Clafen

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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 Clafen

This foundational overview defines the identity and general purpose of Clafen, which is the trade name for the active ingredient Diclofenac.

Property Description
Active ingredient Diclofenac (commonly Diclofenac sodium)
Pharmaceutical form Tablets, capsules, suppositories, solutions, gels, patches
Pharmacological class Non-Steroidal Anti-Inflammatory Drug (NSAID)
General purpose Relief from inflammation, pain, and fever
Origin Synthetic (Phenylacetic acid derivative)

What Type of Medicine is Clafen?

Clafen is a medicinal product whose active substance is Diclofenac, which is consistently classified as a Non-Steroidal Anti-Inflammatory Drug (NSAID). It is a synthetic compound belonging to the phenylacetic acid chemical class, developed to specifically inhibit the production of certain inflammatory mediators in the body. The classification as an NSAID reflects its mechanism of action, which is clinically recognized for addressing inflammation, pain, and fever by targeting the cyclooxygenase (COX) enzyme system.

Composition and Available Forms of Clafen

The core component is Diclofenac sodium, which functions as a single-ingredient product. A distinguishing feature of Diclofenac is its diverse manufacturing into multiple dosage forms, including gastro-resistant tablets, liquid-filled capsules, and topical gels, allowing for various routes of administration, such as oral, rectal, parenteral, and topical. The availability of these forms enables delivery either systemically throughout the body or locally to a specific site of discomfort.

General Purpose and Core Physiological Actions

The general purpose of Clafen is to provide symptomatic relief from inflammation, pain, and fever by interrupting key biological signaling pathways. Its action is centered on interfering with the synthesis of prostaglandins—chemical messengers responsible for initiating and maintaining these symptoms. This mechanism results in the reduction of swelling and the easing of bodily discomfort, serving as the basis for its therapeutic utility in scenarios characterized by acute inflammatory pain.

Regulatory References

  1. NIH: NSAIDs and Analgesics Overview

What side effects are possible with Clafen?

Possible Side Effects and Safety Information

Clafen (diclofenac) is a Non-Steroidal Anti-Inflammatory Drug (NSAID) whose official safety labeling, including the FDA Boxed Warning, highlights risks across several organ systems, primarily:

  • Cardiovascular (CV) Thrombotic Events: Use of Clafen is associated with an increased risk of serious CV thrombotic events, such as myocardial infarction (MI) and stroke, which can be fatal. This risk may increase with higher doses and longer treatment duration. The drug is contraindicated for the treatment of perioperative pain in the setting of Coronary Artery Bypass Graft (CABG) surgery, and its use should generally be avoided in post-MI patients.
  • Gastrointestinal (GI) Adverse Events: NSAIDs cause an increased risk of serious GI events, including bleeding, ulceration, and perforation of the stomach or intestines, which may be fatal. These events can occur without warning symptoms. The risk is higher in elderly patients and those with a prior history of GI disease.

Other Serious Adverse Reactions:

  • Hepatotoxicity: Liver injury, which may be severe and sometimes fatal (e.g., fulminant hepatitis), has been reported.
  • Renal Toxicity: This includes new onset or worsening of renal failure and hyperkalemia. Monitoring of renal function is advised in high-risk patients.
  • Serious Skin Reactions: Reactions such as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) have been reported and can be fatal.
  • Allergic Reactions: Severe, sometimes fatal, anaphylactic reactions can occur, particularly in patients with aspirin-sensitive asthma, for whom the drug is contraindicated.

Population-Specific Restrictions:

  • The drug is contraindicated in patients with established Congestive Heart Failure (NYHA Class II-IV), Ischaemic Heart Disease, Peripheral Arterial Disease, or Cerebrovascular Disease (EMA classification).
  • Use of NSAIDs must be avoided in pregnant women starting at 30 weeks gestation and later due to the risk of premature closure of the fetal ductus arteriosus.

Regulatory authorities recommend using the lowest effective dose for the shortest duration possible to mitigate the potential for these serious dose- and duration-dependent risks.

Overdose and Emergency Response

Overdose and when to seek help

Official regulatory documents define the overdose profile of Clafen (Diclofenac) based on documented clinical manifestations and potential severe outcomes. Acute overdose may initially present with gastrointestinal distress, including nausea, vomiting, abdominal pain, or signs of gastrointestinal bleeding. Central nervous system effects such as drowsiness are also formally documented.


Serious Outcomes and Immediate Action

Severe or life-threatening systemic outcomes listed in official prescribing information include convulsions, loss of consciousness (coma), acute renal failure, and respiratory depression. In the event of any severe manifestation, the official guidance mandates that you seek immediate medical attention or contact emergency services without delay.

Treatment for Diclofenac overdose is primarily symptomatic and supportive, as no specific antidote is known or available. Procedures such as gastric decontamination and the administration of activated charcoal may be considered in a supervised medical setting. Increased risk of severe complications, particularly involving the renal or hepatic systems, is noted in patients with pre-existing impairment.

Therapeutic Uses of Clafen

What Clafen Treats: Main Uses and Benefits

Clafen, which contains diclofenac, is commonly used to help with symptoms related to inflammatory or irritative states and physical discomfort. Its therapeutic role is focused on providing symptomatic relief across multiple domains where acute or fluctuating symptoms create noticeable physiological strain. This medication is applied across conditions presenting with systemic or localized discomfort.


