Pain relievers such as ibuprofen and acetaminophen are effective in reducing fevers and lessening pain, states eMedicineHealth. It is usually best to alternate between these two drugs in order not to overdose. Aspirin may also work for reducing fevers, but it is not recommended over ibuprofen or acetaminophen due to toxicity in large doses. Children under the age of 18 should not take aspirin unless prescribed by a doctor, as this can cause Reye's syndrome.
Ibuprofen reduces fever through its effects on the hypothalamus, which is the part of the brain responsible for controlling body temperature, eMedicineHealth reports. Adults should not take more than two tablets of ibuprofen every four hours, whereas kid's doses vary by weight. Nausea and vomiting may occur if a person takes ibuprofen without food. Stomach pain, heartburn, constipation and diarrhea are more serious side effects. Individuals with stomach ulcers or kidney disease and those with aspirin allergies should not take ibuprofen, which can also be harmful to pregnant women and their fetuses.
The recommended dosage of acetaminophen is also two tablets every four hours, according to eMedicineHealth. Individuals with allergies to acetaminophen may display side effects, although these are generally rare. As overdosing on acetaminophen can damage the liver or cause liver failure, people with liver disease and chronic drinkers should not take it.