Disposition of antipyrine in patients with extensive metastatic liver disease

Impact of Inflammation on Cytochromes P450 Activity in Pediatrics: A Systematic Review

Background and Objective

Cytochromes P450 (CYP) are the major enzymes involved in hepatic metabolism of drugs. Personalization of treatment in pediatrics is a major challenge, as it must not only take into account genetic, environmental, and physiological factors but also ontogeny. Published data in adults show that inflammation had an isoform-specific impact on CYP activities and we aimed to evaluate this impact in the pediatric population.

Methods

Articles listed in PubMed through 7 January, 2021 that studied the impact of inflammation on CYP activities in pediatrics were included in this systematic review. Sources of inflammation, victim drugs (CYP involved), effect of drug–disease interactions, number and age of subjects, and study design were extracted.

Results

Twenty-seven studies and case reports were included. The impact of inflammation on CYP activities appeared to be age dependent and isoform-specific, with some drug–disease interactions having significant pharmacokinetic and clinical impact. For example, midazolam clearance decreases by 70%, while immunosuppressant and theophylline concentrations increase three-fold and two-fold with intensive care unit admission and infection. Cytochrome P450 activity appears to return to baseline level when the disease is resolved.

Conclusions

Studies that have assessed the impact of inflammation on CYP activity are lacking in pediatrics, yet it is a major factor to consider to improve drug efficacy or safety. The scarce current data show that the impact of inflammation is isoform and age dependent. An effort must be made to improve the understanding of the impact of inflammation on CYP activities in children to better individualize treatment.

Pharmacokinetics of controlled release morphine (MST) in patients with liver carcinoma

BACKGROUND

There are no studies reported on the pharmacokinetics of controlled release morphine (MST) in patients with hepatocellular carcinoma, the fifth most common cancer in the world.

METHODS

We have studied the pharmacokinetic profile of MST (30 mg) in 15 patients with liver carcinoma (eight with primary carcinoma on top of chronic hepatitis C, and seven with secondary metastatic liver malignancy as a result of other primary) compared with our previously published data for 10 healthy controls. Plasma morphine concentrations were measured in venous blood samples at intervals up to 12 h by high-pressure liquid chromatography. Total body clearance (Cl) and systemic bioavailability were estimated using a compartmental method.

RESULTS

Morphine bioavailability showed a substantial increase in patients with primary liver and secondary metastatic carcinoma than that of controls (64.8, 62.1, and 16.8%, respectively). The area under the serum concentration-time curve increased 4-fold in primary carcinoma (416 [sem25] microg h(-1) litre(-1)) and 3-fold (303 [21] microg h(-1) litre(-1)) in metastatic liver patients compared with healthy control (92.5 [3] microg h(-1) litre(-1)). No significant difference was found in T(max) between the two malignant groups but C(max) was significantly greater in primary liver carcinoma patients. Impaired morphine elimination was noted in primary carcinoma only (t(1/2) 5.99 [0.39] h).

CONCLUSION

Careful administration of morphine is recommended in patients with liver cancer.

Preoperative galactose elimination capacity predicts complications and survival after hepatic resection

OBJECTIVE

To analyze a single center's 6-year experience with 258 consecutive patients undergoing major hepatic resection for primary or secondary malignancy of the liver, and to examine the predictive value of preoperative liver function assessment.

SUMMARY BACKGROUND DATA

Despite the substantial improvements in diagnostic and surgical techniques that have made liver surgery a safer procedure, careful patient selection remains mandatory to achieve good results in patients with hepatic tumors.

METHODS

In this prospective study, 258 patients undergoing hepatic resection were enrolled: 111 for metastases, 78 for hepatocellular carcinoma (HCC), 21 for cholangiocellular carcinoma, and 48 for other primary hepatic tumors. One hundred fifty-eight patients underwent segment-oriented liver resection, including hemihepatectomies, and 100 had subsegmental resections. Thirty-two clinical and biochemical parameters were analyzed, including liver function assessment by the galactose elimination capacity (GEC) test, a measure of hepatic functional reserve, to predict postoperative (60-day) rates of death and complications and long-term survival. All variables were determined within 5 days before surgery. Data were subjected to univariate and multivariate analysis for two patient subgroups (HCC and non-HCC). The cutoffs for GEC in both groups were predefined. Long-term survival (>60 days) was subjected to Kaplan-Meier analysis and the Cox proportional hazard model.

