Angiotensin II Receptor Blockers Inhibit the Generation of Epoxyeicosatrienoic Acid from Arachidonic Acid in Recombinant CYP2C9, CYP2J2 and Human Liver Microsomes.

Cytochrome P450 (CYP) 2C9, CYP2C8 and CYP2J2 enzymes, which metabolize arachidonic acid (AA) to epoxyeicosatrienoic acids, have cardioprotective effects including anti-inflammation and vasodilation. We have recently shown that some angiotensin II receptor blockers (ARBs) may inhibit AA metabolism via CYP2C8. Using recombinant CYP2C9, CYP2J2 and human liver microsomes (HLMs), the aim was now to compare the ability of six different clinically used ARBs to inhibit AA metabolism in vitro. The rank order of the ARBs for the 50% inhibitory concentration (IC50 ) of AA metabolism was losartan

[Pharmacokinetic drug interaction between miconazole mucoadhesive tablet and tacrolimus: About 3 case-reports in transplant patients]. / Interaction pharmacocinétique entre la forme mucoadhésive de miconazole et le tacrolimus : à propos de 3 observations cliniques chez des patients greffés.

Loramyc® is a mucoadhesive tablet of miconazole, indicated for the treatment of oropharyngeal candidiasis in immunocompromised patients. Miconazole, as others azole antifungals, is known for its potent inhibitory properties of cytochromes P450 enzymes and P-glycoprotein (P-gp). Inhibition of cytochromes P450 enzymes and P-gp can produce pharmacokinetic drug interaction. Immunosuppressive agents, such as calcineurin inhibitors (tacrolimus, cyclosporine) are substrates of cytochromes P450 3A4 and P-gp. Nevertheless, the impact of systemic absorption of miconazole mucoadhesive tablet has not been investigated by the laboratory before regulatory approval. No recommendation currently exists in case of co-prescription of Loramyc® and immunosuppressive agents which are counter-indicated as a matter of principle. Herein, we present 3 cases of transplanted patients, requiring miconazole mucoadhesive tablet, who presented a tacrolimus overdose. These cases illustrate that of therapeutic drug monitoring is feasible in order to prevent the occurrence of overdoses and adverse reactions related.

Therapeutic effect of atorvastatin on kidney functions and urinary excretion of Glimepiride in healthy adult human male subjects.

Glimepiride and atorvastatin in combination are commonly employed for treating the hyperglycemia and dyslipidemia, respectively, in patients of type 2 diabetes. The present study was designed to find out the influence of atorvastatin on urinary excretion and renal clearance of Glimepiride in healthy adult male volunteers. In each experimental subject, Glimepiride 2mg was given orally after an overnight fasting. Samples of blood and urine were taken at different specific time intervals. After a washout period of ten days, Glimepiride 2mg was co-administered with atorvastatin 20mg orally. Post-medication, blood and urine samples were collected following the same sampling schedule as for Glimepiride alone. The samples were analyzed for Glimepiride and creatinine concentration by HPLC-UV and Spectrophotometer, respectively. Mean (±SE) values for blood pH 7.445±0.05 and 7.382±0.05, urine pH 4.972±0.08 and 5.08±0.10, diuresis 0.0207±0.00 and 0.0237±0.00ml/min/kg, endogenous creatinine in plasma 9.048±0.33 and 8.613±0.024µg/ml, endogenous creatinine in urine 512.34±18.20 and 556.72±4.60µg/ml, Glimepiride plasma concentration 0.16069±0.00 and 0.3227±0.01µg/ml, Glimepiride urine concentration 1.5994±0.03 and 0.8665±0.04µg/ml, renal clearance of creatinine 1.224±0.09 and 1.550±0.09ml/min/kg, renal clearance of Glimepiride 0.2064±0.01 and 0.0641±0.00ml/min/kg and clearance ratio 0.1791±0.01 and 0.0414±0.00 were observed for Glimepiride alone and its concurrent administration with atorvastatin, respectively. Atorvastatin decreased the urinary excretion and renal clearance of Glimepiride due to which chances of hypoglycemia provokes and renal handling of Glimepiride involves back diffusion besides glomerular filtration and no influence of atorvastatin was seen on these mechanisms.

Inhibitory effects of curcumin on activity of cytochrome P450 2C9 enzyme in human and 2C11 in rat liver microsomes.

Cytochrome P450 2C9 (CYP2C9), one of the most important phase I drug metabolizing enzymes, could catalyze the reactions that convert diclofenanc into diclofenac 4'-hydroxylation. Evaluation of the inhibitory effects of compounds on CYP2C9 is clinically important because inhibition of CYP2C9 could result in serious drug-drug interactions. The objective of this work was to investigate the effects of curcumin on CYP2C9 in human and cytochrome P450 2C11 (CYP2C11) in rat liver microsomes. The results showed that curcumin inhibited CYP2C9 activity (10 µmol L(-1) diclofenac) with half-maximal inhibition or a half-maximal inhibitory concentration (IC50) of 15.25 µmol L(-1) and Ki = 4.473 µmol L(-1) in human liver microsomes. Curcumin's mode of action on CYP2C9 activity was noncompetitive for the substrate diclofenanc and uncompetitive for the cofactor NADPH. In contrast to its potent inhibition of CYP2C9 in human, diclofenanc had lesser effects on CYP2C11 in rat, with an IC50 ≥100 µmol L(-1). The observations imply that curcumin has the inhibitory effects on CYP2C9 activity in human. These in vitro findings suggest that more attention should be paid to special clinical caution when intake of curcumin combined with other drugs in treatment.