Population Pharmacokinetic Analysis of Bisoprolol in Patients With Acute Coronary Syndrome.

To date, many questions about the extent and cause of pharmacokinetic (PK) variability of even the most widely studied and prescribed ß1-adrenergic receptor blockers, such as metoprolol and bisoprolol, remain unanswered. Given that there are still no published population pharmacokinetic (PopPK) analyses of bisoprolol in routinely treated patients with acute coronary syndrome (ACS), the aim of this study was to determine its PK variability in 71 Serbian patients with ACS. PopPK analysis was conducted using a nonlinear mixed-effects model (NONMEM), version 7.3.0 (Icon Development Solutions). In each patient, the same formulation of bisoprolol was administered once or twice daily at a total daily dose of 0.625-7.5 mg. We separately assessed the effects of 31 covariates on the PKs of bisoprolol, and our results indicated that only 2 covariates could have possible influence on the variability of the clearance of bisoprolol: the mean daily dose of the drug and smoking habits of patients. These findings suggest that possible autoinduction of drug metabolism by higher total daily doses and induction of cytochrome P450 isoform 3A4 (CYP3A4) by cigarette smoke in liver could be the potential causes of increased total clearance of bisoprolol in patients with ACS.

Forecasting oral absorption across biopharmaceutics classification system classes with physiologically based pharmacokinetic models.

OBJECTIVES: The aim of this study was (1) to determine how closely physiologically based pharmacokinetic (PBPK) models can predict oral bioavailability using a priori knowledge of drug-specific properties and (2) to examine the influence of the biopharmaceutics classification system class on the simulation success. METHODS: Simcyp Simulator, GastroPlus™ and GI-Sim were used. Compounds with published Biowaiver monographs (bisoprolol (BCS I), nifedipine (BCS II), cimetidine (BCS III), furosemide (BCS IV)) were selected to ensure availability of accurate and reproducible data for all required parameters. Simulation success was evaluated with the average fold error (AFE) and absolute average fold error (AAFE). Parameter sensitivity analysis (PSA) to selected parameters was performed. KEY FINDINGS: Plasma concentration-time profiles after intravenous administration were forecast within an AAFE < 3. The addition of absorption processes resulted in more variability in the prediction of the plasma profiles, irrespective of biopharmaceutics classification system (BCS) class. The reliability of literature permeability data was identified as a key issue in the accuracy of predicting oral drug absorption. CONCLUSION: For the four drugs studied, it appears that the forecasting accuracy of the PBPK models is related to the BCS class (BCS I > BCS II, BCS III > BCS IV). These results will need to be verified with additional drugs.

Bisoprolol pharmacokinetics and body composition in patients with chronic heart failure: a longitudinal study.

PURPOSE: We investigated bisoprolol pharmacokinetics, including longitudinal changes and importance of patient characteristics in chronic heart failure. METHODS: Forty-six patients with chronic heart failure (57 % male, NYHA class I/II/III = 2/36/8) were followed for an average of 8 ± 2 months. At baseline and follow-up, plasma bisoprolol concentrations were determined and body composition was measured using dual-energy X-ray absorptiometry. A bisoprolol pharmacokinetic model was built with non-linear mixed-effects modeling to analyze the association with various parameters of body composition. RESULTS: Mean bisoprolol clearance (10.2 L/h) was 30 % lower than in healthy individuals and correlated with MDRD4-estimated renal function. The mean volume of distribution (230 L) was similar to healthy population and was associated with total body mass and skeletal muscle index (SMI). During follow-up, we observed minor changes in the absorption rate constant (2.83 vs. 2.27 h(-1), P = 0.030) and volume of distribution (227 vs. 250 L, P = 0.004), which are not clinically relevant. CONCLUSIONS: In patients with chronic heart failure, bisoprolol clearance was associated with estimated renal function; thus, in moderately and severely decreased renal function, patients may need to have their dose adjusted. Patients with low body weight or low SMI have greater fluctuations and higher maximal plasma concentrations of bisoprolol because of the lower volume of distribution. Longitudinal changes of bisoprolol pharmacokinetics were not associated with changes in body composition.

Variability of bioavailability and intestinal absorption characteristics of bisoprolol.

