Intramuscular tramadol increases gastric pH during anesthesia

Tramadol poisoning and its management and complications: a scoping review

Tramadol (TR) is an opioid agonist (μ-opioid receptors) that also affects the noradrenergic and serotonergic systems. TR is a synthetic analgesic substance with opioid agonist properties that has been approved for pain management by affecting the central nervous system.

OBJECTIVE

The primary objective of this scoping review was to determine the poisoning consequences of TR and its associated symptom management techniques, as well as its effect on opioid and non-opioid receptors, metabolism, and complications on various organ systems.

DISCUSSION

Typically, acute overdose of TR is not considered life threatening, and most fatalities are attributed to polysubstance overdose. TR can cause drowsiness, headaches, seizures, respiratory depression, low heart rate, coma, and even death. Additionally, the prolonged use of TR can lead to addiction, with withdrawal resulting in both common and atypical symptoms.

CONCLUSIONS

Therefore, it is recommended that patients with TR poisoning receive close monitoring of their cardiovascular system, along with a comprehensive management plan for their levels of consciousness and respiratory function.

ADME and toxicity considerations for tramadol: from basic research to clinical implications

INTRODUCTION

Tramadol is widely being used in chronic pain management for improving patients' life quality and reducing trauma. Although it is listed in several medicinal guidelines, its use is controversial because of the conflicting results obtained in pharmacokinetic/pharmacodynamic studies. This multi-receptor drug acts as µ₁ opioid receptor agonist, monoamine reuptake inhibitor, and inhibitor of ligand-gated ion channels and some special protein-coupled receptors.

AREAS COVERED

This review provides a comprehensive view on the pharmacokinetic, pharmacodynamic, and toxicity of tramadol with a deep look on its side effects, biochemical and pathological changes, and possible drug interactions. In addition, the main ways of tramadol poisoning management describe according to in vivo and clinical trial studies.

EXPERT OPINION

Given the broad spectrum of targets, increasing the cases of overdoses and toxicity, and probable drugs interaction, it is necessary to take another look at the pharmacology of tramadol. Regarding the adverse effects of tramadol on different tissues, especially the nervous system and liver tissue, more attentions to tramadol metabolites, their interaction with other drugs, and active agents seem critical. Seizure as the most cited effect of tramadol and its destructive effects on tissues would alleviate by co-administration with drugs with antioxidant properties.

Safety and efficacy of reduced dosage ketoprofen with or without tramadol for long-term treatment of osteoarthritis in dogs: a randomized clinical trial

BACKGROUND

This study aimed to evaluate the safety and efficacy of reduced-dosage ketoprofen with or without tramadol in dogs. Five healthy dogs receiving standard-dosage ketoprofen (2 mg/kg SC, then 1 mg/kg PO daily) comprised Group A. Twenty dogs with osteoarthritis were randomized to receive reduced-dosage ketoprofen (0.5 mg/kg SC once; 0.25 mg/kg PO daily) alone (Group B) or in combination with tramadol (5 mg/kg/day PO) (Group C). Treatments were administered for 28 days. Platelet aggregation time (PAT), gastrointestinal (GI) endoscopy and glomerular filtration rate (GFR) were performed up to 60 days after treatment initiation. Pain was scored using a validated clinical metrology instrument up to D120. Data were analyzed with general linear mixed model for repeated measures (α = 0.05).

RESULTS

PAT was not different between groups but was increased with time for all groups. GI lesion scores were higher in Group A than Groups B and C (day 28; P = 0.005) and were increased with time for Group A (P = 0.005). GFR was lower in Group A than Groups B and C (day 28; P < 0.01) and were decreased with time for group A (P < 0.001). Standard-dosage ketoprofen administration resulted in clinically relevant adverse effects. Pain score decreased in both treated groups (B and C) from D0 to D28. Need of rescue analgesia from D29 to D120 was higher in Group B than in Group C (P = 0.039).

