Torborinone

The pharmacokinetics of toborinone was studied in subjects with congestive heart failure (CHF) and concomitant renal and/or hepatic disease. At the time of admission, subjects were grouped based on estimated creatinine clearance and serum bilirubin. Glomerular filtration rate was assessed using iothalamate clearance. Hepatic function was assessed using the caffeine metabolism test and indocyanine green clearance. No significant differences were observed in mean toborinone pharmacokinetic parameters among the four study groups. Positive correlations were observed between toborinone clearance and the measured indices of renal and hepatic function: creatinine clearance, iothalamate renal clearance, paraxanthine/caffeine ratio, and indocyanine green clearance. Toborinone clearance decreased with decreasing creatinine clearance, decreasing glomerular filtration rate, decreasing demethylation metabolic activity, and decreasing hepatic blood flow, although no significant differences were observed in any mean toborinone pharmacokinetic parameters evaluated among the four study groups.

To review systematically the use of intravenous (IV) inotropic agents acting through the adrenergic signalling pathway, compared with placebo or an active agent, in patients with heart failure.

Studies investigating the use of intravenous inotropes in patients with heart failure published between 1966 and 2000 were identified using MEDLINE, the Cochrane register and Embase databases. Reference lists from relevant papers and reviews were hand searched for further papers. In total, 21 trials, that included 632 patients receiving IV inotropic drugs, placebo or non‐treatment control, were identified. Drugs of the following classes were included, the β‐agonists; dobutamine, high‐dose (>2.5 μg/kg/min) dopamine, dopexamine and the phosphodiesterase (PDE) inhibitors; amrinone, milrinone, enoximone and toborinone. Sixteen trials (474 patients) contributed data from acute invasive haemodynamic studies of symptomatically severe heart failure. Five trials (158 patients) were based on intermittent inotropic therapy in an outpatient context.

With few exceptions, trials of intravenous inotropic agents were small and often failed to report clinically important outcomes. Compared to placebo, intravenous inotropic agents acting through the adrenergic system tended to increase mortality (odds ratio 1.50 (95% CI‐0.51 to 3.92) but this did not reach significance and insufficient data were available to determine whether symptoms improved. There appeared to be little difference in the effect of beta‐agonists compared to PDE inhibitors on patient outcomes but this could be attributed to the paucity of data.

Intravenous inotropic agents acting through the adrenergic pathway are often used in patients with worsening heart failure to achieve arbitrary haemodynamic targets. Our analyses show that there is very little evidence that such treatment improves symptoms or patient outcomes and may not be safe. This highlights the need for further well designed randomised clinical trials.