Intravenous Versus Oral Acetaminophen for Pain Control in Neurocritical Care Patients.

BACKGROUND: Acetaminophen (APAP) is used in neurocritical care (NCC) patients for analgesia without sedation or antiplatelet activity. Research suggests that intravenous (IV) APAP produces earlier and higher serum levels compared to oral (PO) APAP. This retrospective study evaluates the associated analgesic effects of IV and PO APAP and use of adjunctive opioids in NCC patients with moderate-severe pain.

METHODS: Patients admitted to the neuroscience intensive care unit (NSICU) between May 2012 and April 2013 who received ≥1 dose of IV APAP were included in the study. IV and PO APAP doses administered with a predose pain score ≥4 within 1 h of dosing were compared. Pain intensity difference (PID) was calculated as the change between the pain score prior to each dose and scores at 30 min, 1, 2, 3, and 6 h postdose. Pre- and postdose morphine milligram equivalents (MME) were also calculated.

RESULTS: 309 NSICU patients received 459 doses of IV and 440 doses of PO APAP meeting our inclusion criteria. The PID at 30 min postdosing was significantly higher among those receiving IV APAP compared to those receiving PO APAP (p = 0.003). No significant difference in PID was seen at 1, 2, 3, and 6 h; and there was no significant difference in pre- or postdose MME between the two groups.

CONCLUSION: IV APAP was more effective than PO APAP at relieving pain within 30 min of dosing, but this difference was not sustained over 6 h. Further studies are needed to assess the benefits of this rapid onset of action.