Penta

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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 Penta

Quick Facts

Property Description
Active ingredient Mefenamic Acid
Form Capsule
Pharmacological class Nonsteroidal Anti-Inflammatory Drug (NSAID)
General purpose Relief of mild to moderate acute pain and inflammation
Origin Synthetic organic compound

What is Penta? Defining the Medicinal Entity

The medication known by the trade name Penta is a pharmaceutical product containing the active ingredient Mefenamic Acid, which is available only by prescription (Rx-only). Mefenamic Acid is the internationally recognized non-proprietary name (INN) for this synthetic compound, which is typically manufactured as an oral capsule for consumption.

This medication is uniquely designated for short-term use, often specified not to exceed seven days, and functions as a single-ingredient product designed to address acute physical discomfort. Its status as a prescription-only agent differentiates it from readily available over-the-counter (OTC) pain relievers.


Pharmacological Classification and Composition

Penta (Mefenamic Acid) belongs to the Nonsteroidal Anti-Inflammatory Drug (NSAID) class of medications, specifically categorized as an Anthranilic acid derivative or Fenamate. The active substance, Mefenamic Acid, is a synthetic organic compound, meaning its molecular structure is chemically derived rather than isolated from natural sources.

This NSAID classification indicates that the drug's core action is to counteract pain and inflammation. Mefenamic Acid is generally regarded as an effective NSAID with established analgesic properties. The final product is delivered as a hard capsule for oral administration, composed of the Mefenamic Acid ingredient combined with essential pharmaceutical excipients necessary for stability and proper absorption.


General Purpose: What is Mefenamic Acid Used for?

The general purpose of Mefenamic Acid is to provide simultaneous analgesic and anti-inflammatory relief by addressing both the sensation of pain and the underlying irritation. Its action is clinically recognized for alleviating mild to moderate acute pain, such as the discomfort experienced during recovery from minor surgical procedures.

Additionally, this compound possesses an antipyretic (fever-reducing) effect. The drug's dual capacity for pain relief and inflammation reduction defines its therapeutic utility for managing acute physical distress.

Regulatory References

  1. Mefenamic Acid (oral route) Drug Information

What side effects are possible with Penta?

Possible Side Effects and Safety Information

This section describes the officially documented adverse reactions and high-level safety constraints for Mefenamic Acid (Penta), as classified in regulatory documents.

Key Regulatory Safety Classifications

The safety profile is primarily characterized by effects across several organ systems, with the Gastrointestinal System being the most frequently associated domain. The risk of adverse events is officially documented to increase with the duration of use.

Classification Examples of Effects
Common Reactions Diarrhea, abdominal pain, nausea, vomiting, dyspepsia, headache, and dizziness. Diarrhea is often the most frequently reported gastrointestinal effect.
System-Organ Classes Gastrointestinal, Nervous System, Renal, Cardiovascular, Skin, and Blood/Lymphatic System Disorders.

Serious Adverse Reactions and Restrictions

Official labeling highlights the potential for serious, clinically significant events. The medicine carries a documented risk of potentially fatal Gastrointestinal Bleeding, Ulceration, and Perforation and an increased risk of serious Cardiovascular Thrombotic Events, such as myocardial infarction (MI) and stroke. Rare but severe Skin Reactions, including Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), are also documented.

Specific regulatory constraints exist for certain patient groups. The medicine is contraindicated for treating pain in the setting of Coronary Artery Bypass Graft (CABG) surgery, and in individuals with a history of allergic reactions to NSAIDs, active gastrointestinal ulceration, or severe renal or hepatic impairment. Safety notes also state that older adults face an increased risk of fatal gastrointestinal events and renal toxicity.

Overdose and Emergency Response

The information below strictly outlines the officially documented clinical manifestations and required emergency actions in the event of an Mefenamic Acid (Penta) overdose, based on government regulatory labeling.

Documented Overdose Manifestations

Overdosage of Mefenamic Acid may lead to a profile of clinical signs primarily affecting the central nervous and gastrointestinal systems. Documented manifestations include common gastrointestinal effects such as nausea, vomiting, epigastric pain, and diarrhea. Central nervous system effects may present as lethargy, drowsiness, headache, and dizziness. Severe, life-threatening outcomes officially cited in regulatory labeling include the occurrence of tonic-clonic convulsions, coma, and serious systemic complications like acute renal failure and metabolic acidosis.

