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Definition

blocker

(blok'ĕr )

  1. A tool or device that blocks a passage.
  2. A drug that prevents the normal action of a system or cell receptor.

    SEE: antagonist; blockade; inhibitor.

alpha b.Alpha-adrenergic blocking agent

beta b.Beta-adrenergic blocking agent.

bronchial b.

ABBR: BB

A device for facilitating single-lung ventilation during thoracic surgery or thoracoscopy. The blocker is placed into the mainstem bronchus on the side of the chest where the operation is being performed, and its balloon is inflated within the airway. Potential complications of the device include dislodgement, misplacement, or accumulation of fluid behind the blockade.

calcium channel b.

ABBR: CCB

Any of a group of drugs that slow the influx of calcium ions into smooth muscle cells, e.g., those found in the walls of blood vessels, resulting in decreased arterial resistance and oxygen demand . These drugs are used to treat angina, hypertension, vascular spasm, intracranial bleeding, congestive heart failure, and supraventricular tachycardia. Because hypotension occurs as both an intended and , occasionally, an unwelcome effect, blood pressure must be monitored especially closely during the initial treatment period.

H2 b.

SEE: H2-receptor antagonist.

ion channel b.Any medication or other chemical agent that prevents specific ions from being transported through cell membranes and stimulating normal cellular responses.