Mefenamic Acid: An Older Pain Reliever Used for Period Pain

Table of Contents

1. An Old Drug Still on the US Market
2. How Mefenamic Acid Works
3. What the US Label Says About Use and Dose
4. The Label's Warnings and Interactions
5. The Evidence for Period Pain
6. Trials Comparing Mefenamic Acid With Herbs
7. The Evidence for Heavy Periods
8. Overdose, Seizures and Rarer Harms
9. What Is Not Known
10. Key Research Papers
11. Connections
12. Featured Videos

An Old Drug Still on the US Market

The US Food and Drug Administration's Drugs@FDA database lists the original new drug application for mefenamic acid (application 015034) with an approval date of 28 March 1967. The first generic versions listed in the same database were approved from 2010 onward, and several generic capsule makers now hold approvals. In the United States the drug comes as a 250 mg capsule taken by mouth.

Chemically, mefenamic acid is N-2,3-xylylanthranilic acid. The label describes it as "a member of the fenamate group" of nonsteroidal anti-inflammatory drugs — a small sub-family built on an anthranilic acid backbone, different in shape from the propionic acids (ibuprofen, naproxen) and from aspirin.

A 2025 case report notes that, unlike ibuprofen, mefenamic acid is not sold over the counter in many countries, and that it is commonly used for period pain. That second point matters for the overdose findings further down this page, because the people who most often have the drug at home are young women.

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How Mefenamic Acid Works

Period pain is driven largely by prostaglandins, hormone-like substances made in the lining of the womb as it breaks down. The 2015 Cochrane review of these drugs for period pain explains that women with dysmenorrhoea have high levels of prostaglandins, which are known to cause cramping abdominal pain. Prostaglandins are made by an enzyme called cyclo-oxygenase (COX), which comes in two forms, cyclo-oxygenase-1 and cyclo-oxygenase-2.

The US label states that the way mefenamic acid works, "like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2)". It calls the drug a potent blocker of prostaglandin production in laboratory tests, and says its effect "may be due to a decrease of prostaglandins in peripheral tissues". Blocking both forms of cyclo-oxygenase is what makes it a "non-selective" drug in the Cochrane review's terms, as opposed to the newer drugs that block only cyclo-oxygenase-2.

The same prostaglandins also widen blood vessels in the womb lining. The 2019 Cochrane review on heavy periods describes prostaglandin levels as raised in women with excessive menstrual bleeding, which is the reason these drugs were tested for heavy periods as well as for pain.

How the body handles it

According to the label, mefenamic acid is absorbed quickly, reaches its peak in the blood in 2 to 4 hours, and has an elimination half-life of about two hours. More than 90% is bound to albumin in the blood. The liver enzyme CYP2C9 breaks it down, and about 52% of a dose leaves in the urine, mostly as broken-down forms; up to 20% leaves in the stool. The label adds that the broken-down forms "may accumulate in patients with renal or hepatic failure", and that the drug's behaviour in people with liver or kidney disease has not been studied.

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What the US Label Says About Use and Dose

The two approved uses

The current US prescribing information lists:

• Mild to moderate pain in adults and in young people aged 14 and older, "when therapy will not exceed one week (7 days)". The label states that safety and effectiveness for this use have not been established below age 14.
• Primary dysmenorrhoea (ordinary period pain). The label states that safety and effectiveness for period pain have been established in young people as well as adults.

The labelled dose

For both uses, the label's dose is 500 mg by mouth as a first dose, followed by 250 mg every 6 hours. For period pain the label says the course starts "with the onset of bleeding and associated symptoms". An older-format version of the same label adds that "effective treatment can be initiated with the start of menses and should not be necessary for more than 2 to 3 days". For general pain the limit is the one-week ceiling written into the indication. The label's maximum recommended human dose, used in its animal comparisons, is 1,500 mg a day.

Like every label in this drug family, it states the general rule that the "lowest effective dose for the shortest duration" consistent with the treatment goal is used.

The label's own trials

The label describes double-blind trials in which women with primary period pain took mefenamic acid or a placebo, starting at the onset of bleeding or of pain, for three menstrual cycles, and then switched to the other treatment for three more cycles. The women on mefenamic acid did better than on placebo on pain ratings by both patient and investigator, on the need for extra painkillers, and on how often and how severely period symptoms occurred. The label gives no numbers for these trials.

