🧊 Antipyretics – EMS Drug Class Overview

Introduction to Antipyretics

Antipyretics are medications used to reduce fever by acting on the body’s internal thermostat. In EMS, they are most commonly used for pediatric fevers, febrile illness, and systemic infections like sepsis. The primary EMS antipyretics are acetaminophen and ibuprofen, while some systems also include ketorolac. Aspirin has antipyretic effects but is rarely used for that purpose in modern EMS.

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📋 Quick Reference: Antipyretics at a Glance

Feature	Info
Mechanism	Inhibits prostaglandin-mediated hypothalamic temperature elevation
Main EMS Uses	Pediatric fever, febrile illness, supportive sepsis care
Onset/Duration	Onset: 15–30 min · Peak: 1–2 hrs · Duration: 4–6 hrs
Watch out for	Liver toxicity (acetaminophen), GI bleeding (NSAIDs), Reye’s syndrome (aspirin)
Common EMS Drugs	Acetaminophen, Ibuprofen (some protocols: Ketorolac, Aspirin)

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🔑 Key Takeaways

• ✅ Antipyretics are frequently used in EMS for fever control, especially in children and sepsis.
• ✅ Acetaminophen is the safest and most commonly used option.
• ⚠️ Ketorolac and Aspirin have antipyretic properties but are not first-line in most EMS protocols.
• 🔁 Antipyretics often overlap with analgesics and NSAIDs.
• 🚑 Local protocols vary—always check your regional guidelines.

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🧬 Mechanism of Action

Antipyretics reduce fever by inhibiting prostaglandin production in the hypothalamus, which lowers the body’s internal “set point.” This leads to heat loss through vasodilation and sweating.

• Acetaminophen: Acts centrally in the CNS.
• NSAIDs (Ibuprofen, Ketorolac, Aspirin): Act centrally and peripherally by inhibiting COX enzymes.

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🩺 Common Indications in EMS

• Febrile pediatric patients (with or without seizure activity)
• Systemic infections (e.g., sepsis)
• Hyperthermia with altered mentation
• General fever-related discomfort
• Heat illness

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⚠️ Contraindications / Cautions

Drug	Contraindications
Acetaminophen	Liver disease, known hypersensitivity
Ibuprofen	GI bleeding, renal impairment, trauma
Ketorolac	Bleeding disorders, recent surgery, kidney disease
Aspirin	Pediatric patients (Reye’s syndrome), GI ulcers, active bleeding

⚠️ Note: Aspirin and Ketorolac are not first-line fever reducers in EMS. Their use depends on local protocols and clinical judgment.

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💊 Common EMS Antipyretics

Generic Name	Trade Name(s)	EMS Notes
Acetaminophen	Tylenol, Ofirmev	Preferred agent. Available PO and IV. Safe and effective.
Ibuprofen	Motrin, Advil	Effective NSAID. PO only. Avoid in trauma.
Ketorolac	Toradol	NSAID used for pain; some protocols use for fever. Injectable.
Aspirin	ASA	Rarely used as antipyretic. Primary EMS use is antiplatelet.

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📏 Dosing Considerations

Drug	Route	Adult Dose	Pediatric Dose
Acetaminophen	PO/IV	650–1000 mg	15 mg/kg
Ibuprofen	PO	400–800 mg	10 mg/kg
Ketorolac	IM/IV	15–30 mg	Not typical
Aspirin	PO	325–650 mg	Contraindicated in children

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👶 Special Considerations

• Pregnancy: Acetaminophen is safest; avoid NSAIDs in 3rd trimester.
• Pediatrics: Use acetaminophen and ibuprofen. Avoid aspirin due to Reye’s syndrome risk.
• Elderly: Use caution with NSAIDs due to renal and GI concerns.
• Overdose Risks: Acetaminophen overdose is a leading cause of acute liver failure and requires N-acetylcysteine (NAC) as an antidote.

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🔁 Related Drug Classes

• NSAIDs – Includes ibuprofen, ketorolac, aspirin.
• Analgesics – Many antipyretics also relieve pain.
• Non-opioid Analgesics – Overlaps with antipyretic medications in action and use.

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🚑 Associated Conditions

• Fever
• Febrile Seizures
• Sepsis
• Heatstroke / Hyperthermia

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📚 References

• DailyMed: https://dailymed.nlm.nih.gov
• MedlinePlus Drug Info: https://medlineplus.gov
• PEPP, AHA PALS, and select regional protocols