Required Emergency Actions

It is a regulatory mandate to seek immediate medical attention for any suspected overdose. Additionally, contact with a Poison Control Center is required. Urgent medical help must be sought if the individual experiences severe symptoms such as seizures, trouble breathing, or loss of consciousness.

Management and Monitoring

There is no specific antidote known for Mefenamic Acid overdosage. Therefore, treatment focuses on symptomatic and supportive care. Official procedures that may be considered include gastric lavage and the administration of activated charcoal to reduce drug absorption, particularly shortly after ingestion. Due to the risk of delayed severe toxicity, particularly acute renal failure, close observation and hospital monitoring are necessary. Increased severity is noted in patients with pre-existing hepatic or renal impairment.

Therapeutic Uses of Penta

The medication, containing Mefenamic Acid, is applied across domains where additional symptomatic support is needed for acute and episodic symptoms. This application helps improve day-to-day comfort during symptomatic periods.

Penta is relevant for managing symptom clusters that may appear suddenly or fluctuate, and is commonly used to help with symptoms related to physical discomfort. Its role is relevant in conditions presenting with systemic or localized discomfort, including primary dysmenorrhea, menorrhagia, various types of headaches, and dental or post-operative pain. This utility is applied during phases of increased distress or discomfort, such as during post-procedural recovery or the onset of menses.

Penta also contributes to easing symptoms related to systemic imbalance, including the management of fever when symptoms are more noticeable.


Quick Fact: Symptomatic Support

Symptom Domain Description of Relief Provided
Menstrual Pain Helps manage intense, cramp-like discomfort; supports during heavy bleeding.
Inflammatory Symptoms Supports the easing of local irritation, swelling, and tenderness.
Acute Pain Assists with managing pain that is mild to moderate in intensity.
Fever Plays a role in managing elevated body temperature (antipyresis).

Eligibility and Restrictions for Use

Eligibility Map: Who can and cannot use Penta (Mefenamic Acid)

The official regulatory documentation for Penta (Mefenamic Acid) defines specific populations who are eligible for use, who require caution, and who are formally excluded.

Populations for Whom Use is Contraindicated

Penta is contraindicated (must not be used) if a patient has a known hypersensitivity to mefenamic acid or has experienced asthma or allergic reactions after taking aspirin or other NSAIDs. Use is also strictly forbidden in patients with active gastrointestinal ulceration or severe failure of the heart, liver, or kidneys. Furthermore, it is contraindicated for patients in the third trimester of pregnancy and for treating pain following Coronary Artery Bypass Graft (CABG) surgery.

Age and Conditional Use Rules

  • Adults and Adolescents ge 14 years: Approved for labeled use, provided no contraindications exist.
  • Children < 14 years: The capsule formulation is not recommended; safety and effectiveness have not been established in this age group.
  • Pregnancy/Lactation: Use is contraindicated in the third trimester and not recommended for nursing mothers or women attempting to conceive.
  • Conditional Use: Caution and monitoring are required for elderly patients and individuals with mild to moderate impairment of renal or hepatic function.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory information identifies specific combinations of Penta (Mefenamic Acid) with other substances that may result in altered drug exposure or increased risk.

Contraindicated and High-Risk Combinations

  • Penta is contraindicated for treating peri-operative pain in the setting of Coronary Artery Bypass Graft (CABG) surgery.
  • Co-administration with other Non-Aspirin NSAIDs should be avoided due to the increased frequency of gastrointestinal ulcers and bleeding.
  • The use with oral anticoagulants (e.g., Warfarin) is contraindicated if continuous monitoring of prothrombin time is unavailable, as Penta can inhibit platelet aggregation and prolong prothrombin time.

