Absorption kinetics of oral sotalol combined with cisapride and sublingual sotalol in healthy subjects

Aims - To study the absorption kinetics of sotalol following administration of different formulations. A formulation which results in fast absorption might be useful in the episodic treatment of paroxysmal supraventricular tachycardia (SVT), atrial fibrillation (Afib) or atrial flutter (Afl). Methods - In an open randomized crossover study seven healthy male volunteers were given an intravenous infusion of 20 mg sotalol, for assessing the absolute bioavailability, an oral solution containing 80 mg sotalol, an oral solution containing both 80 mg sotalol and 20 mg cisapride and an 80 mg sotalol tablet, which was taken sublingually. Results - The addition of cisapride decreased the time at which maximum serum concentrations were reached (t(max)) from 2.79 (1.85-4.34) h to 1.16 (0.68-2.30) h (P = 0.009) [95% CI: -2.59, -0.55] and increased the absorption rate constant (k(a)) from 0.49 (0.31-0.69) h to 1.26 (0.52-5.61) h^-1 (P = 0.017). The absolute bioavailability of sotalol was reduced by cisapride from 1.00 ± 0.15 to 0.70 ± 0.26 (P = 0.006), while maximum serum concentrations of both oral solutions were not significantly different. Compared with the sublingually administered tablet with a median t(max) of 2.12 (0.89-3.28) h, the sotalol/cisapride oral solution gave a smaller t(max) (p = 0.009) [95% CI: -1.64, -0.36]. The k(a) of the sotalol/cisaplride solution was significantly (P = 0.010) larger than the k(a) of 0.56 (0.33-0.75) h^-1 found after sublingual administration of the tablet. Conclusions - The sotalol/cisapride oral solution might be suitable for the episodic treatment of SVT, Afib or Afl.