acetaminophen vs diflunisal

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Side-by-side comparison of acetaminophen and diflunisal. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

Acetaminophen In normal volunteers, concomitant administration of diflunisal and acetaminophen resulted in an approximate 50% increase in plasma levels of acetaminophen. Acetaminophen had no effect on plasma levels of diflunisal. Since acetaminophen in high doses has been associated with hepatotoxicity, concomitant administration of diflunisal tablets and acetaminophen should be used cautiously, with careful monitoring of patients.

Drug Class
acetaminophen Analgesic / Antipyretic
diflunisal Nonsteroidal Anti-Inflammatory Drug (NSAID)
Type
acetaminophen Over-the-Counter
diflunisal Prescription
Summary
acetaminophen

Acetaminophen (Tylenol) is a medicine that can relieve pain and reduce fever. It is available over-the-counter.

diflunisal

Diflunisal is a medicine that can help with pain and swelling. It belongs to a class of drugs called NSAIDs.

What It Treats
acetaminophen

This medicine temporarily relieves minor aches and pains. It can help with headaches, the common cold, backaches, and minor arthritis pain. It can also help with toothaches, muscle aches, premenstrual and menstrual cramps. Acetaminophen can also temporarily reduce fever.

diflunisal

Diflunisal can help with mild to moderate pain. It can also treat the symptoms of osteoarthritis and rheumatoid arthritis. You should use the lowest dose that works for you, for the shortest time needed.

How It Works
acetaminophen

Acetaminophen's exact mechanism is not fully understood. It is believed to work in the brain to reduce pain signals. It also helps to lower body temperature when you have a fever.

diflunisal

Diflunisal reduces pain and swelling by blocking the production of certain chemicals in your body. These chemicals cause inflammation and pain. By blocking them, diflunisal helps to relieve your symptoms.

Common Side Effects
acetaminophen
  • Headache
  • Nausea
diflunisal
  • Nausea
  • Vomiting
  • Upset stomach
  • Stomach pain
  • Diarrhea
FAERS Reports
acetaminophen
  • Fatigue 34,487
  • Nausea 29,567
  • Headache 28,380
  • Pain 28,314
  • Diarrhoea 23,626
diflunisal
  • Nausea 66
  • Fatigue 57
  • Pain 50
  • Drug Hypersensitivity 47
  • Headache 45
Serious Warnings
acetaminophen

Taking more acetaminophen than directed can cause liver damage. Follow the dosage instructions carefully.

diflunisal

NSAIDs like diflunisal can increase your risk of heart problems like heart attack and stroke, which can be deadly. This risk is higher if you take it for a long time. You should not take diflunisal if you are having heart bypass surgery. NSAIDs also raise your risk of serious stomach problems like bleeding and ulcers, which can also be deadly. Older adults are at higher risk for these stomach problems.

Pregnancy
acetaminophen

If you are pregnant or breastfeeding, talk to your doctor before using this medicine. They can help you weigh the risks and benefits.

diflunisal

Tell your doctor if you are pregnant or plan to become pregnant. Taking diflunisal late in pregnancy may harm your baby. It is not known if diflunisal passes into breast milk, so talk to your doctor before breastfeeding.

Also Compare, Nearby Drugs

How to Read This acetaminophen vs diflunisal Comparison

acetaminophen is classified in the Analgesic / Antipyretic drug class, while diflunisal sits within the Nonsteroidal Anti-Inflammatory Drug (NSAID) class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are split between OTC and prescription status, which affects access and supervision.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, acetaminophen has 144,374 submissions while diflunisal has 265. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to diflunisal causes the levels of acetaminophen in your blood to go up by about half. this could increase the risk of liver damage from the acetaminophen.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for acetaminophen or diflunisal.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.