Interactions Affecting Drug Exposure

Interacting Substance Official Interaction Pattern
Lithium / Methotrexate Mefenamic Acid decreases their renal clearance, leading to elevated plasma levels and increased risk of toxicity for the co-administered drug.
Magnesium-containing Antacids Significantly increase the rate and extent of Mefenamic Acid absorption.
Poor CYP2C9 Metabolizers Patients may have abnormally high plasma levels of Mefenamic Acid due to reduced metabolic clearance, as the medicine is a CYP2C9 substrate.

Pharmacodynamic and Efficacy Interactions

  • Penta interferes with the anti-platelet effect of low-dose Aspirin and increases the risk of serious gastrointestinal events.
  • Combining Penta with Antihypertensives (e.g., ACE inhibitors, ARBs, Diuretics) may reduce their blood pressure-lowering effect and increase the risk of renal impairment, particularly in the elderly.
  • The concomitant use of Corticosteroids and SSRIs is associated with an increased risk of gastrointestinal bleeding.
  • Consumption of alcohol may increase the risk of gastrointestinal bleeding, ulceration, and perforation.

These official statements define the necessary restrictions and monitoring requirements when Mefenamic Acid is used alongside other medicines and products.

Mechanism of Action

The active ingredient, Mefenamic Acid, functions by modulating the core biochemical pathways related to the Arachidonic Acid Cascade through enzyme modulation. Its mechanism of action can be understood across three key domains that link molecular targets to physiological consequences.

Inhibiting the Cyclooxygenase Enzyme System

The drug's primary mechanism involves the non-selective inhibition of the Cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2. By blocking the active sites of these enzymes, Mefenamic Acid immediately interrupts the critical enzymatic step in the conversion of Arachidonic Acid into Prostanoids. This action is the initial molecular event leading to subsequent physiological effects.

Suppressing Inflammatory Mediator Synthesis

By inhibiting COX enzymes, the drug prevents the synthesis of powerful chemical messengers called Prostaglandins, particularly PGE2. The reduction in local mediator concentration alters the threshold for peripheral nociceptor (pain receptor) sensitization and modulates localized vascular responses. This action is critical for modulating the concentration of local chemical mediators.

Modulating Central Thermoregulation

The mechanism of Prostaglandin suppression extends to the hypothalamus in the brain, the central area that controls the body’s temperature set point. By reducing PGE2 levels in this region, the drug enables the body’s thermal control system to reset to a normal reference temperature, leading to physiological adjustments that promote heat dissipation.

Dosage and Administration Information

How to Use Penta (Mefenamic Acid)

This section outlines the general principles for the administration of the medicine.

Penta, which contains Mefenamic Acid, is used exclusively via the oral route as a capsule. The usage protocol is defined by a specific initial dose, a fixed frequency, and strict limits on the total duration of treatment.

Administration Framework

Usage Parameter Standard Parameters
Route & Form Oral capsule (250 mg)
Initial Dose 500 mg
Maintenance Dose 250 mg
Frequency Every 6 hours (q6hr), as needed

The treatment begins with the 500 mg initial dose. This is followed by the 250 mg maintenance dose, which is to be taken every six hours as required for acute symptoms. Guidelines indicate that the capsules should be taken with food, milk, or a full glass of water to ensure proper administration and adherence to time-relationship concepts.

Duration and Use Constraints

The usage of Mefenamic Acid is indicated for short-term use only. For general acute pain, the total treatment period typically should not exceed seven days. When used for primary dysmenorrhea, the duration should be limited to two to three days. Treatment for dysmenorrhea is initiated at the onset of menstrual bleeding and associated pain.

The core principle governing administration is to use the lowest effective dose for the shortest possible duration. Furthermore, the medication is not recommended for use in children younger than 14 years of age, establishing a clear age-based constraint for its administration.

Recent Clinical Evidence

Research Evidence: Overview of Studies for Penta (Mefenamic Acid)


Evidence for Use in Primary Dysmenorrhea (Menstrual Pain)

Research investigating conditions characterized by fluctuating or episodic manifestations of pain, such as primary dysmenorrhea, has included Randomized Controlled Trials (RCTs) and systematic reviews that evaluated Mefenamic Acid. Studies explored how symptoms changed over short, defined time intervals, typically spanning one to three menstrual cycles. Researchers monitored patient-reported outcomes describing perceived discomfort, including measurements of pain intensity and the reported need for supplementary pain relief.

