Painkillers, Stomach Medication, Cortisone: Can They Interact With Immunotherapy?
Immunotherapy (checkpoint inhibitors such as pembrolizumab, nivolumab, and dostarlimab) is a type of treatment that enables the immune system to recognize and attack the tumor. Most cancer patients also regularly take medications for other problems such as pain, heartburn, anxiety, and high cholesterol. Whether these medications interact with the immune system and alter how immunotherapy works has long been investigated, but remains unanswered.
- This is not a clinical study collecting new patient data; it is a review/opinion article synthesizing more than 50 previous studies (Journal of Clinical Oncology, January 2026).
- Authors: Dr. Nicholas DeVito (Duke University School of Medicine, medical oncology), Erica Gray, Daniel Schrum, and Scott Antonia.
- Aim: to bring together existing observational evidence and clearly present both clinicians and patients with a picture of “what we know and do not know,” rather than establish a definitive treatment guideline.
| Drug group | Examples | What was found? |
|---|---|---|
| Paracetamol | Tylenol, Parol, Minoset | Some studies observed poorer treatment responses in regular paracetamol users during immunotherapy; an effect through pathways that may influence the immune response is proposed. |
| Stomach acid medications (PPIs) | Omeprazole, pantoprazole, esomeprazole | They are thought to potentially weaken immunotherapy response by changing the gut microbiota (the community of intestinal bacteria known to play an important role in immune response). |
| Corticosteroids | Prednisone, dexamethasone, methylprednisolone, hydrocortisone | The most consistent and most extensively studied association: numerous studies suggest that high-dose, long-term corticosteroid use may reduce immunotherapy efficacy by suppressing immune cells, particularly T cells. |
Corticosteroids are also used as first-line drugs to treat immunotherapy's own adverse effects (immune-related adverse events, irAEs). When a patient develops a serious adverse effect from immunotherapy, the physician may therefore deliberately start corticosteroids for a justified reason; treating the medication as “unnecessary” and stopping it in that situation would be both wrong and dangerous. Whether to use corticosteroids and at what dose should always remain under your oncologist's control.
- Antihistamines (allergy medications): some studies suggest they may strengthen immune cells that fight tumors.
- Statins (cholesterol medications) and SSRI antidepressants were associated with better immunotherapy responses in observational studies; animal studies also provide supporting data for SSRIs.
- GLP1 drugs (weight-loss/diabetes drugs such as semaglutide and tirzepatide): also associated with a better response at an observational level.
Starting these drugs “to boost immunotherapy” is not yet supported by the data; using them solely for this purpose, outside their own medical indications (allergy, cholesterol, depression, diabetes/obesity), is not recommended.
Almost all findings in this review come from observational studies; researchers did not randomly assign patients to two groups, giving the drug to one and not the other, but simply compared patients who were already taking it with those who were not. Confounding is a major problem in this type of study:
- Patients taking painkillers or corticosteroids may already need them because they have more severe symptoms or more advanced disease ; the severity of the underlying disease, rather than the medication, may therefore explain the poorer outcome.
- A recent critical article questioning the paracetamol-immunotherapy association deliberately titled this relationship “guilt by association” , pointing out that the observed association may arise from the characteristics of patients taking the drug rather than the drug itself.
- For corticosteroids, there is a relatively stronger, prospectively designed study on this issue (RADIOHEAD), but this is the exception rather than the rule.
The review's authors therefore do not give a definitive “stop this, use that” recommendation; instead, they emphasize the need for prospective studies, patient educational materials, and systems to alert physicians in electronic patient records.
- Paracetamol and many stomach acid drugs are sold without prescription in Türkiye; this easy access can lead immunotherapy patients to consider them “harmless” and use them without informing their physician. It is important to report every medication you use, including herbal supplements, to your oncologist.
- For information on immunotherapy adverse effects and their management, see our guide to immunotherapy adverse effects (irAEs) .
- For the general framework of food and drug interactions during cancer treatment, you can also explore this article .
The clearest, immediately applicable message of this review is communication, rather than a medication change: if you are receiving immunotherapy, keep an updated list of all prescription and nonprescription medications (including painkillers, stomach medications, allergy medications, vitamins/supplements) and share it with your oncologist at every visit. Do not hesitate to ask before starting a new medication, even a simple painkiller. The decision should always be made by the physician who knows your treatment, rather than by you.
Most immunotherapy patients also use other medications concurrently, but their potential effects on treatment response are not systematically explored in clinical practice. The review draws attention to this gap by bringing together scattered observational evidence.
It comprehensively examines more than 50 studies; presents both “may be harmful” and “may be beneficial” findings in a balanced way; and proposes concrete next steps such as prospective studies, patient education, and electronic record systems before direct clinical implementation.
This is not a study generating new data, but a synthesis of existing, mostly retrospective and observational literature; confounding by indication remains unresolved for most findings. For most drugs other than corticosteroids, there is no prospective, randomized evidence. Mechanisms are largely hypothetical.
There is currently insufficient evidence to stop or start any medication. The main practical change is the emphasis that patients should fully disclose all medications they use, and clinicians should inquire more closely about them.
Will these associations be validated in well-designed prospective studies, or will they largely be explained by confounding? Which medication has an effect with which type of immunotherapy (anti-PD1, anti-PDL1, anti-CTLA4), and in which cancer type? Are there dose and duration thresholds (for example, a difference between short-term low-dose and long-term high-dose corticosteroids)?
Stone ML, et al. The impact of concomitant medications on treatment outcomes in patients with cancer receiving immune checkpoint inhibitors. Nat Rev Cancer. 2025. DOI: 10.1038/s41568-025-00890-z.
Bessede A, et al. Impact of acetaminophen on the efficacy of immunotherapy in cancer patients. Ann Oncol. 2022.
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