Serum aminotransferases after low-dose heparin treatment. Short communication

Hepatotoxicity With Elevated Bilirubin Secondary to Prophylactic Doses of Unfractionated Heparin: A Case Report and Review of Heparin-Induced Hepatotoxicity

Objective: To report a case of heparin-induced hepatotoxicity in a patient without prior liver dysfunction who received prophylactic doses of unfractionated heparin (UFH). Case Summary: A 70-year-old man with no prior liver dysfunction was admitted to the hospital for presyncope, secondary to dehydration, and new-onset congestive heart failure. Prophylactic UFH was initiated for deep vein thrombosis prophylaxis. Within 2 days, he developed increases in aspartate aminotransferase and alanine aminotransferase. By day 4, aspartate aminotransferase and alanine aminotransferase were greater than 5 and 9 times the upper limit of normal, respectively. Alkaline phosphatase and bilirubin were markedly elevated as well. UFH was discontinued on day 4, and liver enzymes subsequently normalized. Discussion: Hepatotoxicity, defined as increases in transaminases greater than 3 times the upper limit of normal, is relatively rare-estimated to occur in only 5% of those receiving therapy with UFH. Concurrent elevations in bilirubin have rarely been reported. Enzymes typically begin to rise after 4 to 5 days of UFH use and return to normal within 2 weeks of discontinuation. Previously published case reports of heparin-induced hepatotoxicity have occurred with therapeutic doses of either UFH or low-molecular-weight heparins. Conclusions: Heparin-induced hepatotoxicity may occur more rapidly than previously described, and even with the use of prophylactic doses of UFH. Given their widespread use, it is important for clinicians to consider heparins in their differential as a potential cause of hepatotoxicity especially in patients without underlying hepatic disease.

Enoxaparin-induced hepatotoxicity: an under-recognised complication of enoxaparin therapy

Low-molecular-weight heparins including enoxaparin are commonly used for anticoagulation as prophylaxis and treatment for deep vein thrombosis (DVT). Prescribers of enoxaparin monitor for common side effects, such as bleeding and thrombocytopenia, but hepatotoxicity, a less common and under-reported adverse effect, may be overlooked. This report describes a case of enoxaparin-induced hepatotoxicity in a 57-year-old man who was started on the drug for a DVT. Within 3 days of taking enoxaparin, elevated transaminases were noted, and the drug was discontinued after 6 days. Similar to other published reports, the patient's transaminases peaked 1 day after discontinuation of the drug and then trended down to normal over 32 days.

Enoxaparin-Induced Liver Injury: Case Report and Review of the Literature and FDA Adverse Event Reporting System (FAERS)

Anticoagulants are a well known cause of drug-induced liver injury (DILI). We recently encountered a 45-year-old male who developed DILI during treatment with enoxaparin, a low-molecular-weight heparin (LMWH), for dural venous thrombosis. The man received enoxaparin 80 mg subcutaneously, twice daily. After 4 days, the patient was asymptomatic but he developed liver aminotransferase elevations: AST 340 U/L and ALT 579 U/L. Investigation revealed an R ratio of 19.9 by day 5 and a Roussel Uclaf Causality Assessment Method score of 10, giving a high probable likelihood that enoxaparin was the cause of hepatic injury. Enoxaparin was discontinued on day 7, and 1 week later AST and ALT had decreased to 61 and 273 U/L, respectively. This case prompted a literature search and a review of the FDA Adverse Event Reporting System (FAERS) database for the range of hepatic adverse events (HAEs) associated with this class. A MEDLINE/PubMed search was conducted using DILI terms and cross-referenced with the anticoagulant classes. A Freedom of Information Act (FOIA) request was also made to identify adverse events (AEs) associated with enoxaparin in FAERS. Case type, severity of outcome, and demographic information were analyzed. Five publications have reported DILI with enoxaparin. Trial data found elevations in ALT >3 times the upper limit of normal (ULN) for unfractionated heparins (UFH) and LMWH in 8 and 4-13 % of subjects, respectively. However, liver injury in all cases was mild, self-limited, and asymptomatic. Our FOIA request yielded 8336 adverse events related to enoxaparin over a 14-year period (Jan 2000-Sept 2014). Specific HAEs were found in 4 % of reports, but all were described with other serious adverse events. The reported outcomes of hospitalization (75 %), death (17 %), and life-threatening medical events (5 %) were likely due to other related serious adverse events such as hemorrhage (28 %) and thrombocytopenia (11 %). We conclude that LMWH-related liver injury is uncommon and reversible. The mechanism of liver injury is not known, although an idiosyncratic effect is postulated. Although the FAERS database lists hepatic injury in 4 % of all enoxaparin-related AEs, it appears that serious outcomes are related to non-hepatic events.

