Not only is it so simple to increase the amount of urine, how much do you know about diuretics?

　In the process of treating acutely ill patients in the emergency department, doctors are often heard to issue doctors to nurses with medical advice such as "use diuretics, intravenous bolus furosemide 20 mg", and sometimes the patient's family members will ask the doctor whether they need diuretics because the patient has less urine. So what are the roles of diuretics in the treatment of acute and severe diseases? Which patients are suitable for diuretics?

　　1. What are diuretics?

　　After the use of diuretics, the patient's urine output will increase significantly within a certain period of time, such an effect is of course one of the reasons for the name of "diuretics", but diuretic drugs play a more important role by affecting the physiological function of the kidneys, regulating the excretion of electrolytes (sodium ions, potassium ions, etc.) and water in the body, and thus further affecting the function of the local or systemic circulatory system, to achieve the effect of treating or assisting the treatment of related diseases. Diuretics have the effect of lowering blood pressure to varying degrees while increasing urine output. There are different types of diuretics, and the corresponding effects are also different, each suitable for different situations, and sometimes it needs to be used in combination.

　　Second, the indications for the use of diuretics in patients with acute and severe diseases

　　The amount of urine in a patient is not the only basis and necessary condition for determining whether diuretic drugs are needed. The main purpose of using diuretic drugs is to reduce local or systemic water retention in the patient's body, improve circulatory dysfunction, and regulate some electrolyte abnormalities. Therefore, diuretics are often used for acute heart failure, acute kidney failure; limb or tissue edema, pericardial effusion, pulmonary edema, pleural effusion, pleural effusion (pleural fluid), peritoneal effusion (ascites), etc. caused by organ and tissue dysfunction such as heart, kidney, liver, pulmonary circulation, lymphatic circulation and other organs and tissue dysfunction, electrolytes, pulmonary edema, pleural effusion (pleural fluid), abdominal effusion (ascites), acute cerebral embolism, cerebral infarction or cerebral hemorrhage, some hypertensive emergencies; some drug overdose, poisoning, etc. In the process of diagnosis and treatment, the emergency medical staff will also ask the patient about the usual medication, and adjust the type or dosage of diuretic drugs in the emergency accordingly to avoid superimposing or synergistic effects with the drugs already used by the patient and aggravating the adverse reactions.

　　3. Under what circumstances can diuretics be used or are they not suitable for diuretics alone?

　　Diuretics should not be used in acute urinary retention, complete ureteral obstruction (stone obstruction, tumor compression, etc.) caused by anutia, dehydration, diabetic ketoacidosis or hypertonicity, and shock (especially blood loss or fluid loss shock).

　　Some acutely ill patients have indications for the use of diuretic drugs, but at the same time accompanied by obvious hypotension or even shock, medical staff will use diuretics in combination with other related drugs, and closely observe the patient's vital signs and urine volume; when patients with electrolyte disorders need to apply diuretics, doctors will also pay special attention to the dynamic changes of the patient's electrolytes, by selecting different diuretic drugs, adjusting the dosage or course of treatment, and applying other measures to correct electrolyte disorders.

　　Fourth, commonly used diuretics and their characteristics

　　1. Loop diuretics that mainly act on the medullary part of the bulbar loop

　　Representative drugs: furosemide (furosemide), bumetanide, torasemide, etc. The common characteristics of this type of drug are fast onset of action, strong effect, short maintenance time after use, and the drug dosage form is both injection and oral, which is quick and convenient to use. It is the most used class of diuretics in the treatment of emergencies.

　　(1) Furosemide (furosemide): a powerful diuretic that makes potassium, sodium and chloride ions quickly excreted with a large amount of water, and has the effect of promoting renal vasodilation and increasing renal blood flow, and does not cause hypercalcemia. The diuretic effect is as soon as 5 minutes after intravenous furosemide injection, the effect is strongest in 30 minutes to 1 hour, and the effect can generally be maintained for 2 to 4 hours; after oral furosemide, the effect is generally onset within 30 minutes, the effect is strongest in 1 to 2 hours, and the effect can be maintained for 6 to 8 hours. It is often used for acute heart failure and cardiogenic edema, acute renal insufficiency and renal edema, cirrhosis of the liver, ascites, etc., and some peripheral edema can also be applied. However, repeated large-scale use is easy to cause hypokalemia, hypochloroemia, metabolic alkalosis, hyperuricemia, blood glucose increase, etc., and the application process needs to monitor the dynamic changes of blood electrolytes, uric acid and blood glucose.

　　(2) Bumetanide: the main mechanism of action, effect, etc. are similar to furosemide, and its required dose is much smaller than furosemide. Therefore, bumetanil can be used as an alternative drug when the treatment effect of furosemide is not good, suitable for some patients with refractory edema and acute pulmonary edema, especially for patients with acute and chronic renal failure. In addition, bumetanide has a relatively weaker effect of potassium ions excreted than furosemide, so the incidence of hypokalemia is lower than that of furosemide. Other adverse effects of bumetanide application are also similar to furosemide.

　　(3) Torasemide: Although the basic mechanism of action is similar to furosemide and bumetanide, it has its own characteristics: potassium drainage is significantly weaker than furosemide and bumetanide, and the diuretic intensity is slightly weaker than that of bumetanide and furosemide; the drug half-life is longer, the effect maintenance time is longer than that of furosemide and bumetanide; the impact on uric acid, blood sugar and blood lipids is small, and the safety of use is relatively higher than that of furosemide and bumetanib. In the treatment of acute and severe diseases, torasemide is often used for acute heart failure, acute pulmonary edema, acute cerebral edema, acute kidney failure, cirrhosis of the liver, ascites, hypertensive emergencies, partial poisoning, etc.; but it is contraindicated in patients with severe renal failure (requiring dialysis treatment) and hepatic encephalopathy without urine.

　　2. Diuretics that mainly act on the cortical part of the loop ascending branch of the tubular myeloid

　　Representative drugs: hydrochlorothiazide (double grams), characterized by a slightly weaker effect than the first class of loop diuretics, so it is defined as a moderate-acting diuretic, often used as a supplement or maintenance treatment of loop diuretics in the treatment of acute and severe diseases.

　　Hydrochlorothiazide (double gram) is only an oral dosage form, which begins to act about 1 hour after oral administration, reaches a maximum effect in about 2 hours, and the effect can be maintained for 12 to 18 hours. Therefore, the drug is generally not used as the drug of choice for the treatment of acutely ill patients, but often as a maintenance therapy, can be used for various types of edema (especially cardiogenic edema), combined with antihypertensive drugs to treat hypertension. Common adverse drug reactions mainly include hypomagnesemia, hypokalemia, hyponatremia, hypercalcemia, hyperuricemia and so on.

　　3. Diuretics that mainly act on distal curved tubules

　　Representative drugs: spironolactone (spironolone), triamterene and so on. Characterized by a weaker diuretic effect and slower onset of action, it is generally used in combination with the first two classes of drugs to enhance synergy; since such drugs have an effect of reducing potassium ion excretion ("potassium-sparing diuretics"), it is often used in acute and severe care for patients who require diuretics but are accompanied by significant reductions in blood potassium concentrations. This class of drugs needs to be aware of the risk of hyperkalemia when used simultaneously with other drugs containing potassium ions or drugs that have a blood potassium accumulation effect.

　　This article was scientifically checked by Xiong Xudong, deputy director of the Department of Internal Medicine of Shuguang Hospital affiliated to Shanghai University of Traditional Chinese Medicine.

　　Contributed by "Da Yi Xiao Nursing"