CONCLUSIONS

The long-term safety profile of reduced-dosage ketoprofen is similar whether the drug is administered alone or in combination with tramadol to dogs with osteoarthritis. Analgesic efficacy of the combination looks attractive.

An overview of tramadol and its usage in pain management and future perspective

Patients with chronic non-malignant pain report impairment of physical and social life along with psychological state affecting their overall quality of life. The purpose of managing pain is to reduce the trauma and improve the patient comfort with better quality of life. Tramadol is a centrally acting weak μ-opioid receptor analgesic and is a racemic mixture of (+)-tramadol and (-)-tramadol enantiomers. Tramadol is used worldwide and is listed in many medical guidelines for pain management. The (+)-tramadol has greater affinity for μ-opioid receptor and provides additional prevention of 5- hydroxy tryptamine reuptake, while the (-)-tramadol is a successful noradrenaline reuptake inhibitor and intensifies its release by activating the auto receptor. Tramadol is prescribed to relieve moderate to severe pain management in patients. Tramadol does not show much serious adverse effects without any dependency potential in therapeutic doses as seen in other opioids, like morphine. Tramadol metabolite M1 also has μ-opioid receptor agonist activity, but it faces poor blood brain barrier permeability. In this review, we report the complete updated status of Tramadol along with its chemistry, synthesis, pharmacology, medicinal uses, adverse effects and its combinations available in the market. We have also covered Tramadol patents so that a complete overview provides a broader perspective for future designing of its derivatives and increase their potential use for pain management in terminal cancer patients.

Gastroscopic Study of Meloxicam, Tramadol, and Their Combined Administration on the Development of Gastric Injuries in Dogs

Opioid and non-steroid anti-inflammatory drugs (NSAIDs) are commonly used to manage post-operative pain that may be chronically extended. Although NSAIDs have been approved for their analgesic effects in canine, they are mostly known to be associated with side effects, particularly gastric ulcers. In the present study, we evaluated short-term co-administration of meloxicam and tramadol to see if this could induce more gastric ulcers than that observed when using these drugs individually. Twenty adult mixed domestic dogs weighing 10 to 20 kg of both sexes, were randomly assigned to four groups of five dogs. In the control group, placebo was administered orally (twice a day), whereas the test groups received tramadol (per OS) twice a day, meloxicam (per OS) daily, and a combination of tramadol (twice a day) and meloxicam (daily) for ten days, respectively. The animals were evaluated for gastric injuries on days 0, 6, 11, 16 and 21 by endoscopy under general anesthesia. Clinical signs of all animals including fecal consistency, appetite, mental and hydration statuses, tempreture, heart rate and respiratory rate were evaluated daily. Based on our results, there was no significant difference between the experimental and control groups. In conclusion, our study demonstrated that a 10-day oral coadministration of tramadol and meloxicam had no deleterious effects on general health status and gastric mucosa in dogs.

Impact of tramadol and morphine abuse on the activities of acetylcholine esterase, Na+/K+-ATPase and related parameters in cerebral cortices of male adult rats

Objective

To determine the effect of the most commonly abused drugs (tramadol and morphine), on acetylcholine esterase (AChE), Na⁺/K⁺-ATPase activities and related parameters, Na⁺ and K⁺ as biomarkers of neurotoxicity.

Methods

Tramadol - as a weak μ opioid receptor agonist- and morphine - as opiate analgesic drugs, were chosen for the present study. Four series of experimental animals were conducted for either tramadol or morphine: control series; repeated single equal doses (therapeutic dose) series; cumulative increasing doses series and delay (withdrawal) series (96 hours withdrawal period after last administration), at time period intervals 7, 14 and 21 days. Acetylcholine esterase (AChE), Na⁺/K⁺-ATPase activities and related parameters, Na⁺ and K⁺ were measured in cerebral cortices of experimental rats.

