacillus Calmette-Guérin (BCG) for tuberculosis [1.2.1]

Healthcare providers recommend that all necessary live vaccinations be completed at least four weeks before starting rituximab therapy to allow the immune system to respond appropriately [1.2.3, 1.4.1].

Major Drug-on-Drug Interactions

Beyond vaccines, several prescription medications can have dangerous interactions with rituximab. These interactions can increase toxicity, amplify side effects, or lead to other severe complications.

Cisplatin: A High-Risk Combination

The concurrent use of rituximab and cisplatin, a chemotherapy agent, is not an approved treatment regimen and is strongly advised against [1.3.1, 1.4.4]. Clinical trials have shown that this combination can lead to severe and sometimes fatal renal toxicity (kidney damage) [1.3.1, 1.3.6]. Patients on this combination must be monitored extremely closely for any signs of kidney failure, such as rising serum creatinine levels [1.3.1].

Other Immunosuppressants and DMARDs

Combining rituximab with other drugs that suppress the immune system can have an additive effect, significantly increasing the risk of serious infections [1.6.2]. While rituximab is often used with methotrexate (a DMARD) for rheumatoid arthritis, this requires careful monitoring [1.6.4]. Adding other biologics or potent immunosuppressants should be done with extreme caution.

Examples of drugs to be cautious with:

Tumor Necrosis Factor (TNF) inhibitors (e.g., adalimumab, infliximab, etanercept) [1.4.5, 1.5.4]
Other biologic DMARDs (e.g., abatacept, belimumab) [1.2.1]
High-dose corticosteroids [1.4.5]

Blood Pressure Medications

Rituximab infusions can cause a temporary drop in blood pressure (hypotension) [1.5.2]. Because of this, physicians often advise patients to withhold their regular antihypertensive medications for 12 to 24 hours before an infusion session [1.5.2, 1.5.3]. This precautionary measure helps prevent a dangerously low blood pressure event during treatment. Always follow your doctor's specific instructions regarding your blood pressure medicine.

Comparison of Key Rituximab Interactions


Drug/Substance Class	Nature of Interaction	Management Recommendation
Live Attenuated Vaccines	Risk of contracting the illness from the vaccine due to immunosuppression [1.2.2].	Strictly contraindicated during and for at least 6 months after therapy [1.2.2]. Complete vaccinations at least 4 weeks prior to starting [1.2.3].
Cisplatin	Significantly increased risk of severe and potentially fatal kidney damage [1.3.1, 1.4.4].	Combination is not an approved regimen and should be avoided [1.3.1].
Antihypertensive Drugs	Potential for severe hypotension (low blood pressure) during the infusion [1.5.2].	Healthcare providers may advise temporarily withholding doses for 12-24 hours before infusion [1.5.2, 1.5.3].
Other Immunosuppressants	Additive immunosuppressive effect, leading to a heightened risk of serious infections [1.6.2].	Use with extreme caution and under close medical supervision. Monitor for signs of infection [1.4.4].
Herbal Supplements (e.g., Echinacea, St. John's Wort)	Some herbs may interfere with drug metabolism or counteract immunosuppressive effects [1.9.1, 1.9.5].	Avoid without consulting your oncologist or rheumatologist. Full disclosure is essential [1.9.2].

OTC Medications and Herbal Supplements

It is crucial to tell your doctor about all over-the-counter (OTC) medicines, vitamins, and herbal supplements you take [1.2.5]. Some supplements, like St. John's Wort, can alter how drugs are metabolized, while others, such as echinacea or astragalus, are believed to stimulate the immune system and could potentially work against rituximab's intended effect [1.9.1, 1.9.5]. Even seemingly harmless probiotics with live bacteria might pose a risk to a compromised immune system and should be discussed with a doctor [1.9.3].

Conclusion: The Importance of Open Communication

Rituximab is a highly effective medication for a range of serious diseases, but its safety depends on careful management of what else you take. The list of potential interactions is long, underscoring the most important rule: maintain open and honest communication with your healthcare team. Always disclose every medication, supplement, and OTC product you are using before starting and during your treatment with rituximab. This partnership is your best defense against preventable, serious health complications.

For more detailed information, you can review the FDA's prescribing information, such as the one provided by Genentech: https://www.gene.com/download/pdf/rituxan_prescribing.pdf [1.3.2]

Frequently Asked Questions

Yes, you can and should get the inactivated influenza vaccine (the flu shot). However, you must avoid the live attenuated influenza vaccine, which is given as a nasal spray [1.2.3].

Rituximab itself can cause a drop in blood pressure during the infusion. Taking your blood pressure medication right before might lead to a severe hypotensive event. Your doctor will likely advise you to temporarily withhold your dose for 12-24 hours before treatment [1.5.2, 1.5.3].

There is no strict contraindication against moderate alcohol use. However, alcohol can worsen side effects like nausea or headaches. It is best to discuss your alcohol consumption with your healthcare provider [1.4.3].

B-cell recovery typically begins around 6 months after the final dose and can take up to 12 months or longer. You should wait until your immune system has recovered, generally at least 6-12 months, before receiving a live vaccine, but you must consult your doctor for specific timing [1.2.2, 1.8.4].

This combination has been linked to severe, and sometimes fatal, kidney toxicity in clinical trials. It is not an approved treatment regimen due to this high risk of renal failure [1.3.1, 1.4.4].

You should always discuss any over-the-counter pain relievers with your doctor. While Tylenol is often acceptable, some NSAIDs can have effects on the kidneys or bleeding risk, which could be a concern, especially if you are also taking other medications that affect kidney function [1.4.3].

Yes, you should be cautious. Avoid supplements that claim to 'boost' the immune system, like echinacea or astragalus, as they may counteract the drug's effect. Also avoid supplements like St. John's Wort that can interfere with drug metabolism. Always tell your doctor about all supplements you take [1.9.1, 1.9.2, 1.9.5].