New guideline for tramadol usage following adverse drug reactions reported to the Iranian Pharmacovigilance Center

A nationwide study on consumption of opioid analgesics in Iran from 2000 to 2018

BACKGROUND

Opioid analgesics play a unique role in pain management. National opioid consumption studies could provide indirect evidence of pain management in a country. National, regional, and global opioid consumption have been studied in other countries so far; however, conducting a focused study to illuminate the consumption of opioid analgesics over the past decades in Iran seemed necessary.

AIM

The main objective of this study was to determine the consumption of opioid analgesics and explore the trend of their use during 19 years in Iran.

METHOD

Iran pharmaceutical wholesale data were used to extract the annual consumption figures of the opioid analgesics in group N02A of the World Health Organization (WHO) Anatomical Therapeutic Chemical classification and were available in Iran (morphine, fentanyl, pethidine, and oxycodone as strong opioids and, tramadol and pentazocine as weak opioids), from 2000 to 2018. Using Defined Daily Dose (DDD) by WHO and Oral Morphine Equivalent (OMEQ), the amount of annual consumption was determined in DDD/1000 inhabitants/Day (DID) and OMEQ (mg)/1000 inhabitants/Day (OID).

RESULTS

Total opioid analgesic utilization based on DID and OID increased 31.12-fold (from 0.0196 to 0.61) and 21.06-fold (from 1.97 to 41.5 mg) over 19 years, respectively with a significant sharp increase from 2003 to 2006 (ß = 1.78 (DID), P value < 0.001). Medications that constituted 70% of annual opioid analgesics utilization were morphine in 2000, compared to tramadol in 2018. The annual weak and strong opioids share were 86.7% and 13.2% in 2018, respectively.

CONCLUSION

Despite considerable growth in the consumption of opioid analgesics in Iran over nearly two decades, the consumption amount remained low, which might signal sub-optimal pain management. On the other hand, misuse and abuse seem to be the main reason behind significant increases in the consumption of opioid analgesics with less controlled distribution.

Estimation of adverse drug reaction reporting in Iran: Correction for underreporting

PROPOSE

Underreporting of Adverse Drug Reactions (ADRs) reduces the sensitivity of pharmacovigilance systems. We described ADR reporting and its trend from 1999 to 2017 and estimated the ADR underreporting in the Iranian Pharmacovigilance Center.

METHODS

We expressed the number of ADR reporting per inhabitants and admissions and their possible trends. Finally, ADR underreporting percentages were estimated by three approaches: prospective studies, literature review, stratification of the country; and the trend of the proportion of ADR per inhabitants was corrected.

RESULTS

The proportion of ADR reporting was 15.3 per 100 000 inhabitants (95% CI: 15.2, 15.8) and 10.0 per 100 000 admissions (95% CI: 9.8, 10.2) in 2017, and its trend was increasing with 16.3% average change per annum during 19 years. The median of estimated percentages of underreporting was 76.0% (IQR: 64.32-81.35). After the correction, the mean proportion of ADR reporting for 19 years reached from 5.87 to 10.33 per 100 000 inhabitants.

CONCLUSIONS

The trend of ADRs reporting has been increasing over the 19 years but is still low. This study showed a considerable underreporting of ADR, and about one of four detected ADRs were reported to the pharmacovigilance center from 1999 to 2017.

Dynamic Distribution and Postmortem Redistribution of Tramadol in Poisoned Rats

In the past dozen years, the cases of tramadol intoxication have become frequent in many countries. Most previous studies focused on tramadol's pharmacology, such as pharmacokinetics, pharmacodynamics and pharmacogenetics. However, the dynamic distribution and postmortem redistribution (PMR) of tramadol remain unclear. Our study aimed to investigate these two issues systematically in various specimens of 216 poisoned male rats. A validated gas chromatography-mass spectrometry method was used in this study to measure the concentrations of tramadol. In the first part, 66 tramadol poisoned rats were sacrificed at 11 different time points and their organs were collected separately for the study of tramadol's dynamic distribution, which made it feasible to investigate its PMR later on. The results of this part showed that tramadol's concentrations varied according to the organ and time, and peaked 2 h after intragastric administration in the specimens of liver, kidney, spleen, lung, brain and heart-blood (except stomach and heart). Based on the results of the first part, the concentration of tramadol peaked 2 h in most tissues. Therefore, this time point was used for the study of tramadol's PMR. In the second part, the remaining 150 rats were sacrificed 2 h after intragastric administration of tramadol, and the carcasses were stored under three different conditions (-20, 4 and 20°C). The autopsy was carried out at eight different time points and their organs were collected separately. The results of this part showed that under storage temperatures of -20 and 4°C, the concentrations of tramadol in individual organs showed no significant changes at different time points whereas under a storage temperature of 20°C, the concentrations in certain organs (liver, kidney, spleen, lung, brain and heart-blood) increased significantly at the last few time points. PMR of tramadol was therefore confirmed. The process of PMR of tramadol could be slowed or stopped at lower storage temperatures (-20 or 4°C), which is significant in cases of suspected tramadol poisoning.

