This study will examine in detail the immediate effects of three common treatments given to children with fevers to lower their temperature. Each child will be given either ibuprofen, acetaminophen, or a combination, and their temperature monitored at five-minute intervals. The temperature-lowering effects of each treatment will be compared to evaluate which is most effective.

There is no substantial evidence that a fever lower than 41°C is harmful to the welfare of an otherwise healthy child, although they can be dangerous to children already in critical condition [1,2]. However, fevers in healthy children commonly cause anxiety in parents and caregivers, so parents and physicians often give antipyretic medications to lower the fever [3,4]. Ibuprofen and acetaminophen are two of the most commonly used medications in children. Most major pediatric medical associations agree about appropriate dosages for children, but give no clear guidelines on whether ibuprofen or acetaminophen should be used [3,5]. Physicians commonly make the decision between the two based on their personal opinions of the efficacy and safety of the medications, or based on habit [6]. Survey data shows that more than half of physicians use combinations of both acetaminophen and ibuprofen to treat fever, either simultaneously or on an alternating schedule, with a variety of dosing patterns [6]. A majority of physicians believed there were established guidelines supporting this use, but in fact there are not [6].

Combining the two medications is widely theorized to improve effectiveness, but clinical trials comparing combination treatments to ibuprofen and/or acetaminophen alone have shown inconsistent results [4,7-12]. Several pharmacodynamic studies have shown that ibuprofen and acetaminophen both produce their largest effects on temperature within the first hour following dosage [9,10,13-16]. Despite this, only one study has been performed examining the change in temperature at intervals shorter than 30 minutes, and that study used substandard monitoring methods [10].

This study will use gold-standard monitoring methods to take temperatures every five minutes through the first one to four hours of treatment. Understanding the pattern of temperature change in the acute stages after dosing will help settle the debate about the optimal medication choice for treating childrens' fevers.

Inclusion Criteria:

• fever between 38 and 41 Celsius (inclusive) on presentation to ER
• assessment by treating physician that patient requires antipyretic treatment

Exclusion Criteria:

• known allergy or hypersensitivity to either study medication
• received any antipyretic medication in past eight hours
• patient requires admission to hospital
• co-morbidities indicating increased risk of complication
• assessment by treating physician that patient is medically unsuitable for the study