A randomized, placebo-controlled trial to determine the course of aminotransferase elevation during prolonged acetaminophen administration

Background

Acetaminophen administration for more than 4 days causes aminotransferase elevation in some subjects. The objective of this randomized, placebo-controlled trial is to describe the course of alanine aminotransferase (ALT) elevation in subjects administered 4 g/day of acetaminophen for at least 16 days.

Methods

A randomized, placebo controlled trial of acetaminophen (4 g/day) vs placebo. Subjects were healthy volunteers with normal liver enzymes. The primary outcome was the course of ALT during acetaminophen administration. All subjects were treated for a minimum of 16 days. Subjects with ALT elevation at day 16 were continued on treatment until these elevations resolved up to a maximum of 40 days. Subjects were also evaluated for elevation of INR or serum bilirubin as evidence of hepatic dysfunction.

Results

157/205 (77%) completed acetaminophen subjects had no ALT elevation or transient elevations that resolved by day 16. Of the 48 subjects who had ALT elevations at study day 16, 47 continued on acetaminophen and had resolution by study day 40. One acetaminophen subject did not have resolution by study day 40, and the course of aminotransferase elevation suggests an alternative cause. One placebo subject had an ALT elevation at day 16 that resolved by day 22. The highest observed ALT among all acetaminophen subjects was 191 IU/L. The mean ALT at day 16 was 4.4 IU/L higher for the acetaminophen than for the placebo group. No subject developed liver dysfunction.

Conclusions

A minority of subjects treated with 4 g/day of acetaminophen for 16 days will have low-grade aminotransferase elevations that are not accompanied by liver dysfunction and resolve if administration is continued.

Trials registration

Clintrials.gov NCT00743093 registered August 26, 2008

The effects of heparins on the liver: application of mechanistic serum biomarkers in a randomized study in healthy volunteers

Heparins have been reported to cause elevations in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) but have not been associated with clinically significant liver injury. The mechanisms underlying these benign laboratory abnormalities are unknown. Forty-eight healthy men were randomized to receive subcutaneous injections of unfractionated heparin (UFH; 150 U/kg), enoxaparin sodium (1 mg/kg), dalteparin sodium (120 IU/kg), or adomiparin sodium (125 IU/kg; a novel heparin) every 12 h for 4.5 days. Asymptomatic elevations in serum ALT or AST were observed in >90% of the subjects. Elevations were also observed in the levels of serum sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GLDH), miR-122, high-mobility group box-1 protein (including the acetylated form), full-length keratin 18, and DNA. Keratin 18 fragments, which are apoptosis biomarkers, were not detected. Biomarker profiles did not differ significantly across heparin treatments. We conclude that heparins as a class cause self-limited and mild hepatocyte necrosis with secondary activation of an innate immune response.