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The Label's Warnings and Interactions

The boxed warning

Like every prescription drug in this family in the United States, mefenamic acid carries a boxed warning with two parts:

• Heart and blood-vessel events. These drugs "cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal". The label states that the risk may appear early in treatment and may increase with longer use. The drug is contraindicated around coronary artery bypass graft surgery.
• Stomach and gut bleeding. These drugs cause an increased risk of bleeding, ulcers and perforation of the stomach or intestines, which can be fatal and "can occur at any time during use and without warning symptoms". Older people and people who have had a peptic ulcer or gut bleeding are at greater risk.

Contraindications

The label lists three situations in which the drug is contraindicated: a known allergy to mefenamic acid (including anaphylaxis or a serious skin reaction to it); a history of asthma, hives or other allergic-type reactions after aspirin or another drug of this family, because severe and sometimes fatal anaphylactic reactions have been reported in such people; and the setting of coronary artery bypass graft surgery.

Other warnings in the label

• Liver. Rises in the liver enzymes alanine aminotransferase or aspartate aminotransferase to three or more times the upper normal limit occurred in about 1% of patients on drugs of this family in clinical trials, and smaller rises in up to 15%. Rare, sometimes fatal, cases of severe liver injury, including liver failure, have been reported. The label lists nausea, tiredness, itching, yellowing of the skin and "flu-like" symptoms among the warning signs.
• Kidneys. Long-term use of these drugs has caused renal papillary necrosis and other kidney injury. The label names the people at greatest risk: those with existing kidney problems, dehydration, heart failure or liver disease, people taking diuretics, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and older people. It adds that the drug "is known to be substantially excreted by the kidney".
• Blood pressure and heart failure. These drugs can start or worsen high blood pressure and can cause fluid retention and swelling.
• Skin. Serious skin reactions — exfoliative dermatitis, Stevens-Johnson syndrome and toxic epidermal necrolysis, which can be fatal — can occur without warning, as can fixed drug eruption. The label says the drug is stopped at the first appearance of a skin rash or other sign of allergy. A separate warning covers drug reaction with eosinophilia and systemic symptoms (DRESS), a whole-body reaction with fever, rash and swollen glands that has sometimes been fatal.
• Blood. Anaemia has occurred in patients on these drugs, from hidden or visible blood loss, fluid retention or an effect on blood production. The adverse-reactions list also names haemolytic anaemia (red cells destroyed in the bloodstream), aplastic anaemia, agranulocytosis and low platelet counts among the less frequent reactions.
• Asthma. People whose asthma is triggered by aspirin can have severe, sometimes fatal, bronchospasm with drugs of this family.

Pregnancy

The label carries the two pregnancy statements now shared across this drug family. From about 20 weeks of pregnancy, these drugs have been linked to fetal kidney problems that reduce the amniotic fluid (oligohydramnios) and, in some cases, kidney problems in the newborn; the label says to "limit dose and duration" between about 20 and 30 weeks, and mentions ultrasound checks if treatment goes beyond 48 hours. From about 30 weeks, these drugs raise the risk of premature closure of the ductus arteriosus, a blood vessel the unborn baby depends on, and the label's words are to "avoid mefenamic acid use at about 30 weeks of gestation and later in pregnancy". In rats, mefenamic acid given late in pregnancy led to more deaths around birth and delayed labour.

Interactions

The label's table of clinically significant interactions includes:

• blood thinners such as warfarin, antiplatelet drugs such as aspirin, and the antidepressant groups known as selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors — a higher risk of serious bleeding;
• painkilling doses of aspirin, other drugs of the same family and salicylates such as diflunisal and salsalate — more stomach and gut harm with little or no extra pain relief; the label also states that mefenamic acid is not a substitute for low-dose aspirin taken for heart protection;
• angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and beta-blockers — a weaker blood-pressure effect, and possible kidney failure in older, dehydrated or kidney-impaired people;
• loop and thiazide diuretics — a weaker diuretic effect;
• lithium — higher lithium levels (the label reports a 15% rise in the lowest lithium level and about 20% lower lithium clearance);
• digoxin, methotrexate, cyclosporine and the cancer drug pemetrexed — higher levels or more toxicity of those drugs;
• antacids containing magnesium hydroxide — in a six-person study, 1.7 g of magnesium hydroxide taken with 500 mg of mefenamic acid raised the drug's peak level by 125% and its total exposure by 36%.

