Naloxone Use for Opioid Reversal in Patients with Sickle Cell Disease

Patients with sickle cell disease (SCD) are known to require increased dosing of drugs including opioids due to differences in renal and hepatic metabolism. While it is known that SCD patients require higher opioid doses to achieve the same degree of analgesia, it is not clear if this is associated with a similar increase in drug toxicities. A significant risk of opioid use is respiratory depression, and naloxone is used for rapid reversal of this adverse effect. In the setting of a nationwide opioid shortage in 2018, our institution established a policy requiring the use of patient-controlled analgesia (PCA) rather than intravenous push (IVP) for hospitalized SCD patients. This coincided with a mandate for end tidal carbon dioxide (ETCO) monitoring with PCA use, effectively implementing ETCO in the routine care of this population. In this study, we describe our experience using naloxone for opioid reversal in hospitalized SCD patients.

We studied naloxone use in patients admitted to the University of Illinois at Chicago for two 24-month time periods (July 31, 2015 - July 31, 2017 and May 1, 2018 - May 1, 2020). These dates were chosen to compare naloxone use before and after implementation of ETCO monitoring. A pharmacy reporting tool was used to identify every dose of naloxone administered within the hospital during these dates. We isolated patients on the inpatient sickle cell service and compared the proportion of SCD patients between study periods using Fisher's exact test. For SCD patients who received naloxone, we obtained baseline patient characteristics and divided doses into episodes when multiple doses were given within a day. For each episode, we studied analgesic regimens, details of the hospitalization, and laboratory values. Given the small data sample, we used descriptive statistics for analysis.

Among 931 total naloxone doses given in the two time periods, 35 were given to SCD patients. Out of 580 total distinct patients, there were 14 patients admitted to the sickle cell service. There were 5 out of 279 (1.8%) SCD patients who received 12 out of 443 (2.7%) doses between July 2015 and July 2017. There were 10 out of 309 (3.2%) SCD patients who received 23 out of 488 (4.7%) doses between May 2018 and May 2020. There was no significant difference in naloxone use by SCD patients before and after implementation of ETCO. For the two time periods combined, there were 14 out of 580 (2.4%) SCD patients who received 35 out of 931 (3.8%) doses. We were able to manually confirm 10 SCD patients and 17 episodes of naloxone use by chart review. Among these, 2 patients who only had 1 episode each received naloxone in the absence of opioid overdose. One patient with multiple episodes had an episode of receiving naloxone for opioid overdose not involving hospital-administered medications. Among the remaining 8 SCD patients who appropriately received naloxone for opioid reversal in the hospital, 100% were black or African American race. Seven (87.5%) out of 8 had Hgb SS genotype, and male-to-female ratio was 1:1. Six out of 14 (42.9%) episodes occurred when patients were not receiving their usual pain regimen. Vaso-occlusive crisis was a diagnosis for 13 out of 14 (92.9%) episodes. A median of 2 doses of naloxone were given per episode. Median creatinine clearance was 20.85 mL/min, and several cases coincided with acute kidney injury. Median sedation scale score prior to naloxone dose was 1 (minimally sedated). One patient was treated with a naloxone continuous infusion.

Our study highlights the relatively low use of naloxone in patients with SCD despite generally high usage of opioids. Nearly every patient admitted to the sickle cell service utilizes opioid pain medications, but the proportion of naloxone use in SCD patients is small. There was no significant difference in naloxone use after policy changes instituted the use of ETCO, but this may be due to sample size. The low rates of naloxone use in SCD patients may be related to mechanisms of hyperfiltration that necessitate increased opioid dosing. Our results suggest that the higher observed opioid dosages are not associated with worsened toxicities in SCD patients. With techniques such as ETCO, SCD patients can more safely be treated for pain using opioid medications, and providers should be mindful of pertinent pharmacological factors when caring for this population.