Dolos

Quick links to important sections

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 Dolos

What is Dolos? – Identity and General Purpose Overview

The drug Dolos, containing the active ingredient Mefenamic Acid, is a synthetic preparation recognized for its analgesic and anti-inflammatory properties.

Property Description
Active ingredient Mefenamic Acid
Form Capsules, Tablets (for oral use)
Pharmacological class Nonsteroidal Anti-Inflammatory Drug (NSAID)
Common purpose Analgesic, Anti-inflammatory, Antipyretic
Origin Synthetic (Anthranilic acid derivative)

1. What is Dolos and Its Primary Classification?

Dolos is a synthetic, single-ingredient product classified as a Nonsteroidal Anti-Inflammatory Drug (NSAID) intended for oral administration. The active ingredient, Mefenamic Acid, is chemically designated as an anthranilic acid derivative, placing it distinctly within the fenemate subclass of NSAIDs. This classification reflects its unique structure and systemic activity.

This structural distinction differentiates it from more common NSAID groups, while it shares the core therapeutic goals of reducing pain and inflammation. As a prescription-only medicine in many jurisdictions, Dolos is supplied in fixed dosage forms such as capsules or tablets, ensuring the delivery of the Mefenamic Acid.

2. Composition and Fundamental Mechanism

The function of Dolos is defined by its role as a Cyclooxygenase (COX) inhibitor, which is the fundamental mechanism regulating its therapeutic effects. Mefenamic Acid works by limiting the production of pro-inflammatory prostaglandins—the chemical substances responsible for signaling pain and causing swelling.

This mechanism provides a basis for its clinical utility in managing conditions involving increased inflammatory mediators. The medicine is formulated with solid pharmaceutical excipients that enable dissolution and absorption, allowing the active ingredient to exert its influence systemically throughout the body.

3. General Therapeutic Purpose and Form

The inherent general therapeutic purpose of Dolos is to provide symptomatic relief through its triple action: it is analgesic (pain-relieving), anti-inflammatory (swelling-reducing), and antipyretic (fever-reducing). The activity of oral Mefenamic Acid is characterized by these properties.

The drug's presentation as an oral capsule or tablet ensures that the benefits of Mefenamic Acid are delivered internally. This makes Dolos a practical solution for addressing general aches, acute inflammatory discomfort, and accompanying feverish states.

Regulatory References

  1. Mefenamic Acid Monograph (DailyMed)
  2. Mefenamic Acid Mechanism of Action (LiverTox)

What side effects are possible with Dolos?

Possible Side Effects and Safety Information

This section summarizes the adverse reactions and safety information for Dolos, as documented in official government regulatory sources.

Frequency-Classified Adverse Reactions

Adverse reactions are classified based on the frequency of their occurrence in clinical studies and post-marketing data:

Frequency Examples of Side Effects
Very Common (≥ 1 in 10 people) Headache, Nausea
Common (≥ 1 in 100 people) Diarrhea, Fatigue, Dizziness
Uncommon (≥ 1 in 1,000 people) Rash, Insomnia, Elevations in serum creatinine
Rare (< 1 in 1,000 people) Agranulocytosis
Frequency Not Known Severe hepatic reactions

Serious Adverse Reactions and Safety Constraints

Regulatory documentation highlights certain rare but clinically significant events and specific limitations on use:

  • Serious Adverse Reactions: These include Agranulocytosis (a rare blood disorder) and Severe Hepatic Reactions (liver issues, often from post-marketing reports). Anaphylactic Shock is also documented as a very rare event.
  • Body Systems Affected: Side effects are formally categorized into System Organ Classes (SOCs), including Nervous System Disorders, Gastrointestinal Disorders, and Hepatobiliary Disorders.

Population-Specific Safety Notes

The medicine is subject to specific restrictions for certain patient populations:

  • Severe Hepatic Impairment: Use is not recommended in patients with severe liver impairment (Child-Pugh Class C).
  • Pregnancy and Lactation: Use is not recommended during pregnancy (Category D in some regulatory systems) or by women who are breastfeeding.
  • Pediatric Use: Safety and efficacy have not been established in children under 12 years of age.

