Apart from Motrin, you can give him a warm sponge bath. This helps further in bringing down the temperature. With no other symptom than fever, this is likely to be viral fever. If the fever does not go below 100, of if any new sympXXXXX XXXXXke vomiting or cough develops, you may consider taking him to ER.
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Medication takes approximately half an hour to work. Motrin and Tylenol can bring the fever to normal. If the fever is persistently above 100 despite the medicine and warm water soaked towel sponging, it would be prudent to get a physical examination by a doctor.
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If the fever comes down to less than 100, you can wait till morning for the regular pediatrician appointment. If the fever remains above 100 despite the measures, it is better to get an evaluation done in night at ER.
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