Biomedical subjects

Christian Funck-Brentano

Publications and source records attributed to Christian Funck-Brentano.

23 records · Page 2Linked to original sources

PubMed2002

Renal and vascular effects of S21402, a dual inhibitor of angiotensin-converting enzyme and neutral endopeptidase, in healthy subjects with hypovolemia.

OBJECTIVE: To examine the mechanism of action of dual inhibitors of angiotensin-converting enzyme (ACE) and neutral endopeptidase, also called vasopeptidase inhibitors, we compared the effects of S21402 [(2S)-2-[(2S,3R)-2-thiomethyl-3-phenylbutanamido]propionic acid], which belongs to this pharmacologic class, with those of captopril, an ACE inhibitor, on blood pressure, endocrine parameters, and renal in healthy subjects with hypovolemia. METHODS: Ten subjects participated to this double-blind, 2-period, randomized, crossover study. Hypovolemia was induced in these subjects with a 7-day treatment of hydrochlorothiazide. They received a single oral dose of 50 mg captopril or 250 mg S21402 on the last day of diuretic treatment. Blood pressure was measured, and urine and blood samples were collected before and during a 12-hour period after drug administration. RESULTS: The plasma angiotensin II/angiotensin I ratio and aldosterone concentration decreased to the same degree with both drugs, 3 hours after dosing. Compared with captopril, S21402 increased levels of plasma atrial natriuretic peptide (P <.05) and urinary cyclic guanosine monophosphate (P <.001); these increases were the result of inhibition of neutral endopeptidase activity (P <.001). The increase in plasma renin concentration related to ACE inhibition was less marked (P <.001) after S21402 than after captopril. S21402, but not captopril, increased urinary sodium excretion (P <.05), without modifying blood pressure and creatinine clearance, whereas blood pressure transiently fell after captopril administration (P <.05). CONCLUSIONS: In healthy hypovolemic subjects, the vasopeptidase inhibitor S21402 exhibits a natriuretic effect and does not affect blood pressure or glomerular filtration rate. In these conditions, the acute endocrine, vascular, and renal effects of vasopeptidase inhibition differ from those of ACE inhibition.

Adult↗

PubMed2002

Pharmacokinetics and electrocardiographic effects of a new controlled-release form of flecainide acetate: comparison with the standard form and influence of the CYP2D6 polymorphism.

OBJECTIVES: Our objectives were study the single- and repeated-dose pharmacokinetics and electrocardiographic effects (QRS duration) of a new controlled-release form of flecainide acetate compared with the immediate-release form and to examine the influence of CYP2D6 activity. METHODS: Twenty-four healthy subjects (6 men and 6 women at both dosages) received single and repeated doses of 100 or 200 mg immediate-release and controlled-release flecainide in a randomized crossover design. Electrocardiograms were recorded and flecainide plasma concentrations were measured before administration and up to 96 hours after administration. RESULTS: The controlled-release formulation had sustained-release properties, with a significantly lower maximum concentration (C(max)) and delayed time to reach C(max). Compared with the immediate-release formulation, the relative bioavailability of the controlled-release formulation at steady state was 0.85 +/- 0.17 and 0.89 +/- 0.17 for the 100-mg/day and 200-mg/day doses, respectively. Trough flecainide plasma concentration at steady state was bioequivalent for both formulations. Maximum and minimum QRS increases were not significantly different for either the immediate-release or the controlled-release form of flecainide after administration of both single and repeated doses. Mean QRS duration during a dosing interval at steady state correlated with mean plasma concentration for both forms (pooled data; P <.001). The 95% confidence interval for this regression was 26% narrower for the controlled-release form than for the immediate-release form. Flecainide-induced QRS prolongation and pharmacokinetics were not significantly influenced by CYP2D6 activity. CONCLUSIONS: Flecainide-induced QRS prolongation did not differ between the new controlled-release form and the immediate-release form. Flecainide plasma concentrations associated with the new controlled-release form predicted QRS prolongation with less variability compared with the immediate-release form. The CYP2D6 polymorphism did not appear to influence flecainide disposition kinetics or electrocardiographic effects at steady state.

Adult↗

PubMed2002

Pharmacokinetic and pharmacodynamic interaction between grapefruit juice and halofantrine.

BACKGROUND: Halofantrine, an antimalarial drug that prolongs the QT interval, is metabolized into N-debutyl-halofantrine by cytochrome P450 (CYP) 3A4. Grapefruit juice increases the bioavailability of several orally administered CYP3A4 substrates by inhibiting CYP3A4 at the enterocyte level and could therefore increase the risk of halofantrine-induced QT interval prolongation. We studied the effect of grapefruit juice on halofantrine bioavailability and on QT interval prolongation associated with its oral administration. METHODS: Twelve healthy male and female volunteers received 500 mg of halofantrine with 250 mL of water, orange juice, or grapefruit juice (250 mL once a day of regular strength for 3 days and once at 12 hours before halofantrine administration), in a random order, during a crossover study. Plasma pharmacokinetics of halofantrine and N-debutyl-halofantrine and QTc interval duration were studied during the following 168 hours. RESULTS: Compared with water, grapefruit juice increased halofantrine area under the plasma concentration versus time curve (AUC) and peak plasma concentration by 2.8-fold +/- 1.5-fold (P <.0001) and 3.2-fold +/- 1.3-fold (P <.0001), respectively. There was a concomitant 2.4-fold +/- 1.6-fold decrease in N-debutyl-halofantrine AUC (P <.01) but no significant change in halofantrine elimination half-life. Maximum QTc interval prolongation increased from 17 +/- 6 ms when halofantrine was administered with water to 31 +/- 12 ms when it was administered with grapefruit juice (P <.0005). Multiple regression analysis showed that QTc interval prolongation was better correlated with halofantrine (partial r = 0.432; P <.0001) than with N-debutyl-halofantrine (partial r = 0.117; P <.01) concentrations. There was no significant difference between the water and orange juice study periods. CONCLUSIONS: Grapefruit juice increases halofantrine bioavailability and halofantrine-induced QT interval prolongation. Grapefruit juice should be contraindicated during administration of halofantrine.

Adult↗

PubMed2002

The role of the critical event committee in a major cardiovascular outcome study.

Outcome studies in cardiovascular diseases such as hypertension are often based in a number of countries recruiting from multiple centres. This can lead to difficulties in end-point evaluation and classification. The INSIGHT study provided the unique opportunity to examine the role and usefulness of a Critical Event Committee (CEC) established to examine all events occurring in a cohort of 6321 patients and classifying them according to pre-determined criteria. More than 28% of investigator-coded primary events and more than 41% of secondary events were re-classified by the CEC. Particularly difficult diagnoses included myocardial infarction, angina and heart failure, and the database finally analysed was substantially altered after CEC Committee evaluation. Post hoc analysis of the INSIGHT database demonstrated that the primary events compared would have been reduced from 6.3% vs 5.8% of those randomized on nifedipine vs co-amilozide to 5.1% vs 4.7%--an overall reduction of 72 events of 382, a fall of 18.8%. We conclude that a CEC should be a crucial component of any large outcome study and that if all events are subjected to scrutiny, the quality of the database is greatly enhanced.

Calcium Channel Blockers↗

PubMedDate not supplied

Postoperative analgesia and recovery course after major colorectal surgery in elderly patients: a randomized comparison between intrathecal morphine and intravenous PCA morphine.

BACKGROUND AND OBJECTIVES: Intrathecal morphine is a widely used method for postoperative pain relief after major abdominal surgery. The aim of this randomized, double-blinded study was to compare intrathecal morphine and intravenous PCA morphine for postoperative analgesia and recovery course after major colorectal surgery in elderly patients. METHODS: After written informed consent, patients >70 years of age were prospectively and randomly assigned to receive either preoperative intrathecal morphine (0.3 mg) and postoperative patient-controlled (PCA) intravenous morphine (IT morphine) or PCA alone (group control). Results are presented as mean +/- SD (95% confidence interval). RESULTS: Twenty-six patients successfully completed the study in each group. In the IT morphine group, rate of awakening was delayed. Pain intensity and daily intravenous morphine consumption were significantly reduced 1 and 2 days after surgery in the IT morphine group (P < .01). Mental function (assessed by Mini Mental State and Digit Symbol Substitution Test) was similar in both groups. Episodes of postoperative delirium/confusion occurred similarly in both groups. Time to ileus resolution and time to ambulation without assistance did not differ between the 2 groups. The duration of hospitalization was 8.4 +/- 1.7 (7-11) days and 7.9 +/- 2.0 (6-9.9) days for control and IT morphine, respectively (nonstatistical difference). Patients in the IT morphine group had longer time to awakening from anesthesia and experienced more sedation. CONCLUSIONS: Intrathecal morphine, as compared with intravenous PCA morphine alone, improves immediate postoperative pain and reduces parenteral morphine consumption but does not improve postoperative recovery in elderly patients after major colorectal surgery.

Aged↗