Optimisation of the dosage of tranexamic acid in trauma patients with population pharmacokinetic analysis

Anti-inflammatory effect of multi-dose tranexamic acid in hip and knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Tranexamic acid (TXA) is considered a potential therapeutic approach to mitigate postoperative inflammatory responses; however, its anti-inflammatory effects remain controversial. This study conducts a systematic review and meta-analysis of randomized controlled trials aiming to investigate the efficacy of multi-dose TXA in exerting anti-inflammatory effects in hip and knee arthroplasty.

METHODS

We identified potential relevant literature evaluating the anti-inflammatory effects of TXA in patients undergoing hip and knee arthroplasty from PubMed, Embase, and the Cochrane Library. Meta-analysis was performed using RevMan 5.3.

RESULTS

Nine randomized controlled studies met the inclusion criteria. Meta-analysis results indicated that, compared with lower doses of TXA, multi-dose TXA significantly reduced the inflammatory markers IL-6 and CRP in patients undergoing hip and knee arthroplasty and shortened the length of hospital stay, with statistically significant results. Nonsignificant differences were found in the incidence of thromboembolic events.

CONCLUSION

Based on the current evidence, our results indicate that multi-dose TXA effectively reduces postoperative inflammatory responses in patients undergoing hip and knee arthroplasty. This anti-inflammatory effect is dose-dependent and is accompanied by a reduction in the length of hospital stay. Nonetheless, further high-quality, multicenter, large-sample-size randomized controlled trials are needed to confirm the anti-inflammatory effects of TXA.

Cost of the Defence Medical Services Patient Group Directive for a 10-minute tranexamic acid (TXA) infusion in trauma: a bolus is safe and saves lives

Tranexamic acid (TXA) is a life-saving drug that reduces the risk of death from haemorrhage. Intervention is time critical with benefit decreasing with delayed administration. The current Joint Service Publication Patient Group Directive (PGD) for giving TXA during the tactical field care phase of the operational patient care pathway specifies it is given over 10 min via intravenous infusion based on TXA's Summary of Product Characteristics. This paper aims to explore the risks of administering TXA as a bolus rather than a 10-minute infusion. There is little evidence to support the risk of quoted adverse events from bolus administration of TXA, good-quality evidence for the mortality benefit of early administration and some evidence that bolus dosing is safe. The Defence Medical Service should consider a default PGD of rapid TXA administration to maximise mortality benefit.

Association of single bolus versus bolus followed by infusion of tranexamic acid with blood loss in adolescent idiopathic scoliosis surgery

BACKGROUND

Adolescent idiopathic scoliosis (AIS) corrective surgery may involve significant blood loss and blood transfusion requirements. Antifibrinolytic agents such as tranexamic acid (TXA) have been used to reduce blood loss, but its optimal dose is uncertain. The objective of this study is to determine the estimated blood loss and rate of blood transfusion between two groups of AIS patients receiving TXA as a single bolus versus bolus followed by infusion in scoliosis surgery.

METHODS

This was a retrospective analysis of a single bolus versus bolus followed by infusion of TXA in AIS surgery. AIS patients undergoing posterior spinal fusion (PSF) from December 2018 to September 2019 at a tertiary university hospital were identified. Inclusion criteria were patients aged between 10 and 21 years who received either a single bolus of 30 mg/kg TXA (Group A) or a single bolus of 30 mg/kg followed by continuous infusion of 10 mg/kg/h of TXA (Group B). Patient demographics, operative data, estimated blood loss, blood transfusion rate, and complications were recorded.

RESULTS

A total of 129 AIS patients were included. All operative surgeries were performed by two senior consultants. The mean age was 14.8 ± 3.4 years old, and 89.1% were female. The Cobb angle, number of fusion levels, number of screws, length of skin incision, and duration of surgery were comparable between the two groups. There was no difference in the total estimated blood loss between the two groups: 723.3 ± 279.4 mL (range: 175.0-1607.0 mL) in Group A and 819.4 ± 302.6 mL (range: 330.0-1556.0 mL) in Group B (p = 0.065). There were no complications, and none received blood transfusion.

CONCLUSION

TXA when administered as a single bolus or bolus followed by infusion in AIS patients undergoing PSF surgery was associated with similar estimated total surgical blood loss and blood transfusion requirement.

Population pharmacokinetic modelling and simulation of tranexamic acid in adult trauma patients

AIMS

The aim of this study is to describe the disposition of tranexamic acid (TXA) in adult trauma patients and derive a dosing regimen that optimizes exposure based on a predefined exposure target.

METHODS

We performed a population pharmacokinetic (popPK) analysis of participants enrolled in the Tranexamic Acid Mechanisms and Pharmacokinetics in Traumatic Injury (TAMPITI) trial (≥18 years with traumatic injury, given ≥1 blood product and/or requiring immediate transfer to the operating room) who were randomized to a single dose of either 2 or 4 g of TXA ≤2 h from time of injury. PopPK analysis was conducted using nonlinear mixed-effects modelling (NONMEM). Simulations were then performed using the final model to generate estimated plasma TXA concentrations in 1000 simulated participants. Dosing schemes were evaluated to determine maintenance of TXA plasma concentrations >10 mg/L for ≥8 h after administration of the initial dose.

RESULTS

TXA PK was best described by a two-compartment model with proportional residual error and allometric scaling on all parameters. Platelet count, skeletal muscle oxygen saturation measured by near-infrared spectroscopy and interleukin-8 concentration were significant covariates on TXA clearance. Based on simulations, a 2 g IV bolus dose, repeated 3 h later, best achieved the target exposure.

CONCLUSIONS

According to simulations from a popPK model of TXA, a 2 g IV bolus with a repeated dose 3 h later would be most likely to maintain concentrations >10 mg/L for 8 h in >95% of adult trauma patients and should be considered for patients with ongoing haemorrhage.

Traumatic bleeding and mortality in mice are intensified by iron deficiency anemia and can be rescued with tranexamic acid

Background

Clinical evidence suggests that anemia exacerbates traumatic bleeding and worsens outcomes.

Objectives

To study the influence of iron deficiency anemia on traumatic bleeding, coagulopathy, and mortality.

