If a client is showing signs of increased intracranial pressure, which medication should the nurse administer?

Mannitol is the correct choice for managing increased intracranial pressure (ICP). It is an osmotic diuretic that works by drawing fluid out of the brain tissue and into the bloodstream, thereby reducing cerebral edema and subsequently lowering ICP. The mechanism involves creating an osmotic gradient, which causes water to move from areas of higher concentration (brain) to areas of lower concentration (blood). This helps alleviate the pressure on the brain, which is crucial in settings of ICP.

Administering mannitol is instrumental in treating conditions such as traumatic brain injury, brain tumors, or any situation where elevated ICP poses a risk to brain function and overall patient safety. The rapid action of mannitol also provides critical relief in acute situations, making it a preferred first-line treatment in these cases.