Sotalol dosage

More hydrophilic /3-blockers, such as atenolol, bisoprolol, celiprolol, pindolol and sotalol are predominantly eliminated via the kidney. In elderly patients this may require adaptation of the dosage. Most of the shorter acting /3-blockers are available as slow release preparations. Accordingly, when used as antihypertensives /3-blockers are usually administered once daily. For other applications such as angina pectoris a twice daily dosage may be required. 

At 30 weeks of gestation in a 41-year-old woman the fetus had hydrops, ascites, a pericardial effusion, and bilateral hydroceles. A supraventricular tachycardia with 1 1 conduction was treated by giving the mother oral flecainide 150 mg bd. However, during the next few weeks the mother developed evidence of hepatic cholestasis. The dosage of flecainide was reduced to 50 mg bd and the liver damage resolved. The child was born healthy but later required sotalol for a re-entry tachycardia. 

In a survey of 1288 patients taking sotalol, dysrhythmias occurred in 56, in 24 cases torsade de pointes (3). There was no relation between these dysrhythmias and previously associated factors, such as bradycardia, a long QT interval, and hypokalemia, but in patients on hemodialysis even a low dosage (40 mg bd) can be associated with torsade de pointes (6). Similar prodysrhythmic effects have been reported in children (7). 

Huynh-Do U, Wahl C, Sulzer M, Buhler H, Keusch G. Torsades de pointes during low-dosage sotalol therapy in haemodialysis patients. Nephrol Dial Transplant 1996 11(6) 1153. ... 

Sotalol may require dosage adjustments with insulin or oral antidiabetic agents because it may increase blood glucose. It also may mask symptoms of hypoglycemia. 

Single-dose pharmacokinetic studies may provide sufficient information for dosage selection in medicinal product that exhibit linear pharmacokinetics. Medicinal products that exhibit non-linearity in absorption, distribution and elimination may require steady-state studies. Such an approach has been used to assess the pharmacokinetics of an extemporaneously prepared sotalol syrup formulation in neonates, infants, and younger and older children. Scheduled blood samples were taken over a 36-hour time interval following dose administration (Saul et al, 2001). 

The use of population pharmacokinetics and a sparse sampling approach allow each patients to contribute as few as two to four observations at predetermined times to an overall population. Use of the area under the curve (AUC) will minimise the number of samples required from each patient. Population models allow researchers to assess and quantify potential sources of variability in exposure and response in the target population. Population pharmacokinetics seeks to discover which measurable pathophysiological factors cause changes in the dose-concentration relationship and to what degree, so that the appropriate dosage can be recommended. The pharmacokinetic-pharmacodynamic approach has been used to assess sotalol syrup formulations (Shi et al, 2001). Ten blood samples were taken from... 

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