Morphine and pholcodine-specific IgE have limited utility in the diagnosis of anaphylaxis to benzylisoquinolines.

BACKGROUND: Investigation of immediate hypersensitivity reactions in the perioperative setting involves skin testing and measurement of specific IgE (sIgE) as standard practice. In the case of the neuromuscular blocking agents (NMBAs), the main allergenic epitopes have been shown to be substituted ammonium groups. Commercial assays are available for detection of sIgE to these epitopes using morphine and pholcodine substrates but questions have been raised about the effectiveness of these assays in the diagnosis of benzylisoquinoline anaphylaxis. This study was therefore undertaken to assess the effectiveness of these assays in the diagnosis of hypersensitivity reactions to this group of NMBAs. METHODS: Analysis was carried out on all available results for patients assessed at the Royal North Shore Hospital Anaesthetic Allergy Clinic during the period June 2009 to June 2016. Standardised intradermal skin tests were performed with a panel of NMBAs. Measurement of sIgE to morphine and pholcodine was performed via the Phadia ImmunoCAP® system. RESULTS: For all patients with positive skin test results to NMBAs which included a benzylisoquinoline NMBA (n = 24), 75% exhibited negative sIgE to both morphine and pholcodine. Where patients were reactive to benzylisoquinoline NMBAs alone (n = 12), 100% exhibited negative sIgE results, indicating 0% sensitivity of the assays relative to skin testing, in this subgroup. CONCLUSION: Use of sIgE testing to morphine and pholcodine in the assessment of NMBA immediate hypersensitivity is a valuable tool particularly in the case of reactions to the aminosteroid NMBAs. However, these assays are unreliable in detecting sensitisation to benzylisoquinoline NMBAs.

Preparation and Characterization of a Monoclonal Antibody Against Morphine.

A monoclonal antibody (MAb) was produced by immunization of a BALB/c mouse with a conjugated morphine C6-hemisuccinated derivative (MHS) to cationized bovine serum albumin (cBSA). The hybridoma clones were screened by indirect ELISA using MHS-BSA. The best hybridoma clone was subcloned thrice by limiting dilution. This hybridoma was found to be of IgG2b class and subclass and contained lambda light chain. The affinity of the MAb to morphine was obtained 2.8×10(9) M(-1). The titer of the cell culture supernatant was at least 1:800. The MAb was cross-reacted with codeine (100%) and apomorphine (16.5%), but not with heroin, naloxone, naltrexone, or papaverine. Morphine was conjugated to HRP using a mixed anhydride method and a direct competitive ELISA was designed using anti-morphine MAb. The assay was sensitive over the 50 ng/mL to 5 µg/mL concentration range. In conclusion, this MAb is useful for the development of immunoassays to measure morphine in urine.

IgE to Poppy Seed and Morphine Are Not Useful Tools to Diagnose Opiate Allergy.

BACKGROUND: Correct diagnosis of genuine IgE-mediated opiate allergy poses a significant challenge, mainly because of uncertainties associated with opiate skin testing and the unavailability of drug-specific IgE (sIgE) assays. Recently, it has been suggested that sIgE to poppy seed extract and morphine would be reliable in the diagnosis of opiate allergy. However, given the high prevalence of sIgE antibodies to these compounds in an allergic population, the predictive value of these tests leaves significant doubts. OBJECTIVE: This study aims at verifying the predictive value of positive poppy seed and morphine sIgE assays results. METHODS: A total of 22 individuals with a positive sIgE to poppy seed or morphine were selected. All had controlled drug challenges with increasing doses of morphine and/or codeine. Of these, 18 patients had an additional basophil activation test (BAT) with morphine and codeine. RESULTS: None of the 22 patients demonstrated objective or subjective symptoms on provocation with morphine and/or codeine. Regarding BAT with morphine and codeine, expression of CD63 on basophils from 14 opiate tolerant individuals remained comparable to spontaneous expression by resting cells. The remaining 4 patients were classified as nonresponders. CONCLUSION: Positive sIgE results to poppy seed and morphine are not per se predictive for genuine opiate allergy and should not be used in isolation to diagnose morphine or codeine allergy. To avoid overdiagnosis, for the time being, we propose to supplement serological diagnosis with an oral provocation test. Whether BAT might help to discriminate between clinical reactivity and sensitization remains to be confirmed in larger collaborative studies.

