Per Package Insert (25% vial)-
"Crystals may form in Mannitol Injection, especially if the solution is exposed to low temperatures. If crystallization occurs, warm the vial in water at 80°C and periodically shake vigorously to dissolve the crystals."
While the above recommends water for rewarming, other resources such as ASHP Injectable Drug Information book suggests, "The use of a water bath is not recommended."
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