Mefan

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Mefan

Quick Facts

Property Description
Active Ingredient Mefenamic Acid (C₁₅H₁₅NO₂)
Form Oral Capsules or Tablets
Pharmacological Class Nonsteroidal Anti-inflammatory Drug (NSAID)
General Purpose Analgesic, Anti-inflammatory, and Antipyretic
Origin Synthetic (Fenamate)

What Type of Medicine is Mefan and What is it Made of?

Mefan is a prescription pharmaceutical product containing the single active ingredient, Mefenamic Acid. It is fundamentally classified as a major Nonsteroidal Anti-inflammatory Drug (NSAID). The availability of Mefan typically requires a prescription (Rx status).

Mefenamic Acid is a synthetic compound derived from anthranilic acid, which specifically places it in the fenamate subgroup of NSAIDs. The medicine is supplied for oral administration and systemic use throughout the body, typically formulated into solid dosage forms like capsules or tablets. This chemical classification is clinically recognized for providing the basis for its anti-inflammatory efficacy, distinguishing it within the broad NSAID category.


What is the General Purpose of Mefenamic Acid?

The general purpose of Mefenamic Acid is to manage acute symptoms by leveraging its characteristic three-part action: it is an analgesic (pain-relieving), an anti-inflammatory (swelling-reducing), and an antipyretic (fever-reducing) agent. These effects are achieved through its role as a cyclooxygenase (COX) inhibitor.

The drug’s mechanism of effect, which involves inhibiting the synthesis of prostaglandins, is key to its utility in symptomatic management, effectively reducing both pain and inflammation signals. Mefan's utility is centered on addressing acute physical discomfort that requires comprehensive relief from pain, swelling, and/or fever.

What side effects are possible with Mefan?

Possible side effects and safety information

The safety profile of Mefenamic Acid (Mefan) is formally organized in regulatory documents by the body system affected and the established frequency of adverse reactions. This classification is intended to communicate the medicine’s systemic impact and potential risks as documented in official clinical data.

Official Adverse Reaction Categories

Adverse reactions are formally classified according to their documented incidence. Common reactions often involve the gastrointestinal system, including diarrhoea, nausea, vomiting, and abdominal pain. Less common reactions may include headache, dizziness, and various forms of hypersensitivity.

System-Organ Class Affected Examples of Documented Effects
Gastrointestinal Disorders Ulceration, bleeding, perforation
Vascular and Cardiac Disorders Hypertension, fluid retention, risk of thrombotic events
Renal and Urinary Disorders Acute renal failure, nephritis
Blood and Lymphatic System Disorders Haemolytic anaemia, agranulocytosis

Serious Adverse Reactions and Regulatory Constraints

The official labeling highlights the potential for serious cardiovascular (CV) thrombotic events, such as myocardial infarction and stroke, which may occur as early as the first weeks of treatment and increase with long-term use. Similarly, serious gastrointestinal adverse events, including bleeding and perforation, are documented risks, with the likelihood increasing with duration and dose.

Specific safety considerations exist for certain populations. Older adults have a documented increased risk of serious GI adverse events. The medicine is formally contraindicated for treating peri-operative pain in the setting of Coronary Artery Bypass Graft (CABG) surgery, and in individuals with pre-existing severe heart, renal, or hepatic failure.

Overdose and Emergency Response

Overdose Manifestations and Severe Outcomes

Overdose with Mefenamic Acid may present with documented signs that affect multiple physiological systems. Documented gastrointestinal manifestations include severe stomach pain, vomiting, or the presence of blood (such as coffee ground-like vomit or black, tarry stools). Central nervous system (CNS) effects are a particular concern, potentially involving extreme tiredness, confusion, severe headache, and, in severe cases, the onset of seizures (convulsions) or loss of consciousness (coma).

Severe outcomes officially noted in regulatory information include acute renal failure and severe gastrointestinal hemorrhage. Regulatory analysis highlights that the risk of CNS toxicity, specifically convulsions, is significantly associated with Mefenamic Acid overdose compared to other similar medications.

