Hypersensitivity reactions to small molecule drugs

Area of Science:

• Pharmacology
• Immunology
• Toxicology

Background:

• Drug hypersensitivity reactions (DHRs) from small molecule drugs present diverse clinical features and mechanisms.
• DHRs are categorized into allergic and non-allergic types.
• Existing theories for allergic DHRs include the hapten theory and the pharmacological interaction with immune receptors (p-i) concept.

Purpose of the Study:

• To review the mechanisms underlying allergic and non-allergic drug hypersensitivity reactions.
• To discuss current research on predictive and preventive strategies for DHRs.
• To highlight the limitations in current diagnostic and predictive methods for small molecule drug hypersensitivity.

Main Methods:

• Literature review of proposed mechanisms for allergic DHRs (hapten theory, p-i concept, altered peptide repertoire, TCR repertoire).
• Summary of proposed mechanisms for non-allergic DHRs (mast cell activation, complement activation, enzyme modulation, bradykinin accumulation, vascular hyperpermeability).
• Overview of investigations in clinical and non-clinical trials for DHR prediction and prevention.

Main Results:

• Allergic DHRs are explained by hapten, p-i, and T-cell repertoire models.
• Non-allergic DHRs involve direct mast cell activation, complement, inflammatory enzymes, bradykinin, and vascular permeability.
• Research efforts are ongoing, but validated predictive and diagnostic tools remain scarce.

Conclusions:

• Understanding the diverse mechanisms of small molecule drug hypersensitivity is crucial.
• Further research is needed to develop reliable methods for predicting and diagnosing DHRs.
• Limited validated approaches hinder effective clinical management of drug hypersensitivity.