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The Evidence for Period Pain

The drug family as a whole

The largest summary is the 2015 Cochrane review by Marjoribanks and colleagues: 80 randomised trials with 5,820 women, covering 20 different drugs of this family. Compared with a placebo, the drugs gave more pain relief (odds ratio 4.37; 35 trials). In plain numbers, the review estimates that if 18% of women on a placebo get moderate or excellent relief, between 45% and 53% of women on one of these drugs will. The same review found more side effects on the drugs than on placebo: overall (odds ratio 1.29), gut side effects (odds ratio 1.58) and nervous-system side effects such as headache and drowsiness (odds ratio 2.74). In plain numbers, if 10% of women on placebo have side effects, between 11% and 14% on the drugs will. Compared with paracetamol, the drugs gave more pain relief (odds ratio 1.89; three trials).

The reviewers rated most of this evidence as low quality, mainly because trial methods were poorly reported, and noted that 59% of the trials were commercially funded and a further 31% did not state their funding.

No drug clearly better than another

When the drugs were compared with each other, the Cochrane review found "little evidence of the superiority of any individual NSAID for either pain relief or safety", and concluded that there is not enough evidence to tell which, if any, is the safest and most effective for period pain. It added that most of these head-to-head comparisons rested on very few small trials, so they had little power to detect a difference. In other words, mefenamic acid's long-standing reputation as a period-pain drug is not backed by trials showing it beats ibuprofen or naproxen.

A 2018 network meta-analysis by Feng and Wang pooled 72 trials (5,723 patients, 13 drugs) and compared the drugs indirectly. For pain relief, mefenamic acid, ibuprofen, naproxen and most of the others did better than aspirin, and fewer women needed extra rescue painkillers on mefenamic acid than on aspirin. On safety, the authors ranked tiaprofenic acid and mefenamic acid as the lowest-risk drugs in their network, and ranked flurbiprofen as the most effective. Indirect comparisons of this kind depend on many small trials, and the Cochrane authors' caution about head-to-head data applies here too.

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Trials Comparing Mefenamic Acid With Herbs

Mefenamic acid is the comparison drug in a long series of trials of plant remedies, most of them from Iran. The 2016 Cochrane review of dietary supplements for period pain (Pattanittum and colleagues) included 27 trials with 3,101 women; 22 of those trials were done in Iran. The reviewers judged all of the evidence to be of low or very low quality, mainly because the trials were very small, and found too few side-effect reports to reach any conclusion about safety.

The Cochrane summary of herbs against these drugs

Comparing supplements with drugs of this family (the abstract does not name which drug was used in each trial), the review reported the following differences on a 0–10 pain scale, where a negative number favours the supplement and a positive number favours the drug:

• fennel: −0.70 points (95% confidence interval −1.81 to 0.41; one trial, 59 women);
• valerian: 0.62 points (0.03 to 1.21; one trial, 99 women);
• dill: 0.13 points (one trial, 47 women); rhubarb: −0.20 points (one trial, 45 women);
• guava: 1.19 points (0.42 to 1.96; one trial, 155 women);
• Damask rose: −0.15 points (one trial, 92 women);
• chamomile: −1.42 points (−1.69 to −1.15; one trial, 160 women).

The review grouped the dill, fennel, guava, rhubarb and valerian results under "no evidence of any difference", even though the valerian and guava intervals lie on the side that favours the drug. It described "very limited evidence" that chamomile was more effective than the drugs. Every one of these comparisons rests on a single trial. The Valerian for Menstrual Cramps page covers the valerian trials in detail.

Ginger

In the Ozgoli 2009 trial, 150 students aged 18 and over were divided into three equal groups taking 250 mg capsules of ginger rhizome powder, 250 mg of mefenamic acid, or 400 mg of ibuprofen, four times a day for three days from the start of the period. Pain fell in all three groups, and the trial found no differences between the groups in severity, pain relief or satisfaction. No severe side effects occurred. Note that the trial gave mefenamic acid at 250 mg four times a day, without the 500 mg first dose in the US label.

In the Shirvani 2015 trial, 122 students with moderate to severe period pain were randomised to 250 mg mefenamic acid every 8 hours or a 250 mg ginger capsule every 6 hours, from the onset of the period until the pain eased, for two cycles. Average pain scores (0–100 scale) were 39.01 with mefenamic acid and 43.49 with ginger in the first month, and 33.75 and 38.19 in the second; the differences were not statistically significant. The ginger group had more days of bleeding in both cycles. More on ginger is on the Ginger for Migraine and Pain page.