The findings describe patterns observed in the measured symptom reports. Comparative evidence was used in studies examining symptom intensity or variability against other active agents or non-active control groups. However, long-term effects are not fully established for consistent use over many months, as follow-up durations were limited in most trials.


Evidence for Use in Acute Mild to Moderate Pain

Mefenamic Acid was evaluated in studies exploring acute, non-chronic pain, such as that experienced after minor surgical procedures or dental work. The research primarily consists of short-term, acute RCTs that focus on episodes where symptoms become more noticeable. Studies monitored outcomes related to physical discomfort over a very short duration, with assessment periods lasting only a few hours after a dose and treatment courses lasting up to seven days.

The data show patterns related to short-term changes in pain levels reported by study participants. Comparative studies explored short-term symptom changes, often against other NSAIDs. A key limitation is the very short nature of the evidence; limited information is available for outcomes when the medicine is used continuously for more than one week.


What is Still Uncertain About Penta's Research

A key area of limited research is the availability of long-term outcomes, as studies monitor use primarily within short, defined time intervals. Furthermore, dedicated, large-scale RCTs focusing solely on the fever-reducing effect are sparse, meaning that certainty remains low for that specific outcome compared to others. The research provides context for the studied groups, but the subgroup findings are uncertain when applied to patients with a high symptomatic burden.

Key Studies & References

  1. Treating menorrhagia in primary care: an overview of drug trials and a survey of prescribing practice (DARE Review)
  2. Mefenamic acid and diclofenac in the treatment of menorrhagia and dysmenorrhea in dysfunctional uterine bleeding: a randomized comparative study
  3. The Antipyretic Effect of High-Dose Paracetamol Versus Mefenamic Acid in the Treatment of Febrile Children: A Randomized Control Trial

Frequently Asked Questions (FAQ)

Common questions about Penta (FAQ)


Q: How long does it typically take to start noticing an effect after starting Penta?

Clinical information, often summarized in patient resources, indicates that the onset of pain relief can generally be noticed in less than 60 minutes following the initial dose.

Q: Is it common for people to feel [non-specific side effect, e.g., tired] when they first take Penta?

Official safety documents for Penta describe nervous system effects like drowsiness and fatigue as documented side effects. These effects are reported by some patients who use the medicine. Unexpected or severe tiredness should be brought to the attention of the prescribing healthcare professional.

Q: Are there any specific foods or drinks I should avoid when taking Penta?

Official product information states that Penta is administered with food, milk, or a full glass of water. The documents do not detail specific foods to avoid, but they do note an interaction with magnesium-containing antacids, which can significantly increase how much medicine your body absorbs.

Q: Can Penta cause changes to my sleeping pattern?

Official safety information includes potential effects on the sleep pattern under Nervous System disorders. These effects are documented as including both insomnia (difficulty falling or staying asleep) and drowsiness (feeling sleepy).

Q: Is Penta safe for older adults or seniors?

Official regulatory documents describe that older adults face an increased risk of serious adverse effects compared to younger populations. These risks specifically include potentially fatal gastrointestinal bleeding and kidney toxicity. For this reason, official labeling emphasizes the need for caution when the medicine is used in the geriatric population.

Q: Does Penta require routine blood tests or monitoring?

Routine monitoring is required when Penta is used alongside certain other medicines, such as oral anticoagulants. Additionally, specific monitoring is often mentioned in official documents for patients who have pre-existing kidney or liver impairment. General requirements for routine blood tests beyond these specific situations are not globally mandated in the product information.

Q: Can Penta affect your driving ability? (General information)

Regulatory documents advise caution when operating heavy machinery or driving if the patient experiences certain side effects. This guidance is given because the medicine has the potential to cause effects such as dizziness or fatigue, which may impact concentration and motor skills.

Q: Is there a generic version of Penta available?

Yes, the active ingredient in Penta, Mefenamic Acid, is listed in official drug documents as being available in a generic form. The generic version of the medicine is available from multiple manufacturers.

Q: Does taking Penta with food change how it works?

