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Side Effect: Infusion Reactions

What are Infusion Reactions?

Infusion reactions are symptoms that occur due to either the body reacting unfavorably to an intravenous medication being given or due to the medication rapidly activating the immune system to attack cancer cells. When reactions are due to the infusion rapidly activating the immune system and, the medication can often still be given as the risk of infusion reactions is usually significantly lower for subsequent treatments. In cases where the body reacts severely to the medication itself, additional precautions may be able to be made to safely give the medication, but sometimes it is too dangerous to give again and treatment will need to be changed to a different medication.

What do Infusion Reactions look like?

Most commonly, symptoms of infusion reactions are mild and may consist of fever, sweats, chills, shaking, skin rash, and/or mild shortness of breath. In rare cases, symptoms can be severe and consist of hives, severe facial swelling, low blood pressure, and/or inability to breath. If mild infusion reactions occur, they are typically seen within 30 to 120 minutes after the start of the infusion. In some cases, reactions may be delayed and can happen up to a week after the infusion is given. Severe reactions can quickly happen within a few minutes after starting the infusion.

Infusion Reactions

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Infusion reaction signs and symptoms

Who gets Infusion Reactions?

Infusion reactions are most commonly seen with monoclonal antibodies (drugs whose generic name ends in “-mab”) but can be seen in other classes of medications as well. Other medications that may cause an infusion-related reaction include:

Reactions can happen anytime during treatment; however, they are typically seen during the first infusion or injection of a medication. Depending on the medication being given and the amount of tumor cells in their body (high tumor burden), some patients may be at higher risk for infusion reactions but overall, it is difficult to predict which patients will experience an infusion reaction.

How long do Infusion Reactions last?

The duration of symptoms of infusion reactions varies, but in many cases, they resolve in less than 30 minutes after stopping the infusion. More severe reactions may take longer to recover from.

How to prevent Infusion Reactions

The risk of infusion reactions can be lowered by giving certain medications prior to each infusion (premedications), slowing down the infusion rate, starting with a slow rate and slowly increase it over time (titration), or start with a low dose of the medication and increase it over time (desensitization).

Medications commonly used to prevent infusion reactions:

How to treat Infusion Reactions

The first step in addressing infusion reactions is to stop the infusion. Based on the type and severity of symptoms, additional medications may be given to help slow down and stop the reaction. Common medications given include histamine-1 blockers, histamine-2 blockers, or corticosteroids as listed above. In cases of severe reactions when patients have trouble breathing, epinephrine may be given as well. Once symptoms resolve, the medication may be restarted at a slower rate if deemed safe by the doctor.


1) Rombouts MD, Swart EL, van den Eertwegh AJM, et al. Systematic Review on Infusion Reactions to and Infusion Rate of Monoclonal Antibodies Used in Cancer Treatment. Anticancer Res 2020;40:1201-1218.

2) Doessegger L and Banholzer ML. Clinical development methodology for infusion-related reactions with monoclonal antibodies. Clin Transl Immunology 2015;4:e39.

3) Lenz HJ. Management and preparedness for infusion and hypersensitivity reactions. Oncologist. 2007 May;12(5):601-9.

Created: September 19, 2023 Updated: September 19, 2023