Methods

C57BL/6J mice received an iron-deficient diet (8 weeks; ±1 mg intraperitoneal iron dextran 2 weeks before trauma). Control mice received a normal diet. Iron deficiency anemia was confirmed by hematocrit, red cell indices, and liver iron. Mice received saline or tranexamic acid (TXA; 10 mg/kg) just before liver laceration. Blood loss, coagulopathy (activated partial thromboplastin time, factor [F]II, FV, FVIII, FX, and fibrinogen), D-dimer, thrombin-antithrombin complexes, and plasmin-alpha-2-antiplasmin complexes were analyzed at 15 and 60 minutes, and a cytokine panel was performed at 60 minutes and 6 hours after trauma. Survival was monitored for 7 days.

Results

Compared with nonanemic mice, anemic mice had lower hematocrit and hepatic iron content. Anemic mice experienced higher blood loss compared with nonanemic mice, which was reduced by TXA. Both groups developed traumatic coagulopathy characterized by activated partial thromboplastin time prolongation, thrombin-antithrombin complex formation, and depletion of FV, FVIII, and fibrinogen. TXA corrected the coagulopathy. However, plasmin-alpha-2-antiplasmin complex formation and D-dimers, markers of fibrinolysis, were higher in anemic mice and were not corrected by TXA. Seven-day survival was low in anemic mice, and rescued by TXA, but high in nonanemic mice without additional improvement by TXA. Among cytokines, only interleukin-6 increased, which was prevented by TXA most notably in anemic mice.

Conclusion

These observations provide first and critical proof-of-principle evidence that anemia accelerates traumatic bleeding and increases mortality, which could be rescued by anemia correction (parenteral iron) or periprocedural TXA.

Hemostatic effects of tranexamic acid in cardiac surgical patients with antiplatelet therapy: a systematic review and meta-analysis

BACKGROUND

The purpose of the current study was to assess the efficacy of tranexamic acid (TXA) on reducing bleeding in cardiac surgical patients with preoperative antiplatelet therapy (APT).

METHODS

Five electronic databases were searched systematically for randomized-controlled trials (RCTs) assessing the impact of intravenous TXA on post-operative bleeding on cardiac surgical patients with preoperative APT until May 2024. Primary outcome of interest was post-operative blood loss. Secondary outcomes of interest included the incidence of reoperation due to post-operative bleeding, post-operative transfusion requirements of red blood cells (RBC), fresh-frozen plasma (FFP), and platelet concentrates. Mean difference (MD) with 95% confidence interval (CI) or odds ratios (OR) with 95% CI was employed to analyze the data. Subgroup and meta-regression analyses were performed to assess the possible influence of TXA administration on reducing bleeding and transfusion requirements.

RESULTS

A total of 12 RCTs with 3018 adult cardiac surgical patients (TXA group, 1510 patients; Control group, 1508 patients) were included. The current study demonstrated that TXA significantly reduced post-operative blood loss (MD =  - 0.38 L, 95% CI: - 0.73 to - 0.03, P = 0.03; MD =  - 0.26 L, 95% CI: - 0.28 to - 0.24, P < 0.00001; MD =  - 0.37 L, 95% CI: - 0.63 to - 0.10, P = 0.007) in patients receiving dual antiplatelet therapy (DAPT), aspirin, or clopidogrel, respectively. Patients in TXA group had significantly lower incidence of reoperation for bleeding as compared to those in Control group. The post-operative transfusion of RBC and FFP requirements was significantly lower in TXA group than Control group. Subgroup analyses showed that studies with DAPT discontinued on the day of surgery significantly increased the risk of post-operative blood loss [(MD: - 1.23 L; 95% CI: - 1.42 to - 1.04) vs. (MD: - 0.16 L; 95% CI: - 0.27 to - 0.05); P < 0.00001 for subgroup difference] and RBC transfusion [(MD: - 3.90 units; 95% CI: - 4.75 to - 3.05) vs. (MD: - 1.03 units; 95% CI: - 1.96 to - 0.10); P < 0.00001 for subgroup difference] than those with DAPT discontinued less than 5-7 days preoperatively.

CONCLUSIONS

This meta-analysis demonstrated that TXA significantly reduced post-operative blood loss and transfusion requirements for cardiac surgical patients with preoperative APT. These potential clinical benefits may be greater in patients with aspirin and clopidogrel continued closer to the day of surgery.

TRIAL REGISTRATION NUMBER

CRD42022309427.

A comparative analysis of tranexamic acid dosing strategies in traumatic major hemorrhage

INTRODUCTION

Tranexamic acid (TXA) is a life-saving treatment for traumatic hemorrhage, but the optimal dosing regimen remains unknown. Different doses and treatment strategies have been proposed, including single bolus, repeated bolus, or bolus plus infusion. The aim of this study was to determine the effect of different TXA dosing strategies on clinical outcomes in bleeding trauma patients.

METHODS

Secondary analysis of a perpetual cohort study from a UK Level I trauma center. Adult patients who activated the local major hemorrhage protocol and received TXA were included. The primary outcome was 28-day mortality. Secondary outcomes were 24-hour mortality, multiple organ dysfunction syndrome, venous thromboembolism, and rotational thromboelastometry fibrinolysis.

RESULTS

Over an 11-year period, 525 patients were included. Three dosing groups were identified: 1 g bolus only (n = 317), 1 g bolus +1 g infusion over 8 hours (n = 80), and 2 g bolus (n = 128). Demographics and admission physiology were similar, but there were differences in injury severity (median Injury Severity Score, 25, 29, and 25); and admission systolic blood pressure (median Systolic Blood Pressure, 99, 108, 99 mm Hg) across the 1-g, 1 g + 1 g, and 2-g groups. 28-day mortality was 21% in each treatment group. The incidence of multiple organ dysfunction syndrome was significantly higher in the bolus plus infusion group (84%) vs. 1 g bolus (64%) and 2 g bolus (62%) group, p = 0.002, but on multivariable analysis was nonsignificant. Venous thromboembolism rates were similar in the 1-g bolus (4%), 2 g bolus (8%) and bolus plus infusion groups (7%). There was no difference in rotational thromboelastometry maximum lysis at 24 hours: 5% in both the 1-g and 2-g bolus groups vs. 4% in bolus plus infusion group.