A preliminary evaluation of the effects of opioids on innate and adaptive human in vitro immune function.

BACKGROUND: Studies have demonstrated that whereas some opioids have little effect on immunity (eg, buprenorphine), others can be immunosuppressive (eg, morphine) or immunostimulatory (eg, tramadol). However, a variety of approaches have been used, especially in vitro and animal models, and the findings are variable. We hypothesised that opioids have differential effects on immunity via direct actions on neutrophils, monocytes, natural killer (NK) and T cells, and this is the first study to systematically evaluate the influence of eight opioids on neutrophil and monocyte phagocytosis and oxidative burst responses, NK cell cytotoxicity and T cell responsiveness in vitro. METHODS: Peripheral blood was obtained from healthy volunteers, and the effects of clinically relevant concentrations of morphine, tramadol, fentanyl, buprenorphine, methadone, oxycodone, diamorphine and codeine on phagocytosis and oxidative burst responses were determined using whole blood flow cytometry. The influence of opioids on the capacity of resting and IL-2 stimulated isolated peripheral blood mononuclear cells (PBMCs) to kill NK cell-sensitive K562 cells, and the responsiveness of PBMC subpopulations to IL-2 and polyclonal stimulation were also evaluated. RESULTS: Methadone, oxycodone and diamorphine inhibited the production of IL-6 by IL-2 stimulated PBMCs. None of the opioids consistently influenced the other measured immune parameters, although there was a trend for morphine, tramadol, fentanyl and buprenorphine to inhibit phagocytosis and oxidative burst responses to Escherichia coli. CONCLUSIONS: Preliminary studies using standardised in vitro methodologies have demonstrated that some therapeutic opioids suppress IL-6 production. Although this might potentially suppress bacterial defence mechanisms, it would have little direct effect on anticancer immunity. These findings should be confirmed in larger in vitro and clinical studies.

Exploring the link between pholcodine exposure and neuromuscular blocking agent anaphylaxis.

Neuromuscular blocking agents (NMBAs) are the most commonly implicated drugs in IgE-mediated anaphylaxis during anaesthesia that can lead to perioperative morbidity and mortality. The rate of NMBA anaphylaxis shows marked geographical variation in patients who have had no known prior exposure to NMBAs, suggesting that there may be external or environmental factors that contribute to the underlying aetiology and pathophysiology of reactions. Substituted ammonium ions are shared among NMBAs and are therefore thought to be the main allergenic determinant of this class of drugs. Substituted ammonium ions are found in a wide variety of chemical structures, including prescription medications, over-the-counter medications and common household chemicals, such as the quaternary ammonium disinfectants. Epidemiological studies have shown parallels in the consumption of pholcodine, a nonprescription antitussive drug which contains a tertiary ammonium ion, and the incidence of NMBA anaphylaxis. This link has prompted the withdrawal of pholcodine in some countries, with an ensuing fall in the observed rate of NMBA anaphylaxis. While such observations are compelling in their suggestion of a relationship between pholcodine exposure and NMBA hypersensitivity, important questions remain regarding the mechanisms by which pholcodine is able to sensitize against NMBAs and whether there are other, as yet unidentified, agents that can elicit similar hypersensitivity reactions. This review aims to explore the evidence linking pholcodine exposure to NMBA hypersensitivity and discuss the implications for our understanding of the pathophysiology of these reactions.

IgE-mediated allergy to pholcodine and cross-reactivity to neuromuscular blocking agents: Lessons from flow cytometry.

BACKGROUND: Immunoglubulin E antibody-mediated allergic reactions to opioids are rare and difficult to document correctly. OBJECTIVE: Assessment of the basophil activation test in the diagnosis of IgE-mediated allergy to the antitussive pholcodine and associated sensitizations to neuromuscular blocking agents (NMBA). METHODS: Three patients with a suspected IgE-mediated allergy to pholcodine were investigated using skin tests, quantification of specific IgE, and flow cytometric activation of basophils. RESULTS AND CONCLUSION: Flow cytometric activation of basophils, with simultaneous analysis of CD63 appearance and median histamine content per cell, is the only technique capable to correctly document pholcodine allergy. The negative predictive value of basophil activation tests might help to elucidate on the controversial putative cross-reactivity between pholcodine and NMBA.

Clinical value of morphine, pholcodine and poppy seed IgE assays in drug-abusers and allergic people.

BACKGROUND: The diagnosis of anaphylactic reactions due to opiates during anaesthesia can be difficult, since in most cases various drugs may have been administered. Detection of specific IgE to poppy seed might be a marker for sensitisation to opiates in allergic people and heroin-abusers. This study assessed the clinical value of morphine, pholcodine and poppy seed skin-prick and IgE determination in people suffering hypersensitivity reactions during anaesthesia or analgesia and drug-abusers with allergic symptoms. METHODS: We selected heroin abusers and patients who suffered severe reactions during anaesthesia and analgesia from a database of 23,873 patients. The diagnostic yield (sensitivity, specificity and predictive value) of prick and IgE tests in determining opiate allergy was analysed. RESULTS: Overall, 149 patients and 200 controls, mean age 32.9 ± 14.7 years, were included. All patients with positive prick to opiates showed positive prick and IgE to poppy seeds, but not to morphine or pholcodine IgE. Among drug-abusers, 13/42 patients (31%) presented opium hypersensitivity confirmed by challenge tests. Among non-drug abusers, sensitisation to opiates was higher in people allergic to tobacco (25%), P<.001. Prick tests and IgE against poppy seed had a good sensitivity (95.6% and 82.6%, respectively) and specificity (98.5% and 100%, respectively) in the diagnosis of opiate allergy. CONCLUSIONS: Opiates may be significant allergens. Drug-abusers and people sensitised to tobacco are at risk. Both the prick and specific IgE tests efficiently detected sensitisation to opiates. The highest levels were related to more-severe clinical profiles.

[Correlation between pholcodine and perioperative anaphylaxis]. / Povezanost folkodina i perioperativne anafilaksije.

A large number of individuals experiencing anaphylactic reaction to neuromuscular blocking agents have not previously been in contact with them. The search for a substance inducing sensitization to muscle relaxants has led Norwegian and Swedish scientists to pholcodine, a cough suppressant, which is widely used in Europe and worldwide. Ammonium ion is an epitope common to pholcodine and neuromuscular blocking agents and it is the basis of their cross-reactivity. Based on the results of published studies that pointed to a connection of the use of pholcodine and perioperative anaphylactic reaction, pholcodine was withdrawn from the Norwegian market and subsequent research revealed a reduction of anaphylactic reactions in that country. In its latest report, the European Medicines Agency made a decision not to withdraw pholcodine mixtures from the market but it urged further research with the aim to clarify the cross-reactivity between pholcodine and neuromuscular blocking agents.

Anesthesia in the patient with multiple drug allergies: are all allergies the same?

PURPOSE OF REVIEW: During the preoperative evaluation, patients frequently indicate 'multiple drug allergies', most of which have not been validated. Potential allergic cross-reactivity between drugs and foods is frequently considered as a risk factor for perioperative hypersensitivity. The aim of this review is to facilitate the recognition of risk factors for perioperative anaphylaxis and help the management of patients with 'multiple drug allergies' during the perioperative period. RECENT FINDINGS: Neuromuscular blocking agents (NMBAs) and antibiotics are the most common drugs triggering perioperative anaphylaxis. Quaternary ammonium ions have been suggested to be the allergenic determinant of NMBAs. Even though the 'pholcodine hypothesis' has been suggested to explain the occurrence of NMBA-induced allergy, this concept remains unclear. Although many practitioners believe that certain food allergies present an issue with the use of propofol, there is no role to contraindicate propofol in egg-allergic, soy-allergic or peanut-allergic patients. IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, but there is no cross-reactivity between them. The allergenic determinants have been characterized for fish, shellfish and povidone iodine and remain unknown for contrast agents. SUMMARY: There are many false assumptions regarding drug allergies. The main goal of this article is to review the potential cross-reactivity among specific families of drugs and foods in order to facilitate the anesthetic management of patients with 'multiple drug allergies'.