Moyamoya Syndrome Presenting as Refractory Status Epilepticus in a 32-Year-Old Female

Moyamoya disease (MMD) is a rare cerebrovascular occlusion condition characterized by ‎progressive stenosis in the terminal portion of the internal carotid arteries on both sides. The measured incidence of MMD is 0.086 per 100,000 people. MMD has variable ‎neurological manifestations, however, seizure is a significant manifestation of MMD with ‎few reported studies. The combination of sickle cell disease (SCD) and MMD confers a much ‎higher risk of ischemic stroke. In this paper, we describe a 32-year-old female with a known ‎case of SCD taking tramadol for a vaso-occlusive crisis, who was presented to the emergency ‎department by a family member due to a low level of consciousness. Despite ongoing ‎management, the patient developed multiple seizure attacks and intubation was ‎performed. A computed tomography (CT) brain angiogram was performed, and the ‎diagnosis of MMD was made. The patient was shifted to the intensive care unit (ICU) and in spite of the ongoing management in the ICU, the patient died. In this case, we highlight the importance of considering MMD as a ‎differential diagnosis when dealing with an SCD patient who developed refractory status epilepticus.‎

Tramadol use and public health consequences in Iran: a systematic review and meta-analysis

BACKGROUND AND AIMS

Misuse of tramadol, an opioid prescription analgesic, is known as a public health challenge globally. We aimed to systematically review studies on the prevalence of non-prescribed use, regular tramadol use and dependence, tramadol-induced poisoning and mortality in Iran.

METHODS

Consistent with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, international (Medline, Scopus, Web of Science) and Persian (SID) databases were systematically searched up to June 2019. Other relevant data were collected through personal contacts and review of reference lists. Pooled estimates of prevalence of tramadol use in subgroups of males and females, percentage of tramadol poisoning among admitted poisoning cases, tramadol-associated seizures and mortality among tramadol poisonings and percentage of tramadol as a cause of death among fatal drug-poisoning records were estimated through a random-effects model.

RESULTS

A total of 84 records were included. Pooled estimates of last 12-month use of tramadol in the Iranian general population were 4.9% [95% confidence interval (CI) = 4.1-5.9] and 0.8% (95% CI = 0.2-1.8) among males and females, respectively. The estimates for last 12-month use among Iranian male and female university students were 4.8% (95% CI = 1.9-8.9) and 0.7% (95% CI = 0.3-1.1), respectively. Six heterogeneous reports indicated the existence of regular use of tramadol and dependence in Iran. Sixty-two studies provided data on tramadol-induced poisoning, seizures and mortality. The pooled estimate of the percentage of tramadol poisoning among all drug-poisoning patients was 13.1% (95% CI = 5.7-22.9). The overall estimates of seizures and mortality among tramadol-poisoning patients were 34.6% (95% CI = 29.6-39.8) and 0.7% (95% CI = 0.0-1.9), respectively. The pooled percentage of tramadol-related fatalities among drug-poisoned cases was 5.7% (95% CI = 0.5-15.4).

CONCLUSION

Despite control policies, tramadol use is as prevalent as the use of illicit opioids in Iran. Numerous cases of tramadol abuse, dependence, poisonings, seizures and hundreds of tramadol-related deaths have been reported in recent years.