Fennel

Two fennel trials point in somewhat different directions. In the Modaress Nejad 2006 trial, 110 high-school girls (average age 13) were randomised to fennel extract or mefenamic acid for two months. Complete relief or less pain was reported by 80% on fennel and 73% on mefenamic acid, and 80% and 62% no longer needed to rest; the difference in pain relief was not significant.

In the Namavar Jahromi 2003 study, 30 women aged 15 to 24 with moderate to severe period pain went through an untreated cycle, then a cycle on mefenamic acid (250 mg every 6 hours), then a cycle on a 2% fennel essence (25 drops every 4 hours). Both relieved pain compared with the untreated cycle, and the time to start working was similar (67.5 minutes for mefenamic acid, 75 minutes for fennel). Mefenamic acid had a stronger effect on the second and third days of the period. No complications were reported in the mefenamic acid cycles, while five women (16.6%) left the study because of fennel's smell and one reported slightly heavier bleeding. The authors concluded that fennel "may have a lower potency than mefenamic acid in the dosages used". The Fennel for Menstrual and Menopausal Symptoms page has the fennel side of these trials.

Mint

In a crossover trial of 127 university students (Masoumi 2016), both mefenamic acid and a peppermint capsule, taken for three days from the start of the period, lowered pain intensity and duration. Bleeding was lower while taking mefenamic acid than while taking peppermint, and fewer extra painkillers were used in the mefenamic acid cycles. Nausea and diarrhoea were less common in the mint cycles.

How to read these trials

Most of these studies were small, many were not blinded or did not report how they were randomised, and almost all were run in students in one country. "No significant difference" in a trial of 50 women per group means the trial could not detect a difference, which is not the same as showing the two are equal. The results run both ways: some trials report the herb doing as well as the drug, and others report the drug acting more strongly on the heaviest days or cutting bleeding more.

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The Evidence for Heavy Periods

Heavy menstrual bleeding is not one of the indications on the US label, but mefenamic acid has been tested for it in trials since the 1980s.

The 2019 Cochrane review by Bofill Rodriguez and colleagues included 19 randomised trials with 759 women who had heavy periods with no other cause. As a group, these drugs reduced bleeding more than a placebo, but less than tranexamic acid, danazol or the levonorgestrel-releasing intrauterine system (a hormonal coil). The review found no evidence of a difference between the two drugs of this family that were tested, naproxen and mefenamic acid, and no clear difference from oral progestogen tablets, ethamsylate or the combined pill, although most of those studies were too small to show one. Evidence quality ranged from low to moderate.

Individual trials with measured blood loss

• Cameron 1990. Of 72 women who reported heavy periods, 32 (44%) had measured blood loss over 80 mL a cycle. On mefenamic acid (500 mg three times a day during the period; 17 women), median blood loss fell from 123 mL to 81 mL and the median number of bleeding days fell from 7 to 5. On norethisterone (15 women), it fell from 109 mL to 92 mL. After two months, 52% of the mefenamic acid group and 67% of the norethisterone group still met the definition of heavy bleeding.
• Bonnar and Sheppard 1996. In 76 women, mefenamic acid (500 mg every 8 hours for five days from the first day of the period) cut average blood loss by 20%, from 186 mL to 148 mL. Tranexamic acid cut it by 54%, from 164 mL to 75 mL. Ethamsylate did not reduce it.
• Reid and Virtanen-Kari 2005. In 51 women with measured heavy bleeding, both treatments reduced loss, but after six cycles the median blood loss was 5 mL with the hormonal coil and 100 mL with mefenamic acid.

Heavy periods over months can lead to iron loss and anaemia; that side of the problem is covered on the Iron Deficiency Anemia page, and one common cause of heavy bleeding on the Uterine Fibroids page.

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Overdose, Seizures and Rarer Harms

Seizures after overdose

Mefenamic acid stands out from its drug family in overdose. Kamour and colleagues (2017) analysed telephone enquiries to the UK National Poisons Information Service between 2007 and 2013. Of 10,398 enquiries about a single drug of this family taken without anything else, 461 involved mefenamic acid. People who had taken mefenamic acid were younger and more often female than those who had taken ibuprofen, diclofenac or naproxen. After adjusting for other factors, they were much more likely to have central nervous system effects — convulsions, drowsiness or reduced consciousness, agitation or confusion — than people who took the other three drugs (adjusted odds ratio 7.77), and especially convulsions (adjusted odds ratio 81.5). The risk rose with the dose taken and with age. The authors concluded that the drug's benefit-risk balance "should now be re-evaluated in light of effective and less toxic alternatives".