IgE-sensitization to the cough suppressant pholcodine and the effects of its withdrawal from the Norwegian market.

BACKGROUND: IgE-mediated anaphylaxis to neuromuscular blocking agents (NMBA), frequent in Norway, was proposed to be caused by exposure to pholcodine (PHO) carrying the allergenic quarternary ammonium ion epitope. Consequently, the PHO-containing drug was withdrawn from the market in March 2007. OBJECTIVE: Describe the effects of withdrawal of PHO on IgE, IgE-antibodies and reported frequencies of anaphylaxis to NMBAs. METHODS: Three hundred sera from supposedly allergic patients sampled yearly through 2006 to 2010 were analysed for IgE antibodies to PHO, suxamethonium (SUX) and morphine (MOR). Furthermore, IgE and preliminary reports from the Norwegian Network for Anaphylaxis under Anaesthesia (NARA) were monitored. RESULTS: PHO exposure was associated with IgE sensitization to PHO, MOR and SUX. However, after withdrawal, within 1 year, antibody prevalences to PHO and SUX fell significantly from 11.0% to 5.0% and from 3.7% to 0.7%, respectively. At 3 years, SUX had fallen to 0.3%, PHO to 2.7% and MOR to 1.3%. By 2 years, the prevalence of elevated IgE was significantly reduced. After 3 years, the incidence of reported suspected anaesthetic anaphylaxis fell significantly, both the total number, the reactions related to NMBAs and those with IgE antibodies to SUX. CONCLUSIONS: Withdrawing of PHO lowered significantly within 1-2 years levels of IgE and IgE antibodies to PHO, MOR and SUX, and, within 3 years, the frequency of NMBA suspected anaphylaxis. The results strengthen the PHO hypothesis considerably and equally the need to question the existence of cough depressants containing PHO.

Roche DAT immunoassay: sensitivity and specificity testing for amphetamines, cocaine, and opiates in oral fluid.

Laboratory testing of oral fluid for drugs of abuse continues to expand in the workplace, legal, treatment, and health settings. In this study, we assessed recently developed homogeneous Roche DAT screening assays for amphetamines, cocaine metabolite [benzoylecgonine (BZE)], methamphetamines, and opiates in oral fluid. Precision and accuracy were assessed using control samples at +/-25% of cutoff. Sensitivity, specificity, and agreement compared to liquid chromatography-tandem mass spectrometry (LC-MS-MS) was assessed by analysis of oral fluid specimens collected from 994 subjects enrolled in a drug treatment or probation and parole drug-testing program. An additional 180 research specimens from Kroll Laboratories were analyzed for amphetamine and methamphetamine. Screening cutoff concentrations (ng/mL) were as follows: amphetamines, 40; cocaine metabolite, 3; methamphetamines, 40; and opiates, 10. LC-MS-MS analyses were performed with the following cutoff concentrations (ng/mL): amphetamine, 40; BZE, 2.0; methamphetamine, 40; and codeine or morphine, 10. The percent coefficient of variation ranged from 3.4% to 7.3%. Sensitivity and specificity of the Roche DAT assays compared to LC-MS-MS were > 94%, and agreement was > 96% for the four assays. The performance of the Roche DAT assays suggests these new homogeneous screening assays will be an attractive alternative to existing more labor-intensive enzyme immunoassays.

National pholcodine consumption and prevalence of IgE-sensitization: a multicentre study.

BACKGROUND: The aim of this study was to test, on a multinational level, the pholcodine (PHO) hypothesis, i.e. that the consumption of PHO-containing cough mixtures could cause higher prevalence of IgE antibodies to PHO, morphine (MOR) and suxamethonium (SUX). As a consequence the risk of anaphylaxis to neuromuscular blocking agents (NMBA) will be increased. METHODS: National PHO consumptions were derived from the United Nations International Narcotics Control Board (INCB) database. IgE and IgE antibodies to PHO, MOR, SUX and P-aminophenyl-phosphoryl choline (PAPPC) were measured in sera from atopic individuals, defined by a positive Phadiatop test (>0.35 kU(A)/l), collected in nine countries representing high and low PHO-consuming nations. RESULTS: There was a significant positive association between PHO consumption and prevalences of IgE-sensitization to PHO and MOR, but not to SUX and PAPPC, as calculated both by exposure group comparisons and linear regression analysis. The Netherlands and the USA, did not have PHO-containing drugs on the markets, although the former had a considerable PHO consumption. Both countries had high figures of IgE-sensitization. CONCLUSION: This international prevalence study lends additional support to the PHO hypothesis and, consequently, that continued use of drugs containing this substance should be seriously questioned. The results also indicate that other, yet unknown, substances may lead to IgE-sensitization towards NMBAs.

