Are there any side effects of oral rehydration salts?

Oral rehydration salts, if used properly, have no side effects. If used improperly, or if the concentrations of the salt, glucose, or solids within the fluids are not balanced properly, the therapy may not work as well. If too much sodium is used in the solution a condition known as hypernatremia, or high blood sodium levels, may result. Signs of hypernatremia include high blood pressure, irritability, restlessness, swelling, irregular heartbeat, convulsions, twitching, and weakness. If you use too much glucose, you may experience further water loss.