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.
Extracellular Fluid (ECF) - all fluids found outside the cells, comprises 40% of all body fluids Interstitial Fluid - 80% of ECF is found in localized areas: lymph, cerebrospinal fluid, synovial fluid, aqueous humor and vitreous body of eyes, between serous and visceral membranes, glomerular filtrate of kidneys.lood Plasma - 20% of ECF found in circulatory system Composition of Body Fluids Water is the main component of all body fluids making up 45-75% of the total body weight. Sources of water include Ingested foods and liquids (preformed water) Metabolic water produced during dehydration synthesis of anabolism.