Fever is defined as an increase in body temperature above the upper limit of normal temperature fluctuations over the course of 1 day, and is usually measured by anal thermometry. Fever is categorized as low fever (37.3-38°C), moderate fever (38.1-39°C), high fever (39.1-41°C), and ultra-high fever (above 41°C). Fever is defined as an increase in body temperature above the upper limit of normal temperature fluctuations over the course of 1 day and is usually measured by anal thermometry. Fever is categorized as low fever (37.3-38 ℃), moderate fever (38.1-39 ℃), high fever (39.1-41 ℃) and ultra-high fever (above 41 ℃). Pros and cons of fever While fever enhances the immune function and strengthens the killing effect on pathogens, excessively high body temperature can also cause the body to develop chills and inhibit the production of digestive enzymes. The purpose of antipyretic fever is not only to reduce the child’s body temperature, but also to relieve the child’s discomfort caused by fever. For a fever that is not too high and is not accompanied by serious illness, it can be reduced without delay by replenishing water and nutrients, vitamins, and so on. However, if there is a high fever or ultra-high fever, accompanied by heart disease and other critical illnesses, it is necessary to reduce the fever at this time. Physical and medication cooling methods Physical cooling recommendations Physical cooling methods include warm wet compresses and cold saline method, but the effect is limited, and can be used as an adjunct to medication cooling. It should be noted that children’s sweat glands are not developed, and the central nervous system is not well developed, so it is not easy to achieve “sweating” by “covering heat”, but it will cause “muffled fever syndrome”. Recommendations on physical hypothermia UK guideline 2 ≤ 5 years old Not recommended to use warm water baths Not recommended to reduce clothing Against excessive wrapping Italian guideline 3 ≤ 5 years old Not recommended to use physical hypothermia Physical hypothermia is only recommended for children with high fever Australia 3 months to 5 years old Not recommended to use any form of physical hypothermia, including warm water baths NSW guideline 4 Reduce the clothing of children who have been over wrapped South Africa guideline 5 Not recommended for all children Cooling with warm baths and reduced clothing How to choose antipyretic medication? Ibuprofen use and adverse effects Ibuprofen has anti-inflammatory, analgesic and antipyretic effects. Ibuprofen has a long-lasting antipyretic effect and is more effective than acetaminophen in reducing fever above 39°C. It is also recognized as the preferred anti-inflammatory drug for children. The recommended dose of ibuprofen is 5-10 mg/kg/dose, once every 6 h, up to 4 times a day. It is permitted for use in children ≥6 months of age in the United States. Ibuprofen Adverse Reactions: 1, Ibuprofen is cross-sensitized to aspirin, so it is contraindicated in children who are allergic to aspirin, but Reye’s syndrome can occur. 2, mild gastrointestinal discomfort occasionally rash and tinnitus, headache, affecting coagulation function and elevated transferase, etc. also cause gastrointestinal bleeding and aggravate ulcers. 3, long-term use can cause renal failure. Acetaminophen use and adverse reactions Acetaminophen (paracetamol) is a non-steroidal anti-inflammatory antipyretic and analgesic drug, used for migraine, headache, fever.WHO recommends that infants over 3 months and children with high fever preferred antipyretic. Acetaminophen is rapidly and completely absorbed and can produce antipyretic effect within 30 min of oral intake. It is important to note that most commonly prescribed children’s cold remedies also contain acetaminophen. The dose of acetaminophen is 10-15 mg/kg/dose (<600 mg total) at 4-6 h intervals up to 4 times a day. What are the adverse effects of acetaminophen? 1.Hepatotoxicity ; overdose or prolonged high dose ; drinking alcohol or drinking alcoholic beverages ; patients with liver disease ; 2.Mixed with other headache and cold medicines containing acetaminophen: few adverse reactions at regular doses, little nephrotoxicity safety is relatively high. 3, obvious dose-dependence - that is, with the rise of the dose and the efficacy of the rise. Neonates are relatively more toxic due to slow excretion. Against the use of glucocorticoids as antipyretic agents in children, there is a lack of any domestic and international research evidence and literature reports on glucocorticoids as antipyretic agents, and against the use of hormones for antipyretic in children. Hormones will suppress the body's immune system and induce and aggravate infections. And may mask the condition and delay diagnosis and treatment. It can also lead to a significant drop in body temperature, resulting in collapse, water-electrolyte disorders, dehydration fever . Alternating medications for fever reduction can be considered in cases of severe persistent high fever. There are two methods of alternation, one is to use ibuprofen 10 mg/kg first, acetaminophen 15 mg/kg after 4-6 h; the other is to use acetaminophen 12.5 mg/kg first, ibuprofen 5 mg/kg after 4-6 h. Both drugs are used in alternation every 4-6 h, and the course of treatment should not be more than 3 d. What are the precautions for antipyretic treatment? 1, physical cooling and antipyretic agent combined use, body temperature decline faster than single antipyretic agent. 2, the dose of antipyretics should not be too large, in order to prevent excessive sweating caused by the child defecation, encourage more water. 3, antipyretic effect time, 30-45 min. 4, small infants with fever or other patients with a temperature of more than 39-40 ℃ (especially with obvious discomfort), should be timely symptomatic treatment. 5, the etiology is unknown, do not abuse antimicrobials, children more than 91% of viral infections. 6, do not advocate the use of ice / alcohol for physical cooling. 7, antipyretic drugs can not prevent febrile convulsions can not be used prophylactically . 8, only when the child shows discomfort to continue to use, discomfort did not reduce the time to consider replacing other drugs. 9, only when the discomfort persists or before the next dose of medication to the time of use before the recurrence of discomfort can be considered to change the drug (antipyretic agents are usually repeated at intervals of 6-8 hours).