CONCLUSION

Clinical outcomes and 24-hour fibrinolysis state were equivalent across three different dosing strategies of TXA. Single bolus administration is likely preferable to a bolus plus infusion regimen.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

The Efficacy and Safety of a Low-Dose Tranexamic Acid Bolus-Only Protocol Compared with the Moderate-Dose Protocol in Valvular Heart Surgery

In 873 propensity score-matched pairs of patients undergoing valvular heart surgery, we compared a "moderate dose" of tranexamic acid (TXA) protocol (group 1; median TXA dose: 24 mg/kg body weight) with a 1.5-g "bolus-only" protocol (group 2; median TXA dose: 19 mg/kg body weight). The number of transfused patients was higher in group 2 than in group 1 (74.5 vs 66.0%, p < 0.001), as was the number of transfused red blood cell concentrates (p = 0.001). The risks of re-exploration and convulsive seizures were similar between groups (p > 0.50). Data indicate an impaired efficacy following the "bolus-only" protocol, without a significant safety improvement.

Efficacy and safety of tranexamic acid in prevention of postpartum hemorrhage: a systematic review and meta-analysis of 18,649 patients

BACKGROUND

In this meta-analysis, we aimed to update the clinical evidence regarding the efficacy and safety of TXA in the prevention of PPH.

METHODS

A literature search of PubMed, Scopus, Web of Science, Google Scholar, and Cochrane Library from inception until December 2022 was conducted. We included randomized controlled trials (RCTs) comparing TXA with a placebo among pregnant women. All relevant outcomes, such as total blood loss, the occurrence of nausea and/or vomiting, and changes in hemoglobin, were combined as odds ratios (OR) or mean differences (MD) in the meta-analysis models using STATA 17 MP.

RESULTS

We included 59 RCTs (18,649 patients) in this meta-analysis. For cesarean birth, TXA was favored over the placebo in reducing total blood loss (MD= -2.11 mL, 95%CI [-3.09 to -1.14], P < 0.001), and occurrence of nausea or/and vomiting (OR = 1.36, 95%CI [1.07 to 1.74], P = 0.01). For vaginal birth, the prophylactic use of TXA was associated with lower total blood loss, and higher occurrence of nausea and/or vomiting (MD= -0.89 mL, 95%CI [-1.47 to -0.31], OR = 2.36, 95%CI [1.32 to 4.21], P = 0.02), respectively. However, there were no differences between the groups in changes in hemoglobin during vaginal birth (MD = 0.20 g/dl, 95%CI [-0.07 to 0.48], P = 0.15). The overall risk of bias among the included studies varies from low to high risk of bias using ROB-II tool for RCTs.

CONCLUSIONS

This meta-analysis suggested that TXA administration is effective among women undergoing cesarean birth or vaginal birth in lowering total blood loss and limiting the occurrence of PPH. Further clinical trials are recommended to test its efficacy on high-risk populations.

Alternative routes for tranexamic acid treatment in obstetric bleeding (WOMAN-PharmacoTXA trial): a randomised trial and pharmacological study in caesarean section births

OBJECTIVE

To examine the safety, efficacy and pharmacology of intravenous (IV), intramuscular (IM) and oral tranexamic acid (TXA) use in pregnant women.

DESIGN

Randomised, open-label trial.

SETTING

Hospitals in Pakistan and Zambia.

POPULATION

Women giving birth by caesarean section.

METHODS

Women were randomised to receive 1 g IV, 1 g IM, 4 g oral TXA or no TXA. Adverse events in women and neonates were recorded. TXA concentration in whole blood was measured and the concentrations over time were examined with population pharmacokinetics. The relationship between drug exposure and D-dimer was explored. The trial registration is NCT04274335.

MAIN OUTCOME MEASURES

Concentration of TXA in maternal blood.

RESULTS

Of the 120 women included in the randomised safety study, there were no serious maternal or neonatal adverse events. TXA concentrations in 755 maternal blood and 87 cord blood samples were described by a two-compartment model with one effect compartment linked by rate transfer constants. Maximum maternal concentrations were 46.9, 21.6 and 18.1 mg/L for IV, IM and oral administration, respectively, and 9.5, 7.9 and 9.1 mg/L in the neonates. The TXA response was modelled as an inhibitory effect on the D-dimer production rate. The half-maximal inhibitory concentration (IC50 ) was 7.5 mg/L and was achieved after 2.6, 6.4 and 47 minutes with IV, IM and oral administration of TXA, respectively.

CONCLUSIONS

Both IM and oral TXA are well tolerated. Oral TXA took about 1 hour to reach minimum therapeutic concentrations and would not be suitable for emergency treatment. Intramuscular TXA inhibits fibrinolysis within 10 minutes and may be a suitable alternative to IV.

The effects of timing of prehospital tranexamic acid on outcomes after traumatic brain injury: Subanalysis of a randomized controlled trial

BACKGROUND

Tranexamic acid (TXA) is an antifibrinolytic that has shown some promise in improving outcomes in traumatic brain injury (TBI), but only when given early after injury. We examined the association between timing of prehospital TXA administration and outcomes in patients with moderate to severe TBI.

METHODS

Patients enrolled in the multi-institutional, double-blind randomized prehospital TXA for TBI trial with blunt or penetrating injury and suspected TBI (Glasgow Coma Scale score ≤ 12, SBP ≥90) who received either a 2-g TXA bolus or a 1-g bolus plus 1 g 8 hour infusion within 2 hours of injury were analyzed. Outcomes were compared between early administration (<45 minutes from injury) and late administration ≥45 minutes from injury) using a χ 2 , Fischer's exact test, t test, or Mann-Whitney U test as indicated. Logistic regression examined time to drug as an independent variable. A p value less than 0.05 was considered significant.

RESULTS

Six hundred forty-nine patients met inclusion criteria (354 early and 259 late). Twenty-eight-day and 6-month mortalities, 6-month Glasgow Outcome Scale-Extended, and disability rating scale scores were not different between early and late administration. Late administration was associated with higher rates of deep venous thrombosis (0.8 vs. 3.4%, p = 0.02), cerebral vasospasm (0% vs. 2%, p = 0.01), as well as prolonged EMS transport and need for a prehospital airway ( p < 0.01).

CONCLUSION

In patients with moderate or severe TBI who received TXA within 2 hours of injury, no mortality benefit was observed in those who received treatment within 45 minutes of injury, although lower rates of select complications were seen. These results support protocols that recommend TXA administration within 45 minutes of injury for patients with suspected TBI.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level II.