Results

Acetylcholine esterase (AChE) activity in the brain cerebral cortex increased after the administration of therapeutic repeated doses of either tramadol (20 mg/kg b.w.) or morphine (4 mg/kg b.w.) in different groups. The daily intraperitoneal injection of cumulative increasing dose levels of either tramadol 20, 40 and 80 mg/kg or morphine 4, 8 and 12 mg/kg revealed a significant increase in the mean of acetylcholine esterase activities. The withdrawal groups of either tramadol or morphine showed significant decreases in their levels. Na⁺/K⁺ ATPase activity in the brain cerebral cortex of either repeated therapeutic doses of tramadol (20 mg/kg) or morphine repeated therapeutic doses (4 mg/kg) for 21 consecutive days at different intervals 7, 14 and 21 days, induced a significant decrease in the levels of Na⁺/K⁺-ATPase in all groups. Withdrawal groups showed a significant decrease in Na⁺/K⁺-ATPase level. Furthermore, the daily intraperitoneal injection of cumulative increasing dose levels of either tramadol (20, 40 and 80 mg/kg b.w.) or morphine (4, 8 and 12 mg/kg b.w.) induced significant decreases in Na⁺/K⁺-ATPase levels in all studied groups. Regarding Na⁺ and K⁺, concentrations of either repeated therapeutic doses or cumulative increasing doses at different time intervals, showed different fluctuations in their levels.

Conclusion

The recorded data suggest that both drugs exert potent effects on AChE and Na⁺/K⁺-ATPase activities which could contribute to cerebral cortex malfunction including, memory deficits and the decline in cognitive function observed in chronic users.

Effects of varying doses of tramadol on gastric pH

Background:

Tramadol is licensed primarily as an analgesic, but has additional properties, one of which is the ability to increase gastric pH. However, it has not been established if this action is dose related, hence we set out to provide further evidence about this action of tramadol.

Patients and Methods:

Fifty-five female adult patients presenting for gynecological surgery were randomized into three groups. After induction, 2.5 ml of gastric juice was aspirated to determine baseline pH, after which groups 1, 2, and 3 received 50 mg, 75 mg, and 100 mg of IV tramadol, respectively. Gastric pH was subsequently assessed every 30 min for as long as the surgery lasted.

Results:

There was no significant difference in the pH of the three groups before anesthesia (3.88 ± 0.75, 3.54 ± 0.73, and 3.75 ± 0.70; P = 0.393). Similarly, no significant statistical difference was observed in the pH of the three tramadol groups during the subsequent three readings (pH1: 4.21 ± 0.93, 4.27 ± 0.95, 4.07 ± 0.82; pH2: 4.75 ± 1.00, 4.68 ± 0.94, 4.59 ± 0.78; pH3: 5.33 ± 0.86, 5.13 ± 0.95, 4.97 ± 0.78; P = 0.793, 0.876, and 0.490). There were statistically significant increases in the pH of each group when the baseline pH was compared with the subsequent three readings, with P values of 0.002, 0.0001, 0.001 in the 50 mg group, 0.0001, 0.0001, 0.0001 in the 75 mg group, and 0.008, 0.0001, 0.001 in the 100 mg group.

Conclusion:

Our result further confirms that tramadol elevates gastric pH. However, the degree of elevation was not found to be dose dependent.

Effect of single oral dose of tramadol on gastric secretions pH

Background:

Tramadol is an atypical analgesic agent. It has been shown that intramuscular or intravenous injection tramadol is able to inhibit M3 muscarinic receptors. Tramadol is able to mediate smooth muscles contraction and glandular secretions. We have evaluated the effects of single oral dose of tramadol given preoperatively on gastric juices pH in patients electively scheduled for laparoscopic cholecystectomy.

