Thank you everyone for following our vasoactive meds week so far. Today it is Epinephrine's day. Since we had great feedback on our historical nerdy side, we will start with some extra history on epinephrine:
“asthma is immediately cured in situations of either sudden alarm or violent fleeting excitements”, this is believed to be the first description of the therapeutic effect of endogenous epinephrine. thelancet.com/journals/lanre…
Epi has potent beta-1 adrenergic receptor activity and moderate beta-2 and alpha-1 adrenergic receptor effects. Clinically, low doses of epinephrine increase CO because of the beta-1 adrenergic receptor inotropic and chronotropic effects...
...while the alpha adrenergic receptor-induced vasoconstriction is often offset by the beta-2 adrenergic receptor vasodilation. The result is an increased CO, with decreased SVR and variable effects on the MAP...
...at higher epinephrine doses the alpha-adrenergic receptor effect predominates, producing increased SVR in addition to an increased CO. This also comes from an oldie, but goodie paper: academic.oup.com/bmb/article-ab…
Even though EPI sounds like the ideal inotrope/pressor, but it comes with several side effects: induction of PH, arrhythmias, lactic acidosis, hyperglycemia, compromise of the hepatosplanchnic perfusion. These adverse effects are dose-related.
So what are the uses of epi? Anaphylactic shock is one the most accepted ones, with extensive evidence, that hasn't been challenged/reviewed in a while, since it has worked ncbi.nlm.nih.gov/pmc/articles/P…
Epi is also the first ACLS drug, and has been considered "standard of care" for decades now, several studies have associated it with increased rate of ROSC, but more recent evidence not showing better survival.
nejm.org/doi/10.1056/NE…
nejm.org/doi/10.1056/NE…
How about septic shock? When compared to Norepi, there has been no convincing evidence that Epi is better in achieving a MAP goal >65mmHg, w/ Epi group having more arrhythmias.
pubmed.ncbi.nlm.nih.gov/18654759/
pubmed.ncbi.nlm.nih.gov/18654759/
Ok, almost done... how about cardiogenic shock? Recent evidence shows that in patients with CS 2/2 MI, the use of Epi was associated with more refractory shock compared to Epi
onlinejacc.org/content/72/2/1…
onlinejacc.org/content/72/2/1…
And a fantastic summary by @PierreSquara et al published @accpchest explains beautifully the physiology behind cardiogenic shock wnad why the above phenomenon was observed journal.chestnet.org/article/S0012-…
In summary: Epi is great for anaphylaxis (IM), and ok as a second/third line for septic and cardiogenic shock (fin).
