Description medications: Urea (Urea pura)
UREA (Urea pura).
Synonyms: Urea, Carbamid, Carbamidum, Ureaphil.
The white crystalline powder or colorless crystals salty-bitter taste, and odorless. Easily soluble in water (1: 1) is soluble in alcohol (1: 5).
Aqueous solutions are neutral. The dissolution in water takes place with heat absorption.
Urea used in the past as a diuretic. It is administered orally (usually sugar or fruit syrup) 15 - 20 g reception 2 - 5 times per day. At these doses, it has a diuretic effect, but if the kidney function can dramatically increase the nitrogen content in the body. The diuretic effect is due to the action of whole molecules of urea; in humans, they are not subjected to metabolism and filtered in a large amount (50 - 60%) at the glomerulus without reabsorption. The high osmotic pressure created in the tubules, causing a strong water diuresis.
Currently, due to the emergence of new effective diuretics urea for this purpose is not used.
Urea generally administered as a dehydrating agent for the prevention and reduction of toxic cerebral edema and pulmonary edema, as well as an effective means of lowering intraocular pressure.
Mechanism decongestant effect and hypotensive effect (with respect to pressure vnutriglaznamu) urea is not clear. It is believed that an important role is played by osmotic effect. The sharp increase in the osmotic pressure of the blood caused by the introduction of hypertonic solutions of urea, leads to the active flow of blood in the fluid channel of tissues and organs, including the brain cavities and tissues and eyes. Through the blood-brain barrier and into the eyeball penetrates poorly urea; thus creating a significant difference between the osmotic pressure of the blood on the one hand, and cerebrospinal fluid, and fluids eye - on the other. The antihypertensive effect for intracranial and intraocular pressure are not directly related to the diuretic effect. It was found that the experimental conditions antihypertensive effect persists after bilateral nephrectomy. Its diuretic effect helps to decrease the pressure. There is also evidence for believing that a role in the hypotensive effect of playing the central mechanisms (the effect of hypertonic saline on osmoretseptivnye field in the hypothalamus).
Urea has found use in neurosurgery to prevent and reduce cerebral edema, especially in the early stages of its development.
In ophthalmic practice urea appointed to glaucoma, especially during an acute attack, as well as in the preparation of patients with high IOP to operations.
Urea used intravenously, as well as inside.