Pain Relievers Compared

NSAIDs: How They Work

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) work by blocking enzymes called COX-1 and COX-2. These enzymes produce prostaglandins, chemicals that promote inflammation, pain, and fever. By blocking prostaglandin production, NSAIDs reduce all three.

The downside is that prostaglandins also protect the stomach lining and help maintain kidney blood flow. That's why NSAIDs can cause stomach irritation and shouldn't be used long-term without medical supervision.

Acetaminophen: How It Works

Acetaminophen's exact mechanism isn't fully understood, but it appears to work primarily in the central nervous system rather than at the site of inflammation. This is why it relieves pain and reduces fever but does not reduce inflammation or swelling.

Because it doesn't affect prostaglandins in the stomach or kidneys, acetaminophen is generally gentler on the digestive system. However, it is processed by the liver, so taking too much (or combining with alcohol) can cause serious liver damage, which is why the FDA caps single-ingredient adult dosing and limits acetaminophen in combination products.

Best Pain Reliever by Condition

Headaches & Migraines

Any OTC pain reliever can help with tension headaches. For migraines, ibuprofen and naproxen tend to work better because inflammation is often involved. For frequent headaches, consult your doctor, overuse of any pain reliever can cause rebound headaches.

Muscle & Joint Pain

NSAIDs are the better choice because they reduce both pain and inflammation. Naproxen's longer duration makes it convenient for chronic joint pain. For arthritis, your doctor may prescribe prescription-strength NSAIDs.

Dental Pain

Ibuprofen is often recommended by dentists for dental pain because it addresses the inflammation at the source. Some studies suggest alternating ibuprofen and acetaminophen provides better relief than either alone.

Fever

All four work for fever. Acetaminophen is preferred for children and during pregnancy (in recommended doses). For adults with no contraindications, any option is appropriate.

Menstrual Cramps

NSAIDs are more effective because menstrual cramps involve prostaglandins. Ibuprofen and naproxen are most commonly recommended. Starting an NSAID a day before your period begins can be more effective than waiting for pain to start.

Important Safety Notes

Pain Reliever Comparison Table

Medication	Max OTC Daily Dose	Best For	Key Risk
Ibuprofen	1,200 mg	Inflammation, fever, acute pain	Stomach bleeding, kidney strain
Naproxen	660 mg	Longer-lasting pain relief	Same as ibuprofen, longer duration
Acetaminophen	3,000 mg	Headaches, fever, mild pain	Liver damage (with alcohol/overdose)
Aspirin	4,000 mg	Pain, heart protection (low-dose)	Stomach bleeding, Reye syndrome (children)
Diclofenac gel	Topical only	Localized joint/muscle pain	Skin irritation (lower systemic risk)

Worked Example: Choosing a Pain Reliever for Back Pain

A 45-year-old office worker develops acute lower back pain after lifting a heavy box. Here is how to choose:

1. Consider medical history: No history of ulcers, kidney disease, or heart conditions. Not on blood thinners. No known drug allergies.
2. Select based on pain type: Back pain from muscle strain involves inflammation. NSAIDs like ibuprofen or naproxen are first-line for inflammatory pain because they block the prostaglandins causing both pain and swelling.
3. Dose correctly: Ibuprofen 400-600 mg every 6 hours with food, or naproxen 220 mg every 8-12 hours with food. Stay under the OTC maximum (1,200 mg ibuprofen, 660 mg naproxen per day).
4. Add acetaminophen if needed: For breakthrough pain, you can add acetaminophen 500 mg every 6 hours (max 3,000 mg/day). It works through a different mechanism and does not increase stomach risk.
5. Duration: OTC NSAIDs are meant for short-term use. If back pain persists beyond 10 days, see a doctor to rule out disc injury, kidney infection, or other causes that need different treatment.

• Don't combine NSAIDs - taking ibuprofen and naproxen together increases side effects without improving pain relief
• You can combine NSAID + acetaminophen - they work through different mechanisms and can be taken together safely
• Aspirin + ibuprofen interaction - if you take daily low-dose aspirin for heart protection, take it 30+ minutes before ibuprofen (ibuprofen can reduce aspirin's blood-thinning effect)
• Stomach protection - take NSAIDs with food or milk to reduce stomach irritation
• Short-term use - OTC NSAIDs are meant for short-term use (up to 10 days for pain). See a doctor for ongoing pain
• Liver warning - never exceed the maximum daily dose of acetaminophen, and avoid it with heavy alcohol use (3+ drinks/day)

Who Should Avoid NSAIDs?

• People with a history of stomach ulcers or GI bleeding
• People with kidney disease
• People on blood thinners (warfarin, etc.)
• People with uncontrolled high blood pressure
• Pregnant women (especially third trimester)
• People who've had allergic reactions to aspirin or other NSAIDs

Who Should Avoid Acetaminophen?

• People with liver disease or hepatitis
• Heavy alcohol users (3+ drinks daily)
• People already taking medications containing acetaminophen (check labels, it's in many combination products like NyQuil, Excedrin, and Percocet)