Tramadol and the occurrence of seizures: a systematic review and meta-analysis

Introduction: Tramadol is a synthetic opioid which is commonly used around the world to relieve moderate to severe pain. One of the serious possible complications of its use is seizures. The present study aims to investigate and summarize the studies related to tramadol and occurrences of seizures after tramadol use and factors influencing these seizures.Methodology: Our systematic review is compliant with PRISMA guidelines. Two researchers systematically searched PubMed/Medline, Web of Sciences, and Scopus. Cohort, case-control, cross-sectional studies, and clinical trials. The risk of bias was assessed using the Newcastle-Ottawa Scale After article quality assessment, a fixed or random model, as appropriate, was used to pool the results in a meta-analysis. Heterogeneity between the studies was assessed with using I-square and Q-test. Forest plots demonstrating the point and pooled estimates were drawn.Results: A total of 51 articles with total sample size of 101 770 patients were included. The results showed that seizure event rate in the subgroups of tramadol poisoning, therapeutic dosage of tramadol, and tramadol abusers was 38% (95% CI: 27-49%), 3% (95% CI: 2-3%), 37% (95% CI: 12-62%), respectively. Tramadol dose was significantly higher in the patients with seizures than those without (mean differences: 0.82, CI 95%: 0.17-1.46). The odds for occurrence of seizures were significantly associated with male gender (pooled OR: 2.24, CI 95%: 1.80-2.77). Naloxone administration was not associated to the occurrence of seizures (pooled OR: 0.47, 95% CI: 0.15-1.49).Conclusions: Our results demonstrate that the occurrence of seizures in patients exposed to tramadol are dose-dependent and related to male gender, but not related to naloxone administration. Given that, most of the evidence derives from studies utilizing a cross-sectional design, the association of tramadol with seizures should not be considered to be definitively established.

Caffeine attenuates seizure and brain mitochondrial disruption induced by Tramadol: the role of adenosinergic pathway

Tramadol (TR) is an analgesic drug used to treat moderate-to-severe pain but it induces seizure even at therapeutic doses. The exact mechanism of TR-inducing seizure is not clear but inhibition of the serotonin, GABA, and nitrous oxide (NOS) pathways are the commonly proposed mechanisms. Adenosinergic system has a crucial function in the modulation of seizure. Also, oxidative damage is an unavoidable effect of the seizure. This study was conducted to evaluate the role of the adenosinergic system on the seizure and oxidative stress biomarkers induced by TR using antagonist of the adenosinergic receptors in the Albino mice. For that purpose, generated clonic seizure, as seizure threshold, was evaluated by TR. Caffeine (CAF; 8 mg/kg, i.p.), a nonselective antagonist of adenosine receptors, was administered 1 hour before the seizure induction. The seizure threshold significantly increased by CAF-treated group when compared to TR group (p < 0.001). Oxidative stress biomarkers such as reactive oxygen species, protein carbonyl content, and lipid peroxidation significantly decreased and glutathione content significantly increased by CAF in brain mitochondria compared to the TR group, whereas oxidative biomarkers significantly increased in the TR group compared to the control group. The results of the present study suggested that the adenosinergic system is involved in seizure induced by TR and meanwhile, inhibition of adenosine receptors can decrease the TR seizure threshold and also decrease the induced oxidative damage in the brain mitochondria.

Detection and quantification of the opioid tramadol in urine using surface enhanced Raman scattering

There is an on going requirement for the detection and quantification of illicit substances. This is in particular the case for law enforcement where portable screening methods are needed and there has been recent interest in breath tests for a range of narcotics. In this study we first developed surface enhanced Raman scattering (SERS) for the detection of tramadol in water and establish robust and reproducible methods based on silver hydroxylamine colloid. We used 0.5 M NaCl as the aggregating agent, with the pH ∼ 7.0 and SERS data were collected immediately (i.e., the analyte association and colloid aggregation times were zero). The limit of detection was rather high and calculated to be 5 × 10(-4) M which would not be practical in the field. Undeterred we continued with spiking tramadol in artificial urine and found that no aggregating agent or modification of pH was necessary. Indeed aggregation occurred spontaneously due to the complexity of the medium which is rich in multiple salts, which are commonly used for SERS. We estimated the limit of detection in artificial urine to be 2.5 × 10(-6) M which is equivalent to 657.5 ng mL(-1) and very close to the levels typically found in individuals who use tramadol for pain relief. We believe this opens up opportunities for testing SERS in real world samples and this will be an area of future study.

