Resonium A and C

Resonium A is an ion-exchange resin that is recommended for the treatment of hyperkalaemia associated with anuria or severe oliguria. It is also used to treat hyperkalaemia in patients requiring dialysis and in patients on regular haemodialysis or on prolonged peritoneal dialysis.

(source: medicines.org.uk)

Calcium resonium powder contains the active ingredient calcium polystyrene sulphonate, which is a type of medicine called an ion exchange resin.

Calcium polystyrene sulphonate binds with potassium in the gut, forming a complex that cannot be absorbed into the blood. This effectively reduces the levels of potassium in the bloodstream.

(source: netdoctor.co.uk)