Elevation of hepatic transaminases after enoxaparin use: case report and review of unfractionated and low-molecular-weight heparin-induced hepatotoxicity

Enoxaparin, a low-molecular-weight heparin (LMWH), is widely used for the treatment and prophylaxis of thromboembolic disorders, such as deep vein thrombosis. Low-molecular-weight heparin products have smaller and more uniform molecular weights than unfractionated heparin, allowing them to exhibit a much greater affinity for factor Xa than factor IIa. Compared with traditional unfractionated heparin, LMWHs have proved to be equally efficacious and may be safer. The distinctive characteristics of LMWHs have resulted in decreased rates of bleeding and equivalent rates of thrombocytopenia compared with unfractionated heparin. This favorable safety profile has been identified in several studies and may have led clinicians to believe that LMWHs have lower frequencies of all common side effects. A 66-year-old woman developed increased hepatic transaminases during treatment with enoxaparin for a deep vein thrombosis; they returned to normal after enoxaparin discontinuation. A causal relationship between unfractionated heparin and asymptomatic, transient increases in hepatic transaminase levels has been documented; these increased levels also appear to be an underrecognized, adverse effect of LMWH therapy.

Fulminant hepatic failure associated with dicoumarol therapy

Coumarins have been associated with non-predictable hepatic injury. In the case of dicoumarol, there is no hard evidence in the literature of a causal connection with liver damage. We report the case of a 73-year-old woman who developed a fatal liver disease of a mixed hepatocellular-cholestatic type after 3 months of treatment with dicoumarol. A thorough diagnostic work-up did not reveal any other possible cause of the liver disease.

Transient hepatic dysfunction in two brothers receiving heparin and streptokinase: a genetic predisposition?

Two brothers with acute myocardial infarction are presented. Subsequent to a standard thrombolysis treatment with streptokinase and heparin, both developed abnormal liver tests, with elevated transaminases only. This liver dysfunction resolved promptly. The occurrence of such side-effects in two siblings raises the question of genetic predisposition to the otherwise uncommon hepatic complications of thrombolysis treatment.

Cholestatic liver reaction during heparin therapy

Three patients are reported who developed liver enzyme abnormalities of a cholestatic pattern, without jaundice, after 10-28 d of heparin treatment. The values normalized within 4 months in all patients. Thus heparin should be added to the list of drugs that may cause a cholestatic liver reaction.

Adverse effects of three different forms of heparin therapy: thrombocytopenia, increased transaminases, and hyperkalaemia

A prospective study has been made of the incidence of changes in transaminase levels, hyperkalaemia and thrombocytopenia in three groups of patients: 89 consecutive patients with venous thrombosis receiving therapeutic heparinization, 49 patients admitted because of hip fracture and receiving prophylactic low-dose conventional heparin, and 43 patients admitted because of hip fracture and randomly allocated to receive low molecular weight heparin. Laboratory measurements were made on admission and 8 days after commencing heparin. Only two patients on high-dose heparin developed thrombocytopenia. Increased transaminases were frequent with conventional heparin (18% and 32% of patients on high-dose heparin developed abnormal AsT and AlT values, respectively compared with 14% and 17% patients on low dose therapy). In contrast, only one patient on low molecular weight heparin developed abnormal AlT activity. Hyperkalaemia was uncommon in patients on any form of heparin therapy, and severe hyperkalaemia occurred in only one patient.

Low molecular weight heparin once daily compared with conventional low-dose heparin twice daily. A prospective double-blind multicentre trial on prevention of postoperative thrombosis

In a randomized, prospective, double-blind multicentre trial, the effect of conventional low-dose heparin 5000 units twice daily, was compared with that of a low molecular weight heparin fragment (4000-5000) 5000 anti-factor Xa units once daily. Four hundred and thirty-two patients fulfilled the inclusion criteria and were analysed for development of deep vein thrombosis (125I-labelled fibrinogen test) and haemorrhagic complications. Thrombosis occurred in a 4.3 per cent of patients in the low-dose heparin group and in 6.4 per cent of patients in the heparin fragment group, a difference which is not significant. There was a significant delay in the onset of thrombosis in the heparin fragment group. Mortality did not differ between the groups, nor did peroperative blood loss or transfusion requirements or infectious complications. Haemorrhagic complications occurred significantly more often in the fragment group (11.6 per cent) than in the conventional heparin group (4.6 per cent). Patients in the heparin fragment group experienced local pain following the subcutaneous injection significantly less often.