When to Seek Urgent Medical Help

Government regulatory guidance mandates seeking immediate medical attention for any suspected overdose. Immediately call emergency services if the affected individual collapses, has trouble breathing, cannot be awakened, or experiences a seizure. Additionally, the poison control helpline should be contacted for urgent guidance.

Official Overdose Management

Management is classified as symptomatic and supportive. Regulatory documents confirm that there is no specific antidote known for Mefenamic Acid overdose. Officially described supportive procedures may include administering activated charcoal in appropriate clinical settings. Monitoring in a hospital setting is required for severe cases, including laboratory assessments of full blood count, electrolytes, and renal function. The regulatory profile notes that pre-existing renal or hepatic impairment may complicate the severity of an overdose.

Therapeutic Uses of Mefan

What Mefan Treats: Main Uses and Benefits

Mefan (Mefenamic acid) is commonly used to help with symptoms related to physical discomfort and inflammatory or irritative states across several key domains. It is considered relevant for easing discomfort caused by these types of physiological manifestations.

Pain Relief for Acute Discomfort

This medication may assist with addressing episodes of acute pain, such as headaches, muscle aches, and toothaches, and is applied across domains where additional symptomatic support is needed. It is considered relevant for managing pronounced symptoms of menstrual cramping (dysmenorrhea) and is commonly used for musculoskeletal discomfort, including symptoms of joint and muscle stiffness.

“This symptomatic relief supports patients during difficult episodes by easing discomfort and supports general well-being during symptomatic phases.”

This medication is generally used during phases when symptoms become more noticeable, providing supportive relief in situations where symptoms create noticeable interference with daily stability. It **provides supportive relief when symptoms interfere with routine activities.


Quick Fact: Relief for Symptoms related to physical discomfort and Menstrual Cramping

Eligibility and Restrictions for Use

Who can and cannot use Mefan?

The eligibility for Mefan (Mefenamic Acid) is determined by official regulatory criteria related to age and pre-existing health status.


Contraindicated Use (Must Not Use)

Mefan is contraindicated for individuals with known hypersensitivity to the drug, aspirin, or other NSAIDs. Use is strictly prohibited for patients with active gastrointestinal ulceration or inflammation, a history of GI bleeding related to NSAIDs, or severe organ failure (renal, hepatic, or heart failure). Use is also strictly prohibited during the last trimester of pregnancy (after 30 weeks) and for pain following CABG surgery.


Age and Conditional Restrictions

The medicine is generally approved for use in individuals 14 years of age and older. Its safety and efficacy have not been established for treating mild to moderate pain in children under 14 (US labeling). Geriatric patients (mathbfge 65 years) must use the drug with caution at the lowest effective dose. Conditional use is required for patients with pre-existing cardiovascular comorbidities. Mefan is not recommended for nursing mothers or women attempting to conceive.

What should I know about interactions with other medicines?

Interactions with other medicines and products

This section describes the officially documented interaction patterns for Mefenamic Acid (Mefan) as stated in government regulatory sources.

Contraindicated and Restricted Use

Mefenamic Acid is formally contraindicated for the treatment of peri-operative pain associated with coronary artery bypass graft (CABG) surgery. Regulatory guidance also advises avoiding co-administration with other Nonsteroidal Anti-inflammatory Drugs (NSAIDs) due to an increased risk of adverse events. Additionally, Mefan should not be taken for 8–12 days following the administration of Mifepristone to prevent reduced efficacy of Mifepristone.

Pharmacokinetic and Pharmacodynamic Interactions

Interacting Substance Official Interaction Outcome
Oral Anticoagulants (e.g., Warfarin) Enhanced effects and increased risk of hemorrhage
Antacids (containing Magnesium Hydroxide) Significantly increase the rate and extent of Mefenamic Acid absorption
Lithium and Methotrexate Reduced renal clearance, leading to elevated plasma levels of the co-administered drug
ACE Inhibitors/ARBs & Diuretics Reduced therapeutic effect of the co-administered drug and increased risk of nephrotoxicity
Alcohol, SSRIs, Corticosteroids Increased risk of gastrointestinal bleeding or ulceration

The drug is metabolized by the CYP2C9 enzyme, and co-administration with inhibitors of this pathway may lead to increased plasma concentration of Mefenamic Acid. The risk of renal impairment with ACE inhibitors is specifically heightened in elderly patients, as documented in official labeling.

