Pharmacology MCQs- 215

A 64-year-old man arrives to the emergency room after recurrent vomiting of blood for the last 2 hours. He recently underwent right hip replacement and had taken heparin to prevent thromboembolic complications. Internal bleeding is suspected and treatment with protamine has begun.

What kind of antagonism is related to this treatment?

A- Chemical

B- Competitive




Protamine antagonize the action of heparin by binding to heparin itself preventing its action therefore, it is considered chemical antagonism. Competitive inhibition is the binding of an inhibitor to the site of action of another drug preventing it from acting on these sites i.e. receptors. Irreversible inhibition is the binding of the inhibitor to the active substance i.e. enzymes and eventually blocking the active substrates to bind to it. Action of insulin on certain receptor-effector system to decrease blood glucose is considered physiological inhibition.

The correct answer is A

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