Pharmacokinetic changes in drugs during protein-calorie malnutrition: correlation between drug metabolism and hepatic microsomal cytochrome P450 isozymes.

The rats with protein-calorie malnutrition (PCM, 5% casein diet for a period of 4-week) were reported to exhibit 60 and 80% suppression in the hepatic microsomal cytochrome P450 (CYP) 1A2 and CYP2C11 levels, respectively, and 40-50% decreases in CYP2E1 and CYP3A1/2 levels compared to control (23% casein diet for a period of 4-week) based on Western blot analysis. In addition, Northern blot analysis showed that CYP1A2, CYP2E1, CYP2C11, and CYP3A1/2 mRNAs decreased in the state of PCM as well. Hence, pharmacokinetic changes of the drugs in rats with PCM [especially the area under the plasma concentration-time curve from time zero to time infinity (AUC) changes of metabolite(s)] reported from literatures were tried to explain in terms of CYP isozyme changes in the rats. Otherwise, the time-averaged nonrenal clearance (CL NR) of parent drug was compared. Pharmacokinetic changes of the drugs in other types of malnutritional state, such as kwashiorkor and marasmus, in both human and animal models were also compared. The drugs reviewed are as follows: diuretics, antibiotics, anticancer agents, antiepileptics, antiarrythmics, analgesics, xanthines, antimalarials, and miscellaneous.

Comparison of lenograstim and filgrastim on haematological effects after autologous peripheral blood stem cell transplantation with high-dose chemotherapy.

OBJECTIVE: To compare the efficacy of lenograstim and filgrastim on haematological recovery following an autologous peripheral blood stem cell transplantation (PBSCT) with high-dose chemotherapy. METHODS: A retrospective case-controlled study. RESULTS: Absolute neutrophil count (ANC) recovery above 0.5 x 10(9)/l and white blood cell (WBC) recovery above 4 x 10(9)/l for 3 consecutive days was achieved earlier with filgrastim than with lenograstim ((13.2 +/- 8.0 vs 19.0 +/- 10.0 days, p = 0.004), (16.9 +/- 9.7 vs 29.9 +/- 16.6 days, p = 0.001), respectively). The platelet recovery above 20 x 10(9)/l was also achieved earlier with filgrastim than with lenograstim (19.5 +/- 11.6 vs 27.2 +/- 13.8 days, p = 0.006). Furthermore, filgrastim-treated patients received fewer days of granulocyte colony simulating factor (G-CSF) administration (12.5 +/- 7.0 vs 18.6 +/- 8.5 days, p = 0.001) and spent less time in hospital (23.7 +/- 10.9 vs 32.0 +/- 17.6 days, p = 0.009). Duration of antibiotic administration was also significantly shorter in the filgrastim group (13.6 +/- 7.6 vs 29.1 +/- 19.8 days, p = 0.001). CONCLUSION: In patients undergoing PBSCT following high-dose chemotherapy, filgrastim significantly reduced the duration of neutropenia, thrombocytopenia and days of G-CSF administration, and led to earlier hospital discharge compared with lenograstim.

Pharmacokinetics of intravenous theophylline in mutant Nagase analbuminemic rats.

It was obtained from our laboratories that the expression of hepatic microsomal cytochrome P450 (CYP) 1A2 increased approximately 3.5 times in mutant Nagase analbuminemic rats (NARs, an animal model for human familial analbuminemia), and theophylline was reported to be metabolized to 1,3-dimethyluric acid (1,3-DMU) and 1-methylxanthine (which was further metabolized to 1-methyluric acid, 1-MU, via xanthine oxidase) via CYP1A2 in rats. Hence, the pharmacokinetic parameters of theophylline, 1,3-DMU and 1-MU were compared after intravenous administration of aminophylline, 5 mg/kg as theophylline, to control Sprague-Dawley rats and NARs. In NARs, the total area under the plasma concentration-time curve from time zero to time infinity (AUC) of theophylline was significantly smaller (1,040 versus 1,750 microg min/ml) than that in control rats and this could be due to significantly faster renal clearance (CL(R), 1.39 versus 0.571 ml/min/kg, due to inhibition of renal reabsorption of unchanged theophylline) and nonrenal clearance (CL(NR), 3.36 versus 2.25 ml/min/kg, due to 3.5-fold increase in CYP1A2) than those in control rats. Based on in vitro hepatic microsomal studies, the intrinsic 1,3-DMU formation clearance was significantly faster in NARs than that in control rats (267 versus 180 x 10(-6) ml/min). After intravenous administration of 1,3-DMU, the renal secretion of 1,3-DMU was inhibited in NARs. Inhibition of renal secretion or reabsorption of various compounds in NARs was also discussed.

Influence of 4-week and 8-week exercise training on the pharmacokinetics and pharmacodynamics of intravenous and oral azosemide in rats.

Cytochrome P450 expression was determined in the livers of control, 4-week exercised (4WE) and 8-week exercised (8WE) rats. Even though the 4-week and 8-week exercise training caused 53 and 25% increases, respectively, in total cytochrome P450 contents in the liver, exercise training did not cause any changes in the levels of P450 1A2 (which primarily metabolizes azosemide), 2E1 and 3A23 in the liver, as assessed by both Western and Northern blot analyses. Also, exercise training failed to alter the activity of NADPH-dependent cytochrome P450 reductase. The plasma concentrations of norepinephrine and epinephrine were significantly (2 to 3 folds) higher in 4WE rats than in controls, presumably due to physical stress, but the catecholamine levels in 8 WE rats returned to control levels. After intravenous administration (10 mg/kg of azosemide), the amount of unchanged azosemide excreted in 8-h urine (Ae(Azo, 0-8 h)) was significantly greater (46% increase) in 4WE rats than that in control rats. This resulted in a significantly faster (82% increase) renal clearance of azosemide. However, the nonrenal clearances were not significantly different between control and 4WE rats. The significantly greater Ae(Azo, 0-8 h) in 4WE rats was mainly due to a significant increase in intrinsic active secretion of azosemide in renal tubules and not due to a decrease in the metabolism of azosemide. After oral administration (20 mg/kg), Ae(Azo, 0-8 h) was also significantly greater (264%) in 4WE rats and this again was due to a significant increase in intrinsic active renal secretion of azosemide and not due to an increase in gastrointestinal absorption. After both intravenous and oral administration, the 8-h urine output was not significantly different between control and 4WE rats although Ae(Azo, 0-8 h) increased significantly in 4WE rats. This could be due to the fact that the urine output reached a plateau at 10 mg/kg after intravenous administration and 20 mg/kg after oral administration of azosemide to rats and possibly due to increase in plasma antidiuretic hormone levels and aldosterone production in 4WE rats.