The role of tranexamic acid in the management of postpartum haemorrhage

In the last decades, tranexamic acid (TXA) has emerged as an essential tool in blood loss management in obstetrics. TXA prophylaxis for postpartum haemorrhage (PPH) has been studied in double-blind, placebo-controlled, randomized clinical trials (RCTs). Given the small observed preventive effect, the systematic use of TXA for vaginal and/or caesarean deliveries remains controversial. The result of a pharmacokinetic modelling suggests that relative to intravenous administration, intramuscular administration may be an equally effective alternative route for preventing PPH and may enable access to this drug in low-resource countries. Prophylaxis is currently studied in high-risk populations, such as women with prepartum anaemia or placenta previa. TXA effectively reduces blood loss and PPH-related morbidity and mortality during active PPH, as demonstrated by high-grade evidence from large RCTs. The drug has a good safety profile: in most cases, only mild gastrointestinal or visual adverse events may be observed. TXA use does not increase the risk of serious adverse events, such as venous or arterial thromboembolism, seizures, or acute kidney injury. The TRACES in vivo analysis of biomarkers of TXA's antifibrinolytic effect have suggested that a dose of at least 1 g is required for the treatment of PPH. The TRACES pharmacokinetic model suggests that because TXA can be lost in the haemorrhaged blood, a second dose should be administered if the PPH continues or if severe coagulopathy occurs. Future pharmacodynamic analyses will focus on the appropriateness of TXA dosing regimens with regard to the intensity of fibrinolysis in catastrophic obstetric events.

Tranexamic acid usage in hip fracture surgery: a meta-analysis and meta-regression analysis of current practice

INTRODUCTION

The use of tranexamic acid (TXA) in hip fracture surgery remains inconclusive. The aim of the present meta-analysis was to assess the role of TXA use in hip fracture surgery, and attempt to disclose possible factors which might influence TXA efficacy and safety.

MATERIALS AND METHODS

A systematic computerized literature search was conducted to retrieve all randomized controlled trials (RCTs) and cohort studies regarding TXA use in hip fracture surgery. Overall efficacy and safety were evaluated. Then, subgroup and meta-regression analyses were conducted to disclose the influence of geographic area, fracture type, administration route, frequency and dosage of TXA, blood transfusion threshold, and follow-up duration on the overall effect.

RESULTS

Thirty-four RCTs and 11 cohort studies were included. Patients receiving TXA had a significant decrease in the need for blood transfusion, reduced total, intra-operative and post-operative blood loss, a decrease in pre- and postoperative hemoglobin difference, without increasing thromboembolic events risk. Subgroup analysis showed that topical TXA had a lower transfusion rate compared with controls, yet the result did not reach statistical significance. Also, TXA had similar efficacy and safety profiles in patients with different frequency and dosage of TXA.

CONCLUSION

Current evidence indicated that intravenous administration of TXA could significantly reduce blood transfusion and blood loss without increasing risk of thromboembolic events. The frequency and dosage of TXA might not alter the beneficial effect. The application of topical TXA should be cautious.

Dosing Medications for Coagulopathy Reversal in Patients with Extreme Obesity

BACKGROUND

The reversal of anticoagulant or antiplatelet medications is a priority in the management of patients with severe injury with the goal of minimizing further bleeding without thrombotic complications. There are few studies, however, evaluating the dosing of reversal agents in the setting of trauma specific to patients with extreme obesity. Nevertheless, clinicians must still make decisions, balancing concerns of ongoing bleeding with excessive thrombosis.

OBJECTIVES

We describe the literature pertaining to dosing of medications used for the reversal of both drug-induced and trauma-related coagulopathy with the intent of providing a framework for clinicians to make dosing decisions in this challenging population.

DISCUSSION

Obesity is known to impact both the volume of distribution and the clearance of medications, but these changes are not usually linear with size nor are they uniform across drugs. Current strategies for dosing reversal agents in obesity include a capped dose (e.g., prothrombin complex concentrates), fixed dosages (e.g., andexanet alfa, idarucizumab, and tranexamic acid), and weight-based dosing (e.g., desmopressin). Extreme obesity, however, was not highly prevalent in the studies that have validated these dosing strategies. In fact, many of the clinical studies fail to report the average weight of the patients included.

CONCLUSION

Future studies should make efforts to increase reporting of patients with obesity included in clinical trials along with results stratified by weight class. In the meantime, doses listed in product labels should be used. Desmopressin should be dosed using either ideal body weight or a dose-capping strategy.

The effect of tranexamic acid dosing regimen on trauma/hemorrhagic shock-related glycocalyx degradation and endothelial barrier permeability: An in vitro model

BACKGROUND

Improved outcomes with early tranexamic acid (TXA) following trauma hemorrhagic shock (T/HS) may be related to its antifibrinolytic, as well as anti-inflammatory properties. Previous in vitro studies have shown that early TXA administration protects against T/HS endothelial barrier dysfunction and associated glycocalyx degradation. An intact endothelial glycocalyx may protect against subsequent neutrophil mediated tissue injury. We postulated that early TXA administration would mitigate against glycocalyx damage and resultant neutrophil adherence and transmigration through the endothelial barrier. This was studied in vitro using a microfluidic flow platform.

METHODS

Human umbilical vein endothelial cell monolayers were subjected to control or shock conditions (hypoxia + epinephrine) followed by administration of TXA 90 minutes or 180 minutes later.

RESULTS

"Early" TXA administration protected against glycocalyx degradation, biomarkers of increased permeability and the development of a fibrinolytic phenotype. This was associated with decreased neutrophil endothelial adherence and transmigration. There were no differences in low versus high TXA concentrations. The protective effects were only significant with "early" TXA administration.

CONCLUSION

There was a concentration and temporal effect of TXA administration on endothelial glycocalyx degradation. This was associated with "vascular leakiness" as indexed by the relative ratio of Ang-2/1 and polymorphonuclear neutrophil transmigration. Tranexamic acid if administered in patients with T/HS should be administered "early"; this includes in the prehospital setting.

