Biological product side effects and hazards: Key points for clinical identification and pharmacovigilance management

Main Types and Characteristics of Adverse Reactions to Biologics

Biologics generally include macromolecular drugs such as monoclonal antibodies, fusion proteins, and cytokines. Their mechanisms of action differ from those of small-molecule chemical drugs, and their adverse reaction profiles also differ. Adverse reactions commonly seen in clinical practice include injection site reactions, infusion-related reactions, increased risk of infection, and immune-related reactions that some drugs may cause. Compared with chemical drugs, adverse reactions to biologics are mostly related to immune system modulation, with relatively obvious individual differences. Some reactions may occur from several hours to several weeks after administration, creating certain difficulties for early identification.

It should be noted that not all people who use biologics will experience serious adverse reactions. The type and severity of occurrence are related to multiple factors such as the type of drug, dose, patient's baseline status, and concomitant medications. For high-risk populations, such as those with chronic infection, immunocompromise, or a history of allergy, a thorough assessment should be conducted before use.

Identification and Assessment of Risk Signals in Clinical Use

Pharmacovigilance emphasizes the continuous collection of adverse reaction signals from real-world use. Medical institutions usually establish registration and follow-up systems for biologic use, recording fever, rash, dyspnea, abnormal liver enzymes, cytopenia, and other conditions occurring after administration. For infusion reactions, nursing staff should observe changes in the patient's vital signs during and for a period after infusion, and report abnormalities promptly.

Some risk signals may be relatively insidious, such as recurrent low-grade fever, progressive fatigue, and persistent local infection, and are easily attributed to the primary disease. The clinical team needs to combine laboratory tests and imaging findings to comprehensively determine whether they are related to the biologic. If serious infection, allergic reaction, or abnormal function of important organs is suspected, the drug should be discontinued promptly and corresponding management measures taken.

Principles for Managing Common Adverse Reactions and Patient Communication

Management strategies differ for adverse reactions of varying severity. Mild injection site reactions can generally be managed symptomatically and observed continuously; moderate reactions may require adjusting the administration rate, using antihistamines, or short-term discontinuation; severe reactions should lead to permanent discontinuation of the biologic and transfer to corresponding specialty treatment. Regarding infection risk, live attenuated vaccines should be avoided during biologic use. If other vaccines need to be administered, it is recommended to consult a physician in advance and arrange the timing reasonably.

Patient education is an important part of reducing harm. Before starting treatment, physicians and pharmacists should inform patients of possible adverse reactions, warning symptoms requiring timely medical attention, and precautions in daily life. Through informed consent and regular follow-up, patients can be helped to understand the risks and benefits and avoid stopping medication on their own or delaying treatment due to fear. Rational use, standardized monitoring, and timely management are key to reducing biologic-related harm.