Formulary
Mefenamic acid: Indications, Dosing, Side Effects and Interactions
Mefenamic acid clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 3 min read
Mefenamic acid: Indications, Dosing, Side Effects and Interactions
Mefenamic acid clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Pain and inflammation in rheumatoid arthritis and osteoarthritis,Postoperative pain,Mild to moderate pain**
- **Adult** (By Mouth): 500 mg 3 times a day.
**Acute pain including dysmenorrhoea,Menorrhagia**
- **Child** (By Mouth): 12-17 years 500 mg 3 times a day.
- **Adult** (By Mouth): 500 mg 3 times a day.
**Acute pain including dysmenorrhoea, Menorrhagia for mefenamic acid**
- **Child 12-17 years** (By mouth): 500 mg 3 times a day.
Cautions
Acute porphyrias ; allergic disorders; cardiac impairment (NSAIDs may impair renal function); cerebrovascular disease; coagulation defects; connective-tissue disorders; dehydration (risk of renal impairment); elderly (risk of serious side-effects and fatalities) (in adults); epilepsy; heart failure; history of gastro-intestinal disorders (e.g. ulcerative colitis, Crohn's disease); ischaemic heart disease; may mask symptoms of infection; peripheral arterial disease; risk factors for cardiovascular events; uncontrolled hypertension
Contraindications
Active gastro-intestinal bleeding; active gastro-intestinal ulceration; following coronary artery bypass graft (CABG) surgery; history of gastro-intestinal bleeding related to previous NSAID therapy; history of gastro-intestinal perforation related to previous NSAID therapy; history of recurrent gastro-intestinal haemorrhage (two or more distinct episodes); history of recurrent gastro-intestinal ulceration (two or more distinct episodes); inflammatory bowel disease; severe heart failure
Side effects
Frequency not known Agranulocytosis; anaemia; angioedema; appetite decreased; asthma; bone marrow disorders; confusion; constipation; Crohn's disease; depression; diarrhoea (discontinue); disseminated intravascular coagulation; dizziness; drowsiness; dyspnoea; dysuria; ear pain; eosinophilia; eye irritation; fatigue; fertility decreased female; gastrointestinal discomfort; gastrointestinal disorders; glomerulonephritis; glucose tolerance impaired; haemolytic anaemia; haemorrhage; hallucination; headache; heart failure; hepatic disorders; hyperhidrosis; hypersensitivity; hypertension; hyponatraemia; hypotension; insomnia; leucopenia; malaise; meningitis aseptic (patients with connective-tissue disorders such as systemic lupus erythematosus may be especially susceptible); multi organ failure; nausea; nephritis acute interstitial; nephrotic syndrome; nervousness; neutropenia; oedema; optic neuritis; oral ulceration; palpitations; pancreatitis; paraesthesia; photosensitivity reaction; proteinuria; rash (discontinue); renal failure (more common in patients with pre-existing renal impairment); renal failure non-oliguric; renal papillary necrosis; respiratory disorders; seizure; sepsis; severe cutaneous adverse reactions (SCARs); skin reactions; thrombocytopenia; tinnitus; vertigo; vision disorders; vomiting Side-effects, further information For information about cardiovascular and gastrointestinal side-effects, and a possible exacerbation of symptoms in asthma, see Non-steroidal anti-inflammatory drugs Overdose Mefenamic acid has important consequences in overdosage because it can cause convulsions, which if prolonged or recurrent, require treatment. For details on the management of poisoning, see Emergency treatment of poisoning , in particular, Convulsions.
Interactions
**Other interactions (17):**
- Anti-coagulants : NSAIDs may enhance the effects of anti-coagulants, such as warfarin (see section 4.4).
- It is considered unsafe to take NSAIDs in combination with warfarin or heparin unless under direct medical supervision.
- Lithium: A reduction in renal lithium clearance and elevation of plasma lithium levels.
- Patients should be observed carefully for signs of lithium toxicity.
- The following interactions have been reported with NSAIDs but have not necessarily been associated with Mefenamic Acid Capsules: Other analgesics including cyclooxygenase-2 selective inhibitors:...
- Antidepressants : Selective serotonin reuptake inhibitors (SSRIs): increased risk of gastrointestinal bleeding (see section 4.4).
Pregnancy
Important safety information For mefenamic acid MHRA/CHM advice: NSAIDs: potential risks following prolonged use after 20 weeks of pregnancy (June 2023) See Non-steroidal anti-inflammatory drugs .
Breast feeding
Use with caution during breast-feeding. Amount too small to be harmful but manufacturer advises avoid.
Hepatic impairment
Manufacturer advises caution in mild to moderate impairment; avoid in severe impairment.
Renal impairment
In general, for NSAIDs the MHRA advises to avoid where possible; if necessary, use with caution (risk of fluid retention and further renal impairment, including renal failure). For mefenamic acid , avoid in severe impairment. M
Medicinal forms
Suspension,Tablet,Capsule,Suspension
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
Inside MedNext for this topic
- 411 MedNext-authored chapters
- 80,000+ MCQ bank
- 15 study modes
- Growing visual cheat sheets
Study modes
- Notes
- MCQ
- Audio
- Video
- Visual
- 3D Anatomy
- Trace
- Flashcards
- Mnemonics
- Image Bank
- Clinical
- Microscopy
- Audio QBank
- Cadaver
- Book Match
Continue reading
Subject HubPharmacology Hub
All pharmacology resources in one place.
Drug SchedulesIndian Drug Schedules
Schedule H, H1, X and G classifications.
FormularyBrowse all drugs
Search 1,850+ drug profiles.
Study Mefenamic acid in the MedNext app
Challenge yourself with targeted pharmacology MCQs on this drug class. Every explanation links back to the chapter that teaches the concept.
Start drug challengeExplore the full formulary