We previously reported that renal function is partly responsible for the interindividual variability of the pharmacokinetics of bisoprolol. The aim of the present study was to examine the variability of bioavailability (F) of bisoprolol in routinely treated Japanese patients and intestinal absorption characteristics of the drug. We first analyzed the plasma concentration data of bisoprolol in 52 Japanese patients using a nonlinear mixed effects model. We also investigated the cellular uptake of bisoprolol using human intestinal epithelial LS180 cells. The oral clearance (CL/F) of bisoprolol in Japanese patients was positively correlated with the apparent volume of distribution (V/F), implying variable F. The uptake of bisoprolol in LS180 cells was temperature-dependent and saturable, and was significantly decreased in the presence of quinidine and diphenhydramine. In addition, the cellular uptake of bisoprolol dissolved in an acidic buffer was markedly less than that dissolved in a neutral buffer. These findings suggest that the rate/extent of the intestinal absorption of bisoprolol is another cause of the interindividual variability of the pharmacokinetics, and that the uptake of bisoprolol in intestinal epithelial cells is highly pH-dependent and also variable.

[Urinary bladder tuberculosis and bacillus calmette-guérin instillation: reduced efficacy of bisoprolol in hypertension]. / Tuberkulose durch Bacillus-Calmette-Guérin-Instillation bei Blasenkarzinom und Hypertonie.

HISTORY AND ADMISSION FINDINGS: A 71-year-old patient with a superficial carcinoma of the urinary bladder and high risk of recurrence was treated with intravesical instillation of Bacillus Calmette-Guérin (BCG) after transurethral resection. As a complication of the catheterization during BCG-instillation therapy the patient suffered from tuberculosis. The patient received a tuberculosis triple-therapy including rifampicin 600 mg once daily, isoniazid 300 mg once daily and ethambutol 400 mg thrice daily. The existing arterial hypertension had successfully been controlled by 3.75 mg bisoprolol medication once daily for the last 15  years. An increase of blood pressure and cardiac arrhythmia were seen after combining the ß (1)-receptor blocker treatment with the triple-therapy. INVESTIGATIONS AND DIAGNOSIS: The blood pressure was 160 / 90 mmHg. The heart rate reflected a value of 98  beats per minute. In the resting ECG monotopic ventricular extrasystoles could be diagnosed. TREATMENT AND COURSE: The dosage of bisoprolol was changed to 3.75 mg in the morning and additional 1.875 mg in the evening. Due to this increase of dosage the blood pressure could be controlled sufficiently. CONCLUSION: Rifampicin is one of the best known potent enzyme inducing drugs. It strongly induces the expression of cytochrome P450 3A4 in the liver. The enzyme induction enhance the hepatic bisoprolol metabolism, hence the metabolic clearance of the drug increased. The maximal plasma level of bisoprolol decrease and in our use the arterial hypertension could not be treated sufficiently. It is well known that half the dose of bisoprolol undergoes oxidative metabolism in the liver and the rest eliminated unchanged in the kidney. A dosage adjustment of bisoprolol is necessary if the clinical status of the patient requires treatment with the antituberculosis drug rifampicin.

[Urinary bladder tuberculosis and Bacillus Calmette-Guérin instillation: reduced efficacy of bisoprolol in hypertension]. / Tuberkulose durch Bacillus-Calmette-Guérin-Instillation bei Blasenkarzinom und Hypertonie: Verminderte Bisoprolol-Wirkung durch Rifampicin.

HISTORY AND ADMISSION FINDINGS: A 71-year-old patient with a superficial carcinoma of the urinary bladder and high risk of recurrence was treated with intravesical instillation of Bacillus Calmette-Guérin (BCG) after transurethral resection. As a complication of the catheterization during BCG-instillation therapy the patient suffered from tuberculosis. The patient received a tuberculosis triple-therapy including rifampicin 600 mg once daily, isoniazid 300 mg once daily and ethambutol 400 mg thrice daily. The existing arterial hypertension had successfully been controlled by 3.75 mg bisoprolol medication once daily for the last 15 years. An increase of blood pressure and cardiac arrhythmia were seen after combining the ß1-receptor blocker treatment with the triple-therapy. INVESTIGATIONS AND DIAGNOSIS: The blood pressure was 160/90 mm Hg. The heart rate reflected a value of 98 beats per minute. In the resting ECG monotopic ventricular extrasystoles could be diagnosed. TREATMENT AND COURSE: The dosage of bisoprolol was changed to 3.75 mg in the morning and additional 1.875 mg in the evening. Due to this increase of dosage the blood pressure could be controlled sufficiently. CONCLUSION: Rifampicin is one of the best known potent enzyme inducing drugs. It strongly induces the expression of cytochrome P450 3A4 in the liver. The enzyme induction enhance the hepatic bisoprolol metabolism, hence the metabolic clearance of the drug increased. The maximal plasma level of bisoprolol decrease and in our use the arterial hypertension could not be treated sufficiently. It is well known that half the dose of bisoprolol undergoes oxidative metabolism in the liver and the rest eliminated unchanged in the kidney. A dosage adjustment of bisoprolol is necessary if the clinical status of the patient requires treatment with the antituberculosis drug rifampicin.