Mannitol is a sugar alcohol that the kidneys cannot reabsorb. Infused into a vein it pulls water out of tissues and into the blood, then out through the urine, which is how it reduces pressure inside the brain and the eye.

What Mannitol Is Used For

Raised pressure inside the skull after brain injury or stroke
Acute glaucoma with very high eye pressure
Promoting urine output in certain kidney situations
Inhaled forms used in lung function testing and to clear mucus

Common Side Effects

Passing large volumes of urine
Thirst and dehydration
Changes in blood salts
Headache and nausea

Precautions

The infusion is given only in hospital with monitoring of fluid balance, salts and kidney function, because both dehydration and fluid overload are risks. It is unsuitable in established kidney failure or severe heart failure. Solutions can crystallise if stored cold and are checked before use.

This page is general information only. It is not a substitute for advice from your doctor or pharmacist, and it does not include dosage. Always follow the directions given to you and read the leaflet inside the pack.