Fighting Parents’ Fever Phobia
A PARENT ASKS:
Do I have to treat my daughter’s fever when she is acting fine? What fever reducer should I use, acetaminophen or ibuprofen? And can I use them together and/or alternate them?
THE PARENT COACH ADVISES:
The accepted “normal” body temperature of 37.0°C was described in 1876 based on the average temperature of healthy adults.1 Although normal body temperature falls within a range, the common definition of fever that is used clinically and in the medical literature is a core temperature of 38.0°C or higher.2
The treatment of fever must be determined on a case-by-case basis based on the child’s medical history and discomfort level. Children with serious underlying medical conditions (such as cardiac or pulmonary disease) might not tolerate an increase in metabolism triggered by an increase in body temperature; therefore, treatment of fever is justified. The rest of the information in this article applies to a child with no other underlying medical conditions.
An elevated body temperature in an otherwise healthy child, even as high as 41°C, typically poses no danger, persists briefly, and might benefit the child.3 It is important to counsel parents that fever is a symptom, not a primary illness. No evidence suggests that the increase in temperature worsens the course of the illness or poses a risk of neurologic complication.4 The underlying illness, most commonly a viral infection, is responsible for any morbidity, not the fever.5 Only when temperatures reach 41°C to 42°C do adverse physiologic changes begin.2,4 Despite this, parents often treat their children with acetaminophen or ibuprofen in response to even a minimal elevation in temperature.6 Approximately 50% of parents consider their child to be febrile with a body temperature of less than 38.0°C, and 25% would begin treatment with antipyretics at these lower temperatures.7,8
Mechanism of fever. The main mechanism of fever secondary to an infectious process involves pyrogens. Pyrogens can be products of viral or bacterial metabolism (extrinsic) or antigen-antibody complexes and complement components (intrinsic). These active products stimulate the release of inflammatory cytokines such as interleukin-1, tumor necrosis factor, and intrinsic factor. The cytokines do not cross the blood-brain barrier, but they stimulate increased production of prostaglandin E, which works in the preoptic nucleus of the hypothalamus to increase the “set point” temperature. Although this will cause temperature to rise, the body remains in homeostasis. Cryogens provide negative feedback and prevent temperatures from rising to dangerous levels.9
Because fever is a homeostatic process, temperature will not continue to rise to dangerous levels under normal febrile circumstances.9 Many parents do not understand this concept and believe their child’s temperature will continue to rise without treatment.7 Parents can be reminded that fever can be beneficial. Certain components of the immune system can be enhanced during fever, and some data supports that allowing the fever to continue will shorten the overall course of the illness.4 Fever hinders microbial replication and enhances neutrophil production and T lymphocyte function.10
Fever treatment. The American Academy of Pediatrics (AAP) recommends reducing fever when doing so will decrease discomfort. The emphasis should be on the level of comfort, not the level of the temperature.4 Careful observation of the child and ensuring adequate fluid intake are important. The risk of serious illness is more accurately predicted by the child’s clinical presentation rather than the height of the fever.9 Cyanosis, rapid breathing, poor peripheral perfusion, and petechial rash are red flags for serious infection.11
Parents are not the only ones who will begin antipyretic therapy at low body temperatures; medical personnel do, too. Despite the benign nature of low-grade fevers, pediatricians most often start antipyretics for fever greater than 38.3°C.12 Antipyretics will lower the child’s temperature but it is unclear whether the change in temperature is what benefits the child; cooling children with other methods (eg, tepid sponge baths) can lower temperature without improving comfort.4 Overall, there is no evidence that reducing fever improves the outcome of an illness or prevents febrile seizures.4
Antipyretic mechanism and dosing. Antipyretics act by lowering the hypothalamic set point through decreased production of prostaglandins. In the pediatric population, dosing of these drugs should be based on weight rather than the height of fever.4
If fever is treated with antipyretics, the parents must be counseled about safety issues and adequate dosing. Appropriate acetaminophen oral dosing is 10 to 15 mg/kg every 4 hours with a maximum daily dose of 90 mg/kg for 3 days (if the course is prolonged, the maximum daily dose drops to 75 mg/kg). Ibuprofen dosing is 5 to 10 mg/kg every 6 hours with a maximum daily dose of 40 mg/kg. Acetaminophen should be given every 4 hours, but 14% of parents give acetaminophen every 3 hours or less.12 Only 33% of caregivers give doses of ibuprofen at the recommended interval of 6 hours or more. Eighty-five percent of parents would wake their child to give them antipyretics.7 However, 80% of pediatricians advise that awakening a child for this purpose is unnecessary and may hinder the sleep needed for recovery.12
Acetaminophen should be prescribed cautiously in infants 3 months of age or younger based on the dosing described above, with parents educated about the strengths of the available suspensions. Ibuprofen should not be given before 6 months of age. Both drugs are absorbed in gastrointestinal tract, metabolized in the liver, and excreted in the urine.4,9,13,14
Acetaminophen, ibuprofen, or alternating regimens. The AAP has concluded that acetaminophen and ibuprofen have no significant difference in safety and efficacy.4 One minor difference is that ibuprofen has a longer duration of antipyresis, up to 8 hours.14 Acetaminophen has an effect that lasts between 4 and 6 hours. If a child has problems with gastritis or peptic ulcers, acetaminophen is safer. If a child has problems with liver function, ibuprofen is safer.
Alternating regimens still is a popular custom, and 50% of pediatricians surveyed have advised using them.15 Studies on alternating regimens have revealed that 4 hours after treatment initiation, body temperature is lower with alternating regimens than with single agent therapy.4 However, the AAP has concluded that there is a paucity of evidence for using alternating regimens, and that using them may result in increased dosing error or overdose.4,16 It is important for pediatric health care providers to focus on increasing a child’s comfort level and not obsess about decreasing the temperature of an otherwise healthy child.
The take-home message. Fever is a homeostatic and a healthy response to infection and other physiologic insults. Aside from specific worrisome situations such as those described here, the fever usually will run a benign course. When the decision is made to treat with antipyretics, ensuring correct dosing and parental education is imperative. Although alternating regimens using acetaminophen and ibuprofen lower temperatures more effectively than either agent alone, this practice may lead to increased dosing errors.
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13.Brown RD, Kearns GL, Wilson JT. Integrated pharmacokinetic-pharmacodynamic model for acetaminophen, ibuprofen, and placebo antipyresis in children. J Pharmacokinet Biopharm. 1998;26(5):559-579.
14.Perrott DA, Piira T, Goodenough B, Champion GD. Efficacy and safety of acetaminophen vs ibuprofen for treating children’s pain or fever: a meta-analysis. Arch Pediatric Adolescent Med. 2004;158(6):521-526.
15.Mayoral CE, Marino RV, Rosenfeld W, Greensher J. Alternating antipyretics: is this an alternative? Pediatrics. 2000;105(5):1009-1012.
16.Saphyakhajon P, Greene G. Alternating acetaminophen and ibuprofen in children may cause parental confusion and is dangerous. Arch Pediatric Adolesc Med. 2006;160(7):757.
The authors thank Deepak M. Kamat, MD, PhD, for his expertise and review of this article.
Ms Radis is a medical student at West Virginia University School of Medicine in Morgantown.
Linda S. Nield, MD––Series Editor:Dr Nield is professor of pediatrics at West Virginia University School of Medicine in Morgantown.