A 2025 case report from Japan (Inoue and colleagues) describes a 22-year-old woman who took 2.5 g of mefenamic acid (60 mg per kg of body weight) together with other painkillers. She had two generalised tonic-clonic seizures three hours later. Her kidney function was normal on arrival, but on day 3 she developed acute kidney injury, with creatinine peaking at 4.21 mg/dL, which recovered without dialysis. Her blood level of mefenamic acid on arrival was 42.2 µg/mL, against a toxic threshold of 25 µg/mL quoted by the authors.

The US label's overdose section is the general one for the drug family: it states that there is no specific antidote and that care is supportive, and it gives the US Poison Help Line number, 1-800-222-1222. Convulsions and coma appear in the label's list of less frequent adverse reactions. A seizure, collapse or reduced consciousness after taking extra tablets are signs hospitals treat as an emergency.

Long-term diarrhoea and gut damage

A 2017 review by Kaosombatwattana and colleagues gathered 20 published cases and five of their own of gut damage caused by mefenamic acid. Most of these people had taken ordinary doses regularly for at least three months before symptoms began. All had long-lasting diarrhoea with marked weight loss, and about a third had some anaemia and low blood albumin. Biopsies showed flattened villi in the small intestine, the finger-like folds that absorb food. All symptoms improved sharply once the drug was stopped, and some patients then took other drugs of the same family without the problem returning. The authors write that, unlike other traditional drugs of this family, mefenamic acid could cause this flattening of the villi.

Haemolytic anaemia

In 1968, Scott and colleagues reported three patients who developed autoimmune haemolytic anaemia, in which the immune system destroys red blood cells, while taking mefenamic acid. All three recovered when the drug was stopped. In the same report, 36 other patients on long-term mefenamic acid were tested and only one had a briefly positive antibody test. The current US label lists haemolytic anaemia among its less frequent adverse reactions without giving a rate.

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What Is Not Known

• Whether it is better or worse than ibuprofen or naproxen for period pain. The 2015 Cochrane review found too few, too small head-to-head trials to say. The network meta-analysis ranked mefenamic acid among the lowest-risk drugs, but that ranking came from indirect comparisons.
• How it compares with herbs in well-run trials. The herb trials are small, mostly from one country, and rated low or very low quality; most compared one herb with the drug in a single trial.
• Long-term safety of repeated monthly courses. Period-pain trials last a few cycles. Most of what is known about harms over years comes from the drug family as a whole, from case reports and from the label, not from long trials of mefenamic acid itself.
• How common its specific harms are. The seizure finding comes from poisons-centre calls, which record reported cases rather than every overdose. The gut-villi damage and haemolytic anaemia come from case reports, which show that a harm can happen but not how often.
• Its behaviour in liver or kidney disease. The label states that its pharmacokinetics have not been studied in people with liver or kidney impairment, and that the effect of food on its absorption has not been studied.
• Use for heavy periods in the United States. Heavy bleeding is not a labelled US use; the trial evidence comes from other countries and is mostly small.

Decisions about prescription painkillers, especially for people with kidney, heart, stomach or bleeding problems, or during pregnancy, belong with a clinician who knows the person's history.

