In this study, we screened the children with DILI in the PIC database in the past ten years, collecting their medication information and evaluating the drugs by RUCAM. In this retrospective, single center study, antibiotics and nutritional preparation agents were considered to be causative drugs of newborns’ DILI. Antibiotics and gastrointestinal medicine were found to give rise to children’s DILI during hospitalization. Meropenem was the most common individual antibiotics drug. Between the DILI patients of newborns and children, there was not much difference in the peak level of laboratory findings and number of drugs used during hospitalization. Neonates and children varied in the type of DILI. After dividing the patients by R ratio, we found that newborns’ DILI were dominant in mixed type, while children were dominant in the hepatocellular type. The distribution of types of liver injury in critically ill children in our study differed slightly from the types summarized in other studies. After collecting information on the drugs associated with important CYP enzymes, we compiled a summary of the combinations that are commonly seen in clinical practice. The combination of these drugs may lead to competition for the same enzyme’s site of effect or a conflict of action, which may in turn result in accumulation of the drug and cause liver injury. Finally, we compared the impact of length of stay and prognosis of patients with DILI in some common diseases.
For the first time, we focused on the issue of drug-related hepatic injury in neonates as opposed to children and adults, who are often studied, and also compared the results to children. The neonate is a very special patient population and a unique recipient [11], as a result of immaturity at birth and the daily evolution of many metabolic functions, including drug carriers in blood or the enteric canal, drug metabolizing enzymes in liver cells and renal function. These factors all influence the efficacy and toxicity of medicines [12]. As a consequence of the incomplete maturity of such vital functions at birth, neonates show significant differences in absorption, distribution, metabolism, and excretion, compared to adults [13]. The main types of liver injury in neonates are mixed and cholestatic, which may also be related to the way we currently determine the type of liver injury, using the R value, which is calculated as the ratio of serum ALT and its maximum value to ALP and its maximum value. The laboratory biochemical assessments for DILI including ALP are not quite appropriate in newborns. ALP is expressed in liver tissue and is increased in hepatic dysfunction, but increased serum ALP can also be a result of bone growth and excessive enzyme secretion by osteoblasts [14], which may cause some inaccuracy in our results. The predominant type of liver injury in children was roughly the same as in other studies, with the vast majority being hepatocellular.
In other studies in China [4, 15], the drugs that mainly cause liver damage are Chinese herbs, drugs for tuberculosis, antibiotics, and NSAIDs, and in antibiotics are responsible for most liver damage in studies of other countries [16–18]. In our newborns, the main causes of liver damage are nutritional agents and antibiotics; in our pediatric patients, the main cause is antimicrobials and digestives system drugs. This may be related to the common diseases in critically ill patients. In our study, gastrointestinal and respiratory diseases were common in patients, who required dietary supplements and more advanced antibiotics, also the demand for traditional Chinese herbal medicine would be reduced. Moreover, newborns and children are at an essential period of growth and development, and the diseases of critically ill children often lead to malabsorption of nutrients that affect their development, thus creating a greater need for nutritional preparations. This result suggests that pediatricians and pharmacists should also pay more attention to the liver function indicators of critically ill newborns and children when using nutritional preparations.
As seen in Tables 4 and 5, the length of hospital stay was remarkably or slightly longer in DILI groups than in non-DILI groups. The treatment of patients with liver protection while not interfering with the treatment of other diseases, or DILI aggravated the pre-existing conditions, which made the treatment of critically ill patients more complicated and prolonged the treatment time. However, we can find that DILI did not dramatically increase the mortality rate of neonates and children with the same disease, which may be due to the following reasons: First, statistical bias caused by the small number of patients in the DILI groups. Then, detection and measures taken by health care professionals to effectively stop the deterioration of the diseases. Finally, the mild degree of DILI is in patients, which didn’t cause irreversible and sever damage to liver function.
Although we cannot precisely evaluate the relationship between the drugs and hepatic injury, it is generally perceived that DILI is rare in newborns and children. They use fewer medicines that are well known to induce hepatotoxicity, often for a much shorter duration [19].
It is noteworthy that chronic liver injury did not develop in any of our patients, and the mortality was lower than 1% in both neonates and children. The death cases all died of other etiologies, such as organ dysfunction or tumor, which means that hepatitis and liver injury did not have much to do with the death in these cases. Most patients with DILI were expected to recover or improve their condition after withdrawing the suspected drug and beginning supportive treatment.
According to our statistics, newborns and children both used at least five and more medications during their hospitalization. The concomitant use of drugs acting on the same enzyme can have some impact on drug metabolism and excretion, and may also be implicated in liver damage. Hines et al. suggested that there are three patterns of the developmental expression of CYP450: 1. Expression in the fetal liver, decreasing gradually with gestational age (e.g., the subtype CYP3A7); 2. Expression begins in the early neonatal period (e.g., CYP2D6 and CYP2E1); 3. Expression starts in late neonate development (e.g., CYP1A2 and CYP3A4) [20]. The most abundant is enzyme in the human liver is CYP3A4, which is widely considered to be involved in the metabolism of more than half of medicines [21]. CYP3A4 activities in the liver of neonates are much lower than in adults, resulting in lower metabolism and clearance of antibiotics, antiviral, hormones, and other drugs in the liver, and the easy accumulation of drugs [22]. After birth, CYP1A2 activity towards its substrates, caffeine and theophylline, is low but reaches adult levels at 4–5 months [23]. One of the substrates of CYP2E1is acetaminophen and, if glutathione is depleted, the enzyme irreversibly damages the liver tissue [24]. The amount of this enzyme increases rapidly after roughly three months [25]. Co-administration of the same substrates of CYP2E1 was not found in this study. Neonatal CYP2D6 activity is only about 3–5% of that of adults, resulting in less hepatotoxicity metabolites being converted when substrates are ingested and a lower incidence of DILI than in adults [26]. Typical substrates for CYP2C9 and CYP2C19 include NSAIDs, sartans, proton pump inhibition, warfarin and propranolol. At around five months of age, about half of children reach adult levels [25]. That is to say, most enzyme activities in newborns and some children are lower than in adults. From the results of Table 3 we could also find many drugs related to DILI that were summarized in this study, such as omeprazole and budesonide, which are frequently seen in neonatal species, like midazolam and ibuprofen which are commonly seen in children, especially when multiple drugs with the same metabolic enzymes are combined at the same time, which can significantly affect drug metabolism and may cause drug accumulation thus liver damage.
Our study has several limitations. First, it is a retrospective and single center study, which means a smaller sample size. Second, due to the lack of thresholds of hepatic injury in newborns and children, we refer to the DILI standard for adults, which may lead to the deviation in the screening results. Third, subjective bias existed when the drugs were assessed by RUCAM. Throughout the study, most of the research focused on DILI in patients during hospitalization [18, 27];thus, our research on outpatients is deficient.
Due to the particularity of neonates and children, they are seldom of concern in DILI. However, DILI is a potential but preventable cause of hepatic injury, drug interactions in combination with multiple drugs are also a problem that cannot be ignored, and more accurate standards of diagnosis and higher attention are urgently needed in DILI in neonatal or children.