The Role of Pharmacogenomics in Opioid Prescribing.

OPINION STATEMENT: Pharmacogenomics is increasingly important to guide objective, safe, and effective individualised prescribing. Personalised prescribing has revolutionised treatments in the past decade, allowing clinicians to maximise drug efficacy and minimise adverse effects based on a person's genetic profile. Opioids, the gold standard for cancer pain relief, are among the commonest medications prescribed in palliative care practice. This narrative review examines the literature surrounding opioid pharmacogenomics and its applicability to the palliative care cancer population. There is currently limited intersection between the fields of palliative care and pharmacogenomics, but growing evidence presents a need to build linkages between the two disciplines. Pharmacogenomic evidence guiding opioid prescribing is currently available for codeine and tramadol, which relates to CYP2D6 gene variants. However, these medications are prescribed less commonly for pain in palliative care. Research is accelerating with other opioids, where oxycodone (CYP2D6) and methadone (CYP2B6, ABCB1) already have moderate evidence of an association in terms of drug metabolism and downstream analgesic response and side effects. OPRM1 and COMT are receiving increasing attention and have implications for all opioids, with changes in opioid dosage requirements observed but they have not yet been studied widely enough to be considered clinically actionable. Current evidence indicates that incorporation of pharmacogenomic testing into opioid prescribing practice should focus on the CYP2D6 gene and its actionable variants. Although opioid pharmacogenomic tests are not widely used in clinical practice, the progressively reducing costs and rapid turnover means greater accessibility and affordability to patients, and thus, clinicians will be increasingly asked to provide guidance in this area. The upsurge in pharmacogenomic research will likely discover more actionable gene variants to expand international guidelines to impact opioid prescribing. This rapidly expanding area requires consideration and monitoring by clinicians in order for key findings with clinical implications to be accessible, meaningfully interpretable and communicated.

Implementing a pragmatic clinical trial to tailor opioids for acute pain on behalf of the IGNITE ADOPT PGx investigators.

Opioid prescribing for postoperative pain management is challenging because of inter-patient variability in opioid response and concern about opioid addiction. Tramadol, hydrocodone, and codeine depend on the cytochrome P450 2D6 (CYP2D6) enzyme for formation of highly potent metabolites. Individuals with reduced or absent CYP2D6 activity (i.e., intermediate metabolizers [IMs] or poor metabolizers [PMs], respectively) have lower concentrations of potent opioid metabolites and potentially inadequate pain control. The primary objective of this prospective, multicenter, randomized pragmatic trial is to determine the effect of postoperative CYP2D6-guided opioid prescribing on pain control and opioid usage. Up to 2020 participants, age ≥8 years, scheduled to undergo a surgical procedure will be enrolled and randomized to immediate pharmacogenetic testing with clinical decision support (CDS) for CYP2D6 phenotype-guided postoperative pain management (intervention arm) or delayed testing without CDS (control arm). CDS is provided through medical record alerts and/or a pharmacist consult note. For IMs and PM in the intervention arm, CDS includes recommendations to avoid hydrocodone, tramadol, and codeine. Patient-reported pain-related outcomes are collected 10 days and 1, 3, and 6 months after surgery. The primary outcome, a composite of pain intensity and opioid usage at 10 days postsurgery, will be compared in the subgroup of IMs and PMs in the intervention (n = 152) versus the control (n = 152) arm. Secondary end points include prescription pain medication misuse scores and opioid persistence at 6 months. This trial will provide data on the clinical utility of CYP2D6 phenotype-guided opioid selection for improving postoperative pain control and reducing opioid-related risks.

Pain Management Following Otological Surgery: A Prospective Study of Different Strategies.