Mechanism of Action

Blocking the Synthesis of Prostaglandins

The drug Mefenamic Acid acts as a reversible inhibitor of the Cyclooxygenase ( COX) enzymes, specifically COX-1 and COX-2 . This key mechanism blocks the conversion of Arachidonic Acid into Prostaglandins ( PGs), which are signaling mediators involved in the pathways for nociception and thermoregulation.

Dual Modulation of Receptor Pathways

Beyond enzyme inhibition, Mefan engages two secondary mechanisms: it acts as an antagonist on specific Prostanoid Receptors ( EP) and as a modulator of certain GABA A receptor subtypes in the central nervous system ( CNS). This dual modulation results in the modulation of prostaglandin-mediated smooth muscle contractility and increases GABA A-mediated inhibitory neurotransmission in central pathways.

Physiological Consequences of Mechanistic Inhibition

The reduction in PG signaling limits the chemical sensitization of afferent nerves and results in the reduction of the hypothalamic temperature set-point. This mechanistic cascade establishes a reduction in the excitability of peripheral nociceptors and promotes heat dissipation following the set-point reduction.

Dosage and Administration Information

How to use Mefan: Administration Guidelines

The usage of Mefan (Mefenamic Acid) is defined by established administration guidelines, specifying the administration route, standard doses, and maximum duration of use.


Administration Scope

Category Instruction
Route of administration Oral (by mouth).
Dosing schedule Initial Adult Dose: 500 mg once, followed by 250 mg every six hours (q6h) as needed.
Timing in relation to meals (if applicable) Must be taken with food, milk, or a full glass of water (8–12 ounces) to support proper administration.
Age-group administration rules Use for the specified adult regimens is generally not recommended in patients under 14 years of age.
Missed-dose rules If a dose is missed, it should be skipped entirely and the patient should resume the regular schedule; do not take a double dose.
Special procedural conditions The total course for acute pain should not exceed 7 days, and treatment for menstrual pain is limited to 2 to 3 days.

Instruction Classifications (High-Level)

Category Classification
Administration method type Oral.
Frequency pattern Multi-daily and as-needed (PRN), typically administered every six hours.
Use-context constraints Duration-limited use (maximum 7 days or 2–3 days).

Resulting Procedural Structure

Standard step sequence:

  • Initiate treatment with the 500 mg starting dose via oral administration.
  • Continue with 250 mg doses every six hours (q6h) as required for symptom management.
  • Administer each dose with food or milk and limit the entire treatment course to the shortest necessary period.

The usage parameters establish Mefan as a duration-restricted medication defined by a standard 500 mg initial dose and a fixed 250 mg maintenance dose taken on an as-needed basis. These procedural instructions limit the maximum duration of use to seven days or less, depending on the acute condition being managed, and mandate administration alongside food or milk.

Recent Clinical Evidence

Research evidence / Overview of studies for Mefan

This section summarizes the evidence base for Mefan (Mefenamic Acid) as established by official regulatory reviews and high-quality peer-reviewed research, focusing solely on the design and scope of the clinical evaluation.


Evidence for Use in Primary Dysmenorrhea (Menstrual Pain)

The research base for primary dysmenorrhea, a condition characterized by fluctuating or episodic manifestations, is largely composed of short-term, acute Randomized Controlled Trials (RCTs). Research was conducted to evaluate patient-reported outcomes describing perceived discomfort related to menstrual cramping. The populations included in the trials were typically adolescent and adult women experiencing periods of heightened symptom activity.

Studies monitored specific outcomes related to physical discomfort, such as changes in pain intensity reported by patients using standardized scales, and whether there was a need for rescue medication. Studies described changes measured during the observation period, and these descriptions were generally similar across multiple aggregated scientific reviews. However, the follow-up durations were limited, often spanning only one to three menstrual cycles.


Evidence for Use in Mild to Moderate Acute Pain

The research base exploring the substance for general acute discomfort, such as post-procedure pain or muscle aches, consists mainly of short-duration RCTs. Studies monitored specific outcomes related to episodic or acute changes, including measurements of the time to onset of patient-reported comfort and changes in overall pain intensity observed over a few hours. The trial populations were adults and adolescents (aged 14 and older).