The official administration protocol states that Penta is administered with food, milk, or a full glass of water. This instruction is given to help ensure proper absorption and to reduce the likelihood of experiencing gastrointestinal irritation, such as stomach discomfort or upset.

Q: What is the typical duration of action for one dose of Penta?

The intended duration of action for one dose is reflected by the official prescribing frequency. The maintenance dose is scheduled to be taken every six hours as needed for acute symptoms, which is the time interval intended to maintain a consistent therapeutic effect.

Q: How is eligibility for Penta typically determined?

Official documents define patient eligibility based on two main criteria. The patient must require the medicine for short-term treatment, and they must have no official contraindications listed in the product information, such as severe organ failure or a known allergy to NSAIDs.

Q: Do studies suggest Penta is more effective for certain subtypes of patients?

Official research summaries indicate that while studies provide findings for the studied populations, the application of this evidence to certain patient subgroups remains an area of uncertainty. Specifically, there is limited information regarding outcomes for patients who have a particularly high symptomatic burden.

Q: What is the difference between the immediate-release and extended-release forms of Penta?

According to the official regulatory documents, the medicine contains Mefenamic Acid and is only described as a conventional, immediate-release capsule for oral administration. The product is not officially described as having an extended-release form.

Q: Does the time of day matter when taking Penta?

The official instruction for administration is to take the medicine every six hours as needed for acute symptoms. Regulatory documents do not prescribe a specific time of day (such as morning or evening) for the medicine to be taken, focusing instead on the required time interval between doses.

Q: Are there any common reasons why someone might need to stop taking Penta?

Official warnings state that the medicine must be discontinued immediately if signs of a serious adverse reaction occur. Key examples of these signs include a severe skin rash, indicators of gastrointestinal bleeding, or the development of severe diarrhea.

Q: If I stop taking Penta, what generally happens?

Since the medicine is officially designated only for short-term use and not chronic treatment, patients are not typically expected to experience withdrawal symptoms upon stopping its use.

Q: Is Penta a controlled substance?

Official drug listings and regulatory documents confirm that Penta, which contains Mefenamic Acid, is not classified as a federally controlled substance.

Q: Is Penta commonly used in other countries?

The active substance, Mefenamic Acid, is internationally recognized by the INN system and is authorized and used in numerous jurisdictions worldwide. This is evidenced by its inclusion in regulatory documentation from bodies like the EMA and TGA.

Q: Is Penta known to cause weight gain or loss?

Official safety information notes documented, though usually uncommon, effects like edema, which is swelling caused by fluid retention. However, significant changes in appetite or body weight are generally not listed as common side effects of the medicine.

Q: Is Penta known to affect mood or mental health?

Official documents describe potential effects related to the nervous system, which can include dizziness and insomnia. There have also been rare reports of effects like nervousness associated with the use of the medicine.

Q: What is the risk of dependence or addiction described for Penta?

Official regulatory text confirms that the medicine is not a controlled substance and that dependence, tolerance, or addiction has not been documented with the use of Mefenamic Acid.

Q: Where can I find the official patient information leaflet for Penta?

Official patient counseling instructions describe that the official patient information leaflet, sometimes called the Medication Guide, is available through government resources such as MedlinePlus or those provided by the FDA.

Q: Does Penta interfere with laboratory test results?

Official documents caution that Mefenamic Acid may interfere with the diagnostic outcomes of certain laboratory test results. One specific interference noted is the potential for tests to show false-positive bilirubinuria (a misleading result for bilirubin in the urine).

How should Penta be stored and disposed of?

The storage and disposal of Penta (Mefenamic Acid) capsules must adhere strictly to regulatory requirements to preserve the product's stability.

Storage Conditions

Official labeling mandates storing the capsules at Controlled Room Temperature, specifically between 20 C and 25 C. The container must be kept tightly closed and in its original packaging, protected from excess moisture and excess heat. Store this medication in a secure location that is out of the sight and reach of children.

Disposal Instructions

Unused or expired Penta should be disposed of via an official drug take-back program. If no program is available, the product may be mixed with undesirable material, placed in a sealed container, and discarded in household trash. Do not flush the capsules down the toilet or pour them into a drain.

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

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