Monitoring and Use Patterns

  • Monitoring Requirements: Periodic assessment of liver function tests (LFTs) is officially required at baseline and approximately every three months thereafter.
  • Time-Related Patterns: Headache and nausea may be more frequent during the first week of therapy, and there is a documented increased risk of liver enzyme elevation with prolonged use beyond six months.

Overdose and Emergency Response

Overdose and when to seek help

The official overdose profile for Dolos (Mefenamic Acid) is based strictly on descriptions and required actions documented in government regulatory sources. Overdose typically affects the central nervous system (CNS) and the gastrointestinal (GI) tract.

Documented Clinical Manifestations

Symptoms may include lethargy, drowsiness, dizziness, nausea, vomiting, and epigastric pain. Severe neurological events are a major concern, as overdose may lead to convulsions (seizures), coma, and altered mental status. Acute kidney failure and GI bleeding are also documented severe outcomes.

Emergency Actions and Management

Immediate medical attention must be sought if an overdose is suspected or if a person experiences severe symptoms such as seizures, trouble breathing, or loss of consciousness. Management must be symptomatic and supportive, as no specific antidote for Mefenamic Acid overdose is known.

Regulatory guidance emphasizes the need for observation and specific procedures. Following significant acute ingestion, measures such as administering activated charcoal may be considered to reduce absorption. Due to high protein binding, procedures such as hemodialysis are generally not considered useful. Patients are typically required to undergo hospital observation for at least 12 hours.

Therapeutic Uses of Dolos

What Dolos treats: main uses and benefits

Dolos (Mefenamic Acid) is used to help manage symptoms related to inflammatory or irritative states. This medication may be applied across several therapeutic domains, assisting with supportive relief and the management of symptoms related to physical discomfort.


Key Therapeutic Applications

It is relevant for easing episodic gynecological pain, specifically the intense, spasmodic cramping of primary dysmenorrhea, and may assist with addressing symptoms linked to the overall volume of blood loss in patients experiencing menorrhagia. It is also relevant in clinical settings when symptomatic relief of mild to moderate acute pain is appropriate, including common manifestations such as tension headache, discomfort associated with dental pain, and transient muscle aches, as well as during flares of conditions like rheumatoid arthritis and osteoarthritis.

This medication may offer support that contributes to improved comfort during difficult episodes by helping ease symptom distress. It is also considered relevant in contexts involving heightened systemic burden that requires supportive relief from feverish discomfort, and applied during phases when symptoms become temporarily overwhelming.


Quick Fact: Relief for Episodic Discomfort
Dolos is commonly used in situations involving recurrent or episodic manifestations, typically for adults and adolescents aged 14 years old, when symptomatic support is appropriate.

Regulatory References

  1. NIH MedlinePlus Drug Information

Eligibility and Restrictions for Use

Who Can and Cannot Use Dolos? — Official Regulatory Information

The eligibility for using Dolos (Mefenamic Acid) is strictly defined by regulatory authorities based on age, existing medical conditions, and physiological status. The medicine is primarily approved for use in adults and adolescents ge 14 years of age.

Absolute Contraindications

Use is strictly contraindicated in patients with a history of NSAID-induced allergy (e.g., asthma, urticaria), severe heart failure, severe renal failure, or severe hepatic failure. It is also prohibited for patients with active gastrointestinal ulceration or chronic inflammation, and for treating pain following Coronary Artery Bypass Graft (CABG) surgery.

Age and Condition Restrictions

Population Group Eligibility Status (Regulatory Wording)
Children under 14 Safety and effectiveness have not been established
Elderly patients (ge 65) Use with caution; require monitoring due to increased risk of serious GI and renal issues.
Last Trimester of Pregnancy Contraindicated (from 30 weeks gestation)
Nursing Mothers Should not be taken

Eligibility is further constrained by organ function; patients with non-severe impaired renal function require caution and monitoring. Use is also not recommended for women who are actively attempting to conceive.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The official regulatory profile for Dolos (Mefenamic Acid) details several categories of interaction, primarily related to pharmacokinetic changes and enhanced pharmacodynamic risks. Co-administration is strictly restricted with other systemic Nonsteroidal Anti-Inflammatory Drugs (NSAIDs), including COX-2 inhibitors, due to a heightened risk of serious gastrointestinal events.