OBJECTIVES: The aim of this study was to prospectively assess pain and associated analgesic consumption after otological surgery comparing two prescription patterns. STUDY DESIGN: A prospective nonrandomized consecutive cohort study. METHODS: 125 adult patients undergoing ambulatory otologic surgery-cochlear implantation and endaural middle ear surgery, were assigned (according to surgeon's preference) and prospectively studied in two arms: 1) acetaminophen 500 mg + ibuprofen 400 mg; 2) acetaminophen 500 mg + codeine 30 mg. Pain levels, medication dose, disposal patterns of opioids, and suspected side effects were evaluated. RESULTS: All patients reported mild to moderate pain. There was a statistically significant reduction of pain from day to day, which was on average 0.26 lower than the day before. Sufficient pain control could be achieved with both drug regimens with no significant difference in pain levels. Only 50% of patients who were prescribed opioids used them. Additionally, the median tablet intake was 3 tablets while 10 to 20 tablets were prescribed. The majority of patients (97%) did not dispose of these drugs safely. CONCLUSION: Adequate analgesia was achieved in both arms of this study. Pain control following otologic surgery with a combination of acetaminophen and nonsteroidal anti-inflammatory drugs is recommended unless contraindications or chronic opioid use are present. If opioids such as codeine (30 mg) are prescribed, the amount should be reduced as low as possible, such as five tablets, based on our studied population. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:204-211, 2022.

Managing postoperative pain in adult outpatients: a systematic review and meta-analysis comparing codeine with NSAIDs.

BACKGROUND: Analgesics that contain codeine are commonly prescribed for postoperative pain, but it is unclear how they compare with nonopioid alternatives. We sought to compare the effectiveness of codeine and nonsteroidal anti-inflammatory drugs (NSAIDs) for adults who underwent outpatient surgery. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials comparing codeine and NSAIDs for postoperative pain in outpatient surgery. We searched MEDLINE and Embase from inception to October 2019 for eligible studies. Our primary outcome was the patient pain score, converted to a standard 10-point intensity scale. Our secondary outcomes were patient-reported global assessments and adverse effects. We used random-effects models and grading of recommendations assessment, development and evaluation (GRADE) to assess the quality of evidence. RESULTS: Forty studies, including 102 trial arms and 5116 patients, met inclusion criteria. The studies had low risk of bias and low-to-moderate heterogeneity. Compared with codeine, NSAIDs were associated with better pain scores at 6 hours (weighted mean difference [WMD] 0.93 points, 95% confidence interval [CI] 0.71 to 1.15) and at 12 hours (WMD 0.79, 95% CI 0.38 to 1.19). Stronger NSAID superiority at 6 hours was observed among trials where acetaminophen was coadministered at equivalent doses between groups (WMD 1.18, 95% CI 0.87 to 1.48). NSAIDs were associated with better global assessments at 6 hours (WMD -0.88, 95% CI -1.04 to -0.72) and at 24 hours (WMD -0.67, 95% CI -0.95 to -0.40), and were associated with fewer adverse effects, including bleeding events. INTERPRETATION: We found that adult outpatients report better pain scores, better global assessments and fewer adverse effects when their postoperative pain is treated with NSAIDs than with codeine. Clinicians across all specialties can use this information to improve both pain management and opioid stewardship.

Analgesic effect of oral ibuprofen 400, 600, and 800 mg; paracetamol 500 and 1000 mg; and paracetamol 1000 mg plus 60 mg codeine in acute postoperative pain: a single-dose, randomized, placebo-controlled, and double-blind study.

PURPOSE: Effect size estimates of analgesic drugs can be misleading. Ibuprofen (400 mg, 600 mg, 800 mg), paracetamol (1000 mg, 500 mg), paracetamol 1000 mg/codeine 60 mg, and placebo were investigated to establish the multidimensional pharmacodynamic profiles of each drug on acute pain with calculated effect size estimates. METHODS: A randomized, double-blind, single-dose, placebo-controlled, parallel-group, single-centre, outpatient, and single-dose study used 350 patients (mean age 25 year, range 18 to 30 years) of homogenous ethnicity after third molar surgery. Primary outcome was sum pain intensity over 6 h. Secondary outcomes were time to analgesic onset, duration of analgesia, time to rescue drug intake, number of patients taking rescue drug, sum pain intensity difference, maximum pain intensity difference, time to maximum pain intensity difference, number needed to treat values, adverse effects, overall drug assessment as patient-reported outcome measure (PROM), and the effect size estimates NNT and NNTp. RESULTS: Ibuprofen doses above 400 mg do not significantly increase analgesic effect. Paracetamol has a very flat analgesic dose-response profile. Paracetamol 1000/codeine 60 mg gives similar analgesia as ibuprofen from 400 mg, but has a shorter time to analgesic onset. Active drugs show no significant difference in maximal analgesic effect. Other secondary outcomes support these findings. The frequencies of adverse effects were low, mild to moderate in all active groups. NNT and NTTp values did not coincide well with PROMs. CONCLUSION: Ibuprofen doses above 400 mg for acute pain offer limited analgesic gain. Paracetamol 1000 mg/codeine 60 mg is comparable to ibuprofen doses from 400 mg. Calculated effect size estimates and PROM in our study seem not to relate well as clinical analgesic efficacy estimators. TRIAL REGISTRATION: NCT00699114.

