Drug Interactions

Chemical Antagonism

TRKimyasal Antagonizma
Also known as:Neutralization antagonism · Chemical neutralization

Inactivation of a drug by direct chemical combination with another substance to form an inactive complex, independently of receptors or physiological effects.

In depth

The antagonist binds or neutralizes the active drug itself, lowering its free concentration. Examples include protamine neutralizing heparin by ionic binding, chelating agents (dimercaprol, deferoxamine, sodium calcium edetate) binding metal ions, sugammadex encapsulating rocuronium and vecuronium, idarucizumab binding dabigatran, and digoxin-specific antibody fragments binding digoxin.

The interaction is essentially stoichiometric, so the amount of antagonist needed depends on the quantity of drug to be neutralized rather than on receptor occupancy. Several antidotes work in this way.

Clinical pearl

Because neutralization is stoichiometric, the protamine dose is calculated from the amount of heparin given and the time elapsed; neutralization may be incomplete, and rebound anticoagulation can occur.

Example drugs

Protamine Heparin Sugammadex Idarucizumab Dimercaprol Deferoxamine
TRIn Turkish

Kimyasal Antagonizma

Bir ilacın başka bir maddeyle doğrudan kimyasal olarak birleşip inaktif bir kompleks oluşturması yoluyla, reseptörlerden ve fizyolojik etkilerden bağımsız olarak etkisizleştirilmesidir.

Antagonist, etkin ilacın kendisini bağlar veya nötralize ederek serbest konsantrasyonunu düşürür. Örnekler arasında heparinin iyonik bağlanma yoluyla protaminle nötralizasyonu, metal iyonlarını bağlayan şelatör ajanlar (dimerkaprol, deferoksamin, kalsiyum disodyum edetat), roküronyum ve veküronyumu kapsülleyen sugammadeks, dabigatranı bağlayan idarusizumab ve digoksini bağlayan digoksine özgü antikor fragmanları yer alır.

Etkileşim esas olarak stokiyometriktir; gereken antagonist miktarı reseptör işgaline değil, nötralize edilecek ilaç miktarına bağlıdır. Birçok antidot bu şekilde etki eder.

Nötralizasyon stokiyometrik olduğundan protamin dozu uygulanan heparin miktarına ve geçen süreye göre hesaplanır; nötralizasyon eksik kalabilir ve antikoagülan etki yeniden ortaya çıkabilir (rebound).

Diğer adları:Kimyasal nötralizasyon
Updated 24.09.2026 1 views Educational reference — verify against current sources before clinical use.

Read next

Physiological AntagonismFizyolojik Antagonizma

Opposition between two drugs that act on different receptors or pathways to produce opposing physiological effects, so that each counteracts the other's action.

 AntidoteAntidot

A substance that counteracts the effects of a poison or drug overdose by preventing its absorption, binding or inactivating it, antagonising it at its site of action, enhancing its elimination or reversing its toxic effects.

 ChelationŞelasyon

The formation of a stable ring-shaped complex between a metal ion and a molecule bearing two or more donor groups; in pharmacology it underlies both metal antidotes and important absorption interactions.

 AntagonistAntagonist

A drug that binds to a receptor or other target without activating it (affinity but no efficacy) and thereby prevents or reduces the response to an agonist.

 Pharmacodynamic InteractionFarmakodinamik Etkileşim

An interaction in which one drug modifies the response to another at the same or related receptors, physiological systems or pathways, independently of any change in plasma concentrations.