Adverse Reactions & Pharmacovigilance

Drug Hypersensitivity

TRİlaç Aşırı Duyarlılığı
Also known as:Drug hypersensitivity reaction · DHR

An adverse drug reaction that clinically resembles allergy; when a specific immunological mechanism (IgE or T cells) is demonstrated it is termed drug allergy, otherwise non-allergic hypersensitivity.

In depth

Reactions are classified by timing into immediate reactions, typically within an hour of exposure and often IgE-mediated (urticaria, angioedema, bronchospasm, anaphylaxis), and non-immediate reactions appearing hours to weeks later, usually T-cell-mediated (maculopapular exanthem, SJS/TEN, DRESS). The Gell–Coombs scheme (types I–IV) describes the underlying immune mechanisms.

Non-allergic mechanisms include direct mast-cell activation, for example by opioids, vancomycin or radiocontrast media, and COX-1 inhibition in NSAID-exacerbated respiratory disease. Diagnosis relies on a detailed history, skin testing, specific IgE and, when appropriate, supervised drug provocation testing.

Clinical pearl

Most patients labelled penicillin-allergic tolerate penicillins after formal allergy evaluation; delabelling reduces unnecessary use of broader-spectrum or less effective alternatives.

Example drugs

Amoxicillin Carbamazepine Allopurinol Vancomycin Acetylsalicylic acid
TRIn Turkish

İlaç Aşırı Duyarlılığı

Klinik olarak alerjiye benzeyen advers ilaç reaksiyonudur; belirli bir immünolojik mekanizma (IgE veya T hücreleri) gösterildiğinde ilaç alerjisi, gösterilemediğinde alerjik olmayan aşırı duyarlılık olarak adlandırılır.

Reaksiyonlar zamanlamaya göre, genellikle maruziyetten sonraki ilk bir saat içinde ortaya çıkan ve sıklıkla IgE aracılı olan erken (immediate) reaksiyonlar (ürtiker, anjiyoödem, bronkospazm, anafilaksi) ile saatler ile haftalar sonra görülen ve çoğunlukla T hücre aracılı olan geç (non-immediate) reaksiyonlar (makülopapüler döküntü, SJS/TEN, DRESS) olarak sınıflandırılır. Altta yatan immün mekanizmalar Gell–Coombs sınıflamasıyla (tip I–IV) tanımlanır.

Alerjik olmayan mekanizmalar arasında opioidler, vankomisin veya radyokontrast maddelerle doğrudan mast hücresi aktivasyonu ve NSAİİ ile alevlenen solunum yolu hastalığında COX-1 inhibisyonu yer alır. Tanı ayrıntılı öykü, deri testleri, spesifik IgE ve uygun durumlarda gözetim altında yapılan ilaç provokasyon testine dayanır.

Penisilin alerjisi etiketi taşıyan hastaların çoğu formal alerji değerlendirmesinden sonra penisilinleri tolere eder; etiketin kaldırılması daha geniş spektrumlu veya daha az etkili alternatiflerin gereksiz kullanımını azaltır.

Diğer adları:İlaç aşırı duyarlılık reaksiyonu · İlaç hipersensitivitesi
Updated 24.09.2026 1 views Educational reference — verify against current sources before clinical use.

Read next

AnaphylaxisAnafilaksi

A severe, potentially life-threatening systemic hypersensitivity reaction of rapid onset that causes airway, breathing or circulatory compromise, usually but not always with skin or mucosal changes.

 Cross-ReactivityÇapraz Reaktivite

The occurrence of a hypersensitivity reaction to a drug in a patient sensitised to a different drug, because both share a structural determinant or trigger the same reaction pathway.

 Stevens–Johnson SyndromeStevens–Johnson Sendromu

A rare, severe, usually drug-induced mucocutaneous reaction with widespread keratinocyte death, blistering and mucosal erosions, in which epidermal detachment involves less than 10% of body surface area.

 DRESS SyndromeDRESS Sendromu

A severe, delayed, T-cell-mediated drug hypersensitivity syndrome with fever, extensive rash, lymphadenopathy, haematological abnormalities such as eosinophilia, and internal organ involvement.

 Type B Adverse ReactionTip B Advers Reaksiyon

An adverse drug reaction that is not expected from the drug's known pharmacology, is largely independent of dose, and is uncommon but frequently serious.

 Idiosyncratic Reactionİdiyosenkratik Reaksiyon

An uncommon, qualitatively abnormal response to a drug that is not explained by its known pharmacology, occurs in only a small proportion of exposed patients and is not clearly dose-related.