In outpatient and ward work, we encounter children with fever. Fever is a manifestation of disease, and fever reduction is a strong desire of most parents to ask doctors to use in a short period of time to reduce fever, thinking that it is better if they do not have a fever, and it is a good doctor if the doctor gives a shot of medicine to stop fever, and it is not a good doctor if they eat antipyretic drugs or have fever, and sometimes they have to add hormones to reduce fever. In fact, fever is a self-protective mechanism to fight disease by mobilizing the whole body immune system. 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 hyperthermia for 3-5 days is very common, so in the process of reducing fever, we should actively look for treatment of the original disease, purely and simply reducing fever is not the purpose. I. When to apply antipyretic drugs? A general temperature axillary over 37.5 is defined as fever. It is further divided into low fever 37.5-38℃; medium fever 38.1-39℃; high fever 39.1-41℃; super high fever: above 41℃. 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 over 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. It is 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, it is necessary to pay attention 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 with high fever prone to 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, small 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 action is to inhibit cyclooxygenase activity, blocking the biosynthesis of prostaglandin-like substances, leukocyte mediator release and polymorphonuclear leukocytes related to the 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 May State Drug Administration issued a notice that In May 2011, the State Drug Administration issued a notice restricting the application of Nimesulide and “prohibiting its oral formulation to be used in children under 12 years of age”. Name of antipyretic drug Dose and method of use 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, course of treatment not more than 5d 3 months of age and above Antipyretic preferred; caution for children with liver disease or viral hepatitis, hepatic and renal 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. Above 6 months of age Can be used in children with G-6-PD deficiency; 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, intervals of not less than 4h Intravenous or intramuscular injection. Commonly used in pediatrics, suitable for children with high fever prone to convulsions and those who cannot be administered orally Long-term application may induce gray baby syndrome, or even induce anaphylaxis 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 contraindicated in children under 14 years of age Nimesulide is contraindicated in children under 12 years of age III. Application principles of pediatric antipyretics Infants younger than 3 months of age are not recommended to use antipyretics. Physical cooling or mild-acting herbs can be used 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 is still 4 times a day. Drink more water when taking medicine to reduce fever, to speed up excretion in favor of taking away body heat. (1) Pediatric thermoregulatory center is not perfect, so pediatric fever reduction should be based on physical cooling. (2) Fever is a manifestation of the body’s resistance to disease, and the cause should be actively investigated and the primary disease treated. (3) Master the active ingredients, drug action characteristics, adverse reactions, contraindications, and contraindications of various antipyretic and analgesic drugs to prevent damage to the body due to improper use of drugs. (4) According to the characteristics of pediatric antipyretics, reasonably grasp the use interval of pediatric antipyretics. (5) The dosage should be taken on time and in accordance with the dosage, do not arbitrarily increase the dosage or shorten the interval of administration. (6) During the period of fever reduction, the child should be advised to drink more water to avoid deficiency caused by profuse sweating. (7) Generally use one kind of antipyretic drugs, and consider combining them when the efficacy is really unsatisfactory. Check the body temperature about one hour after each dose to judge the effect of antipyretic. (8) Reasonable control of the use of the course of treatment, the fever is stopped. (9) Pay attention to the toxic side effects of drugs, such as blood picture changes, gastrointestinal reactions, liver and kidney function damage, etc. during the use of drugs. (10) If necessary, subhypnotic therapy can be used for children with severe and persistent high fever.