Pharmacogenetics and prediction of adverse events in prescription opioid use disorder patients.

The threats involved in the long-term opioid treatment of chronic non-cancer pain (CNCP) have increased notably. Strategies to identify at-risk patients are important because there is no clear evidence showing which screening or deprescription programmes are appropriate. Our aim was to evaluate the evidence provided by pharmacogenetics applied to predict an analgesic toxicity profile in prescription opioid use disorder (POUD) patients participating in an opioid deprescription programme. Pharmacogenetic markers were analysed in an observational, prospective deprescription programme for POUD patients (n = 88) treated for CNCP. It consisted of monitoring visits (baseline, follow-up and final), opioid rotation or discontinuation and the recording of adverse events and suspected adverse drug reactions (ADRs). Variants in OPRM1 (A118G), ABCB1 (C3435T), COMT (G472A), OPRD1 (T921C) and ARRB2 (C8622T) genes were tested by real-time PCR. Ethics committee approved the study. Wild-type OPRM1-AA genotype carriers reported a significantly higher number of adverse events than OPRM1-AG/GG (median [p25-75], 7 [5-11] vs 5 [3-9]), particularly gastrointestinal system events (90% vs 63%) such as nausea (33% vs 0%). Suspected ADRs (affecting 17% of the patients) were three times higher in males than in females (30% vs 11%). The deprescription programme was effective and safe, and it achieved a significant progressive reduction in the morphine equivalent daily dose, strong opioids and other analgesics' use, without causing any changes in pain intensity or opiate abstinence syndrome. OPRM1 gene polymorphisms could identify the risk of gastrointestinal adverse events in POUD patients. Deprescription programmes including pharmacogenetic analysis should be considered during the follow-up of this population.

Treatment with non-selective beta-blockers affects the systemic inflammatory response to bacterial DNA in patients with cirrhosis.

BACKGROUND & AIMS: The use of non-selective beta-blockers has been associated with lower rates of infection and reduced infection-associated morbidity in patients with cirrhosis. However, it is unknown if these drugs modify the systemic inflammatory response to circulating bacterial DNA. METHODS: Sixty-three patients with cirrhosis were included during an episode of decompensation by ascites. Thirty of those patients were on beta-blockers. Blood samples were obtained after each patient had been in the supine position for at least 30 minutes in a quiet atmosphere. Bacterial DNA, serum cytokines, nitric oxide, and LPS were determined. Phagocytic and oxidative burst activities were determined in polymorphonuclear cells from the patients. RESULTS: The detection rate of bacterial DNA in the blood was the same (33%) for patients not treated and treated with non-selective beta-blockers. Patients naive to non-selective beta-blockers showed significantly higher serum levels of IL6, IFN-gamma and IL10 in response to the presence of bacterial DNA. Patients treated with non-selective beta-blockers showed higher basal inflammatory activity that did not change with the presence of bacterial DNA. Monocytes and granulocytes from patients treated with non-selective beta-blockers showed a significantly increased phagocytic capacity in the presence of bacterial DNA. CONCLUSIONS: In patients with cirrhosis, chronic treatment with beta-blockers is associated with a higher unstimulated production of serum cytokines and an increased phagocytic activity in the presence of bacterial DNA.

OPRM1 influence on and effectiveness of an individualized treatment plan for prescription opioid use disorder patients.

Screening for opioid use disorder should be considered in chronic non-cancer pain (CNCP) patients with long-term use of opioids. The aim of our study was to assess the effectiveness of an individualized treatment plan (ITP) for prescription opioid dependence that included screening of pharmacogenetic markers. An observational prospective study was performed using prescription opioid-dependent CNCP outpatients (n = 88). Patients were divided into nonresponders, responders, or high responders according to their response to the ITP. Genotyping of OPRM1 (A118G), OPRD1 (T921C), COMT (G472A), ABCB1 (C3435T), and ARRB2 (C8622T) was performed by real-time PCR. Our ITP achieved a significant reduction of the morphine equivalent daily dose (MEDD) in 64% of responders, including 33% of high responders. Nonopioid medication or buprenorphine use was significantly higher at final versus basal visit. 118-AA OPRM1 patients required significantly lower MEDD at basal and final visits. Our ITP showed effectiveness and security in reducing MEDD in opioid-dependent patients, with good conversion to buprenorphine that was more pronounced in 118-AA OPRM1 patients.

ß2­adrenergic receptor functionality and genotype in two different models of chronic inflammatory disease: Liver cirrhosis and osteoarthritis.

The present study was designed to investigate the functional status of ß2 adrenoceptors (ß2AR) in two models of chronic inflammatory disease: liver cirrhosis (LC) and osteoarthritis (OA). The ß2AR gene contains three single nucleotide polymorphisms at amino acid positions 16, 27 and 164. The aim of the present study was to investigate the potential influence of lymphocyte ß2AR receptor functionality and genotype in LC and OA patients. Blood samples from cirrhotic patients (n=52, hepatic venous pressure gradient 13±4 mmHg, CHILD 7±2 and MELD 11±4 scores), OA patients (n=30, 84% Kellgren­Lawrence severity 4 grade, 14% knee replacement joint) and healthy volunteers as control group (n=26) were analyzed. Peripheral blood mononuclear cells (PBMC) were isolated from whole blood and basal and isoproterenol induced adenylate cyclase activity (isoproterenol stimulus from 10­9 to 10­4 mM), and ß2AR allelic variants (rs1042713, rs1042714, rs1800888) were determined. ß2AR functionality was decreased in the two different models of chronic inflammatory disease studied, OA (50% vs. control) and LC (85% vs. control). In these patients, the strength of the ß2AR response to adrenergic stimulation was very limited. Adrenergic modulation of PBMC function through the ß2AR stimulus is decreased in chronic inflammatory processes including LC and OA, suggesting that the adrenergic system may be important in the development of these processes.

