Lethal morphine intoxication in a patient with a sickle cell crisis and renal impairment: case report and a review of the literature

PBPK-PD model for predicting morphine pharmacokinetics, CNS effects and naloxone antagonism in humans

Morphine and morphine-6-glucuronide (M6G) produce central nervous system (CNS) effects by activating mu-opioid receptors, while naloxone is used mainly for the reversal of opioid overdose, specifically for the fatal complication of respiratory depression, but also for alleviating opioid-induced side effects. In this study we developed a physiologically-based pharmacokinetic-pharmacodynamic (PBPK-PD) model to simultaneously predict pharmacokinetics and CNS effects (miosis, respiratory depression and analgesia) of morphine as well as antagonistic effects of naloxone against morphine. The pharmacokinetic and pharmacodynamic parameters were obtained from in vitro data, in silico, or animals. Pharmacokinetic and pharmacodynamic simulations were conducted using 39 and 36 clinical reports, respectively. The pharmacokinetics of morphine and M6G following oral or intravenous administration were simulated, and the PBPK-PD model was validated using clinical observations. The Emax model correlated CNS effects with free concentrations of morphine and M6G in brain parenchyma. The predicted CNS effects were compared with observations. Most clinical observations fell within the 5th-95th percentiles of simulations based on 1000 virtual individuals. Most of the simulated area under the concentration-time curve or peak concentrations also fell within 0.5-2-fold of observations. The contribution of morphine to CNS effects following intravenous or oral administration was larger than that of M6G. Pharmacokinetics and antagonistic effects of naloxone on CNS effects were also successfully predicted using the developed PBPK-PD model. In conclusion, the pharmacokinetics and pharmacodynamics of morphine and M6G, antagonistic effects of naloxone against morphine-induced CNS effects may be successfully predicted using the developed PBPK-PD model based on the parameters derived from in vitro, in silico, or animal studies.

Opioid Use in Adults With Sickle Cell Disease Hospitalized During Vaso-Occlusive Crisis: A Systematic Review

Background

While pain is the hallmark of sickle cell disease (SCD), healthcare personnel are often ill-equipped to adequately treat patients who present in vaso-occlusive crisis (VOC). Although symptom severity varies from individual to individual, SCD is characterized by intervallic pain as a result of oxygen deprivation in tissues and organs. Regardless of pain severity, SCD patients are often viewed as drug seekers by healthcare personnel who have concerns regarding patients’ dependence on opioids which may lead to addiction. The objective was to assess the types and amount of opioids used to treat VOC in comparison to Centers for Disease Control opioid prescription guidelines.

Methods

Literature search was conducted using CINAHL, PubMed, the Cochrane Library, Web of Science and hand search. Data were analyzed from 1999 to 2018. Randomized trials, observational, and case studies involved hospitalized adults with SCD who were prescribed opioids to treat VOC. Quality assessment was conducted using Downs and Black checklist. Meta-analysis was not conducted.

Results

Five studies were conducted in the USA, Arabia and the Netherlands, and the USA and Canada were included. Participants were treated with either morphine or morphine milligram equivalent (MME). No study used the same method of opioid administration.

Conclusions

Patients with SCD who are hospitalized secondary to VOC mostly received opioids for pain well within the Centers for Disease Control and Prevention prescription guidelines. No uniform method exists. Additional research is warranted.

Associations of Opioid Prescriptions with Death and Hospitalization across the Spectrum of Estimated GFR

BACKGROUND AND OBJECTIVES

Most opioids undergo kidney excretion. The goal of this study was to evaluate opioid-associated risks of death and hospitalization across the range of eGFR.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study population included adult primary care patients in Geisinger Health (Danville, PA) between 2008 and 2017. People receiving their first opioid prescription were propensity matched to people receiving NSAIDS (and, in sensitivity analysis, gabapentinoids) and the risk of death and hospitalization were compared, classifying opioid medication exposure as time-varying daily oral morphine milligram equivalents (MMEs) across time-varying eGFR.

