Pediatric fever is a self-protective mechanism that mobilizes the whole body immune system to fight the disease. The temperature is closely related to the child’s physical condition, nutritional status, time (such as morning and evening, four seasons), but not to the severity of the disease, that is, not the higher the temperature, the more serious the disease, sometimes repeated high fever for 3-5 days is very common, so in the process of reducing fever, we should actively look for treatment of the original disease, do not simply focus on reducing fever. I. When to apply antipyretic drugs? A fever is defined as a fever when the axillary exceeds 37.3°C (or 37.5°C). It is further divided into low fever 37.4~38°C; medium fever 38.1-39°C; high fever 39.1-41°C; ultra-high fever: 41°C or more. A fever of ≤1 week is considered acute fever. For patients with a temperature below 38.5°C, if they are in good spirits, they can suspend the use of antipyretic drugs, and physical cooling is sufficient. For patients with temperatures above 38.5°C, antipyretic drugs need to be applied to reduce energy consumption and avoid complications such as hyperthermia. The World Health Organization (WHO) recommends two classic oral antipyretics with high safety in pediatrics: “acetaminophen” and “ibuprofen”. 1. Acetaminophen (paracetamol, Tylenol): preferred, for children over 3 months of age. Regular dosage for children: 10-15mg/kg/dose orally, once every 4-6h; less than 5 times every 24h for children aged 3-12 yrs. Rectal administration is no longer recommended in pediatrics. Acetaminophen has a high safety profile at reasonable doses, with occasional nausea, vomiting, sweating, and abdominal pain, and a few cases of dermatitis, granulocytopenia, and thrombocytopenia. Excessive doses can cause liver damage. Contraindicated in severe hepatic and renal insufficiency. Use with caution in children with liver disease or viral hepatitis, hepatic or renal insufficiency, severe cardiopulmonary disorders, and G-6-PD deficiency. Some compound preparations often contain the ingredient “acetaminophen”, such as aminoglutethimide granules, aminophenflavonamil granules, aminoglutethimide syrup, phenomethimide suspension, etc., but paracetamol and tylenol are single preparations. Be sure to avoid repeated medication when taking them. 2. Ibuprofen (Merlin): For children over 6 months of age. Single preparations include Merlin, Fenbuterol, etc. The recommended dosage of ibuprofen for children is 5-10mg/kg every 6 hours, up to 4 times every 24h. Ibuprofen has a strong antipyretic effect, and the process of reducing fever may cause the body to sweat a lot. Therefore, when using ibuprofen to reduce fever, attention should be paid to whether the child is dehydrated or has insufficient intake, and if necessary, intravenous rehydration can be used. Also, ibuprofen is excreted through the kidneys, so it should be used with caution in patients with poor kidney function. Children with G-6-PD deficiency can use “ibuprofen”. 3.Lysine: It is a compound salt of aspirin and lysine, and its mechanism of action is the same as that of aspirin. It is administered intravenously or intramuscularly to reduce or avoid the occurrence of gastrointestinal reactions, with strong antipyretic effect, fast onset of action and mild effect, and can be used as a common drug for reducing fever in pediatrics. It is used for children who are prone to fever convulsions and cannot be administered orally. However, long-term application may induce the possibility of Richter’s syndrome, and even induce anaphylaxis and severe asthma attacks. Used for intravenous antipyretic, the dose is generally 10-20mg/kg, not more than 4 times in 24 hours, the interval should not be less than 4h. 4, aspirin: traditional antipyretic and analgesic drugs, the World Health Organization does not recommend aspirin routine use for pediatric antipyretic, it is recommended to use other categories of antipyretic drugs. China’s pediatrics has basically not used such drugs for antipyretic, only for the treatment of some special diseases, such as Kawasaki disease, rheumatic fever, juvenile arthritis, etc. 5, diclofenac: a new type of potent anti-inflammatory and analgesic, it exerts its pharmacological effects by inhibiting prostate synthesis, has anti-rheumatic, anti-inflammatory, analgesic and antipyretic effects, analgesic, anti-inflammatory and antipyretic effects are 2 to 2.5 times stronger than indomethacin, 26 to 50 times stronger than aspirin, strong, less adverse reactions, small dose, little individual differences, used for fever caused by various inflammatory diseases. There are views that children under 14 years of age are prohibited. 6, Nimesulide: new non-steroidal anti-inflammatory, analgesic, antipyretic, pharmacological effect is to inhibit cyclooxygenase activity, blocking the biosynthesis of prostaglandin-like substances, leukocyte mediator release and polymorphonuclear leukocyte oxidation reaction, so as to play an antipyretic, anti-inflammatory effect, for fever caused by upper respiratory tract infections, the effect can last 6 to 8 hours. 