Polystyrene sulfonates are a group of medications used to treat high blood potassium. Effects generally take hours to days. They are also used to remove potassium, calcium, and sodium from solutions in technical applications. Common side effects include loss of appetite, gastrointestinal upset, constipation, and low blood calcium. These polymers are derived from polystyrene by the addition of sulfonate functional groups. Sodium polystyrene sulfonate was approved for medical use in the United States in 1958.A polystyrene sulfonate was developed in the 2000s to treat Clostridium difficile associated diarrhea under the name Tolevamer, but it was never marketed. Medical uses
Polystyrene sulfonate is usually supplied in either the sodium or calcium form. It is used as a potassium binder in acute and chronic kidney disease for people with hyperkalemia (abnormal high blood serum potassium levels). However, it is unclear if it is beneficial and there is concern about possible side effects when it is combined with sorbitol.Polystyrene sulfonates are given by mouth with a meal or rectally by retention enema. Side effects
Intestinal disturbances are common, including loss of appetite, nausea, vomiting, and constipation. In rare cases, it has been associated with colonic necrosis. Changes in electrolyte blood levels such as hypomagnesemia, hypocalcemia, and hypokalemia may occur. Polystyrene sulfonates should not be used in people with obstructive bowel disease and in newborns with reduced gut motility. Intestinal injury
A total of 58 cases of intestinal injury including necrosis of the colon have been reported with polystyrene sulfonate as of 2013.
Desensitization
This form of treatment is meant to reduce the intensity or altogether eliminate the allergic reactions people have by gradually increasing exposure to the form of radiation that brings about the reaction. In the case of solar urticaria, phototherapy and photochemotherapy are the two major desensitization treatments.Phototherapy can be used for prevention. Exposure to a certain form of light or UV radiation  enables the patient to build up a tolerance and outbreaks can be reduced. This type of treatment is generally conducted in the spring. However, the benefits of this  therapy only last for two to three days.Photochemotherapy, or PUVA, is considered superior to phototherapy because it produces a longer-lasting tolerance of the radiation that initiates the outbreak. When treatment first begins, the main goal is to build up the patients tolerance to UVA radiation enough so that they can be outdoors without having an episode of solar urticaria. Therefore, treatments are regulated at three per week while constantly increasing the exposure to UVA radiation. Once the patient has reached an adequate level of desensitization, treatments are reduced to once or twice per week. Immunoglobulin E (IgE) Therapy
Some patients and researchers have successfully treated solar urticaria with Omalizumab (trade name Xolair) which is commonly used to treat Idiopathic Urticaria. Omalizumab is a recombinant humanized monoclonal antibody against IgE.