Dobutamine Shortage Woes: Examining Alternative Regimens

Volume 17, Issue 2

Drug shortages have become an unfortunate part of everyday life for most practicing pharmacists. Indeed, the hospital where I practice has had a weekly drug shortage committee meeting for the entire 7 years that I’ve been here.

Recently, news of an impending shortage of dobutamine started circulating, and this week we were forced to take emergency measures at my institution to conserve our remaining supply and construct alternative regimens for patients in need of this important medication.

In this week’s issue of Talking Therapeutics, we review the unique pharmacology of dobutamine and propose some solutions for managing this shortage.

Point 1: Dobutamine Pharmacology

Dobutamine is an inotropic agent with mild vasodilator properties (ie inodilator). It works by agonizing B1 receptors on the cardiac myocytes to product a robust positive inotropic response. Agonism of B2 receptors on the vascular smooth muscle is responsible for the mild vasodilating effects of dobutamine.

No drug has this specific combination of inotropic and vasodilator properties. Milrinone is also a positive inotropic agent, but it augments cardiac output more through its vasodilator properties. In other words, milrinone is much more of an inodilator than dobutamine, and because it’s a more vasodilatory drug, hypotension tends to occur more frequently with milrinone than dobutamine.

Epinephrine is an agonist of A1 receptors as well as B1 receptors, making this drug the only pure inoconstrictor available. Because epinephrine has such strong vasoconstrictor properties, it would not be an ideal substitute for dobutamine in most clinical scenarios.

Point 2: Dobutamine Alternatives

In most cases of uncomplicated cardiogenic shock, such as with acute decompensated heart failure or myocardial infarction, milrinone is a fine alternative to dobutamine. A recent randomized trial published in the New England Journal of Medicine failed to show any appreciable difference between these agents for the treatment of patients with general cardiogenic shock.

For selected patients with more complicated cardiogenic shock scenarios, a more nuanced approach may be needed. For instance, many patients recovering from cardiac surgery require both positive inotropy and positive chronotropy, the latter of which milrinone generally lacks. Therefore, a combination of dopamine, which has positive chronotropic effects, with milrinone may be reasonable for these patients.

For patients with mixed shock etiologies, such as those with both cardiogenic and distributive shock features, milrinone may not be an acceptable alternative to dobutamine. For these patients, a drug like dopamine or epinephrine, both of which have inotropic and vasoconstrictor properties, may be the best alternative to dobutamine.