4 doctors agreed: Maybe not allergic: It's not unusual for pain medications such as morphine, demerol, or Dilaudid to be associated with some itching. They all can cause histamine release. This doesn't necessarily mean you are allergic to them. True allergy produces severe symptoms such as hives and trouble breathing. Sometimes Benadryl can help with itching. Or you can ask your doctor to try a different pain medication.
What is the most important electrolyte for the maintenance of osmotic pressure and volume in the extracellular fluid compartment? The most abundant positive ion or cation in the extracellular fluid  is sodium (Na+). Chloride (Cl-) is the most abundant negative ion  or anion.
The principal component of crystalloid fluids is the inorganic salt sodium chloride (NaCl). Sodium is the most abundant solute in the extracellular fluids, and it is distributed uniformly throughout the extracellular space.