The reported findings indicate patterns measured during the study period that were consistent with the data reported for active comparators included in the trial designs. The regulatory evidence is structured around studies focusing on episodes where symptoms become more noticeable, with maximum treatment duration of seven days.


What is Still Uncertain About Mefan's Research Base

The evidence base for Mefan is structured around trials assessing short-term or episodic symptom patterns. Data for other groups, such as very young children or older adults with specific comorbidities, remain limited within the core research context. A key limitation is the absence of comprehensive long-term data, which means that long-term effects are not fully established. Additionally, comparative evidence is limited in some areas, specifically head-to-head trials against certain other treatment options. Studies help show what has been observed so far; research does not determine whether an individual will respond similarly.

Key Studies & References

  1. Efficacy of minor analgesics in primary dysmenorrhoea: a systematic review

Frequently Asked Questions (FAQ)

Common questions about Mefan (FAQ)


Q: How long does one dose of Mefan typically last?

Official product information indicates that the standard maintenance dose is designed to be taken every six hours (q6h) as needed. This dosing frequency suggests the time interval used for dosing when managing symptoms.


Q: Can Mefan be taken by children?

Regulatory documents state that Mefan is indicated for pain relief and menstrual pain only in patients who are 14 years of age and older. Safety and effectiveness in patients under this age have not been established for these specific uses in the official labeling.


Q: What are the most common side effects of Mefan people talk about?

According to official regulatory documents, common adverse reactions reported include gastrointestinal issues like diarrhea, nausea, vomiting, and stomach pain, as well as neurological effects such as dizziness and headache.


Q: Does Mefan cause drowsiness or affect driving?

Side effects such as dizziness, headache, and sleepiness have been reported in the labeling. Official regulatory information includes warnings for situations like driving or operating machinery, should these effects occur.


Q: Are there any long-term safety concerns associated with Mefan use?

Official product information states that Mefan is intended for the shortest duration possible. The risk of serious adverse events, including cardiovascular issues (heart attack, stroke) or gastrointestinal complications (bleeding), may increase with longer periods of use.


Q: Is Mefan an opioid or a controlled substance?

Mefan (Mefenamic Acid) is classified as a Non-Steroidal Anti-Inflammatory Drug (NSAID). It is a prescription-only medicine (Rx only) and is not an opioid or a controlled substance, and regulatory information does not indicate a risk of physical dependence.


Q: Has Mefan been approved in countries outside of the US?

Yes. Mefan (Mefenamic Acid) is a well-established drug that has been approved and utilized for many years in numerous countries worldwide, including the UK, Canada, and various European nations.


Q: Why is Mefan sometimes described with certain safety warnings?

Mefan carries an FDA-mandated Boxed Warning, which is the most serious level of warning. This warning informs patients and doctors about the potential for serious cardiovascular risks, such as heart attack and stroke, and serious gastrointestinal risks, like bleeding and ulcers.


Q: Is it true that some people cannot take Mefan?

Yes. The drug is contraindicated (should not be taken) by individuals with certain pre-existing conditions. These include a history of allergic reactions to NSAIDs, active stomach ulcers or bleeding, or severe kidney disease, as stated in official labeling.


Q: Does Mefan interact with alcohol?

Regulatory warnings state that using alcohol while taking this medicine may increase the risk of serious gastrointestinal complications, such as bleeding or ulcers.


Q: What should I do if a side effect feels severe?

Official safety information describes specific signs and symptoms that require stopping the medication and seeking emergency medical help immediately. These include signs of a severe allergic reaction, heart attack, or stroke.


Q: Is there a generic version of Mefan available?

Yes, Mefan is the brand name for the generic drug Mefenamic Acid. This generic version is widely available and contains the same active ingredient.


Q: Is Mefan safe to take with common vitamins or supplements?

Regulatory documents advise that patients should discuss using other medicines, including certain supplements or antacids, with their healthcare provider, as they may be associated with an interaction with Mefan.


Q: Can Mefan affect other health conditions someone already has?

