Adverse Reactions & Pharmacovigilance

Adverse Drug Reaction ADR

TRAdvers İlaç Reaksiyonu
Also known as:Adverse reaction · Adverse drug effect

A noxious and unintended response to a medicinal product in which a causal relationship with the drug is at least a reasonable possibility.

In depth

The classical WHO definition limited ADRs to responses occurring at doses normally used for prophylaxis, diagnosis or therapy; current EU-type pharmacovigilance legislation also covers reactions arising from overdose, misuse, abuse, medication errors and use outside the terms of the marketing authorisation. Unlike an adverse event, an ADR implies that the drug is suspected of causing the reaction.

ADRs are classically divided into dose-related, pharmacologically predictable type A reactions and non-dose-related, unpredictable type B reactions; extended schemes add chronic (C), delayed (D), end-of-use (E) and failure-of-therapy (F) categories. Causality is assessed with structured tools such as the WHO-UMC system or the Naranjo algorithm, and seriousness is judged separately from severity.

Clinical pearl

Suspected ADRs, particularly serious or unexpected ones and those involving newly marketed drugs, should be reported to the national centre (TÜFAM in Turkey); certainty about causality is not required to report.

TRIn Turkish

Advers İlaç Reaksiyonu

Bir tıbbi ürüne karşı gelişen, zararlı ve istenmeyen, ilaçla nedensellik ilişkisinin en azından makul bir olasılık olarak değerlendirildiği yanıttır.

Klasik DSÖ tanımı advers ilaç reaksiyonunu profilaksi, tanı veya tedavi amacıyla olağan dozlarda ortaya çıkan yanıtlarla sınırlar; güncel AB tipi farmakovijilans mevzuatı ise doz aşımı, yanlış kullanım, kötüye kullanım, ilaç hataları ve ruhsat koşulları dışındaki kullanım sonucu gelişen reaksiyonları da kapsar. Advers olaydan farklı olarak advers ilaç reaksiyonu, ilacın reaksiyona neden olduğundan şüphelenildiğini ifade eder.

Advers ilaç reaksiyonları klasik olarak doza bağımlı ve farmakolojik olarak öngörülebilir tip A ile doza bağımlı olmayan ve öngörülemeyen tip B reaksiyonlar olarak ikiye ayrılır; genişletilmiş sınıflamalar kronik (C), gecikmiş (D), kullanımın sonlanmasına bağlı (E) ve tedavi başarısızlığı (F) kategorilerini ekler. Nedensellik DSÖ-UMC sistemi veya Naranjo algoritması gibi yapılandırılmış araçlarla değerlendirilir; ciddiyet ise şiddetten ayrı olarak ele alınır.

Şüphelenilen advers ilaç reaksiyonları, özellikle ciddi veya beklenmeyen olanlar ve yeni ruhsatlanmış ilaçlarla ilişkili olanlar, ulusal merkeze (Türkiye'de TÜFAM) bildirilmelidir; bildirim için nedenselliğin kesinleşmesi gerekmez.

Diğer adları:Advers reaksiyon · İstenmeyen ilaç etkisi
Updated 24.09.2026 0 views Educational reference — verify against current sources before clinical use.

Read next

Adverse EventAdvers Olay

Any untoward medical occurrence in a patient or clinical-trial subject given a medicinal product, whether or not it is considered causally related to the treatment.

 Side EffectYan Etki

An unintended effect of a medicine, occurring at normal doses, that arises from its pharmacological properties and may be harmful, neutral or occasionally beneficial.

 Type A Adverse ReactionTip A Advers Reaksiyon

An adverse drug reaction resulting from an exaggeration of a drug's known pharmacological action; it is dose-related, predictable and usually common but rarely fatal.

 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.

 PharmacovigilanceFarmakovijilans

The science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other medicine-related problem (WHO definition).

 Naranjo AlgorithmNaranjo Algoritması

A 10-item questionnaire that estimates the probability that an adverse event was caused by a drug, classifying the relationship as definite, probable, possible or doubtful.