There are various contraindications for the use of TA: in cases of active thromboembolic disease, e.g., deep venous thrombosis or pulmonary embolism, TA has been shown to have a procoagulant effect and can be unsafe in patients with thromboembolism, those in a hypercoagulable state, and those with thrombogenic vascular diseases. Sundström et al. [3] suggested that TA was associated with an increased risk of venous thromboembolism, although the risk estimate did not reach statistical significance. Hypersensitivity reactions to TA are not uncommon, and care should be taken during its slow, intravenous administration. Visual effects are known side effects of TA, and retinal arterial and venous occlusion have even been reported in the literature. When administered at a high dosage, TA is known to produce seizure in cases of cardiac surgery, where it is commonly used at a high dose, to ensure an effective concentration, secondary to gamma-aminobutyric acid (GABA) receptor inhibition. Murkin et al. [4] suggested the epileptogenic potential of TA at higher doses in susceptible individuals. They suggested that nonischemic seizure is associated with TA at doses of 61–259 mg/kg [4]. After this review, dosing guidelines have been modified to a low dose of tranexamic acid as 30 mg/kg loading dose followed by 15 mg/kg/h as infusion [4]. Many authors have suggested that use of TA at doses exceeding 80 mg/kg should be avoided. However, one of the largest retrospective data analyses, of 4,883 cardiac surgical patients, indicated that even a moderate TA dose of 24 mg/kg was associated with almost double the rate of convulsions and in-hospital mortality in comparison to a reference group that did not receive the drug [5].

Extreme caution is required regarding the use of this drug in patients with disseminated intravascular coagulation requiring antifibrinolytic therapy. Even among patients with acute ureteral obstruction, clot formation has been reported in those with upper urinary tract bleeding. Concurrent administration of TA with oral contraceptives is not recommended, as the risk of thromboembolism is further increased. Concurrent administration with factor IX complexes or anti-inhibitor coagulant complexes is also not recommended, due to the risk of thrombosis. Cerebral infarction and edema have been reported in patients with subarachnoid hemorrhage receiving TA. Concurrent use of tretinoin with TA may exacerbate procoagulant effects. Accidental intrathecal injection of 500 mg of TA was reported to be associated with spinal myoclonus, and even death. TA is labeled a category B drug in pregnancy, as it is well known to be excreted in breast milk. Fibrinolytic activity is very high in neonates, however, there is little evidence of any deleterious effect of suppressing it by TA in the first hours of life.

There are strong evidences regarding the relation between use of TA and reduction of bleeding during the perioperative period. However, the drug doge-effect relationship of TA in different surgeries, as well as its effect on thromboembolic events, seizure potential, morbidity, and mortality remain uncertain. For safe usage, anesthesiologists should be familiar with the mechanism of action of TA and its known side effects (nausea, vomiting, chills, fever, headache, muscle pain, stuffy nose, giddiness, dizziness, thromboembolic events, ocular effects, and hypotension on rapid intravenous injection). Most studies performed to date have examined the efficacy of TA after excluding patients with contraindications for its use, as well as those with a high-risk profile. Therefore, it is necessary for clinicians to assess the thromboembolic and seizure risks on an individual basis before administering TA. This drug should not be used in all surgeries, but rather its role should be well defined depending upon the patient’s profile, and the duration and type of surgery.