Patient-Centered Decision-making for Postoperative Narcotic-Free Endocrine Surgery: A Randomized Clinical Trial.

Importance: Historically, opioid pain medications have been overprescribed following thyroid and parathyroid surgery. Many narcotic prescriptions are incompletely consumed, creating waste and opportunities for abuse. Objective: To determine whether limiting opioid prescriptions after outpatient thyroid and parathyroid surgery to patients who opt in to narcotic treatment reduces opioid consumption without increasing postoperative pain compared with usual care (routine narcotic prescriptions). Design, Setting, and Participants: A randomized clinical trial of Postoperative Opt-In Narcotic Treatment (POINT) or routine narcotic prescription (control) was conducted at a single tertiary referral center from June 1 to December 30, 2020. A total of 180 adults undergoing ambulatory cervical endocrine surgery, excluding patients currently receiving opioids, were assessed for eligibility. POINT patients received perioperative pain management counseling and were prescribed opioids only on patient request. Patients reported pain scores (0-10) and medication use through 7 daily postoperative surveys. Logistic regression was used to determine factors associated with opioid consumption. Interventions: Patients in the POINT group were able to opt in or out of receiving prescriptions for opioid pain medication on discharge. Control patients received routine opioid prescriptions on discharge. Main Outcomes and Measures: Daily peak pain score through postoperative day 7 was the primary outcome. Noninferiority was defined as a difference less than 2 on an 11-point numeric rating scale from 0 to 10. Analysis was conducted on the evaluable population. Results: Of the 180 patients assessed for eligibility, the final study cohort comprised 102 patients: 48 randomized to POINT and 54 to control. Of these, 79 patients (77.5%) were women and median age was 52 (interquartile range, 43-62) years. A total of 550 opioid tablets were prescribed to the control group, and 230 tablets were prescribed to the POINT group, in which 23 patients (47.9%) opted in for an opioid prescription. None who opted out subsequently required rescue opioids. In the first postoperative week, 17 POINT patients (35.4% of survey responders in the POINT group) reported consuming opioids compared with 27 (50.0%) control patients (P = .16). Median peak outpatient pain scores were 6 (interquartile range, 4-8) in the control group vs 6 (interquartile range, 5-7) in the POINT group (P = .71). In multivariate analysis, patients with a history of narcotic use were 7.5 times more likely to opt in (95% CI, 1.61-50.11; P = .02) and 4.8 times more likely to consume opioids (95% CI, 1.04-1.52; P = .01). Higher body mass index (odds ratio, 1.11; 95% CI, 1.01-1.23; P = .03) and highest inpatient postoperative pain score (odds ratio, 1.24; 95% CI, 1.04-1.52; P = .02) were also associated with opioid consumption. Conclusions and Relevance: In this trial, an opt-in strategy for postoperative narcotics reduced opioid prescription without increasing pain after cervical endocrine surgery. Trial Registration: ClinicalTrials.gov Identifier: NCT04710069.

Oral and intravenous pharmacokinetics of metformin with and without oral codeine intake in healthy subjects: A cross-over study.

The aim of the study was to investigate if there is a clinically relevant drug interaction between metformin and codeine. Volunteers were randomized to receive on four separate occasions: (A) orally administered metformin (1 g), (B) intravenously administered metformin (0.5 g), (C) five doses of tablet codeine 25 mg; the last dose was administered together with oral metformin (1 g), and (D) five doses of tablet codeine 25 mg; the last dose was administered together with metformin (0.5 g) intravenously. Blood samples were drawn for 24 h after administration of metformin, and for 6 h after administration of codeine and analyzed using liquid chromatography and tandem mass spectrometry. Healthy volunteers genotyped as CYP2D6 normal metabolizers (*1/*1) without known reduced function variants in the OCT1 gene (rs12208357, rs34130495, rs34059508, and rs72552763) were invited. The median absorption fraction of metformin was 0.31 and was not influenced by codeine intake. The median time to maximum concentration ( T max ) after oral intake of metformin was 2 h without, and 3 h with codeine (p = 0.06). The geometric mean ratios of the areas under the plasma concentration time-curve (AUCs) for morphine and its metabolites M3G and M6G for oral intake of metformin-to-no metformin were 1.21, 1.31, and 1.27, respectively, and for i.v. metformin-to-no metformin 1.28, 1.34, and 1.30, respectively. Concomitant oral and i.v. metformin increased the plasma levels of morphine, M3G and M6G. These small pharmacokinetic changes may well contribute to an increased risk of early discontinuation of metformin. Hence, a clinically relevant drug-drug interaction between metformin and codeine seems plausible.

