Intramuscular Vasopressin: A Promising Alternative in Neonatal Resuscitation?

In neonatal cardiopulmonary resuscitation (CPR), time is critical and rapid administration of a vasopressor can mean the difference between life and death. While current neonatal resuscitation guidelines recommend epinephrine, emerging research suggests that vasopressin might be a viable alternative—potentially offering unique hemodynamic benefits, especially in asphyxiated neonates.

However, like epinephrine, the effectiveness of vasopressin depends on how quickly and reliably it can be delivered—and intravenous (IV) access is not always immediately available in newborns.

That’s why our team explored the potential of intramuscular (IM) vasopressin as a faster, more accessible alternative. In a dose-response study using healthy neonatal piglets, we compared two IM doses of vasopressin (4 IU/kg and 8 IU/kg) to a standard IV dose (0.4 IU/kg).

All piglets (aged 1–3 days) were anesthetized, intubated via tracheostomy, and continuously monitored for hemodynamic and cardiac function parameters. We also collected blood samples before and after drug administration to evaluate pharmacokinetics and pharmacodynamics.

What did we learn?

• The lower IM dose (4 IU/kg) was ineffective, showing poor absorption and no meaningful systemic effects.

• In contrast, the higher IM dose (8 IU/kg) produced robust and rapid cardiovascular effects that were comparable to those of IV vasopressin.

• Pharmacokinetic analysis showed that the 8 IU/kg IM dose was rapidly absorbed and distributed, making it a potentially effective route for emergency use.

Why is this important?

Our findings suggest that 8 IU/kg of IM vasopressin could be an effective alternative to IV vasopressin when vascular access is delayed or unavailable during neonatal resuscitation. The IM route offers a practical solution—it’s fast, simple, and does not require specialized training or equipment.

While further studies, including clinical trials, are needed to confirm these findings in human neonates, this work adds to the growing body of evidence supporting alternative vasopressor strategies that can improve outcomes in the most vulnerable patients—newborns requiring resuscitation at birth.