RESULTS

In the entire group of 258 patients, a GEC less than 6 mg/min/kg was the only preoperative biochemical parameter that predicted postoperative complications and death by univariate and stepwise regression analysis. A GEC of more than 6 mg/min/kg was also significantly associated with longer survival. This predictive value could also be shown in the subgroup of 180 patients with tumors other than HCC. In the subgroup of 78 patients with HCC, a GEC less than 4 mg/min/kg predicted postoperative complications and death by univariate and stepwise regression analysis. Further, a GEC of more than 4 mg/min/kg was also associated with longer survival.

CONCLUSIONS

This prospective study establishes the preoperative determination of the hepatic reserve by GEC as a strong independent and valuable predictor for short- and long-term outcome in patients with primary and secondary hepatic tumors undergoing resection.

Antipyrine clearance in chronic and neoplastic liver diseases: a study of 518 patients

Antipyrine metabolism is widely used as an index of the drug-metabolizing reserve of the liver. It is well known that metabolism of this drug is impaired in subjects with acute hepatitis or cirrhosis, but conflicting data have been reported regarding patients with chronic postinfectious hepatitis or liver cancer. We studied conventional liver-function parameters and antipyrine metabolism (antipyrine per o.s. 18 mg/kg) in 518 subjects. One hundred and one patients had liver metastases (various primaries). Based on the number and size of lesions, the hepatic involvement was considered minimal in 47 and massive in 54 (groups B1 and B2, respectively). One hundred and two had chronic active hepatitis (CAH); 51 patients with histological evidence of fibrosis/early cirrhosis and 51 patients were without histological evidence of fibrosis/early cirrhosis. Ninety-two had histologically confirmed cirrhosis (group D), and the remaining 120 had cirrhosis and hepatocellular carcinoma (group E). The control group was composed of 103 subjects with healthy livers (group A). Antipyrine clearance (AP Cl) in CAH patients with fibrosis (0.246 +/- 0.98 mL/min per kg) was similar to that observed in patients with cirrhosis (0.223 +/- 0.148 mL/min per kg), and both values were significantly lower than that found in CAH patients without fibrosis (0.406 +/- 0.159 mL/min per kg, P < 0.01). Antipyrine clearance in patients with liver metastases (0.426 +/- 0.174 mL/min per kg) was similar to that of the healthy group (0.489 +/- 0.210 mL/min per kg). Cirrhotics and cirrhotics with hepatocellular carcinoma (HCC) presented similar degrees of impairment. Antipyrine clearance was positively correlated with serum albumin (r2 = 0.10, P = 0.01) and prothrombin time (r2 = 0.129, P < 0.01) in all groups, except those with liver metastases. In patients with CAH, the presence of fibrosis/cirrhosis is associated with impaired antipyrine metabolism. The lack of impairment in groups with liver metastases suggests that the functional hepatic reserve is maintained even in the presence of massive neoplastic invasion.

Assessment of doxylamine influence on mixed function oxidase activity upon multiple dose oral administration to normal volunteers

The primary purpose of this study was to assess the influence of doxylamine and phenobarbital on antipyrine/metabolites pharmacokinetics and 6 beta-hydroxycortisol urinary excretion. This study was conducted in 48 healthy male human volunteers (16 per treatment group) using a parallel study design. Treatment groups consisted of 12.5 mg of doxylamine succinate, placebo, or 30 mg of phenobarbital administered orally every 6 h for 17 days. Results indicate that no statistically significant differences were observed between the doxylamine and placebo groups that are indicative of enzyme induction. For the phenobarbital group, a significant increase for antipyrine total (36 versus 45 mL/h/kg) and nonrenal (35 versus 44 mL/h/kg) clearances and 6 beta-hydroxycortisol excretion (338 versus 529 micrograms) and a significant decrease in the terminal exponential half-life (11 versus 9 h) of antipyrine were observed.

Variables affecting nicotine metabolism

Nicotine metabolism is exceedingly sensitive to perturbation by numerous host factors. To reduce the large variations and discrepancies in the literature pertaining to nicotine metabolism, investigators in future studies need to recognize and better control these host factors. Recent advances in the understanding of nicotine metabolism have suggested new approaches to elucidating underlying mechanisms of certain toxic effects associated with cigarette smoking.