Naloxone IM dosing

Firstly, when delivering Naloxone nasally, subcutaneously, intramuscularly, or intraosseously there is slower absorption and delayed elimination, making the drug much more difficult to titrate. Additionally, if the clinician "overshoots" the appropriate dose of Naloxone in a patient with opioid use disorder, withdrawal will ensue. This is the reason we attempt to titrate the Naloxone dose slowly to reverse hypoventilation and breathing is adequately restored versus just simply delivering a large dose. As you mentioned there is not a lot of literature surrounding the titration of doses for Naloxone when being delivered any other route other than intravenous (IV). This is one of the reasons IV Naloxone is the preferred route of administration. All other routes of delivery are much less predictable. The medical directive utilizes a dosing regimen that is meant to incorporate the slower absorption and unpredictability of Naloxone via the other routes and is why the doses are slightly higher than IV.

One main challenge with attempting to titrate Naloxone such as giving lower doses to start with may mean multiple administrations, ie: multiple IM injections. This is not ideal for several reasons such as increased exposure to needles and increased chances of infection.

Once opioid toxicity is suspected, initial management should focus on support of the patient's airway and breathing. Attention should be paid to the depth and rate of ventilation. The apneic patient and patients with extremely low respiratory rates or shallow respirations should be ventilated by bag-valve mask attached to supplemental oxygen prior to and during naloxone administration to reduce the chance of acute respiratory distress syndrome.

If you believe that your patient would benefit from a lower dose overall, we recommend consulting with a base hospital physician to further discuss the patient, situation, and plan of care.