Should Codeine Still be Considered a WHO Essential Medicine?

Codeine continues to be widely used as an analgesic, antidiarrhoeal and antitussive agent. Its analgesic effect depends on its biotransformation to morphine, a strong opioid. The highly variable biotransformation of codeine to morphine, catalysed by CYP2D6, underlies the pronounced interindividual variability of its analgesic response. Randomized controlled trials have demonstrated that codeine administered alone has the poorest analgesic effect among all commonly used analgesics in acute postoperative pain. Moreover, it is highly unlikely that the low dose of codeine contributes to the pain-relieving effect of the non-opioid component in combination analgesic products. In addition, there is a lack of reliable clinical evidence to support the use of codeine as an antitussive in acute or chronic cough. Codeine use, through its active metabolite morphine, has the potential to lead to abuse and dependence. The World Health Organization (WHO) removed codeine from the essential medicines list for children in 2011. Based on the available information in the scientific literature on the efficacy and safety of codeine, the WHO should seriously consider removing it also from the list of essential medicines for adults, which would be a strong signal for all health professionals to prescribe and dispense codeine with the utmost caution.

The effect of codeine administration on oxidative stress biomarkers and the expression of the neuron-specific enolase in the brain of Wistar rats.

The study aimed to assess the effects of codeine medication on some oxidative stress parameters and how it affects the expression of enolase in neuronal cells. The codeine medication used for the study was Archilin™ with codeine syrup and dihydrocodeine 30 mg. The study used 30 male Wistar rats which were grouped in five: A, B, C, D, and E (n = 6), while treatments were administered for 21 days. Based on the LD50s of 6.09 ml/kg body weight (b.wt.) Archilin™ with codeine syrup and 3.145 mg/kg b.wt. dihydrocodeine, group A served as control and were given normal saline; groups B and C were treated with 1 mg/kg and 2 mg/kg b.wt. dihydrocodeine, respectively; while groups D and E were treated with 2 ml/kg and 4 ml/kg b.wt. Archilin™ with codeine syrup, respectively. After treatments, animals were sacrificed via cervical dislocation and the brains were harvested and prepared for determination of oxidative stress biomarkers as well as immunohistochemical studies of neuron-specific enolase (NSE) to assess for neuronal cell integrity. Significantly decreased mean values (p < 0.05) of superoxide dismutase (SOD) and catalase (CAT) activities were observed while malondialdehyde (MDA) is significantly increased (p < 0.05) among treated groups. The expression of enolase was downregulated in treatment groups when compared to control. Animals in group A which are control showed strong staining intensity of the prefrontal cortex compared to groups C, D, and E which showed mild staining. The scoring of group A for cerebellum showed strong staining intensity, groups B and C showed mild staining, while groups D and E showed weak staining intensity. From the findings of this study, prolonged codeine syrup administration causes oxidative stress and this affects the expression of enolase in neuronal cells resulting in glucose hypometabolism which eventually results in functional brain failure.

Relationship of perioperative anaphylaxis to neuromuscular blocking agents, obesity, and pholcodine consumption: a case-control study.