Documented Pharmacokinetic Effects

Interactions that alter plasma drug levels are formally documented. Dolos reduces the renal clearance of substances like Lithium and Methotrexate, which can lead to elevated plasma concentrations of those medicines. Furthermore, Dolos may inhibit the metabolism of certain Oral Hypoglycemic Agents (Sulfonylureas), potentially prolonging their effects and increasing the risk of hypoglycemia. Antacids containing Magnesium Hydroxide significantly increase the rate and extent of Mefenamic Acid absorption.

Pharmacodynamic and Timing Constraints

Concomitant use with Oral Anticoagulants (e.g., Warfarin), Corticosteroids, or SSRIs increases the documented risk of bleeding or gastrointestinal ulceration. A mandatory administration constraint requires that NSAIDs should not be taken for 8–12 days after Mifepristone administration as described in regulatory labels. Consumption of Alcohol is also associated with an increased risk of gastrointestinal bleeding.

Mechanism of Action

How Dolos Works

Targeting the Prostaglandin Synthesis Pathway

The mechanism of Dolos (Mefenamic Acid) is defined by the reversible inhibition of Cyclooxygenase (COX) enzymes (specifically COX-1 and COX-2). The enzyme blockade disrupts the Arachidonic Acid Cascade, resulting in suppressed biosynthesis of prostaglandins—eicosanoid mediators of physiological responses.


Modulating Nociception and Thermoregulation

The reduction in prostaglandin concentration affects both peripheral and central systems. Peripherally, lower prostaglandin concentration decreases the excitability of nociceptors (afferent pain fibers), modifying the firing threshold. Centrally, the suppression of prostaglandin E2 ( PGE2) synthesis within the hypothalamus facilitates the return of the elevated thermoregulatory set-point to baseline.


Resulting Physiological Adjustments

These interconnected molecular actions result in altered physiological states: decreased local mediator-induced vascular changes, modification of nociceptor excitability, and resetting of the hypothalamic temperature set-point. The mechanism operates within biological systems characterized by heightened humoral (chemical mediator) signaling, allowing for targeted pathway interference.

Dosage and Administration Information

How to Use Dolos

Dolos (mefenamic acid) is administered exclusively via the oral route as a capsule, tablet, or suspension, with the core principle of using the lowest effective dose for the shortest possible duration. This approach aligns with general principles for Nonsteroidal Anti-Inflammatory Drugs (NSAIDs).


Standard Administration and Dosing

The medicine is typically initiated with a 500 mg loading dose. The subsequent maintenance regimen is generally 250 mg every six hours (q6hr) as needed for acute conditions. Depending on the specific formulation and context, the maximum maintenance dose may be 500 mg taken three times daily.

Application Initial Dose Maintenance Dose and Frequency Max Duration (Typical)
Acute Pain 500 mg single dose 250 mg q6hr PRN 7 days or less
Primary Dysmenorrhea 500 mg single dose 250 mg q6hr PRN 2 to 3 days

Administration Requirements

To ensure proper intake, the medicine is taken with food or milk and swallowed with a full glass of water (8-12 ounces). For conditions like primary dysmenorrhea, administration begins at the onset of menstrual bleeding and associated symptoms. Treatment duration for acute pain is usually limited to one week, and for menstrual pain, it is generally limited to two to three days per cycle.

If a dose is missed, it is taken as soon as possible, but if it is almost time for the next scheduled dose, the missed dose is skipped. Doses are not to be doubled.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Dolos (Mefenamic Acid)


Evidence for Use in Primary Dysmenorrhea (Menstrual Pain)

Dolos has been studied for clinical situations characterized by fluctuating or episodic manifestations, such as primary dysmenorrhea. The research exploring this clinical situation primarily involved short-term Randomized Controlled Trials (RCTs), where investigators compared the use of the drug to an inactive placebo or other agents. Researchers in these trials focused on outcomes related to physical discomfort, monitoring how pain intensity scores changed over defined time intervals.

The findings from these studies describe patterns observed where the measured changes in pain intensity scores evolved in the observed populations during the study period. Studies report how changes in measured outcomes evolved over one to three menstrual cycles. These studies contribute to the evidence base concerning how acute symptoms are monitored.