Norfloxacin modulates the inflammatory response and directly affects neutrophils in patients with decompensated cirrhosis.

BACKGROUND & AIMS: Patients with cirrhosis undergoing selective intestinal decontamination with norfloxacin show a reduction in serum cytokine levels, probably because of a combined effect of norfloxacin on bowel flora and neutrophils. METHODS: Thirty-one patients with cirrhosis receiving norfloxacin (400 mg/day) were included. Blood samples were collected at 0.5-4 hours (peak samples group, n = 47) and at 22-24 hours (trough samples group, n = 84) after dose. Fifty-nine ascitic fluid samples were obtained. Single doses of norfloxacin and trimethoprim/sulfamethoxazole were administered to 13 and 5 patients, respectively, (temporal profile group) and samples were collected at 0, 0.5, 1, 1.5, 2, 4, and 24 hours. Norfloxacin, trimethoprim/sulfamethoxazole, cytokines, nitric oxide, expression levels of nuclear factor (NF)-kappaB and inhibitor of NF-kappaB (IkB-alpha), neutrophil oxidative burst, and rate of apoptotic events were determined. RESULTS: All samples were bacterial DNA negative and had no significant levels of lipopolysaccharide. Serum and ascitic levels of tumor necrosis factor-alpha, interferon-gamma, interleukin-12, and nitric oxide were significantly lower in peak than in trough samples. A correlation was present between serum norfloxacins concentrations and tumor necrosis factor-alpha (r = -0.68; P < .001), interferon-gamma (r = -0.66; P < .001), interleukin-12 (r = -0.66; P < .001), and nitric oxide (r = -0.68; P < .001). Serum norfloxacin's highest concentrations (1 +/- 0.5 microg/mL) were achieved at 1-2 hours and concurred in time with the lower levels of cytokines and nitric oxide. Intracellular norfloxacin's highest levels (2 +/- 1 microg/mL/10(7) cells) were observed at 2 hours and concurred with a lower NF-kappaB expression, a reduced anion superoxide generation, and apoptotic rate in response to phorbol myristate acetate. Trimethoprim/sulfamethoxazole did not significantly modulate cytokine expression. CONCLUSIONS: Norfloxacin but not trimethoprim/sulfamethoxazole modulates inflammatory response and directly affects neutrophils in patients with cirrhosis.

Causality assessment of liver injury after chronic oral amiodarone intake.

BACKGROUND/AIM: The number of patients receiving amiodarone will increase in future years. As clinically significant hepatotoxicity associated with oral amiodarone is infrequent and difficult to predict, a new Bayesian-developed model is proposed to help in the causality assessment of amiodarone-induced liver injury. METHODS: Incidence of abnormal liver enzymes in patients receiving amiodarone was obtained from placebo controlled clinical trials. Published case reports of amiodarone-induced hepatotoxicity were identified through a literature search. Maximum number of expected hepatotoxicity cases in amiodarone and placebo-treated patients was calculated using Poisson distribution. The calculated odds ratio was used as a Prior Odds (PrO) to subsequent quantification, using a Bayesian-approach, of individual amiodarone-induced hepatotoxicity likelihood. RESULTS: PrO of amiodarone-induced hepatotoxicity was 0.48. Thirty nine amiodarone-associated hepatotoxicity case reports were retrieved. Half of published case reports developed an irreversible damage. The amiodarone Bayesian model combining information about latency period and period of remission, together with analytical parameters properly defines the toxicity profile shown in published case reports. The analytical pattern defined by this model is different from the one expected if liver injury in published cases was caused by other etiologies. CONCLUSIONS: A method based on a Bayesian-approach, which links information from clinical trials with clinical hepatotoxicity profile from published case reports can be a useful tool for amiodarone-induced liver injury causality assessment. At present, this method is limited due to scarcity and quality of available data. Further efforts are needed to improve model ability in order to identify amiodarone-induced liver injury.

Lack of morphine-6-glucuronide antinociception after morphine treatment. Is morphine-3-glucuronide involved?

Morphine, morphine-6-glucuronide (M6G) tolerance and cross-tolerance between morphine and M6G have been evaluated in mice. Daily administration of equipotent doses of M6G and morphine induced similar declines in antinociception over 9 days of treatment. However, a higher dose of M6G than morphine is required in tolerant animals to recover the initial response. In studies where daily morphine doses were substituted by M6G administration, on specific days, there was a significant fall in M6G antinociception on those days immediately following morphine administration, relative to the response to continued morphine (a decrease of 53.7% on day 2, P < 0.001 and a decrease of 62.5% on day 11, P < 0.05) and M6G (a decrease of 45.4% on day 2, P < 0.05) exposure. The decrease was independent of treatment duration and dosage. This decrease in the antinociceptive effect of M6G after morphine was avoided after clofibrate treatment, an inhibitor of (-)morphine metabolism. Determination of morphine and its metabolites in plasma revealed that morphine-3-glucuronide (M3G) concentration was significantly lower (P < 0.001) in animals treated with clofibrate (8.3 +/- 8.3 ng/ml) than in controls (422 +/- 80 ng/ml). The dose-response curve for M6G was shifted to the right by prior administration of M3G. These results suggest that during morphine treatment the antinociceptive effect of M6G may be antagonized by the other metabolite, M3G.