BACKGROUND: The observation that patients presenting for bariatric surgery had a high incidence of neuromuscular blocking agent (NMBA) anaphylaxis prompted this restricted case-control study to test the hypothesis that obesity is a risk factor for NMBA anaphylaxis, independent of differences in pholcodine consumption. METHODS: We compared 145 patients diagnosed with intraoperative NMBA anaphylaxis in Western Australia between 2012 and 2020 with 61 patients with cefazolin anaphylaxis with respect to BMI grade, history of pholcodine consumption, sex, age, comorbid disease, and NMBA type and dose. Confounding was assessed by stratification and binomial logistic regression. RESULTS: Obesity (odds ratio [OR]=2.96, χ2=11.7, P=0.001), 'definite' pholcodine consumption (OR=14.0, χ2=2.6, P<0.001), and female sex (OR=2.70, χ2=9.61, P=0.002) were statistically significant risk factors for NMBA anaphylaxis on univariate analysis. The risk of NMBA anaphylaxis increased with BMI grade. Confounding analysis indicated that both obesity and pholcodine consumption remained important risk factors after correction for confounding, but that sex did not. The relative rate of rocuronium anaphylaxis was estimated to be 3.0 times that of vecuronium using controls as an estimate of market share, and the risk of NMBA anaphylaxis in patients presenting for bariatric surgery was 8.8 times the expected rate (74.9 vs 8.5 per 100 000 anaesthetic procedures). CONCLUSIONS: Obesity is a risk factor for NMBA anaphylaxis, the risk increasing with BMI grade. Pholcodine consumption is also a risk factor, and this is consistent with the pholcodine hypothesis. Rocuronium use is associated with an increased risk of anaphylaxis compared with vecuronium in this population.

Application of Model Informed Precision Dosing to Address the Impact of Pregnancy Stage and CYP2D6 Phenotype on Foetal Morphine Exposure.

Guidance regarding the effect of codeine and its metabolites on foetal development is limited by small studies and inconsistent findings. The primary objective was to use physiologically based pharmacokinetic modelling to investigate the impact of gestational stage and maternal CYP2D6 phenotype on foetal morphine exposure following codeine administration. Full body physiologically based pharmacokinetic models were developed and verified for codeine and morphine using Simcyp (version 19.1). The impact of gestational age and maternal CYP2D6 phenotype on foetal and maternal morphine and codeine exposure following oral codeine administration was modelled in a cohort of 250 pregnant females and foetuses at gestational weeks 0 (mothers only), 6, 12, 24 and 36. Consistent with the known effect on codeine metabolism, a clinically meaningful (> 1.65-fold) increase in foetal morphine AUC was observed in the CYP2D6 UM phenotype cohort compared to the CYP2D6 EM and PM phenotype cohorts. The mean (95% CI) foetal morphine AUC in the CYP2D6 UM cohort of 0.988 (0.902 to 1.073) ng/mL.h was 1.8-fold higher than the CYP2D6 EM cohort of 0.546 (0.492 to 0.600) ng/mL.h (p < 0.001). Despite a 2.8-fold increase in maternal CYP2D6 protein abundance between gestational weeks 6 and 36, the mean foetal morphine AUC in the CYP2D6 EM and UM phenotype cohorts reduced by 1.55- and 1.75-fold, respectively, over this period. Maternal CYP2D6 phenotype is a significant determinant of foetal morphine AUC. Simulations suggest that the greatest risk with respect to foetal morphine exposure is during the first trimester of pregnancy, particularly in CYP2D6 UM phenotype mothers.

Identification of factors influencing tampering of codeine-containing medicines in England: a qualitative study.

BACKGROUND: Tampering of psychoactive medicines presents challenges to regulation and public health. However, little is currently known about what influences the decisions to treat codeine-containing medicines (CCM) with cold water extraction (CWE) from the perspective of individuals employing these techniques. The article identifies factors influencing utilisation of CWE to separate codeine from compounded analgesics, such as paracetamol and ibuprofen, found in CCM. METHODS: Purposive sampling of 27 participants residing in England who took part in a qualitative interview. Of these, 14 individuals (11 males and 3 females) reported tampering of psychoactive medicines, and the relevant transcripts were included in the analyses for the study. Participants were recruited from one addiction treatment service and from an online survey. The mean age of the participants was 31.5 years (range = 18-42 years). Qualitative data analysis followed the processes of iterative categorization (IC). The codes 'harm reduction', 'information sources' and 'changes on the drug markets' were grouped and summarised. The coding of the data was done in a Microsoft® Word document. RESULTS: Two groups of participants were identified in the data analysis: (i) individuals who used CCM (n = 5), and (ii) individuals who used CCM and heroin (n = 9). Participants in both groups used CWE due to concerns of paracetamol overdose from the use of excessive dosages of CCM. For both of them, information obtained from the internet encouraged the use of CWE. Participants using CCM described how the many steps involved in conducting CWE, including sourcing codeine boxes from pharmacies (over the counter), presented a barrier against using CWE. Participants using CCM and heroin explained how reduced availability in the local heroin supply influenced utilisation of CWE techniques to maintain their use of opioids and avoid withdrawal. Withdrawal symptoms and cravings outweighed the concerns about the quality of the extracted codeine mixtures in this participant group, especially the ability of CWE to remove paracetamol and tablet fillers. CONCLUSIONS: Utilisation of CWE of codeine was influenced by several factors including drug market supply, the availability of detailed information on the internet about CWE and restrictions on codeine sourcing in pharmacies. Risks identified with CWE include consumption of unknown doses of paracetamol if the CWE techniques are not used correctly. Attempts at extracting codeine from CCM should be considered in risk assessments of opioid medicines.

