• Cardiovascular
  • Cardiac dysrhythmias (premature ventricular contractions)
  • ECG changes (widened QRS segment, S-T segment depression, first-degree AV heart block)
  • Potentiates digitalis toxicity
  • Postural hypotension
• Neuromuscular
  • Skeletal muscle weakness (hypoventilation)
  • Hyporeflexia
  • Confusion
• Renal
  • Polyuria
  • Concentrating defect
• Metabolic
  • Glucose intolerance
  • Potentiation of hypercalcemia and hypomagnesemia

AV = atrioventricular; ECG = electrocardiograph.