Reducing the risk of infusion reactions to monoclonal antibodies
Protocol-directed premedication (drugs given beforehand) and a slow, stepwise start lower the risk of an infusion-related reaction to a monoclonal antibody (an antibody made as one identical clone).
Remember
Premedication (a corticosteroid to dampen inflammation, an antihistamine and/or paracetamol, as the product protocol directs) and a slow starting rate raised step by step if tolerated reduce the risk of a reaction. Telling patients the warning symptoms, close monitoring and ready emergency drugs support prompt treatment if a reaction occurs.
A monoclonal antibody is an antibody made in the laboratory as one identical clone, and the immune system can react to it as something foreign. The result is an infusion-related reaction: inflammatory chemicals are released, such as histamine (the chemical behind flushing and itching) and cytokines (small signalling proteins). Symptoms include flushing, itching, fever and chills, and sometimes breathlessness, and they are most likely at the first treatment. Some patients have a mild reaction after the first infusion and tolerate later infusions better, while a few people develop a severe reaction.
Two measures lower the risk. The first is premedication, which means giving drugs beforehand. A protocol may call for a corticosteroid (to dampen inflammation), an antihistamine (to block the effects of histamine) and/or paracetamol, shortly before the infusion. The benefit differs between drugs, so the protocol for the individual product should be followed. The second is a slow starting rate that is raised step by step if the patient tolerates it. A slow start means that, if the first signs of a reaction appear, only a small amount of drug has entered the body and the nurse can stop the infusion.
Safe care adds more than drugs and rate. Patients need the warning symptoms explained so that they can report them at once, and they are watched closely. Emergency drugs should be ready, or prescribed according to local protocol, before treatment starts. These steps support prompt treatment if a reaction occurs. Premedication can fail to prevent a severe reaction such as anaphylaxis, and reactions can appear after earlier uneventful doses, so the team should keep watching at later infusions.
Key facts
- Timing
- Reactions are most likely at the first treatment.
- Premedication
- Shortly before the infusion, a corticosteroid, an antihistamine and/or paracetamol may be given, as the product's own protocol directs.
- Rate
- Start slowly and increase in steps if the infusion is tolerated.
- Rituximab example
- Rituximab is a monoclonal antibody; for its first infusion, one example is to start at 50 mg per hour and, if there is no reaction, raise the rate by 50 mg per hour every 30 minutes up to a stated maximum.
- Safety net
- Patients are informed about the red-flag symptoms and watched closely, and emergency drugs are available or prescribed before the infusion begins.
- Evidence
- The benefit of premedication varies by drug, so the product protocol should be followed.
Exam traps
- Switching to a different monoclonal antibody with a shorter half-life (how long a drug stays in the body) does not make a reaction less likely, because half-life has no bearing on whether the immune system reacts to an antibody protein.
- Starting an infusion at the full licensed rate and slowing it after flushing or itching appears removes the planned slow start, because a first infusion should begin slowly so that it can be stopped as soon as a reaction begins.
- Giving the warning-symptom advice after an infusion has finished does not help the team treat a reaction during the infusion, because patients need the symptoms explained beforehand so that they can report a reaction at once.
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