<p>The synthesis of atenolol resulted from attempts to produce a &beta;-adrenoceptor antagonist that would competitively block &beta;1 (cardiac) receptors but have no effect on &beta;2-receptors. It is classified as a &beta;1 selective (cardioselective) &beta;-adrenergic receptor antagonist with no membranestability activity and no partial agonist activity. It is markedly the most hydrophilic of the currently available &beta;- blockers and thus penetrates the lipid of cell membranes poorly</p>