RESULTS

The propensity-matched cohort included 46,246 patients prescribed either opioids or NSAIDs between 2008 and 2017 (mean [SD] age, 54 [16] years; 56% female; 3% of black race). Prescriptions for 1-59 and ≥60 MMEs were associated with higher risk of death (HR, 1.70; 95% CI, 1.41 to 2.05 for 1-59 MMEs; HR, 2.25; 95% CI, 1.82 to 2.79 for ≥60 MMEs) and hospitalization (HR, 1.38; 95% CI, 1.30 to 1.46 for 1-59 MMEs; HR, 1.68; 95% CI, 1.56 to 1.81 for ≥60 MMEs) compared with NSAID prescriptions, when evaluated at eGFR 80 ml/min per 1.73 m². The relative risk of death associated with ≥60 MMEs was higher at lower GFR (e.g., eGFR, 40 ml/min per 1.73 m²; HR, 3.94; 95% CI, 2.70 to 5.75; P for interaction, 0.01). When gabapentinoids were used as the comparison medication, only ≥60 MMEs were significantly associated with higher risk of death (HR, 2.72; 95% CI, 1.71 to 4.34), although both 1-59 and ≥60 MMEs were associated with risk of hospitalization (HR, 1.22; 95% CI, 1.04 to 1.43 for 1-59 MMEs; HR, 1.54; 95% CI, 1.28 to 1.86 for ≥60 MMEs).

CONCLUSIONS

The receipt of prescription opioids was associated with a higher risk of death and hospitalization compared with other pain medications, particularly with higher doses and at lower eGFR.

An Approach to Pain Management in End Stage Renal Disease: Considerations for General Management and Intradialytic Symptoms

The prevalence and severity of symptoms in patients with advanced chronic kidney disease is higher than those of the general population and comparable to those with other chronic and serious medical conditions. Despite the prevalence and severity in this population, symptoms continue to be under-recognized and inadequately managed. The recognition of specific intradialytic pain syndromes such as pain related to arteriovenous access, headaches, muscle cramps or generalized pain by providers may aid in improving patient compliance and quality of life. The approach to pain management in end stage renal disease patients follows that of the general population with specific considerations regarding clearance and potential side effects guiding selection of agents. Overall, evidence is limited regarding the pharmacology of many medications in this population.

Patient considerations in the use of tapentadol for moderate to severe pain

Poorly controlled acute and chronic pain can increase morbidity, impair quality of life and prolong disability. Over 80 percent of post surgical patients report moderate to severe uncontrolled postoperative pain. Over-reliance on potent opioid agonists can lead to several opioid related side effects such as gastrointestinal intolerability, respiratory depression and cognitive impairment. A recently approved dual acting central analgesic tapentadol may offer improved tolerability over traditional opioid agonists while having multimodal opioid and nonopioid analgesic benefits. Tapentadol, classified by the US Food and Drug Administration as a class 2 opioid, is currently marketed in the United States as immediate release (IR) NUCYNTA® for moderate to severe acute pain in tablets of 50 mg, 75 mg, and 100 mg, and as extended release (ER) NUCYNTA ER® for the treatment of chronic moderate to severe pain in tablets of 50 mg, 100 mg, 150 mg, 200 mg, and 250 mg. Tapentadol is a low affinity mu opioid receptor agonist and a norepinephrine reuptake inhibitor. Tapentadol has no active metabolites and this property makes it useful in patients with hepatic and renal failure. Clinical trials with tapentadol IR showed that there was improved gastrointestinal tolerability and similar pain relief as compared to oxycodone IR. Tapentadol ER allows for twice daily dosing. Clinical trials showed that tapentadol ER could effectively relieve moderate to severe chronic pain and was associated with significantly fewer gastrointestinal adverse effects as compared to oxycodone controlled release. Tapentadol ER is indicated and has Food and Drug Administration approval for the treatment of chronic painful diabetic neuropathy. The most common side effects of tapentadol are nausea (30%), vomiting (18%), dizziness (24%), and somnolence (15%). Tapentadol, due to its potential synergistic effects on norepinephrine levels, is contraindicated in patients who have taken monoamine oxidase inhibitors within the last 14 days. Caution has to be exercised with the use of tapentadol IR and tapentadol ER in the presence of other central nervous system depressants such as neuroleptics, opioids, illicit drugs, muscle relaxants, sedatives, and anxiolytics.