Dental opioid prescribing rates after the up-scheduling of codeine in Australia.

The misuse of pharmaceutical opioids is a major public health issue. In Australia, codeine was re-scheduled on 1 February 2018 to restrict access; it is now only available on prescription. The aim of this study was to measure the change in dental opioid prescriptions, one year before and after the codeine re-scheduling in Australia and to assess dental prescribing rates of opioids for 2018 by population and by clinician. Data was extracted for dental opioids for the year immediately prior and after the codeine up-schedule (1 February 2017-31 January 2019) from the publicly-available national prescription database (Pharmaceutical Benefits Scheme). Descriptive statistics, T-tests and odds ratios were used to identify significant prescribing differences. Codeine, codeine/paracetamol, oxycodone and tramadol use increased significantly the year after the codeine restriction than the previous year (13.8-101.1%). Australian dentists prescribed 8.6 prescriptions/1,000 population in 2018, with codeine/paracetamol accounting for most prescriptions (96%). The significant increase in opioid prescribing highlights that Australian dentists may be contributing to the misuse of pharmaceutical opioids. Educational efforts should be targeted at the appropriate use of opioids and patient selection. Dentists should be added to the prescription monitoring system SafeScript so they can make informed decisions for patients who are potentially misusing opioids.

Use of analgesics following rescheduling of codeine in Australia: An interrupted time series analysis in the veteran population.

BACKGROUND: The Australian medicines regulator, the Therapeutic Goods Administration (TGA), rescheduled all codeine-containing medicines to be available only on prescription on 1 February 2018. This study was conducted to determine whether use of analgesics changed following codeine re-scheduling to prescription only status, and whether there was a change in the use of codeine preparations and a therapeutic shift to stronger opioids or other analgesics in the Australian veteran population following the change. METHODS: Interrupted time series analysis using Repatriation Pharmaceutical Benefits Scheme (RPBS) claims data from the Australian Government Department of Veterans' Affairs (DVA) for clients with dispensing of opioid and non-opioid analgesics between January 2015 and April 2019. Trends in the monthly rate of analgesic dispensings (opioid and non-opioid) were compared for the period between January 2015 and January 2018 with the period February 2018 to April 2019. RESULTS: Paracetamol with codeine 8mg was the only analgesic with an increased rate of dispensing following the February 2018 codeine scheduling changes. Prior to codeine re-scheduling, the rate of dispensing of paracetamol with codeine 8mg was decreasing by 0.9% each month. Immediately after the scheduling changes, dispensing of paracetamol with codeine 8mg increased by 45% (95%CI=1.282-1.676, p<0.001) and in the fifteen month period thereafter (February 2018 to April 2019), the rate of dispensing increased by 4% each month (95%CI=1.027-1.054, p<0.001). Therapeutic shift from over-the-counter codeine products to other opioids was not observed, with no increase in the rate of dispensing of any of the other opioid (or non-opioid) analgesics following the codeine scheduling changes. CONCLUSION: A significant increase in prescription use of paracetamol with codeine 8mg was observed after the February 2018 codeine re-scheduling. Therapeutic shift to stronger opioid analgesics was not observed in the study population.

Testicular toxicity following chronic codeine administration is via oxidative DNA damage and up-regulation of NO/TNF-α and caspase 3 activities.