Recurrent seizures in tramadol intoxication: implications for therapy based on 100 patients

Tramadol is an atypical opioid analgesic used in the treatment of mild to moderate pain. Despite being a GABA(A) agonist, seizures are a prominent complication with its therapeutic use, abuse or overdose. For patients who have had a tramadol-induced seizure, the likelihood of recurrent seizures and the need for emergent anticonvulsant prophylaxis is unknown. However, treatment of patients with anticonvulsants prophylactically may cause adverse effects and increased morbidity in tramadol poisoning. We studied the outcome and frequency of recurrent seizures in tramadol-intoxicated patients in an attempt to determine the need for prophylactic anticonvulsant therapy. This was a retrospective cohort study of tramadol-intoxicated patients who had at least one seizure. Patients' age, sex, cause(s) of intoxication, route of poisoning, dose or number of capsules or tablets taken, vital signs, other signs or symptoms, numbers of seizures, length of stay, co-ingestions and past medical history were ascertained. Exactly 100 patients met the inclusion criteria. Eighty-two per cent were men, and 50% were between 21 and 30 years old. By our standard clinical protocol, none were treated with seizure prophylaxis after their first seizure. Only 7% had recurrent seizures and all patients recovered without sequelae. Because of the low risk of multiple seizures in tramadol poisoning and the lack of morbidity in patients who do seize, it appears to be unnecessary to administer prophylactic anticonvulsant therapy in patients with tramadol poisoning, even if they have an initial seizure.

Factors related to seizure in tramadol poisoning and its blood concentration

This study examines the relation between seizure and plasma tramadol concentration in patients with tramadol poisoning, as a novel centrally acting analgesic used for the treatment of mild to severe pain. All patients admitted with a history of tramadol overdose accompanied by unconsciousness or seizures referred to Baharloo Hospital Poison Center, Tehran, Iran from March 2008 to March 2009 were included. Demographic information, clinical findings, and blood tramadol concentrations were studied. There were 401 patients with a history of tramadol overdose; 121 (30.2%) with a history of seizure and 14 (3.5%) with a history of unconsciousness were included. Most of overdoses involved men (83%). The mean age was 22.9 years (range, 14-50 years). Intentional overdose was the most common mode of poisoning (51.9%). The mean dose ingested was 1,511 mg (SD, 1,353; range, 200-7,000). Mean back-extrapolated tramadol blood concentrations were 3,843 ng/mL (3,715; 269-20,049). Back-extrapolated blood concentrations were correlated with dose (r = 0.313; P < 0.001) as well as blood concentration levels (r = 0.801; P < 0.001). Seizure was significantly correlated to higher reported dose (P < 0.001) and tramadol only to overdose (P < 0.001). However, it was neither related to higher tramadol blood concentrations, nor related to time elapsed, age, sex, history of addiction, and observed Glasgow Coma Scale of patients. Most patients experienced just one seizure (76%). The tramadol-induced seizure is dose dependent. Although higher doses of tramadol was related to higher blood concentration, blood tramadol concentrations was not associated with seizure.

Current trends in tramadol-related fatalities, Tehran, Iran 2005-2008

Tramadol is a widely prescribed drug. Abuse of tramadol as well as tramadol-related deaths have been increasing in Iran. The objective of the present study is to evaluate the trends of tramadol-related deaths that occurred between 2005 and 2008 in Tehran, Iran. Biological samples obtained during the autopsy were analyzed. Tramadol was detected in 294 cases by itself or together with other drugs. The majority of the cases were young male adults. Tramadol-related deaths in 2008 were 32.5 times more than in 2005. These results suggest that tramadol-related fatalities are growing in Iran especially among substance abusers.

Dose-independent occurrence of seizure with tramadol

INTRODUCTION

Tramadol, as a centrally-acting, opioid-like analgesic with serotonin reuptake inhibition property, is one of the most prescribed analgesics in the world. We assessed the incidence of seizure, as it is one of the most important adverse effects.

METHODS

In a cross-sectional study, 215 cases of tramadol users or abusers who were admitted to Loghman-Hakim Hospital Poisoning Center (LHHPC) in Tehran during a 5-month period, from April 2007 to September 2007, were assessed to evaluate the occurrence of seizure. Patients with positive history of co-ingestion of other drugs, addiction, convulsive disorders, renal diseases, or head trauma with abnormal electroencephalography (EEG) or computerized tomography (CT) scan of the brain were excluded, thus 132 patients were included in the study. For patients who had seizure, CT scan of the brain and EEG were performed, and frequency and type of seizure were identified. Mean tramadol dose was compared between patients with and without seizure.

