Adverse drug reactions and drug allergy
Classifying ADRs (types A to F), immune mechanisms from IgE to T cells and mast cell MRGPRX2, the high-yield ADRs of each drug class, putting the drug in the differential, penicillin and beta-lactam allergy (PEN-FAST, PALACE, ASCIA 2026), sulfonamide, NSAID, contrast and perioperative allergy, and TGA reporting.
Tier 1Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- An adverse drug reaction (ADR) is a harmful, unintended response at normal doses. Drug allergy is the subset with an immune mechanism; it accounts for a minority of ADRs.
- Medication-related problems cause 2 to 3% of Australian hospital admissions, about 230,000 a year (Roughead, 2016).
- Put a drug in every differential. Timing against the medication chart, dechallenge and rechallenge are the core tools.
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Sources
- ASCIA Guidelines: Adult Penicillin Allergy Management 2026 UpdateAU/NZAustralasian Society of Clinical Immunology and Allergy (ASCIA), 2026 (webpage updated October 2026)
- ASCIA drug allergy resources (drug allergy terms, challenge position paper, radiocontrast hypersensitivity, antibiotic allergy clinical update)AU/NZAustralasian Society of Clinical Immunology and Allergy (ASCIA), updated April 2026
- Therapeutic Guidelines: Antibiotic (antimicrobial hypersensitivity) and Prescribing in Special PopulationsAU/NZTherapeutic Guidelines Limited
- Database of Adverse Event Notifications (DAEN) and reporting adverse eventsAU/NZTherapeutic Goods Administration, 2026
- Khan DA et al. Drug allergy: a 2022 practice parameter update. J Allergy Clin Immunol 2022;150:1333-1393AAAAI/ACAAI Joint Task Force on Practice Parameters, 2022
- Trubiano JA et al. Development and validation of a penicillin allergy clinical decision rule (PEN-FAST). JAMA Intern Med 2020;180:745-752AU/NZJAMA Internal Medicine, 2020
- Copaescu AM et al. Efficacy of a clinical decision rule to enable direct oral challenge in patients with low-risk penicillin allergy: the PALACE randomized clinical trial. JAMA Intern Med 2023;183:944-952AU/NZJAMA Internal Medicine, 2023
- Roughead EE, Semple SJ, Rosenfeld E. The extent of medication errors and adverse drug reactions throughout the patient journey in acute care in Australia. Int J Evid Based Healthc 2016;14:113-122AU/NZInternational Journal of Evidence-Based Healthcare, 2016
- Last updated
- 14 November 2026
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