Evidence update: The drug-label and public-health sources linked in this guide were checked on August 8, 2026. This is general education, not an individual diagnosis or prescription.
The key distinction is product identity: naproxen 500 mg and naproxen sodium 550 mg may represent corresponding prescription strengths, while formulations and directions still differ.
The names are not interchangeable
A prescription described as “naproxen 500 mg” is not necessarily a naproxen sodium 500 mg product. Common immediate-release prescription labeling pairs naproxen 500 mg with naproxen sodium 550 mg because the salt adds weight. The safest check is the exact generic name, strength, formulation, and directions printed by the pharmacy.
Four details to read on the bottle
| Detail | Why it matters |
|---|---|
| Active ingredient | Distinguishes naproxen from naproxen sodium and prevents a faulty milligram comparison. |
| Release type | Immediate-, delayed-, and extended-release forms can have different timing and should not be substituted casually. |
| Indication | Arthritis, acute pain, menstrual pain, gout, tendinitis, and bursitis do not share one universal regimen. |
| Stop/review date | Repeated treatment carries different monitoring needs than a short course. |
Do not fill gaps with OTC directions
The 220 mg Drug Facts label is written for a specific nonprescription product. It is not a conversion chart for a 500 mg prescription. If the label is missing, damaged, or unclear, the dispensing pharmacy can retrieve the original directions.
Risk review for a prescription-strength product
Before use, disclose previous ulcer or bleeding, kidney or liver disease, high blood pressure, heart disease or heart failure, recent heart attack, aspirin-sensitive asthma, pregnancy, and all medicines. The prescription label identifies anticoagulants, antiplatelet drugs, aspirin, other NSAIDs, steroids, SSRIs/SNRIs, diuretics, ACE inhibitors, ARBs, lithium, and methotrexate among combinations that may require avoidance or monitoring.
If a dose was taken incorrectly
Do not automatically take another tablet or “balance” the schedule. Record the product, amount, and times taken, then call the pharmacist, prescriber, or Poison Control for case-specific advice. Severe drowsiness, confusion, seizure, fainting, breathing difficulty, heavy bleeding, or collapse requires emergency care.
Common questions
Is naproxen sodium 500 mg a standard equivalent of naproxen 500 mg?
Do not assume that wording. Common corresponding immediate-release strengths are naproxen 500 mg and naproxen sodium 550 mg; verify the exact prescription.
What if the tablet appearance changed?
Generic manufacturers can use different shapes and colors. Match the imprint and pharmacy label, and call the dispensing pharmacy before taking an uncertain tablet.
Can I replace a missing prescription with OTC naproxen?
Not without professional advice. OTC directions are not a replacement for an indication-specific prescription.
Related guides on this site
- Navigating Prescription Strength: Naproxen 375 mg Effects, Uses, and Safety Limits
- Naproxen Sodium 550 mg: Prescription Uses and Safety Boundaries
- Naproxen Sodium 220 mg: Label Directions and Safety Tips
Primary sources and scope
The links below are the evidence base for the label statements in this article. Product labels can change, so the package or dispensing label in hand remains the controlling instruction.
- Naproxen sodium prescribing information — DailyMed
- Naproxen drug information — MedlinePlus
- Naproxen sodium 220 mg Drug Facts label — DailyMed
- Naproxen overdose guidance — Poison Control
Urgent boundary: call local emergency services for chest pressure, severe breathing difficulty, one-sided weakness, fainting, vomiting blood, black tar-like stool, or rapidly progressing facial or throat swelling. In the United States, a possible overdose can also be discussed with Poison Control at 1-800-222-1222.