Pharmacokinetics of Curative Tranexamic Acid in Parturients Undergoing Cesarean Delivery

The aim of this study was to evaluate the population pharmacokinetics of tranexamic acid (TXA) administered intravenously at a single dose of 0.5 or 1 g in parturients undergoing active hemorrhagic cesarean delivery and to evaluate the influence of patient variables on TXA pharmacokinetics. Subjects from three recruiting centers were included in this PK sub-study if randomized in the experimental group (i.v TXA 0.5 g or 1 g over one minute) of the TRACES study. Blood samples and two urinary samples were collected within 6 h after TXA injection. Parametric non-linear mixed-effect modeling (Monolix v2020R1) was computed. The final covariate model building used 315 blood and 117 urinary concentrations from seventy-nine patients. A two-compartment model with a double first-order elimination from the central compartment best described the data. The population estimates of clearance (CL), central volume of distribution (V1), and half-life for a typical 70 kg patient with an estimated renal clearance of 150 mL/min (Cockroft–Gault) were 0.14 L/h, 9.25 L, and 1.8 h. A correlation between estimated creatinine clearance and CL, body weight before pregnancy, and V1 was found and partly explained the PK variability. The final model was internally validated using a 500-run bootstrap. The first population pharmacokinetic model of TXA in active hemorrhagic caesarean section was successfully developed and internally validated.

Pharmacokinetics of tranexamic acid after intravenous, intramuscular, and oral routes: a prospective, randomised, crossover trial in healthy volunteers

BACKGROUND

In response to the World Health Organization call for research on alternative routes for tranexamic acid (TXA) administration in women with postpartum haemorrhage, we examined the pharmacokinetics of TXA after i.v., i.m., or oral administration.

METHODS

We conducted a randomised, open-label, crossover trial in 15 healthy volunteers who received i.v. TXA 1 g, i.m. TXA 1 g, or oral TXA solution 2 g. Blood samples were drawn up to 24 h after administration. Tranexamic acid concentration was measured with liquid chromatography-mass spectrometry, and the parameters of the pharmacokinetic models were estimated using population pharmacokinetics.

RESULTS

The median time to reach a concentration of 10 mg L^-1 was 3.5 min for the i.m. route and 66 min for the oral route, although with the oral route the target concentration was reached in only 11 patients. Median peak concentrations were 57.5, 34.4, and 12.8 mg L^-1 for i.v., i.m., and oral routes, respectively. A two-compartment open model with body weight as the main covariate best fitted the data. For a 70 kg volunteer, the population estimates were 10.1 L h^-1 for elimination clearance, 15.6 L h^-1 for intercompartmental clearance, 7.7 L for the volume of central compartment, and 10.8 L for the volume of the peripheral compartment. Intramuscular and oral bioavailabilities were 1.0 and 0.47, respectively, showing that i.m. absorption is fast and complete. Adverse events were mild and transient, mainly local reactions and low-intensity pain.

CONCLUSIONS

The i.m. (but not oral) route appears to be an efficient alternative to i.v. tranexamic acid. Studies in pregnant women are needed to examine the impact of pregnancy on the pharmacokinetics.

CLINICAL TRIAL REGISTRATION

EudraCT 2019-000285-38; NCT03777488.

Efficacy and safety of the second in-hospital dose of tranexamic acid after receiving the prehospital dose: double-blind randomized controlled clinical trial in a level 1 trauma center

Background

Prehospital administration of tranexamic acid (TXA) to injured patients is increasing worldwide. However, optimal TXA dose and need of a second infusion on hospital arrival remain undetermined. We investigated the efficacy and safety of the second in-hospital dose of TXA in injured patients receiving 1 g of TXA in the prehospital setting. We hypothesized that a second in-hospital dose of TXA improves survival of trauma patients.

Methods

A prospective, double-blind, placebo-controlled randomized, clinical trial included adult trauma patients receiving 1 g of TXA in the prehospital settings. Patients were then blindly randomized to Group I (second 1-g TXA) and Group II (placebo) on hospital arrival. The primary outcome was 24-h (early) and 28-day (late) mortality. Secondary outcomes were thromboembolic events, blood transfusions, hospital length of stay (HLOS) and organs failure (MOF).

Results

A total of 220 patients were enrolled, 110 in each group. The TXA and placebo groups had a similar early [OR 1.000 (0.062–16.192); p = 0.47] and late mortality [OR 0.476 (95% CI 0.157–1.442), p = 0.18].The cause of death (n = 15) was traumatic brain injury (TBI) in 12 patients and MOF in 3 patients. The need for blood transfusions in the first 24 h, number of transfused blood units, HLOS, thromboembolic events and multiorgan failure were comparable in the TXA and placebo groups. In seriously injured patients (injury severity score > 24), the MTP activation was higher in the placebo group (31.3% vs 11.10%, p = 0.13), whereas pulmonary embolism (6.9% vs 2.9%, p = 0.44) and late mortality (27.6% vs 14.3%, p = 0.17) were higher in the TXA group but did not reach statistical significance.

Conclusion

The second TXA dose did not change the mortality rate, need for blood transfusion, thromboembolic complications, organ failure and HLOS compared to a single prehospital dose and thus its routine administration should be revisited in larger and multicenter studies.

Trial registration

ClinicalTrials.gov Identifier: NCT03846973.

Clinical Validation of a Volumetric Absorptive Micro-Sampling Device for Pharmacokinetic Studies With Tranexamic Acid

We assessed the accuracy of tranexamic acid (TXA) concentrations measured in capillary whole blood using volumetric absorptive micro-sampling (VAMS) devices. Paired venous and VAMS capillary blood samples were collected from 15 healthy volunteers participating in a pharmacokinetic study of alternative routes (oral, IM and IV) of administering TXA. To assess accuracy across a range of concentrations, blood was drawn at different times after TXA administration. We measured TXA concentrations in plasma, whole blood from samples collected by venepuncture and whole blood from venous and capillary samples collected using VAMS devices. TXA was measured using a validated high sensitivity liquid chromatography - mass spectrometry method. We used Bland-Altman plots to describe the agreement between the TXA concentrations obtained with the different methods. In the 42 matched samples, the mean plasma TXA concentration was 14.0 mg/L (range 2.6-36.5 mg/L) whereas the corresponding whole blood TXA concentration was 7.7 mg/L (range 1.6-17.5 mg/L). When comparing TXA concentrations in VAMS samples of venous and capillary whole blood, the average bias was 0.07 mg/L (lower and upper 95% limits of agreement: -2.1 and 2.2 mg/L respectively). When comparing TXA concentrations in venous whole blood and VAMS capillary whole blood, the average bias was 0.7 mg/L (limits of agreement: -2.7 and 4.0 mg/L). Volumetric absorptive micro-sampling devices are sufficiently accurate for use in pharmacokinetic studies of tranexamic acid treatment in the range of plasma concentrations relevant for the assessment of fibrinolysis inhibition.

