Eclectic Mannitol

Author: Yu Hong, Deputy Director and Pharmacist, Sports New City Branch, Dalian Women and Children's Medical Center (Group)

Reviewer: Wu Gaolei, Deputy Director and Pharmacist, Dalian Women and Children's Medical Center (Group), Sports New City Branch

Eclectic Mannitol

Summer is hot, and people are trying their best to prevent heatstroke and cool down. Similarly, most medicines as special commodities are also extremely afraid of heat, but there is a kind of medicine that is not afraid of heat. Today we will talk about this unconventional medicine.

Normal storage temperature

When we get the drug instructions, we see the "Storage" column, which has storage requirements such as room temperature, cool place, and refrigeration, and the storage methods have different requirements. Room temperature refers to the temperature of storing drugs at 10℃~30℃. A cool place refers to a place where the temperature does not exceed 20℃. A cool and dark place means to avoid light on the basis of a cool place. Refrigeration means that the temperature of storing drugs is 2℃~10℃, such as some probiotics, insulin, growth hormone, blood products, etc., which need to be refrigerated in the refrigerator. In addition, for some special drugs, such as vaccines, lower temperatures may be required for storage, such as freezing (-20℃). Studies have shown that for every 10℃ increase in temperature, the chemical reaction rate of various materials in the drug will increase by 3~4 times accordingly, and strong light and high temperature can easily cause the drug to deteriorate. From this point of view, most drugs have requirements for temperature, and high temperature is avoided by most drugs. But the drug we are going to mention next is not afraid of heat.

Eclectic Mannitol

Mannitol is a good diuretic in medicine, which can reduce intracranial pressure, intraocular pressure, and treat kidney medicine, dehydration medicine, sugar substitute, and is also used as an excipient for tablets and a diluent for solids and liquids. Mannitol injection, as a hypertonic antihypertensive drug, is a commonly used drug for clinical rescue, especially for brain diseases. It has the characteristics of fast and accurate antihypertensive effect required by drugs that reduce intracranial pressure. "Chinese Expert Consensus on Mannitol for the Treatment of Increased Intracranial Pressure" (2019): Mannitol is the most commonly used first-line drug for the treatment of increased intracranial pressure (ICP) and is widely used in clinical practice. "Chinese Hypertensive Emergency Diagnosis and Treatment Guidelines" (2020): For patients with acute cerebral hemorrhage, when the amount of bleeding is large and the space-occupying effect is obvious, dehydration treatment such as mannitol and intravenous antihypertensive drugs are needed to lower blood pressure and reduce the risk of further aggravation of bleeding. However, in clinical application, nurses are often worried about the crystallization of mannitol injection, which must be processed before clinical application. What is the reason?

Mannitol for cold

The storage conditions of mannitol injection are as follows: light-shielded, airtight storage. Since the temperature requirement is not specified, why does crystallization occur during daily use? Mannitol injection is a colorless, clear liquid under normal circumstances. The solubility of mannitol in water is 1:5.5, which is a supersaturated solution. When the ambient temperature is below 15°C, mannitol particles are easily produced. As the temperature decreases, the amount of dissolution decreases, resulting in crystallization. When the temperature continues to decrease, the precipitated crystals increase in size, presenting columnar and flocculent shapes. Generally, crystallized mannitol at room temperature cannot dissolve on its own. Crystallization is usually a normal phenomenon. However, crystallized mannitol not only fails to achieve the expected therapeutic effect, but may also block the infusion pipeline and cause local blood circulation disorders. If the crystalline substance enters the blood circulation, it may cause thrombosis, posing a serious threat to the patient's health. In addition, mannitol will also crystallize when mixed with other electrolyte solutions for injection.

Image source: Self-photographed

Mannitol is not afraid of heat

So how to deal with the crystallized mannitol injection?

The drug instructions mention that this product is easy to crystallize when cold, and should be carefully checked before use. If crystallization occurs, the injection solution can be heated and shaken at a maximum of 70°C to redissolve. In clinical practice, a constant temperature box is often used, or hot water at 60-70°C is used to heat the bottle, and the crystals are gently shaken to disperse and accelerate dissolution. After heating and dissolving, the efficacy is not affected. It should be noted that the heated solution should be used immediately to avoid repeated heating that may lead to decreased efficacy or drug deterioration.

Under the storage conditions of conventional drugs, mannitol, which is not afraid of heat, has become a unique existence. Mannitol injection is also one of the few clinical drugs that need to be heated before use. Drug safety is no small matter. Mannitol injection must not be directly infused after crystallization. Make sure it is fully dissolved before use.