Opioid agonist doses for oxycodone and morphine dependence: Findings from a retrospective case series

One year of methadone maintenance treatment in a fentanyl endemic area: Safety, repeated exposure, retention, and remission

INTRODUCTION

Fentanyl is a potent synthetic opioid that has contributed to increasing overdose deaths in the United States in recent years. Concern over safety and efficacy of agonist treatment for fentanyl use may limit access to treatment. This study sought to address these potential concerns in a naturalistic setting.

OBJECTIVES

Measure 12-month treatment outcomes for methadone maintenance treatment (MMT) in a fentanyl endemic area.

OUTCOMES

Primary: 1) Treatment retention; 2) sustained remission (defined as 3 consecutive negative screens); 3) return to use; 4) methadone dosage required; and 5) number of days to achieve remission. Secondary: Mortality.

METHODS

A naturalistic follow-up study and retrospective review of consecutive patients newly admitted to a single methadone maintenance treatment program in Rhode Island.

RESULTS

We observed 154 unique intake events (representing 151 patients). Eighty percent (n = 121) tested positive for fentanyl at intake. Seventy-five percent of patients achieved remission within the 12-month study period. One-year retention was 53% for fentanyl-exposed individuals and 47% for those not exposed. The majority (99%) of patients who remained in treatment at 12 months achieved remission. We saw prolonged, sustained remission in 44% of patients exposed to fentanyl at intake and 47% of those who were not. Dose and time to remission were similar. Unfortunately, 4 patients died after leaving MMT prematurely.

CONCLUSIONS

This study suggests MMT is safe despite repeated exposure to fentanyl while taking methadone. Remission is achievable, and MMT is protective against death among fentanyl-exposed patients while in treatment.

Methadone maintenance treatment among patients exposed to illicit fentanyl in Rhode Island: Safety, dose, retention, and relapse at 6 months

INTRODUCTION

Illicitly manufactured fentanyl (IMF) is a potent synthetic opioid that has been contributing to overdose deaths in the United States. This study examined intake toxicology and six-month treatment outcomes for patients newly admitted to a single methadone maintenance treatment program (MMTP) in Rhode Island with a high prevalence of illicit fentanyl.

METHODS

We conducted a retrospective chart review of patients admitted to a single MMTP between November 1^st, 2016 and August 31^st, 2017 followed for six months. Outcomes measured included: 1) retention in treatment at 6 months; 2) evidence of sustained abstinence; 3) relapse; 4) methadone dosage required to achieve sustained abstinence; and 5) the number of days required to achieve abstinence.

RESULTS

We observed 154 unique intake events (representing 147 patients). 80% (n = 123) tested positive for fentanyl at intake. During the six-month follow up period, 32% (n = 49) left treatment before six months, two individuals died within five weeks of discontinuation. No deaths were seen among those remaining in treatment. The majority (89%) who remained in treatment at six months achieved abstinence. No significant difference was seen for dose or time to achieve abstinence. Relapse was common (57%). Repeated exposure to fentanyl was seen frequently (71%) while in MMT before and after achieving abstinence.

CONCLUSION

While there is concern that the potency of IMF may reduce the effectiveness of MAT, this study suggests that MMT is safe, abstinence achievable, and MMT is protective against death among fentanyl-exposed patients.

The novel dopamine D3 receptor antagonists/partial agonists CAB2-015 and BAK4-54 inhibit oxycodone-taking and oxycodone-seeking behavior in rats

The use of prescription opioid analgesics, particularly oxycodone, has dramatically increased, and parallels escalated opioid abuse and drug-related deaths worldwide. Understanding the molecular mechanisms underlying the development of opioid dependence and expanding treatment options to counter prescription opioid abuse has become a critical public health matter. In the present study, we first evaluated the reinforcing effects of oxycodone in a rat model of self-administration and then explored the potential utility of two novel high affinity dopamine D3 receptor (D3R) antagonists/partial agonists, CAB2-015 and BAK4-54, for treatment of prescription opioid abuse and dependence. We found that rats acquired oxycodone self-administration rapidly within a range of unit doses that was similar to that for heroin, confirming that oxycodone has significant abuse potential. Strikingly, pretreatment with either CAB2-015 or BAK4-54 (0.4-10 mg/kg, i.p.) dose-dependently decreased oxycodone self-administration, and shifted the oxycodone dose-response curve downward. Repeated pretreatment with CAB2-015 or BAK4-54 (0.4-4 mg/kg) facilitated extinction and inhibited oxycodone-induced reinstatement of drug-seeking behavior. In addition, pretreatment with CAB2-015 or BAK4-54 (4-10 mg/kg) also dose-dependently decreased oxycodone-enhanced locomotor activity, but only CAB2-015 decreased oral sucrose self-administration. These data suggest that D3R antagonists may be suitable alternatives or adjunctive to opioid-based medications currently used clinically in treating opioid addiction and that the D3R-selective ligands (CAB2-015 or BAK4-54) provide new lead molecules for development.