Can Acetaminophen Cause Fever as a Side Effect?

Acetaminophen (paracetamol) is designed to reduce fever and relieve mild to moderate pain, so it generally does not cause fever as a side effect. ^[1] It typically lowers body temperature within 1–2 hours after a dose, though a mild fever can persist depending on the illness causing it. ^[2] If a fever worsens or lasts more than 3 days despite acetaminophen, it’s advisable to stop and speak with a clinician, as this often indicates the underlying condition needs attention rather than a medication side effect. ^[3]

What acetaminophen does

• Acetaminophen is an antipyretic, meaning it temporarily reduces fever by acting on temperature-regulating centers in the brain. ^[4]
• Over-the-counter (OTC) and prescription labels consistently list “temporarily reduces fever” as a primary intended effect. This is why it’s commonly used for colds, flu, and other febrile illnesses. ^{[5] [1]}

Can it paradoxically cause fever?

• Fever as a direct side effect of acetaminophen is not recognized in standard drug labeling or major patient guidance. The more likely scenario is that the fever is due to the underlying infection or condition, not the acetaminophen itself. ^{[3] [2]}
• Rare severe allergic skin reactions (like Stevens–Johnson syndrome or toxic epidermal necrolysis) can occur and may be accompanied by fever as part of the illness picture, but in these cases the fever is a symptom of the reaction, not a typical “side effect” of the drug. These reactions are rare but serious and require urgent care. ^{[6] [7] [8] [9]}

When to seek medical advice

• If your fever gets worse or lasts beyond 3 days while taking acetaminophen, stop using it and contact a clinician for assessment. Persistent fever may signal a condition that needs diagnosis rather than more antipyretics. ^[3]
• Seek immediate help if you notice signs of a severe skin reaction such as widespread rash, blisters, or skin peeling, especially when accompanied by fever or malaise. These can indicate serious reactions like SJS/TEN. ^{[6] [7]}
• Get urgent help if you might have taken more than 4,000 mg in 24 hours (all sources combined), even if you feel well, because serious liver injury can occur without early symptoms. Overdose can present later with nausea, abdominal pain, or abnormal labs. ^{[6] [10]}

Practical coping tips for fever management

• Use acetaminophen as directed: typical adult maximum is 4,000 mg per 24 hours from all products; children should follow weight-based dosing and package instructions. Check labels for “acetaminophen” or “APAP” to avoid double-dosing from combination cold/flu medications. ^{[1] [6]}
• Allow 1–2 hours for effect; mild fever may persist. If the temperature doesn’t improve at all, consult a clinician to reassess the cause. ^[2]
• Supportive care helps: rest, fluids, light clothing, and a comfortably cool room. Avoid alcohol while using acetaminophen to reduce liver risk. ^[1]
• For ongoing symptoms beyond recommended durations (fever >3 days, pain >5 days), stop acetaminophen and seek medical advice to look for underlying causes. This timing guidance is part of standard consumer instructions. ^[3]

Red flags to act on now

• Severe rash, blistering, or skin peeling; skin pain; mouth or eye involvement. Stop acetaminophen and seek urgent care. ^{[6] [7]}
• Possible overdose (more than 4,000 mg/day in adults or more than 5 pediatric doses/day), or combining multiple APAP-containing products. Contact medical services immediately, even if asymptomatic. ^{[1] [6]}

Bottom line

• Acetaminophen does not typically cause fever; it’s used to reduce it. ^[1]
• Persistent or worsening fever often suggests the illness is continuing rather than a medication side effect; follow duration limits and speak with a clinician as advised. Be alert to rare but serious skin reactions and to dosing limits to avoid liver injury. ^{[3] [6] [1]}