Is mannitol contraindicated in hypertensive crisis (high blood pressure)?

From the Guidelines

Mannitol is contraindicated in patients with hypertensive crisis or severe hypertension due to its potential to worsen blood pressure and cause dangerous complications. When administering mannitol, an osmotic diuretic commonly used to reduce intracranial pressure or treat cerebral edema, it should be avoided in patients with uncontrolled hypertension. According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1, there is no recommendation for the use of mannitol in hypertensive emergencies. Instead, the guideline suggests the use of antihypertensive agents such as nicardipine, clevidipine, sodium nitroprusside, and others, which are listed in Table 19 of the guideline 1. Mannitol works by drawing fluid from tissues into the bloodstream, which increases intravascular volume, and this volume expansion can worsen already elevated blood pressure in hypertensive patients, potentially leading to dangerous complications such as stroke, heart failure, or hypertensive encephalopathy. Additionally, the rapid osmotic shift can cause a transient increase in intracranial pressure before the therapeutic reduction occurs, which could be particularly dangerous in hypertensive patients who may already have compromised cerebral autoregulation. Before administering any treatment, blood pressure should be adequately controlled, and alternative treatments should be considered for patients with severe hypertension. If mannitol must be used in patients with hypertension, close monitoring of blood pressure, neurological status, and fluid balance is essential, with appropriate antihypertensive therapy administered concurrently.

Some key points to consider when managing hypertensive emergencies include:

• The selection of an antihypertensive agent should be based on the drug’s pharmacology, pathophysiological factors underlying the patient’s hypertension, degree of progression of target organ damage, the desirable rate of BP decline, and the patient’s clinical profile 1.
• Continuous infusion of short-acting titratable antihypertensive agents is often preferable to prevent further target organ damage 1.
• The use of antihypertensive agents such as nicardipine, clevidipine, sodium nitroprusside, and others, which are listed in Table 19 of the guideline 1, may be considered in the management of hypertensive emergencies.

It is essential to prioritize the management of blood pressure and consider alternative treatments for patients with severe hypertension to minimize the risk of complications and improve patient outcomes.

From the FDA Drug Label

4 CONTRAINDICATIONS Mannitol Injection is contraindicated in patients with: Well established anuria due to severe renal disease. Severe pulmonary congestion or frank pulmonary edema. Active intracranial bleeding except during craniotomy. Severe dehydration. Progressive heart failure or pulmonary congestion after institution of mannitol therapy. Do not administer to patients with a known hypersensitivity to mannitol.

CONTRAINDICATIONS Well established anuria due to severe renal disease. ( 4) Severe pulmonary congestion or frank pulmonary edema. ( 4) Active intracranial bleeding except during craniotomy ( 4) Severe dehydration. ( 4) Progressive heart failure or pulmonary congestion after institution of mannitol therapy. ( 4) Do not administer to patients with a known hypersensitivity to mannitol ( 4)

The FDA drug label does not answer the question about mannitol use in hypertensive tension. Key points to consider are:

• Contraindications: The labels list several contraindications, including severe pulmonary congestion, active intracranial bleeding, and severe dehydration, but do not directly address hypertensive tension.
• Indications: The labels mention the use of mannitol for reducing intracranial pressure and brain mass, but do not provide information on its use in hypertensive tension.
• Warnings and Precautions: The labels warn about potential complications, such as renal failure and fluid and electrolyte imbalances, but do not provide guidance on using mannitol in patients with hypertensive tension 2, 2.

From the Research

Hypertensive Tension and Mannitol

• There is no direct evidence in the provided studies that mannitol is used to treat hypertensive tension.
• However, mannitol is used to reduce intracranial pressure (ICP) in patients with cerebral injuries, as shown in a study published in 2020 3.
• The study found that mannitol is effective in reducing pathological ICP, proportionally to the degree of intracranial hypertension.
• Another study published in 2012 compared the use of mannitol and hypertonic saline for intracranial hypertension, and found that both agents are effective and have an acceptable risk profile 4.

Treatment of Hypertensive Emergencies

• The treatment of hypertensive emergencies typically involves the use of parenteral drugs, such as sodium nitroprusside, nitroglycerin, and hydralazine, as discussed in a study published in 1995 5.
• Other studies have discussed the use of newer agents, such as nicardipine, fenoldopam, and clevidipine, which have been shown to be effective and safer than traditional agents 6, 7.
• The selection of a specific agent should be based on the agent's pharmacology and patient-specific factors, such as comorbidity and the presence of end-organ damage 7.

Mannitol and Hypertension

• There is no evidence to suggest that mannitol is contraindicated in patients with hypertensive tension.
• However, mannitol may precipitate acute renal failure if serum osmolarity exceeds 320 mOsm/L, as noted in a study published in 2012 4.
• Therefore, caution should be exercised when using mannitol in patients with hypertension, and serum osmolarity should be closely monitored.