RESULTS

Among the patients, 97 (73.5%) were male. Seizure occurred in 61 patients (46.2%) within 24 hours after tramadol ingestion. The majority of patients who had seizure were male (male, 83.6% vs. female, 16.4%). Mean tramadol dose was lower among females than males (males, 2413 mg vs. females, 1706 mg), but the difference was not statistically significant. Of 35 patients with documented seizure type, all showed generalized tonic-clonic seizure and 12 patients had abnormal EEG (35.3%). No statistically significant difference was observed in mean tramadol intake between patients with or without seizure. Analysis of patients with seizure, according to tramadol intake, indicated that most patients used tramadol in the dose range of 500-1000 mg followed in occurrence by 1500-2000 mg, then 100-500 mg, 2500-3000 mg, and 3500-4000 mg.

CONCLUSIONS

Mean tramadol intake does not differ between patients with and without seizure, and the most common dose range in those with seizure is 500-1000 mg. We thus conclude that the incidence of seizure with tramadol is not dose dependent.

Tramadol intoxication: a review of 114 cases

Tramadol as a centrally acting analgesic is extensively used in the management of moderate to severe pain. It slightly affects opioid receptors and inhibits the reuptake of norepinephrin and serotonin in the CNS. There are reports about toxicity and abuse of tramadol. The objective of the present study was to evaluate epidemiology of intentional tramadol intoxications. All poisoning cases that admitted to Loghman-Hakim Hospital Poison Center from April to May 2007 were studied. A total of 114 cases (82 men and 32 women) of intentional tramadol intoxications with the median age of 23.66 +/- 6.87 years (range 16-54 years) were identified. Other illicit drugs were found to be used in combination with tramadol in some of the cases, which among them benzodiazepines were the most common. Tramadol overdose has been one of the most frequent causes of drug poisoning in the country in the recent years, especially in male young adults with history of substance abuse and mental disorders. Nausea, vomiting, Central Nervous System (CNS) depression, tachycardia, and seizure are the most common findings in this kind of poisoning. Cardiopulmonary arrest was found as the cause of death in cases who had ingested more than 5000 mg tramadol.

Developing an adverse drug reaction reporting system at a teaching hospital

Adverse drug reactions (ADRs) are a frequent cause for hospitalization and occur often in hospitalized patients. The objective of this study was to establish an ADR reporting and monitoring system at a teaching hospital. The pharmacovigilance unit of Masih Daneshvari hospital was established by a clinical pharmacist and a clinical pharmacologist. Healthcare professionals were encouraged to report any suspected ADRs encountered in in-patients. The incidence, pattern, seriousness, severity and preventability of the reported ADRs were analysed. During the period of 12 months, for 6840 patients, 112 spontaneous reports were received. The most frequently reported reactions were due to anti-infective agents (58.2%). Ceftriaxone accounted for the highest number of the reported ADRs among anti-infective agents. The skin and appendages system was the most frequently affected system (32.5% of all reactions). Seventeen per cent of the ADRs were reported as serious reactions. Although the incidence of ADRs reported by physicians and nurses was found to be low, this programme was useful as a preliminary programme in initiating a culture of ADR reporting among healthcare professionals. Improved communication between the physicians and nurses with the pharmacovigilance centre in the hospital is suggested.

Applying quantitative methods for detecting new drug safety signals in pharmacovigilance national database

OBJECTIVES

To applies three different methods of signal detection to the registered adverse events in Iranian Pharmacovigilance database over the period of 1998-2005.

METHODS

All adverse drug reactions (ADRs) reported to Iranian Pharmacovigilance Center (IPC) from March 1998 through January 2005, were used for the analysis. The data were analysed based on three different signal detection methods including reporting odds ratios (RORs), information component (IC) and proportional reporting ratios (PRRs). The signals detected were categorised based on the number of reports per drug-adverse event combination, severity of the event and labelled or unlabelled ADRs.

RESULTS

During the study period, 6353 cases of ADR reports describing 11 130 reactions were received by IPC. The dataset involved 4975 drug-adverse event combinations. The count of drug-event combinations was 1, 2 and 3 or more for 3470, 726 and 779 combinations, respectively. According to PRRs, there were 2838, 872 and 488 drug-event combinations known as a signal for the pairs with the reporting frequency of 1, 2 and 3 reports, respectively. The results of estimating RORs showed that 2722, 862 and 481 drug-adverse event combinations were detected to be signal for the pairs with the reporting frequency of 1, 2 and 3 reports, respectively, while measuring IC and IC-2SD detected 1120, 378 and 235 for the same reporting frequencies. Diclofenac-induced paralysis and tramadol-induced severe reactions were the most important signals.

CONCLUSION

Applying quantitative signal detection methods to the database of national pharmacovigilance centres is necessary to early detection of drug safety alerts.