What are the side effects of osmotic diuretics?

From the Guidelines

Osmotic diuretics like mannitol can cause several serious side effects, including fluid and electrolyte imbalances, renal complications, and neurological symptoms, and their use should be carefully monitored and managed to minimize these risks. The most common side effects of osmotic diuretics include:

• Fluid and electrolyte imbalances, particularly hyponatremia (low sodium), hypokalemia (low potassium), and dehydration 1
• Renal complications, such as acute kidney injury, especially in patients with pre-existing renal impairment 1
• Neurological symptoms, such as confusion, disorientation, or seizures, particularly with rapid administration of mannitol 1
• Pulmonary edema or heart failure exacerbation in susceptible individuals due to the initial volume expansion that occurs before diuresis begins 1
• Hyperglycemia in diabetic patients, as osmotic diuretics can interfere with glucose metabolism 1
• Hypersensitivity reactions, though rare, can occur and manifest as skin rashes or more severe allergic responses 1
• Tissue damage and inflammation can occur if mannitol extravasates during IV administration 1

It is essential to carefully monitor patients receiving osmotic diuretics, particularly those with pre-existing renal impairment or other comorbidities, to minimize the risk of these side effects 1. The use of osmotic diuretics should be guided by the most recent and highest quality evidence, and patients should be closely monitored for signs of adverse effects, with adjustments to treatment made as needed to prioritize morbidity, mortality, and quality of life.

From the FDA Drug Label

Renal complications, including irreversible renal failure have been reported in patients receiving mannitol. Reversible, oliguric acute kidney injury (AKI) has occurred in patients with normal pretreatment renal function who received mannitol Osmotic nephrosis, a reversible vacuolization of the tubules of no known clinical significance, may proceed to severe irreversible nephrosis, The obligatory diuretic response following rapid infusion of 25% mannitol may further aggravate pre-existing hemoconcentration. Excessive loss of water and electrolytes may lead to serious imbalances. With continued administration of mannitol, loss of water in excess of electrolytes can cause hypernatremia Electrolyte measurements, including sodium and potassium are therefore of vital importance in monitoring the infusion of mannitol. The shift of sodium-free intracellular fluid into the extracellular compartment following mannitol infusion may lower serum sodium concentration and aggravate pre-existing hyponatremia By sustaining diuresis, mannitol administration may obscure and intensify inadequate hydration or hypovolemia. Accumulation of mannitol may result in overexpansion of the extracellular fluid which may intensify existing or latent congestive heart failure Mannitol injection may increase cerebral blood flow and the risk of postoperative bleeding in neurosurgical patients. Mannitol may increase cerebral blood flow and worsen intracranial hypertension in children who develop generalized cerebral hyperemia during the first 24 to 48 hours post injury. Most common adverse reactions are pulmonary congestion, fluid and electrolyte imbalance, acidosis, electrolyte loss, dryness of mouth, thirst, marked diuresis, urinary retention, edema, headache, blurred vision, convulsions, nausea, vomiting, rhinitis, arm pain, skin necrosis, thrombophlebitis, chills, dizziness, urticaria, dehydration, hypotension, tachycardia, fever and angina-like chest pains.

The side effects of osmotic diuretics, such as mannitol, include:

• Renal complications: irreversible renal failure, acute kidney injury (AKI), and osmotic nephrosis
• Fluid and electrolyte imbalances: hypernatremia, hyponatremia, and excessive loss of water and electrolytes
• Cardiovascular complications: overexpansion of the extracellular fluid, congestive heart failure, and angina-like chest pains
• Central nervous system (CNS) toxicity: increased cerebral blood flow, postoperative bleeding, and intracranial hypertension
• Other adverse reactions: pulmonary congestion, acidosis, electrolyte loss, dryness of mouth, thirst, marked diuresis, urinary retention, edema, headache, blurred vision, convulsions, nausea, vomiting, rhinitis, arm pain, skin necrosis, thrombophlebitis, chills, dizziness, urticaria, dehydration, hypotension, tachycardia, and fever 2, 2

From the Research

Side Effects of Osmotic Diuretics

The use of osmotic diuretics, such as mannitol, can lead to several side effects, including:

• Impairment of proximal tubular reabsorption of water, electrolytes (Na, Cl, K, Pi, Ca, but not Mg), urea, and uric acid 3
• Increased renal blood flow and glomerular filtration rate of superficial nephrons 3
• Wash out of medullary hypertonicity, leading to a decline in medullary osmolarity 3
• Impairment of water reabsorption in descending limbs and moderate impairment of NaCl, Ca, and Mg reabsorption in the ascending limbs of Henle's loop 3
• Inhibition of water and urea reabsorption and modest inhibition of NaCl reabsorption in the collecting duct 3

Clinical Implications

Osmotic diuretics like mannitol can be used in various clinical situations, including:

• Prophylactically, as a diagnostic aid, or as therapy for the oliguric state 4
• To reduce intracranial pressure 4, 5
• To treat refractory edema or intoxications by aspirin, barbiturates, or bromide 4
• To ameliorate symptoms of dialysis dysequilibrium 4

Specific Side Effects

Rapid administration of mannitol can lead to:

• Hypotension 5
• Hyperosmolar states 5
• Rebound phenomenon and hypervolaemia 5