Postoperative course of serum aminotransferases after total hip arthroplasty

Skeletal muscle trauma and acute coronary occlusion increase the values of aminotransferases, which might render the diagnosis of myocardial infarction in connection with major orthopaedic surgery more difficult. To find clinically useful distinctions, the postoperative course of serum aminotransferases (ASAT, ALAT, LD, GT and ALP) was recorded for the first 3 weeks following total hip arthroplasty and compared with the values found in patients with acute myocardial infarction. The level of ASAT increased during the first days following surgery. The highest recorded value of ASAT during the first 4 days was found to be lower than corresponding values in patients with myocardial infarction, although an overlap between the groups was seen. However, the LD value did not increase significantly following surgery, in contrast to the findings in patients with myocardial infarction. Later in the postoperative course, values for ALAT, GT and ALP rose as well. Two case reports on myocardial infarction after total hip replacement are included.

Toxicity of heparin in isolated rat hepatocytes

The effect of heparin on isolated rat hepatocytes in monolayer culture was assessed to investigate the observed increase in serum aminotransferase activity in patients treated with heparin for thromboembolic disorders. Cells were treated with porcine intestinal mucosal heparin or beef lung heparin in concentrations ranging from 0.01 to 100 units/ml. Toxicity was evaluated based on cell damage or death measured by LDH release into the culture media as a fraction of total system LDH (LDH index). Toxicity appeared at concentrations between 1 and 10 units/ml (P less than 0.05). The uptake and binding of heparin by the hepatocyte were evaluated by addition of tritium-labeled heparin to the cultures. Sucrose gradient centrifugation with isolation of the liver plasma membranes (LPM) showed little membrane binding of heparin. The majority of intracellular heparin was located in the cytosol fraction. Heparin gains access to hepatocytes and causes a dose-related toxic effect resulting in cell damage and death. This investigation indicates that the increased serum aminotransferase concentrations seen with heparin treatment may be due to a direct hepatotoxic effect of heparin.

Hepatic dysfunction after open-heart surgery

In a prospective study, 93 patients were observed up to nine months after open-heart surgery using hypothermia, hemodilution and cold cardioplegia. In the first two weeks frequent determinations were made of serum aminotransferase, alkaline phosphatases (ALP), lactic dehydrogenase isoenzymes, gamma glutamyltransferase (GT), total and free bilirubin and bile acids. Plasma hemoglobin was measured at the end of the operation. After the first period, aminotransferases, alkaline phosphatases and bilirubin were determined monthly. On the first postoperative day almost all of the patients showed abnormal aspartate aminotransferase (ASAT) activity and ASAT/ALAT (alanine aminotransferase) greater than 1, and about 25% had hyperbilirubinemia. The findings suggested early postoperative leakage of enzymes not only from the myocardium, but also from the liver. After two weeks the patients presented another pattern of liver dysfunction, with abnormal ALAT in 50%, ASAT/ALAT less than 1, and abnormal ALP and GT in 28 and 45%, respectively. Eight patients were judged to have post-transfusion hepatitis of non-A, non-B type. Six of them had abnormal aminotransferases for more than six months.

Biological variations in hyperlipidemic children and adolescents treated with fenofibrate

Beside their pharmacological action drugs may have unexpected side effects which must be known and taken into account in the interpretation of laboratory tests. In this work, we followed 17 hyperlipidemic subjects, aged 4-19 years, treated with fenofibrate only. We performed several plasma tests before and during treatment. The hypolipidemic action of fenofibrate was evident: decreases of cholesterol and triglycerides mean values were, respectively, 22% and 39% after 3 months of treatment. Other plasma constituents were also significantly decreased: uric acid, 20%; bilirubin, 19%; alkaline phosphatases, 15%. The aminotransferase activities (both AST and ALT) were increased in only four subjects after 3 months. The highest values were 88 U/l for AST and 109 U/l for ALT (the initial values were, respectively, 28 U/l and 23 U/l). These activities decreased when the treatment was stopped. These variations were isolated and transient.