mefenamic acid
Brand names: Ponstel
Mefenamic acid is a medicine used to treat mild to moderate pain and menstrual cramps. It is a type of nonsteroidal anti-inflammatory drug (NSAID).
Drug Pricing (NADAC)
Generic Price
$0.98/unit
Generic Available
Yes (3 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Mefenamic acid is used to relieve mild to moderate pain in people 14 years and older.
Common side effects
Abdominal pain, Constipation, Diarrhea
Key warnings
Mefenamic acid may increase the risk of serious heart problems, including heart attack and stroke, which can be fatal.
How It Works
Mefenamic acid reduces pain and inflammation in the body. It does this by blocking substances in the body that cause pain and swelling. This medicine helps to reduce pain and discomfort.
How to Take It
Take mefenamic acid exactly as your doctor tells you. For pain, the usual starting dose is 500 mg, followed by 250 mg every 6 hours as needed. Do not take it for more than one week. For menstrual cramps, the usual starting dose is 500 mg, followed by 250 mg every 6 hours, starting when bleeding and symptoms begin. You should not need to take it for more than 2 to 3 days.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. Mefenamic acid may harm your unborn baby. It is not known if mefenamic acid passes into breast milk. Talk to your doctor before breastfeeding.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store at room temperature, away from heat and moisture.
Side Effects (from patient reports)
Based on 2,101 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 2,104 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
2,104
Death-Related Reports
81
Hospitalization Reports
707
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DRUG INEFFECTIVE | 352 |
| 2 | NAUSEA | 296 |
| 3 | FATIGUE | 253 |
| 4 | HEADACHE | 227 |
| 5 | PAIN | 202 |
| 6 | DIZZINESS | 177 |
| 7 | MALAISE | 170 |
| 8 | ARTHRALGIA | 152 |
| 9 | PAIN IN EXTREMITY | 139 |
| 10 | VOMITING | 133 |
| 11 | STRESS | 130 |
| 12 | DIARRHOEA | 129 |
| 13 | DRUG INTOLERANCE | 127 |
| 14 | DYSPNOEA | 121 |
| 15 | RHEUMATOID ARTHRITIS | 120 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Mefenamic acid may increase the risk of serious heart problems, including heart attack and stroke, which can be fatal. This risk may occur early in treatment and may increase with longer use. You should not take this medicine if you are having heart bypass surgery. Mefenamic acid can also increase the risk of serious stomach and intestinal problems, including bleeding, ulcers, and holes, which can be fatal. These problems can occur without warning. The elderly and those with a history of stomach ulcers or bleeding are at higher risk.
Known Drug Interactions
Methotrexate Clinical Impact: Concomitant use of NSAIDs and methotrexate may increase the risk for methotrexate toxicity (e.g., neutropenia, thrombocytopenia, renal dysfunction). Intervention: During concomitant use of mefenamic acid and methotrexate, monitor patients for methotrexate toxicity.
Mechanism: This pain medicine can prevent your body from clearing out methotrexate, which can lead to toxic levels in your system.
What to do: Your doctor should monitor you for signs of toxicity, such as kidney issues or changes in your blood cell counts.
NSAIDs and Salicylates Clinical Impact: Concomitant use of mefenamic acid with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy (see Warnings ; Gastrointestinal Bleeding, Ulceration and Perforation ).
Mechanism: Taking these two drugs together increases the risk of stomach bleeding and ulcers without providing extra relief. Both drugs are similar and can irritate the lining of your digestive system.
What to do: Avoid taking these two medications at the same time. Your doctor should help you choose just one of these drugs to manage your symptoms safely.
Table 3: Drugs that Can Increase the Risk of Bleeding Drug Class Specific Drugs Anticoagulants argatroban, dabigatran, bivalirudin, desirudin, heparin, lepirudin Antiplatelet Agents aspirin, cilostazol, clopidogrel, dipyridamole, prasugrel, ticlopidine Non-steroidal Anti-Inflammatory Agents celecoxib, diclofenac, diflunisal, fenoprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, mefenamic acid, naproxen, oxaprozin, piroxicam, sulindac Serotonin Reuptake Inhibitors citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, paroxetine, sertraline, venlafa...
Mechanism: Mefenamic acid can increase the risk of bleeding when used with warfarin. These drugs work together to slow down blood clotting more than usual.
What to do: Use this combination with caution and under a doctor's supervision. Your healthcare provider may need to change your medication plan.
In the absence of data regarding potential interaction between pemetrexed and NSAIDs with longer half-lives (e.g., meloxicam, nabumetone), patients taking these NSAIDs should interrupt dosing for at least five days before, the day of, and two days following pemetrexed administration.
Mechanism: Both of these drugs are NSAIDs that work in the same way, so taking them together increases the risk of stomach issues without helping more with pain.
What to do: Do not take these two medications together unless your doctor specifically tells you to.
Diuretics Clinical Impact: Clinical studies, as well as post-marketing observations, showed that NSAIDs reduced the natriuretic effect of loop diuretics (e.g., furosemide) and thiazide diuretics in some patients.
Mechanism: Mefenamic acid can block the effects of furosemide, making it harder for your body to remove extra salt and water through your urine.
What to do: Your doctor may need to check your blood pressure and fluid levels more often while you are taking both drugs.
Common Questions
Can I take mefenamic acid with aspirin?
Can mefenamic acid affect my blood pressure?
Can I take mefenamic acid if I have kidney problems?
Can mefenamic acid cause liver problems?
How quickly does mefenamic acid work?
Can I drink alcohol while taking mefenamic acid?
Can mefenamic acid interact with other medications?
What should I do if I experience severe side effects?
Can I use mefenamic acid for long-term pain relief?
Is it okay to take mefenamic acid on an empty stomach?
What are the common side effects of mefenamic acid?
Does mefenamic acid interact with other medications?
What drug class is mefenamic acid?
Is mefenamic acid safe during pregnancy?
Related Medications in Nonsteroidal Anti-Inflammatory Drug (NSAID)
Other drugs grouped near mefenamic acid — same-class peers and common alternatives.
abatacept
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Vicodin, Norco
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What the FDA Data Shows for mefenamic acid
The FDA label for mefenamic acid (sold under brand names such as Ponstel) classifies it as a prescription-only medication in the Nonsteroidal Anti-Inflammatory Drug (NSAID) class. Mefenamic acid is used to relieve mild to moderate pain in people 14 years and older. Official labeling lists 11 commonly reported side effects, including Abdominal pain, Constipation, Diarrhea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 2,101 voluntary reports. The database also lists 15 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.98.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: July 19, 2024
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages