Hypokalaemia, which can be caused by potassium-depleting 
diuretics such as the loop or 
thiazide diuretics, increases the 
toxicity of 
digoxin. 
 Potassium levels should be routinely monitored during diuretic therapy. However, if 
symptoms of 
digoxin toxicity occur (see above) it may be prudent to re-check potassium levels.