Clinical use of tranexamic acid: evidences and controversies

Tranexamic acid (TXA) significantly reduces blood loss in a wide range of surgical procedures and improves survival rates in obstetric and trauma patients with severe bleeding. Although it mainly acts as a fibrinolysis inhibitor, it also has an anti-inflammatory effect, and may help attenuate the systemic inflammatory response syndrome found in some cardiac surgery patients. However, the administration of high doses of TXA has been associated with seizures and other adverse effects that increase the cost of care, and the administration of TXA to reduce perioperative bleeding needs to be standardized. Tranexamic acid is generally well tolerated, and most adverse reactions are considered mild or moderate. Severe events are rare in clinical trials, and literature reviews have shown tranexamic acid to be safe in several different surgical procedures. However, after many years of experience with TXA in various fields, such as orthopedic surgery, clinicians are now querying whether the dosage, route and interval of administration currently used and the methods used to control and analyze the antifibrinolytic mechanism of TXA are really optimal. These issues need to be evaluated and reviewed using the latest evidence to improve the safety and effectiveness of TXA in treating intracranial hemorrhage and bleeding in procedures such as liver transplantation, and cardiac, trauma and obstetric surgery.

The impact of prehospital tranexamic acid on mortality and transfusion requirements: match-pair analysis from the nationwide German TraumaRegister DGU®

Background

Outcome data about the use of tranexamic acid (TXA) in civilian patients in mature trauma systems are scarce. The aim of this study was to determine how severely injured patients are affected by the widespread prehospital use of TXA in Germany.

Methods

The international TraumaRegister DGU® was retrospectively analyzed for severely injured patients with risk of bleeding (2015 until 2019) treated with at least one dose of TXA in the prehospital phase (TXA group). These were matched with patients who had not received prehospital TXA (control group), applying propensity score-based matching. Adult patients (≥ 16) admitted to a trauma center in Germany with an Injury Severity Score (ISS) ≥ 9 points were included.

Results

The matching yielded two comparable cohorts (n = 2275 in each group), and the mean ISS was 32.4 ± 14.7 in TXA group vs. 32.0 ± 14.5 in control group (p = 0.378). Around a third in both groups received one dose of TXA after hospital admission. TXA patients were significantly more transfused (p = 0.022), but needed significantly less packed red blood cells (p ≤ 0.001) and fresh frozen plasma (p = 0.023), when transfused. Massive transfusion rate was significantly lower in the TXA group (5.5% versus 7.2%, p = 0.015). Mortality was similar except for early mortality after 6 h (p = 0.004) and 12 h (p = 0.045). Among non-survivors hemorrhage as leading cause of death was less in the TXA group (3.0% vs. 4.3%, p = 0.021). Thromboembolic events were not significantly different between both groups (TXA 6.1%, control 4.9%, p = 0.080).

Conclusion

This is the largest civilian study in which the effect of prehospital TXA use in a mature trauma system has been examined. TXA use in severely injured patients was associated with a significantly lower risk of massive transfusion and lower mortality in the early in-hospital treatment period. Due to repetitive administration, a dose-dependent effect of TXA must be discussed.

WOMAN-PharmacoTXA trial: Study protocol for a randomised controlled trial to assess the pharmacokinetics and pharmacodynamics of intramuscular, intravenous and oral administration of tranexamic acid in women giving birth by caesarean section

Background: Intravenous tranexamic acid (TXA) within 3 hours of birth significantly reduces death due to bleeding in women with postpartum haemorrhage (PPH). Most PPH deaths occur in the first hours after giving birth and treatment delay decreases survival.  One barrier to rapid TXA treatment is the need for intravenous injection. Intramuscular injection and oral solution of TXA would be easier and faster to administer and would require less training. However, the pharmacokinetics (PK), pharmacodynamics and safety of TXA administered by different routes in pregnant women have not been established. The main aim of this study is to ascertain whether IM and oral solution of TXA will be absorbed at levels sufficient to inhibit fibrinolysis in pregnant women.

Methods: WOMAN-PharmacoTXA is a prospective, randomised, open label trial to be conducted in Zambia and Pakistan.  Adult women undergoing caesarean section with at least one risk factor for PPH will be included.  Women will be randomised to receive one of the following about 1 hour prior to caesarean section: 1-gram TXA IV, 1-gram TXA IM, 4-grams TXA oral solution or no TXA. Randomisation will continue until 120 participants with at least six post randomisation PK samples are included. TXA concentration in maternal blood samples will be measured at baseline and at different time points during 24 hours after receipt of intervention. Blood TXA concentration will be measured from the umbilical cord and neonate.

The primary endpoint is maternal blood TXA concentrations over time. Secondary outcomes include umbilical cord and neonate TXA concentration D-dimer concentration, blood loss and clinical diagnosis of PPH, injection site reactions and maternal and neonate adverse events.

Discussion: The WOMAN-PharmacoTXA trial will provide important data on pharmacokinetics, pharmacodynamics and safety of TXA after IV, intramuscular and oral administration in women giving birth by caesarean section.

Trial registration: ClincalTrials.gov, NCT04274335 (18/02/2020).

Hemostatic Strategies in Trauma

Bleeding is a leading cause of early death from trauma. Consequently, effective hemostasis can improve the odds of survival after severe traumatic injury. Understanding the pathophysiology of trauma-induced coagulopathy can provide insights into effective strategies to assess and halt hemorrhage. Both physical assessment and appropriate laboratory studies are important in the diagnosis and evaluation of coagulopathy to identify the most effective mechanical and pharmacological strategies to achieve hemostasis. This article uses a case study approach to explore evidence-based techniques to evaluate hemorrhage and strategies to promote hemostasis.

Impact of Obesity on Tranexamic Acid Efficacy in Adult Patients With Major Bleeding

BACKGROUND

Tranexamic acid (TXA) is an antifibrinolytic used for prophylaxis and treatment of acute bleeding. Although fixed dosing is often used in practice, weight-based dosing is sometimes used in the operating room (OR). The efficacy and safety of fixed-dose TXA is not well established in patients with above average weight or body mass index.

OBJECTIVE

To characterize the efficacy and safety of intravenous TXA in obese patients with major bleeding.