BACKGROUND: Codeine, a 3-methylmorphine, and other related opioids have been implicated in androgen suppression, although the associated mechanisms remain unclear. AIM: Therefore, the objective of the current study was to elucidate the in vivo molecular mechanisms underlying codeine-induced androgen suppression. METHODS: This study made use of twenty-one healthy male rabbits, distributed into three groups randomly, control and codeine-treated groups. The control had 1ml of normal saline daily p.o. The codeine-treated groups received either 4mg/kg b.w of codeine or 10mg/kg b.w of codeine p.o. for six weeks. Reproductive hormonal profile, testicular weight, testicular enzymes, oxidative and inflammatory parameters, testicular DNA fragmentation, histological examination and apoptosis marker were evaluated to examine the effects of codeine use. KEY FINDINGS: Oral administration of codeine resulted in testicular atrophy and alterations in testicular histomorphology, elevated testicular enzymes, and suppression of circulatory and intra-testicular testosterone. These changes were associated with a marked rise in oxidative markers and decline in the activities of testicular enzymatic antioxidants, as well as oxidative DNA damage, inflammatory response, testicular DNA fragmentation, and caspase-dependent apoptosis (p<0.05). SIGNIFICANCE: In conclusion, chronic codeine use resulted in testicular degeneration and testosterone suppression, which is attributable to TNF-α/nitric oxide-/oxidative stress-mediated caspase-dependent apoptotic testicular cell death and loss of testicular function.

A Study of Opiate, Opiate Metabolites and Antihistamines in Urine after Consumption of Cold Syrups by LC-MS/MS.

Studying the origin of opiate and/or opiate metabolites in individual urine specimens after consumption of cold syrups is vital for patients, doctors, and law enforcement. A rapid liquid chromatography-tandem mass spectrometry method using "dilute-and-shoot" analysis without the need for extraction, hydrolysis and/or derivatization has been developed and validated. The approach provides linear ranges of 2.5-1000 ng mL-1 for 6-acetylmorphine, codeine, chlorpheniramine, and carbinoxamine, 2.5-800 ng mL-1 for morphine and morphine-3-ß-d-glucuronide, and 2.5-600 ng mL-1 for morphine-6-ß-d-glucuronide and codeine-6-ß-d-glucuronide, with excellent correlation coefficients (R2 > 0.995) and matrix effects (< 5%). Urine samples collected from the ten participants orally administered cold syrups were analyzed. The results concluded that participants consuming codeine-containing cold syrups did not routinely pass urine tests for opiates, and their morphine-codeine concentration ratios (M/C) were not always < 1. In addition, the distribution map of the clinical total concentration of the sum of morphine and codeine against the antihistamines (chlorpheniramine or carbinoxamine) were plotted for discrimination of people who used cold syrups. The 15 real cases have been studied by using M/C rule, cutoff value, and distribution map, further revealing a potential approach to determine opiate metabolite in urine originating from cold syrups.

Cold water extraction of codeine/paracetamol combination products: a case series and literature review.

Introduction: Tampering with opioid containing medications for use other than their prescribed indication is well documented; however, the published literature has concentrated on stronger, prescription opioids. Less potent opioids, such as codeine, are available without prescription in many European countries in the form of combination analgesic products and these can also be altered, with reports in particular of "cold-water extraction" being a tampering method achievable using household kitchen equipment.Methods: We searched a database of patients attending two South London emergency departments for cases of self-reported ingestion of the products of cold-water extraction, with subsequent review of their case notes. We searched the scientific and grey literature to identify current knowledge of this technique.Results: We identified seven presentations in six patients, none of whom developed paracetamol toxicity or had concentrations suggesting ingestion of a significant dose of paracetamol. A review of the scientific literature on the method also demonstrated that the technique reduces recovered paracetamol in experimental laboratory settings. Additionally, the established literature characterizes the use of codeine in a recreational setting and reports one fatality associated with the method. Review of grey literature user-forums further describes recreational codeine use in relation to the method and frequent adverse events including hospital admission for paracetamol toxicity.Discussion: Whilst the method appears capable of providing a recreational dose of codeine with reduction in the recovered paracetamol, it cannot be considered safe. Pharmaceutical production methods have been successfully developed to prevent tampering through other means but none thus far have been directed at the cold water extraction technique.Conclusions: Clinicians should be aware of the potential toxicity from tampered nonprescription analgesics. There is also the need for public health education regarding the potential risks associated with these methods.

Supply of codeine combination analgesics from Australian pharmacies in the context of voluntary real-time recording and regulatory change: A simulated patient study.