Materials and Methods:

Sixty adult, American Society of Anesthesiologist I and II patients scheduled for laparoscopic cholecystectomy were included in the study. Patients were randomly assigned to receive either placebo (n = 30) or oral tramadol 50 mg (n = 30). General anesthesia was induced using propofol, fentanyl and cisatracurium. After induction of anesthesia 5 ml of gastric fluid was aspirated through orogastric tube. The gastric fluid pH was measured using pH meter.

Result:

There was no significant difference in the pH between the groups. Gastric pH of the placebo and tramadol groups was 1.97 versus 1.98 (P = 0.092) respectively.

Conclusion:

Preoperatively single oral dose of tramadol was unable to elevate the desired level of gastric acid secretions pH (>2.5). This may be due to pharmacokinetic disparity between the analgesic and pH elevating properties of tramadol.

The recent progress in research on effects of anesthetics and analgesics on G protein-coupled receptors

The exact mechanisms of action behind anesthetics and analgesics are still unclear. Much attention was focused on ion channels in the central nervous system as targets for anesthetics and analgesics in the 1980s. During the 1990s, major advances were made in our understanding of the physiology and pharmacology of G protein coupled receptor (GPCR) signaling. Thus, several lines of studies have shown that G protein coupled receptors (GPCRs) are one of the targets for anesthetics and analgesics and especially, that some of them inhibit the functions of GPCRs, i.e,, muscarinic receptors and substance P receptors. However, these studies had been focused on only G(q) coupled receptors. There has been little work on G(s)- and G(i)-coupled receptors. In the last decade, a new assay system, using chimera G(i/o)-coupled receptor fused to Gq(i5), has been established and the effects of anesthetics and analgesics on the function of G(i)-coupled receptors is now more easily studied. This review highlights the recent progress of the studies regarding the effects of anesthetics and analgesics on GPCRs.

Pharmacological aspects of the effects of tramadol on G-protein coupled receptors

Tramadol is an analgesic that is used worldwide, but its mechanisms of action have not been elucidated. It has been speculated that tramadol acts primarily through the activation of micro-opioid receptors and the inhibition of monoamine reuptake. The majority of studies to date have focused on ion channels in the central nervous system as targets of anesthetics and analgesics. During the past decade, major advances have been made in our understanding of the physiology and pharmacology of G-protein coupled receptor (GPCR) signaling. Several studies have shown that GPCRs and ion channels are targets for analgesics and anesthetics. In particular, tramadol has been shown to affect GPCRs, including muscarinic acetylcholine receptors and 5-hydroxytryptamine receptors. Here, the effects of tramadol on monoamine transporters, GPCRs, and ion channels are presented, and recent research on the pharmacology of tramadol is discussed.

Analgesic and antacid properties of i.m. tramadol given before Caesarean section under general anaesthesia

BACKGROUND

Intramuscular (i.m.) tramadol increases gastric pH during anaesthesia similar to famotidine. We investigated the antacid analgesic value of a single dose of i.m. tramadol given 1 h before elective Caesarean section performed under general anaesthesia.

METHODS

Sixty ASA I parturients undergoing elective Caesarean section were included in a randomized double-blind study. The patients were randomly allocated to receive i.m. tramadol 100 mg (n=30) or famotidine 20 mg (n=30) 1 h before general anaesthesia.

RESULTS

At the beginning and the end of anaesthesia, patients receiving tramadol had a median gastric fluid pH of 6.4, which was not significantly different from those treated with famotidine (median 6.3). The infant well-being, as judged by Apgar score, cord blood gas analysis, and neurobehavioural assessment showed no significant difference between the two groups. Nalbuphine consumption in the first 24 h after operation was reduced by 35% in the tramadol group. Pain intensity score on sitting and sedation were significantly greater in famotidine group up to 24 h after surgery. There was no significant difference in incidence and severity of nausea and vomiting between the two groups.

CONCLUSION

A single i.m. dose of tramadol is useful pre-treatment to minimize the risk of acid aspiration during operation, and in improving pain relief during 24 h after surgery.