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Key Research Papers

1. Marjoribanks J, Ayeleke RO, Farquhar C, Proctor M. Nonsteroidal anti-inflammatory drugs for dysmenorrhoea. Cochrane Database Syst Rev. 2015;2015(7):CD001751. PubMed PMID: 26224322
2. Feng X, Wang X. Comparison of the efficacy and safety of non-steroidal anti-inflammatory drugs for patients with primary dysmenorrhea: A network meta-analysis. Mol Pain. 2018;14:1744806918770320. PubMed PMID: 29587566
3. Pattanittum P, Kunyanone N, Brown J, Sangkomkamhang US, Barnes J, Seyfoddin V, Marjoribanks J. Dietary supplements for dysmenorrhoea. Cochrane Database Syst Rev. 2016;3(3):CD002124. PubMed PMID: 27000311
4. Ozgoli G, Goli M, Moattar F. Comparison of effects of ginger, mefenamic acid, and ibuprofen on pain in women with primary dysmenorrhea. J Altern Complement Med. 2009;15(2):129-32. PubMed PMID: 19216660
5. Shirvani MA, Motahari-Tabari N, Alipour A. The effect of mefenamic acid and ginger on pain relief in primary dysmenorrhea: a randomized clinical trial. Arch Gynecol Obstet. 2015;291(6):1277-81. PubMed PMID: 25399316
6. Modaress Nejad V, Asadipour M. Comparison of the effectiveness of fennel and mefenamic acid on pain intensity in dysmenorrhoea. East Mediterr Health J. 2006;12(3-4):423-7. PubMed PMID: 17037712
7. Namavar Jahromi B, Tartifizadeh A, Khabnadideh S. Comparison of fennel and mefenamic acid for the treatment of primary dysmenorrhea. Int J Gynaecol Obstet. 2003;80(2):153-7. PubMed PMID: 12566188
8. Masoumi SZ, Asl HR, Poorolajal J, Panah MH, Oliaei SR. Evaluation of mint efficacy regarding dysmenorrhea in comparison with mefenamic acid: A double blinded randomized crossover study. Iran J Nurs Midwifery Res. 2016;21(4):363-7. PubMed PMID: 27563318
9. Bofill Rodriguez M, Lethaby A, Farquhar C. Non-steroidal anti-inflammatory drugs for heavy menstrual bleeding. Cochrane Database Syst Rev. 2019;9(9):CD000400. PubMed PMID: 31535715
10. Cameron IT, Haining R, Lumsden MA, Thomas VR, Smith SK. The effects of mefenamic acid and norethisterone on measured menstrual blood loss. Obstet Gynecol. 1990;76(1):85-8. PubMed PMID: 2359570
11. Bonnar J, Sheppard BL. Treatment of menorrhagia during menstruation: randomised controlled trial of ethamsylate, mefenamic acid, and tranexamic acid. BMJ. 1996;313(7057):579-82. PubMed PMID: 8806245
12. Reid PC, Virtanen-Kari S. Randomised comparative trial of the levonorgestrel intrauterine system and mefenamic acid for the treatment of idiopathic menorrhagia: a multiple analysis using total menstrual fluid loss, menstrual blood loss and pictorial blood loss assessment charts. BJOG. 2005;112(8):1121-5. PubMed PMID: 16045528
13. Kamour A, Crichton S, Cooper G, Lupton DJ, Eddleston M, Vale JA, Thompson JP, Thomas SH. Central nervous system toxicity of mefenamic acid overdose compared with other NSAIDs: an analysis of cases reported to the United Kingdom National Poisons Information Service. Br J Clin Pharmacol. 2017;83(4):855-862. PubMed PMID: 27785820
14. Inoue F, Okazaki Y, Ichiba T, Namera A. Mefenamic Acid Poisoning Revisited: Central Nervous System Toxicity and Acute Kidney Injury. Cureus. 2025;17(10):e95848. PubMed PMID: 41328133
15. Kaosombatwattana U, Limsrivilai J, Pongpaibul A, Maneerattanaporn M, Charatcharoenwitthaya P. Severe enteropathy with villous atrophy in prolonged mefenamic acid users - a currently under-recognized in previously well-recognized complication: Case report and review of literature. Medicine (Baltimore). 2017;96(44):e8445. PubMed PMID: 29095288
16. Scott GL, Myles AB, Bacon PA. Autoimmune haemolytic anaemia and mefenamic acid therapy. Br Med J. 1968;3(5617):534-5. PubMed PMID: 5676955

Regulatory Sources

1. US prescribing information for mefenamic acid capsules (generic label, revised 2026), DailyMed. DailyMed set ID d15733a9-d5fd-4d5f-86ce-e7ed8c706c7f
2. US Food and Drug Administration. Drugs@FDA: application 015034 (mefenamic acid). Drugs@FDA NDA 015034

PubMed Topic Searches

1. PubMed: mefenamic acid and dysmenorrhea
2. PubMed: mefenamic acid and heavy menstrual bleeding
3. PubMed: mefenamic acid overdose and convulsions
4. PubMed: mefenamic acid compared with herbs for dysmenorrhea

Connections

• Drugs — every drug page on the site
• Dysmenorrhea (Menstrual Cramps) — the condition this drug is used for
• Valerian for Menstrual Cramps — the valerian trials and the Cochrane comparison
• Fennel for Menstrual and Menopausal Symptoms — the fennel side of the head-to-head trials
• Ginger for Migraine and Pain — the ginger period-pain trials
• Aspirin — the oldest drug of the same family
• Salsalate — a related salicylate
• Endometriosis — a cause of secondary period pain
• Iron Deficiency Anemia — a result of long-term heavy periods

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