Dopaminergic drugs in the management of chronic heart failure.

The importance of the dopaminergic system in heart failure is unknown and the therapeutic potential of orally active compounds stimulating dopaminergic receptors has yet to be established. Despite similar acute haemodynamic changes in heart failure and despite a comparable profile of receptor stimulation, oral levodopa (the prodrug of dopamine) and oral ibopamine (the prodrug of epinine) produce opposite effects on plasma norepinephrine and have different pharmacokinetics. Placebo-controlled studies indicate a beneficial effect of ibopamine on exercise tolerance in patients with heart failure, whereas invasive evaluation of left ventricular function indicate that at the doses used in these trials, ibopamine does not act as a positive inotropic drug but rather as a vasodilator. This suggests that DA1 and DA2 receptor stimulation may be beneficial in heart failure. Further studies are, however, needed to specify the exact role of this therapeutic approach in comparison with other agents, such as ACE inhibitors, also able to modulate neuro-humoral activation in heart failure.