Yes. The safety profile requires caution for individuals with pre-existing conditions such as heart disease, high blood pressure, liver or kidney problems, or a history of stomach ulcers or bleeding, as the drug may impact these conditions.


Q: What is the risk of becoming dependent on Mefan?

Mefan is not classified as an opioid or a controlled substance by regulatory bodies. Therefore, official product information does not indicate a risk of physical dependence with its use.


Q: What kind of patient is Mefan generally intended for?

Mefan is officially indicated for the short-term treatment (up to 7 days) of mild to moderate pain and the treatment of primary dysmenorrhea (menstrual pain). It is indicated for use in patients aged 14 and older.


Q: What are the main things I need to tell my doctor before starting Mefan?

Official warnings emphasize discussing any history of heart attack, stroke, stomach ulcers or bleeding, kidney or liver disease, high blood pressure, fluid retention, or aspirin-sensitive asthma to determine suitability.


Q: Is Mefan a good option for chronic use?

No. Regulatory guidelines strictly limit the treatment duration to a maximum of 7 days for pain and 2 to 3 days for menstrual pain. This duration restriction is due to the increased risk of serious adverse events associated with long-term use.


Q: Are headaches a known side effect of Mefan?

Yes, headaches are listed among the common adverse reactions reported in official regulatory documents.


Q: How often do people have allergic reactions to Mefan?

Severe allergic-type reactions (such as anaphylaxis and serious skin reactions) have been reported, although the exact frequency is often low. The medication is contraindicated for anyone with a known history of reaction to it or other NSAIDs.


Q: Is Mefan safe for people with kidney or liver problems?

Mefan is contraindicated for patients with pre-existing or severe kidney disease. Official documents describe that Mefan is for use only with caution in patients with liver impairment, as severe hepatic (liver) reactions have been reported.


Q: What does the box warning for Mefan mean?

The Boxed Warning is a regulatory notice to inform patients and prescribers about the drug's potential for two main serious risks: cardiovascular risks (like heart attack and stroke) and gastrointestinal risks (like bleeding and ulcers).


Q: Is Mefan a relatively new drug or has it been around for a long time?

Mefan (Mefenamic Acid) was initially approved in the US in 1967. This indicates it is a drug that has been in use for a long time.


Q: Are there specific patient groups where Mefan is not well studied?

According to regulatory labeling, safety and effectiveness for the indicated uses have not been established in pediatric patients under 14 years of age.


Q: Does Mefan change how other medicines are absorbed in the body?

Mefan can interact with and affect the levels of certain other medicines in the body, such as Lithium, Methotrexate, and blood thinners (anticoagulants), which may require careful medical monitoring.


Q: Can Mefan cause problems with sleep?

Side effects related to the central nervous system, such as dizziness and sleepiness or drowsiness, have been reported in some patients.


Q: What are the most serious, but rare, side effects of Mefan?

Serious, though rare, side effects reported in official documentation include severe gastrointestinal bleeding, acute kidney failure, and severe skin reactions like Stevens-Johnson syndrome.


Q: Do studies show Mefan works better than a placebo?

Yes, Mefan was approved based on clinical trials. These studies demonstrated that the drug was effective in treating the indicated conditions (pain and dysmenorrhea) compared to a placebo.


Q: Is it true that Mefan can cause weight changes?

Official adverse reaction listings include unusual weight gain. This is an adverse event that should be discussed with a healthcare provider, as it may be a sign of fluid retention or heart failure.

How should Mefan be stored and disposed of?

Official Storage and Disposal Requirements

Official regulatory information for mefenamic acid (Mefan) defines specific environmental and security requirements for its safe storage and disposal.

Storage and Protection Requirements
Temperature & Moisture Store at room temperature, away from excess heat and moisture. Do not store in the bathroom.
Container Security Keep the medicine in its original container, tightly closed.
Child Safety Store out of the sight and reach of children. Always use locked safety caps.

Disposal Rules

Unused or expired mefenamic acid should not be flushed down a toilet or sink. The preferred method of disposal is a drug take-back program or mail-back service. If these options are unavailable, the medicine should be mixed with an undesirable substance (such as dirt or coffee grounds), placed in a sealed container, and then thrown in the household trash. Personal information must be scratched off the original packaging prior to disposal.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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