METHODS

This was a retrospective review of 165 patients receiving fixed-dose TXA for acute bleeding outside the OR. Blood product administration (BPA) before and after TXA was collected, along with demographic and bleed-related information. Thrombotic events were the major safety end point. A prespecified subgroup analysis was conducted in patients weighing at least 100 kg compared with a lower weight. Logistic regression was performed to determine whether an association exists between body weight and blood product requirement after TXA administration.

RESULTS

In the 24 hours after TXA, patients received an average of 4.17 units of blood product. Patients weighing at least 100 kg averaged 4.04 total units, compared with 4.19 units in the lower weight group (P = 0.603). Administration of individual blood products did not differ between groups, and thrombotic events were similar. Regression analysis did not associate weight with total BPA.

CONCLUSION AND RELEVANCE

In patients receiving fixed-dose TXA, weight does not appear to alter blood product requirements or rates of adverse thrombotic events. These data support continued use of fixed-dose TXA for treatment of acute major bleeding in obese patients.

Efficacy of Intravenous Tranexamic Acid in Reducing Perioperative Blood Loss and Blood Product Transfusion Requirements in Patients Undergoing Multilevel Thoracic and Lumbar Spinal Surgeries: A Retrospective Study

Introduction: Acute perioperative blood loss is a common and potentially major complication of multilevel spinal surgery, usually worsened by the number of levels fused and of osteotomies performed. Pharmacological approaches to blood conservation during spinal surgery include the use of intravenous tranexamic acid (TXA), an anti-fibrinolytic that has been widely used to reduce blood loss in cardiac and orthopedic surgery. The primary objective of this study was to assess the efficacy of intraoperative TXA in reducing estimated blood loss (EBL) and red blood cell (RBC) transfusion requirements in patients undergoing multilevel spinal fusion.

Materials and Methods: This a single-center, retrospective study of subjects who underwent multilevel (≥7) spinal fusion surgery who received (TXA group) or did not receive (control group) IV TXA at The Ohio State University Wexner Medical Center between January 1st, 2016 and November 30th, 2018. Patient demographics, EBL, TXA doses, blood product requirements and postoperative complications were recorded.

Results: A total of 76 adult subjects were included, of whom 34 received TXA during surgery (TXA group). The mean fusion length was 12 levels. The mean total loading, maintenance surgery and total dose of IV TXA was 1.5, 2.1 mg per kilo (mg/kg) per hour and 33.8 mg/kg, respectively. The mean EBL in the control was higher than the TXA group, 3,594.1 [2,689.7, 4,298.5] vs. 2,184.2 [1,290.2, 3,078.3] ml. Among all subjects, the mean number of intraoperative RBC and FFP units transfused was significantly higher in the control than in the TXA group. The total mean number of RBC and FFP units transfused in the control group was 8.1 [6.6, 9.7] and 7.7 [6.1, 9.4] compared with 5.1 [3.4, 6.8] and 4.6 [2.8, 6.4], respectively. There were no statistically significant differences in postoperative blood product transfusion rates between both groups. Additionally, there were no significant differences in the incidence of 30-days postoperative complications between both groups.

Conclusion: Our results suggest that the prophylactic use of TXA may reduce intraoperative EBL and RBC unit transfusion requirements in patients undergoing multilevel spinal fusion procedures ≥7 levels.

Pharmacokinetics of intramuscular tranexamic acid in bleeding trauma patients: a clinical trial

BACKGROUND

Intravenous tranexamic acid (TXA) reduces bleeding deaths after injury and childbirth. It is most effective when given early. In many countries, pre-hospital care is provided by people who cannot give i.v. injections. We examined the pharmacokinetics of intramuscular TXA in bleeding trauma patients.

METHODS

We conducted an open-label pharmacokinetic study in two UK hospitals. Thirty bleeding trauma patients received a loading dose of TXA 1 g i.v., as per guidelines. The second TXA dose was given as two 5 ml (0·5 g each) i.m. injections. We collected blood at intervals and monitored injection sites. We measured TXA concentrations using liquid chromatography coupled to mass spectrometry. We assessed the concentration time course using non-linear mixed-effect models with age, sex, ethnicity, body weight, type of injury, signs of shock, and glomerular filtration rate as possible covariates.

RESULTS

Intramuscular TXA was well tolerated with only mild injection site reactions. A two-compartment open model with first-order absorption and elimination best described the data. For a 70-kg patient, aged 44 yr without signs of shock, the population estimates were 1.94 h^-1 for i.m. absorption constant, 0.77 for i.m. bioavailability, 7.1 L h^-1 for elimination clearance, 11.7 L h^-1 for inter-compartmental clearance, 16.1 L volume of central compartment, and 9.4 L volume of the peripheral compartment. The time to reach therapeutic concentrations (5 or 10 mg L^-1) after a single intramuscular TXA 1 g injection are 4 or 11 min, with the time above these concentrations being 10 or 5.6 h, respectively.

CONCLUSIONS

In bleeding trauma patients, intramuscular TXA is well tolerated and rapidly absorbed.

CLINICAL TRIAL REGISTRATION

2019-000898-23 (EudraCT); NCT03875937 (ClinicalTrials.gov).

Hypothesis for a partially non urinary elimination of tranexamic acid in haemorrhagic caesarean section: Traces pilot pharmacokinetic study: Pharmacokinetics of tranexamic acid in obstetrics

BACKGROUND

In previous studies, the choice of doses of tranexamic acid was empirically defined as no pharmacokinetic study had been conducted in haemorrhagic caesarean section.

OBJECTIVE

The objective was to build a pharmacokinetic model in patients receiving a single 0.5, 1 or 2 g intravenous bolus.

METHOD

A preliminary monocentric open study was performed in the Lille centre. Blood samples and one urinary sample were collected in the 6 h following the injection. Nine patients were included. Tranexamic acid concentration was measured using liquid chromatography system coupled with tandem mass spectrometry. We used Monolix 2019R1 for population pharmacokinetic modelling. A structural model was constructed followed by the investigation of potential covariates.

RESULTS

Data were best described with a two-compartment model with a double first-order elimination from the central compartment. The model was improved when the variable ideal weight per dose was affected as a covariate for the apparent volume of distribution. Assuming a dose of 1 g and a height of 160 cm, the pharmacokinetic parameters were estimated at 10.26 L.h^-1 for total clearance, 11.5 L for the volume of the central compartment, 15.8 L for the volume of the second compartment, a diffusional clearance of 30.36 L.h^-1 , and a urinary excretion fraction of 25.8%.