2011 February media reported a number of fatal cases In May 2011, the State Drug Administration issued a notice to restrict the application of Nimesulide and “prohibit its oral preparation for children under 12 years old”. Name of antipyretic drugs Dose and method of application Age of application Side effects Remarks Acetaminophen (paracetamol, Tylenol) 10-15mg/kg/dose, po, q4-6h; not more than 5 times in 24h for children aged 3-12 years, the course of treatment does not exceed 5d 3 months of age or older Antipyretic preferred; caution for children with liver disease or viral hepatitis, liver and kidney insufficiency, severe cardiopulmonary disorders, G-6-PD deficiency Occasionally nausea, vomiting, sweating, abdominal pain, etc., dermatitis, granulocytopenia, thrombocytopenia, etc. may occur in a few cases. Overdose can cause liver damage High safety Ibuprofen (Merlin) 5-10mg/kg/dose, po, q6h, up to 4 times per 24h. Can be used in children with G-6-PD deficiency above 6 months of age; use with caution in poor renal function Gastrointestinal adverse effects Strong antipyretic effect, sweating, pay attention to whether the child is dehydrated, insufficient intake, etc., if necessary, intravenous rehydration Lysine (lysine + aspirin) 10-20mg/kg/dose, iv OR im, no more than 4 times in 24 hours, interval not less than 4h. Intravenous or intramuscular injection The drug is commonly used in pediatrics, suitable for children with high fever prone to convulsions and children who cannot take the drug orally. Long-term application may induce gray baby syndrome, or even induce anaphylactic shock and severe asthma attacks Strong antipyretic effect, rapid onset of action, moderate action Aspirin is only used for the treatment of specific diseases, such as Kawasaki disease, rheumatic fever, juvenile arthritis, etc. Diclofenac is prohibited for children under 14 years old. The application principles of clinical pediatric antipyretics Infants younger than 3 months are not recommended to use antipyretics, but can use physical cooling or mild-acting herbs to reduce fever. When the body temperature is lower than 38.5℃, antipyretics are generally not used, and physical cooling can be used to reduce fever, except for those with recurrent febrile convulsions. When the body temperature is higher than 38.5℃, safe antipyretic drugs can be used to treat the fever. Acute fever reduction should be avoided, and the patient should be alert to possible dehydration and intravenous rehydration if necessary. Super high fever (>41℃) can cause permanent damage to brain cells and even other serious complications, such as pulmonary edema, cerebral edema, liver failure, etc., which can lead to death in serious cases, so active and effective rescue measures should be used to rapidly lower the temperature. If a child with persistent high fever does not reduce fever with a single drug, acetaminophen and ibuprofen can be applied alternately. The time interval between the two drugs should be at least 2 hours. When alternating, the maximum number of times each drug can be used per day is still 4. Drink more water when taking medication to reduce fever to speed up excretion and help take away body heat. At the same time, it is also necessary to take medicine to reduce fever along with physical means of cooling, which includes taking a warm bath or wiping the whole body with a hot wet towel, and not using alcohol, which can easily pass through children’s tender skin and lead to alcohol poisoning. Avoid the simultaneous use of multiple antipyretic drugs, increasing the risk of side effects. (1) pediatric thermoregulatory center is not perfect, so pediatric antipyretic should be based on physical cooling; (2) fever is a manifestation of the body’s resistance to disease, should actively find the cause of the disease, treatment of the primary disease; (3) master the active ingredients of various antipyretic and analgesic drugs, drug action characteristics, adverse reactions, contraindications, contraindications, etc., to prevent improper use of drugs to produce the body (4) According to the characteristics of pediatric antipyretic drugs, reasonably grasp the interval of pediatric antipyretic drugs; (5) should be taken on time and in accordance with the dosage, do not arbitrarily increase the dose or shorten the dosing interval; (6) during the antipyretic period, the child should be advised to drink more water, so as to avoid deficiency due to profuse sweating; (7) generally choose an antipyretic drug, and then consider the combination when the efficacy is really unsatisfactory. (8) Reasonable control of the course of treatment, the fever is stopped; (9) during the use of drugs should pay attention to the toxic side effects of drugs, such as blood changes, gastrointestinal reactions, liver and kidney function impairment; (10) severe, high fever persistently children can be used when necessary, sub-hibernation therapy.