The pholcodine story.

Anaphylactic reactions to neuromuscular blocking agents during general anesthesia constitute a major cause of concern and a great source of debate among anesthesiologists. The authors' recent investigations, taking the striking differences of incidence between Norway and Sweden as the point of departure, have provided valuable insights into the pathogenetic mechanisms and the highly uneven geographical distribution of these rare, but dramatic and notoriously unpredictable, events. Eventually, a cough syrup containing pholcodine emerged as the most likely suspect. This new knowledge led to the withdrawal of the drug from the Norwegian market and to the examination of the role of pholcodine-containing drugs in other countries. The present article is a brief summary of the research behind this development.

Group-selective antibodies based fluorescence immunoassay for monitoring opiate drugs.

A novel carboxylic acid derivative of monoacetylmorphine (MAM-COOH) was synthesized and conjugated with bovine serum albumin (BSA) for generating polyclonal antibodies against the target molecule heroin and its major metabolites. The conjugate was characterized by fluorescence spectroscopy, polyacrylamide gel electrophoresis, and mass spectrometry to confirm the extent of haptenization of the carrier protein. A high titer (1:64,0000) of antibody was obtained by using the conjugate with an optimum protein/hapten molar ratio of 1:100. The generated antibody showed good binding affinity with heroin and its metabolites monoacetylmorphine (MAM) and morphine. The relative affinity constant (K (aff)) of the antibody was 3.1 x 10(7) l mol(-1), and the IC(50) values obtained for heroin, MAM, morphine, and codeine were 0.01, 0.013, 0.012, and 0.014 ng ml(-1), respectively. A fluorescence-based competitive inhibition immunoassay procedure was developed for the estimation of heroin and its major metabolites in standard and biofludic samples over a concentration range up to 0.01 ng ml(-1) with good signal reproducibility (p < 0.05). The method can be used as a convenient quantitative tool for the sensitive screening of major metabolites of heroin in biological samples.

Pholcodine exposure raises serum IgE in patients with previous anaphylaxis to neuromuscular blocking agents.

BACKGROUND: Neuromuscular blocking agents (NMBAs) can cause anaphylaxis through immunoglobulin E (IgE) antibodies that bind quaternary ammonium ion epitopes. These epitopes are present in numerous common chemicals and drugs, exposure to which, theoretically, could be of importance in the development and maintenance of the IgE sensitization promoting allergic reactions. Pholcodine is one such drug, which in a recent pilot study was shown to induce a remarkable increase in serum IgE levels in two IgE-sensitized individuals. The present study explores the effect of pholcodine exposure on IgE in a population with previously diagnosed IgE-mediated anaphylaxis towards NMBAs. METHODS: Seventeen patients were randomized to 1 week's exposure with cough syrup containing either pholcodine or guaifenesin. The primary variables serum IgE and IgE antibodies towards pholcodine, morphine and suxamethonium were measured before and 4 and 8 weeks after start of exposure. RESULTS: Patients exposed to pholcodine had a sharp rise in levels of IgE antibodies towards pholcodine, morphine and suxamethonium, the median proportional increases 4 weeks after exposure reaching 39.0, 38.6 and 93.0 times that of the base levels respectively. Median proportional increase of IgE was 19.0. No changes were observed in the guaifenesin group. CONCLUSION: Serum levels of IgE antibodies associated with allergy towards NMBAs increase significantly in sensitized patients after exposure to cough syrup containing pholcodine. Availability of pholcodine should be restricted by medical authorities because of the potential risk of future allergic reactions to muscle relaxants.