CONCLUSIONS

The population pharmacokinetic model of tranexamic acid in haemorrhagic caesarean section was successfully established in our tiny sample of patients. The results of this preliminary TRACES pharmacokinetic study suggested that elimination of tranexamic acid is partially non urinary in contrast with healthy patients.

Tranexamic acid quantification in human whole blood using liquid samples or volumetric absorptive microsampling devices

Background: Recent clinical trials demonstrate the benefits of the antifibrinolytic drug tranexamic acid but its pharmacokinetics remain to be investigated more in depth. Although pharmacokinetics studies are usually performed with plasma, volumetric absorptive microsampling devices allow us to analyze dried whole blood samples with several advantages. Materials & methods: High-sensitivity LC-MS/MS methods for the quantification of tranexamic acid in human whole blood using liquid samples or dry samples on volumetric absorptive microsampling devices were developed and validated based on International Association from Therapeutic Drug Monitoring and Clinical Toxicology, European Medicines Agency and US FDA guidance. Conclusion: The method performances were excellent across the range of clinically relevant concentrations. The stability of tranexamic acid in blood samples stored up to 1 month at +50°C was demonstrated. The methods' suitability was confirmed with clinical samples.

Tranexamic Acid for Acute Hemorrhage: A Narrative Review of Landmark Studies and a Critical Reappraisal of Its Use Over the Last Decade

The publication of the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage-2 (CRASH-2) study and its intense dissemination prompted a renaissance for the use of the antifibrinolytic agent tranexamic acid (TXA) in acute trauma hemorrhage. Subsequent studies led to its widespread use as a therapeutic as well as prophylactic agent across different clinical scenarios involving bleeding, such as trauma, postpartum, and orthopedic surgery. However, results from the existing studies are confounded by methodological and statistical ambiguities and are open to varied interpretations. Substantial knowledge gaps remain on dosing, pharmacokinetics, mechanism of action, and clinical applications for TXA. The risk for potential thromboembolic complications with the use of TXA must be balanced against its clinical benefits. The present article aims to provide a critical reappraisal of TXA use over the last decade and a "thought exercise" in the potential downsides of TXA. A more selective and individualized use of TXA, guided by extended and functional coagulation assays, is advocated in the context of the evolving concept of precision medicine.

Topical tranexamic acid inhibits fibrinolysis more effectively when formulated with self-propelling particles

BACKGROUND

Endogenous fibrinolytic activation contributes to coagulopathy and mortality after trauma. Administering tranexamic acid (TXA), an antifibrinolytic agent, is one strategy to reduce bleeding; however, it must be given soon after injury to be effective and minimize adverse effects. Administering TXA topically to a wound site would decrease the time to treatment and could enable both local and systemic delivery if a suitable formulation existed to deliver the drug deep into wounds adequately.

OBJECTIVES

To determine whether self-propelling particles could increase the efficacy of TXA.

METHODS

Using previously developed self-propelling particles, which consist of calcium carbonate and generate CO2 gas, TXA was formulated to disperse in blood and wounds. The antifibrinolytic properties were assessed in vitro and in a murine tail bleeding assay. Self-propelled TXA was also tested in a swine model of junctional hemorrhage consisting of femoral arteriotomy without compression.

RESULTS

Self-propelled TXA was more effective than non-propelled formulations in stabilizing clots from lysis in vitro and reducing blood loss in mice. It was well tolerated when administered subcutaneously in mice up to 300 to 1000 mg/kg. When it was incorporated in gauze, four of six pigs treated after a femoral arteriotomy and without compression survived, and systemic concentrations of TXA reached approximately 6 mg/L within the first hour.

CONCLUSIONS

A formulation of TXA that disperses the drug in blood and wounds was effective in several models. It may have several advantages, including supporting local clot stabilization, reducing blood loss from wounds, and providing systemic delivery of TXA. This approach could both improve and simplify prehospital trauma care for penetrating injury.

The impact of early outcome events on the effect of tranexamic acid in post-partum haemorrhage: an exploratory subgroup analysis of the WOMAN trial

Background

In severe post-partum haemorrhage, death can occur within hours of bleeding onset so interventions to control the bleeding must be given immediately. In clinical trials of treatments for life-threatening bleeding, established treatments are given priority and the trial treatment is usually given last. However, enrolling patients in whom severe maternal morbidity or death is imminent or inevitable at the time of randomisation may dilute the effects of a trial treatment.

Methods

We conducted an exploratory analysis of data from the WOMAN trial, an international, randomised placebo-controlled trial of the effects of tranexamic acid on death and surgical intervention in 20,060 women with post-partum haemorrhage. We assessed the impact of early maternal death or hysterectomy due to exsanguination on the effect of tranexamic acid on each of these respective outcomes. We conducted repeated analyses excluding patients with these outcomes at increasing intervals from the time of randomisation. We quantified treatment effects using risk ratios (RR) and 99% confidence intervals (CI) and prepared cumulative failure plots.

Results

Among 14,923 women randomised within 3 h of delivery (7518 tranexamic acid and 7405 placebo), there were 216 bleeding deaths (1.5%) and 383 hysterectomies due to bleeding (2.8%). After excluding deaths from exsanguination at increasing time intervals following randomization, there was a significant reduction in the risk of death due to bleeding with tranexamic acid (RR = 0.41; 99% CI 0.19–0.89). However, after excluding hysterectomies at increasing time intervals post-randomization, there was no reduction in the risk of hysterectomy due to bleeding with tranexamic acid (RR = 0.79; 99% CI 0.33–1.86).

Conclusions

Findings from this analysis provide further evidence that tranexamic acid reduces the risk of death from exsanguination in women who experience postpartum haemorrhage. It is uncertain whether tranexamic acid reduces the risk of hysterectomy for bleeding after excluding early hysterectomies.

Trial registration

ISRCTN trial registration number ISRCTN76912190, 8 Dec 2008; ClinicalTrials.gov number NCT00872469, 30 March 2009; PACTR number PACTR201007000192283, 9 Feb 2010; EudraCT number 2008–008441-38, 8 Dec 2010 (retrospectively registered).

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1855-5) contains supplementary material, which is available to authorized users.