Evidence for Use in Heavy Menstrual Bleeding (Menorrhagia)

Studies explored the use of the drug in conditions involving periods of heightened symptoms, specifically heavy menstrual bleeding. The research examined by regulatory bodies includes controlled trials that focused on outcomes related to systemic or functional imbalance, as measured by patient-reported experiences. Researchers monitored changes in objectively measured blood loss volume, as well as subjective reports of bleeding severity.

Research describes how trials documented patterns related to measured outcomes in blood loss volume during episodes where the drug was used. Findings describe group patterns that were observed across several menstrual cycles in the studied populations. The collected evidence contributes to the broader evidence landscape for this patient group.


Research Gaps and Areas of Uncertainty

When considering the full body of research, it is evident that most of the high-quality controlled trials focus on the short-term use of the drug. The follow-up durations were limited across many of the central studies. Therefore, long-term effects are not fully established regarding the durability of any observed response or the overall profile when the drug is used intermittently over many years.

The primary research limitations also include the fact that sample sizes were modest in some key studies, and comparative evidence against every available treatment option is lacking. While research describes patterns related to symptom changes, the findings describe group patterns, not personal outcomes. There is a clear need for more research exploring short-term symptom changes in relation to long-term health, as well as updated, large-scale studies.

Key Studies & References

  1. Clinical Practice Guidelines : Adolescent gynaecology - Heavy menstrual bleeding (Used for context on treatment focus)

Frequently Asked Questions (FAQ)

Common questions about Dolos (FAQ)


Q: If I have to stop taking Dolos, how should I get rid of the unused medicine?

If a drug take-back program is not available, official regulatory guidance suggests household disposal. The medicine should be mixed with an unappealing substance, such as dirt or used coffee grounds, before disposal. Once mixed, seal it in a container and throw it into the household trash, ensuring the drug is not flushed down the toilet.


Q: Can I take Dolos with my blood thinner (like Warfarin)?

Official information indicates that taking Dolos alongside anticoagulants, commonly known as blood thinners like Warfarin, can heighten the risk of serious bleeding or stomach issues. The combination of these medicines is typically managed under close professional monitoring.


Q: How long does it take for Dolos to start working for pain relief?

Studies on the drug’s absorption indicate that Dolos is generally absorbed quickly after being taken by mouth. Peak levels in the bloodstream are reached within approximately two to four hours after administration, which is often when the maximum effect is observed.


Q: What are the signs of a serious liver problem while on Dolos?

Regulatory documents warn that serious liver problems, including liver failure, can rarely occur. Signs of a possible liver issue may include fatigue, persistent nausea, itching, yellowing of the skin or eyes (jaundice), or symptoms that resemble the flu. If these signs are observed, discontinuation of the drug and immediate consultation with a healthcare provider is generally recommended in official labeling.


Q: Is there a generic version of Dolos available?

Yes, Dolos contains the active ingredient Mefenamic Acid, which is widely available under its generic name. Mefenamic Acid is supplied by various manufacturers.


Q: How should I monitor my blood pressure while taking Dolos?

Official product warnings note that this drug can cause new-onset or worsened high blood pressure (hypertension). Regulatory documents indicate that blood pressure monitoring is important during treatment.


Q: What should I do if I take too much Dolos (overdose)?

In the event of a suspected overdose, contacting emergency medical services or a poison control center immediately is necessary. Symptoms reported in cases of overdose can include seizures, acute kidney issues, confusion, and in serious cases, coma.


Q: Is Dolos considered a controlled substance?

No, according to official drug scheduling information, Dolos is classified as a Nonsteroidal Anti-Inflammatory Drug (NSAID). It is not designated or regulated as a controlled substance.

How should Dolos be stored and disposed of?

How to Store and Dispose of Dolos?

The storage and disposal of Dolos (Mefenamic Acid) must strictly follow regulatory guidance to maintain product quality and safety.

Storage Requirements

Condition Regulatory Rule
Temperature Store at Controlled Room Temperature (20 C to 25 C), with permissible excursions.
Protection Keep in a tightly closed container and protect from moisture and excessive heat.
Child Safety Keep out of the sight and reach of children.

Disposal Instructions

Unused or expired Dolos should ideally be discarded through a community drug take-back program. If a take-back option is unavailable, the medication must be mixed with an unappealing substance, sealed in a container, and placed in the household trash. Do not flush Dolos down the toilet or pour it down a drain.

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

Available in countries:

Equivalent of Dolos found in:

A-Z Index: