β Adrenergic Blocking Drugs
| Home | | Pharmacology |Chapter: Essential pharmacology : Antiadrenergic Drugs (Adrenergic Receptor Antagonists) And Drugs For Glaucoma
The dichloro derivative of isoprenaline was the first compound found in 1958 to block adrenergic responses which could not be blocked till then by the available adrenergic antagonists.
β ADRENERGIC
BLOCKING DRUGS
These
drugs inhibit adrenergic responses mediated through the β receptors.
The
dichloro derivative of isoprenaline was the first compound found in 1958 to
block adrenergic responses which could not be blocked till then by the
available adrenergic antagonists. However, it was not suitable for clinical
use. Propranolol introduced in 1963
was a therapeutic breakthrough. Since then, drugs in this class have
proliferated and diversified.
All
β blockers are
competitive antagonists. Propranolol blocks β1 and β 2
receptors but has weak activity on β3 subtype. It is also
an inverse agonist: reduces resting heart rate as well.
CLASSIFICATION
Nonselective
(β1 and β2)
a.
Without intrinsic sympathomimetic activity
Propranolol, Sotalol, Timolol.
a.
With intrinsic sympathomimetic activity
Pindolol
b.
With additional α blocking property
Labetalol, Carvedilol
Cardioselective
(β1)
Metoprolol, Atenolol,
Acebutolol, Bisoprolol, Esmolol, Betaxolol, Celiprolol, Nebivolol
Another system of
classifying β blockers into 3 generations
has been proposed.
Related Topics
