Blockade of tolerance to morphine analgesia by cocaine

Poverty and Excess Length of Hospital Stay in Neonatal Opioid Withdrawal Syndrome

OBJECTIVES

To study the impact of sociodemographic factors on length of stay (LOS) for infants with neonatal opioid withdrawal syndrome (NOWS) secondary to fetal opioid exposure.

METHODS

In this retrospective cohort study, we included term infants with NOWS, excluding those with other significant medical issues. Comprehensive clinical and sociodemographic data were collected. Multivariate regression modeling was used to identify factors which contributed to excess LOS, which was defined as the number of days beyond the standard monitoring and/or treatment protocol.

RESULTS

In all, 129 infants were identified; mean gestational age of 37.9 ± 1.3 weeks and mean body weight of 2880 ± 496 g. Among them, 68% of infants were exposed to opioids; 27% were exposed to methadone; and 67% required pharmacologic treatment. The degree of poverty was assessed using the Area Deprivation Index (ADI) based on the mother's address at the time of birth. Median LOS for treated infants was 23 days versus 8 days for those who did not need pharmacologic treatment. The median excess LOS was 4 days (range 0-24).Excess hospital days were strongly correlated with degree of deprivation in the mother's community (r = 0.55, P < 0.01). ADI remained a strong predictor of excess LOS, even when controlling for pharmacologic treatment, placement in state's custody, race, and gestational age at birth.

CONCLUSIONS

These results suggest poverty is associated with excess LOS and that early allocation of resources for at-risk families may help to reduce overall length of hospital stay.

Buprenorphine + naloxone plus naltrexone for the treatment of cocaine dependence: the Cocaine Use Reduction with Buprenorphine (CURB) study

AIMS

To examine the safety and effectiveness of buprenorphine + naloxone sublingual tablets (BUP, as Suboxone(®) ) provided after administration of extended-release injectable naltrexone (XR-NTX, as Vivitrol(®) ) to reduce cocaine use in participants who met DSM-IV criteria for cocaine dependence and past or current opioid dependence or abuse.

METHODS

This multi-centered, double-blind, placebo-controlled study, conducted under the auspices of the National Drug Abuse Treatment Clinical Trials Network, randomly assigned 302 participants at sites in California, Oregon, Washington, Colorado, Texas, Georgia, Ohio, New York and Washington DC, USA to one of three conditions provided with XR-NTX: 4 mg/day BUP (BUP4, n = 100), 16 mg/day BUP (BUP16, n = 100, or no buprenorphine (placebo; PLB, n = 102). Participants received pharmacotherapy for 8 weeks, with three clinic visits per week. Cognitive behavioral therapy was provided weekly. Follow-up assessments occurred at 1 and 3 months post-intervention. The planned primary outcome was urine drug screen (UDS)-corrected, self-reported cocaine use during the last 4 weeks of treatment. Planned secondary analyses assessed cocaine use by UDS, medication adherence, retention and adverse events.

RESULTS

No group differences were found between groups for the primary outcome (BUP4 versus PLB, P = 0.262; BUP16 versus PLB, P = 0.185). Longitudinal analysis of UDS data during the evaluation period using generalized linear mixed equations found a statistically significant difference between BUP16 and PLB [P = 0.022, odds ratio (OR) = 1.71] but not for BUP4 (P = 0.105, OR = 1.05). No secondary outcome differences across groups were found for adherence, retention or adverse events.

CONCLUSIONS

Buprenorphine + naloxone, used in combination with naltrexone, may be associated with reductions in cocaine use among people who meet DSM-IV criteria for cocaine dependence and past or current opioid dependence or abuse.

Pain imaging: future applications to integrative clinical and basic neurobiology

We have entered a new era in understanding CNS circuitry involved in acute and chronic pain. The ability to objectively measure a pain or analgesic state of the brain using non-invasive methods that define neural activation provides the possibility for top-down approaches to drug discovery. These brain maps represent the specific brain state. In the future, correlations with such states and behavioral, genetic, epigenetic or other chemical markers may help define specific diagnostic tools and novel approaches to drug discovery.

Enhancement of morphine-induced analgesia and attenuation of morphine-induced side-effects by cocaine in rats

Effect of cocaine on morphine-induced analgesia and the accompanying respiratory depression, bradycardia and hypolocomotion/sedation was studied in rats. Cardiovascular and respiratory effects were studied under pentobarbitone-induced anaesthesia. Cocaine enhanced morphine-induced analgesia in the formalin test, hot plate test and heat-induced tail withdrawal test in intact rats. However, in spinal rats a similar combination of cocaine with morphine did not produce increased latencies in the tail withdrawal test. Of the three analgesic tests used, the formalin test was the most sensitive to the enhancement, as well as to the effects of morphine or cocaine alone. Morphine at the dose of 6 mg/kg produced complete analgesia in the formalin test, significant hypolocomotion/sedation, significant bradycardia and significant decrease in the respiratory rate. At an equianalgesic dose (complete analgesia in the formalin test) of morphine (3 mg/kg)-cocaine (5 mg/kg)-combination no significant changes in heart rate, respiratory rate or locomotion(/alertness) were observed. Changes in skin blood flow determined by the laser Doppler flow method were not significant in any of the experimental conditions. The results indicate that cocaine enhances morphine-induced analgesia, mainly due to supraspinal mechanisms. In contrast, the morphine-induced bradypnoea, bradycardia and hypolocomotion/sedation are attenuated by cocaine.

Endogenous opiates: 1989

This paper is the twelfth installment of our annual review of the research published during 1989 involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal and renal functions; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; locomotor activity; sex, development, pregnancy, and aging; immunological responses; and other behavior.

Cocaine attenuates the severity of naloxone-precipitated opioid withdrawal

Cocaine dependence in opioid addicts is associated with less severe naloxone-precipitated opioid withdrawal compared to opioid addicts who are not cocaine dependent, suggesting that cocaine may reduce opioid withdrawal severity. The present study examines this effect further by comparing withdrawal severity in these two groups of opioid addicts. To control for dose, length of exposure, and time of administration of drugs, we also studied this effect in rats. Cocaine reduced the overall severity of opioid withdrawal in both human and rat. This drug-drug interaction may occur through alpha-2 adrenergic neurons in the locus coeruleus, similar to the effect of clonidine on opioid withdrawal.