BACKGROUND: In recent years there have been growing concerns regarding non-prescription codeine use in Australia. Efforts to mitigate risks associated with non-prescription codeine, such as addiction and toxicity, have been primarily through two initiatives; regulatory changes restricting their availability, and voluntary live-recording supply of non-prescription codeine combination analgesics (CCAs). This study sought to explore the supply of CCAs in the climate of regulatory change. METHODS: Eighty University of Sydney pharmacy students mystery-shopped 34 community pharmacies across metropolitan Sydney, Australia from August 2016 to November 2017, with scripted symptom-based (SBR) or direct product requests (DPR) for a CCA. Questions asked, staff involvement, regulatory compliance, voluntary recording, and product(s) supplied were recorded. RESULTS: Of 158 total visits, a non-prescription CCA was supplied in 101 instances. Sixty-one (60%) of these supplies complied with the legislative requirement for a pharmacist to supply the medicine. Voluntary recording was surmised to have been utilised 13 times (13% CCA supplies). CCAs were supplied less frequently in 2017 DPR scenarios compared to 2016 DPR scenarios (64% vs 86%; p = 0.024), and a greater proportion of 2017 DPR supplies were compliant with the legislative requirement of pharmacist supply (72% vs 46%; p = 0.041). No difference in proportion of sales surmised to have been voluntarily recorded was observed between the years. Interactions involving pharmacists resulted in less frequent supply of codeine than those without (58% vs 82%; p = 0.012). CONCLUSION: Mandatory legislative regulation of pharmacist supply of non-prescription codeine was more likely to be complied with than voluntary recording. Compliance with pharmacist supply for DPRs appeared to improve following the announcement of regulatory change to prescription-only, whereas voluntary recording of supply did not appear to change.

Impaired consciousness, hypokalaemia and renal tubular acidosis in sustained Nurofen Plus abuse.

Ibuprofen-induced renal tubular acidosis is a rare but important diagnosis which should be considered in patients presenting with hypokalaemia and metabolic acidosis. This case report details the case of a 33-year-old woman presenting with reduced conscious state, metabolic acidosis and profound hypokalaemia without an obvious cause. With correction of the patient's electrolyte and acid-base disturbance, her conscious state improved allowing disclosure of her use of Nurofen Plus for its euphoric opiate effects. The diagnosis of renal tubular acidosis had been considered and subsequent disclosure of excessive chronic ingestion of ibuprofen suggested this to be the underlying cause. The striking feature of our patient was the insidious development of the problem and delayed accurate drug history. An important safety message arising from our case is the composite risk of dependence on the opiate component of over the counter analgesics, such as Nurofen Plus, and adverse events related to the ibuprofen component.

Adult and infant pharmacokinetic profiling of dihydrocodeine using physiologically based pharmacokinetic modeling.

We previously analysed the serum concentrations of dihydrocodeine in a 1-month-old infant with respiratory depression after being prescribed dihydrocodeine phosphate 2.0 mg/day divided t.i.d. for 2 days. The purpose was to develop a full physiologically based pharmacokinetic (PBPK) model that could account for these and other drug monitoring results. Based on experiments in Caco-2 cell monolayers, the effective permeability of dihydrocodeine in human jejunum was established as 1.28 × 10-4 cm/s. The in vitro Vmax /Km values for dihydrocodeine demethylation mediated by recombinant cytochrome P450 2D6 and 3A4 were 0.19 and 0.066 µl/min/pmol, respectively, and for dihydrocodeine 6-O-glucuronidation mediated by recombinant UGT2B4 and 2B7, the Vmax /Km values were 0.14 and 0.22 µl/min/mg protein, respectively. Renal clearance was calculated as 5.37 L/h on the total clearance value multiplied by the fraction recovered in urine. The reported plasma concentration-time profiles of dihydrocodeine after intravenous administration in healthy volunteers were used to adjust the tissue partitioning ratios. The developed model simulated the pharmacokinetic profiles of dihydrocodeine after single and multiple oral administrations reasonably well in the same population. Subsequently, the validated model was used to simulate pharmacokinetic profiles for five pediatric cases, including the 1-month-old Japanese boy and a 14-year-old Japanese girl who took an overdose of dihydrocodeine phosphate (37 mg). The simulated pharmacokinetic profiles for five virtual pediatric subjects matching the age, gender, and P450 2D6 phenotype of each case approximately reflected the observed values. These results suggested that our dihydrocodeine PBPK model reproduced the results of clinical cases reasonably well for subjects.