Pharmacokinetic, pharmacodynamic, and safety evaluation of an accelerated dose titration regimen of sotalol in healthy middle-aged subjects.

BACKGROUND: Current labeling recommends that therapy with sotalol be initiated in a monitored setting at 80 mg every 12 hours for 2 to 3 days, followed by 120 to 160 mg every 12 hours for at least 2 days before safety and efficacy can be ascertained and patients discharged. An accelerated titration regimen that shortens hospital stay without compromising patient safety would improve the usefulness of the drug. Although such regimens have been used by clinicians, they have not been formally evaluated. METHODS: Healthy, middle-aged sedentary men and women received sotalol in a double-blind, two-way crossover study with a 2-week washout phase to evaluate an accelerated titration regimen--placebo every 6 hours for four doses, followed by 80 mg sotalol every 6 hours for four doses, then 160 mg sotalol every 12 hours for nine doses--and compare it with the standard titration--placebo alternating with 80 mg sotalol every 6 hours for eight doses, followed by 160 mg sotalol every 12 hours for nine doses. QT intervals, RR intervals, and sotalol concentrations in plasma were measured at specific times throughout the study and during washout in a similar fashion for both regimens. RESULTS: Thirty-four subjects completed both regimens. The target prolongation of QTc (90% of the value achieved at steady state) was achieved 22 1/2 hours sooner with the accelerated titration regimen (P = .0003). There were no cardiovascular adverse events during either loading phase. At no time during the accelerated titration regimen did the sotalol concentrations in plasma or the QTc or RR interval prolongation exceed the values eventually achieved at steady state. The relationship between sotalol concentration and QTc was linear and independent of the regimen. CONCLUSION: The accelerated titration regimen for sotalol can shorten the time to attain the dosage usually required to effectively control arrhythmias, without excessive QT prolongation and the associated increased risk of torsades de pointes. The hospital stay of patients in whom antiarrhythmic therapy with sotalol is initiated can be shortened by 1 day if this accelerated titration regimen is used.