The medication is relevant for easing symptoms associated with conditions such as Osteoarthritis, Rheumatoid Arthritis, Ankylosing Spondylitis, migraine attacks, pronounced menstrual pain (primary dysmenorrhea), and acute gout flares. In these situations, Clafen helps address symptom clusters that may become intense, specifically joint pain, stiffness, tenderness, and swelling, along with generalized fever.

“Clafen supports the patient during difficult episodes by easing distress when symptoms become more noticeable and interfere with routine activities.”

Used in settings where symptoms become momentarily overwhelming, Clafen offers symptomatic relief that helps reduce the overall burden of distressing manifestations. This supportive relief is relevant when short-term symptomatic assistance is needed, such as during phases of heightened discomfort following post-traumatic inflammation or postoperative pain.

Quick Fact: Relief for Pain and Inflammation
Clafen assists with maintaining functional stability and contributes to easing day-to-day discomfort in conditions marked by increased physiological stress.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Clafen (Diclofenac) eligibility is strictly determined by regulatory documents, defining specific groups who are permitted, restricted, or absolutely contraindicated from use.


Contraindicated Populations

Clafen must not be used by the following groups, as formally listed in prescribing information:

  • Patients with known hypersensitivity to Diclofenac, aspirin, or any other NSAID (Non-Steroidal Anti-Inflammatory Drug), including those with a history of NSAID-precipitated asthma or allergic-type reactions.
  • Patients who have active gastric or intestinal ulceration, bleeding, or perforation.
  • Patients in the setting of Coronary Artery Bypass Graft (CABG) surgery.
  • Women starting at 30 weeks gestation and later in pregnancy (third trimester).
  • Patients with severe cardiac failure (NYHA Class II-IV) and established ischemic heart disease, peripheral arterial disease, or cerebrovascular disease.
  • Patients with severe renal failure or hepatic failure (severe liver impairment).

Age-Related and Conditional Eligibility

Population Group Regulatory Status
Adults (18+) Generally allowed for labeled indications.
Children/Adolescents Safety and efficacy are not established for most systemic forms in those under 12 years of age; limited use in specific forms only.
Older Adults Use is allowed, but caution is warranted due to an increased risk of serious gastrointestinal events and age-related organ issues.
Cardiovascular Risk Use is restricted in patients with significant risk factors (e.g., uncontrolled hypertension) and must involve the lowest effective dose for the shortest duration.
Pregnancy Contraindicated in the third trimester; use should be avoided or severely limited between 20 and 30 weeks gestation.
Lactation Use is not generally recommended as Diclofenac passes into breast milk in small amounts.

What should I know about interactions with other medicines?

Clafen, which contains Diclofenac, has officially documented interactions that are classified based on their potential to alter drug exposure or amplify specific clinical risks.

Interaction Classifications (High-Level)

Classification Examples of Interacting Agents
Contraindicated Other systemic NSAIDs (including Aspirin); use for perioperative pain in CABG surgery [2.3].
Exposure Increased Strong CYP2C9 Inhibitors (e.g., Voriconazole); Lithium and Digoxin (Diclofenac increases their plasma levels) [1.1, 4.4].
Risk Amplification Anticoagulants, SSRIs, Corticosteroids (increased GI bleeding risk); Cyclosporin or Tacrolimus (increased nephrotoxicity risk) [2.6, 4.4].
Reduced Efficacy Diuretics and Antihypertensive Agents (Diclofenac may decrease their blood pressure-lowering effect) [1.1, 2.5].

Official Interaction Statements

  • Co-administration with Methotrexate may increase the risk for toxicity (e.g., myelosuppression, renal dysfunction) due to increased plasma levels [4.4].
  • The combination of Diclofenac with alcohol increases the documented risk of serious gastrointestinal adverse events, including bleeding [1.6].
  • The consequences of adverse events resulting from interactions are generally more serious in the elderly [1.1, 2.6].
  • Interactions with certain antihypertensive agents may lead to the progression of renal function deterioration in vulnerable patients [2.5].

Connection to the overall interaction profile: The regulatory profile is structured around prohibiting combinations with high additive GI risk and for specific conditions like CABG surgery [2.3]. It details pharmacokinetic changes, specifically CYP2C9 inhibition increasing Diclofenac exposure, and pharmacodynamic effects that amplify the risk of bleeding or organ toxicity with co-administered agents [1.1, 4.4].

Mechanism of Action

Clafen's mechanism of action is multimodal, centered on the inhibition of the Cyclooxygenase (COX) enzyme system, with a functional preference for the inducible COX-2 isoform. This enzymatic blockade prevents the conversion of arachidonic acid into prostaglandins, which are chemical messengers that influence nociceptive pathways and vascular tone. By interrupting this cascade, the mechanism results in decreased magnitude of inflammatory signaling and a lowered sensitivity threshold of peripheral sensory nerves.

Beyond enzyme inhibition, the Diclofenac molecule modulates the electrical activity of peripheral neurons by acting as a blocker of certain ion channels and altering the membrane's electrical potential. This mechanism decreases cellular excitability, consequently modulating afferent signal generation and transmission along nociceptive pathways. Furthermore, the molecule can access the central nervous system (CNS), where its inhibition of prostaglandin synthesis in the hypothalamus leads to the modulation of thermoregulation.

Dosage and Administration Information

How to Use Clafen (Diclofenac) — Administration Guidelines

This section outlines the standardized usage instructions for Diclofenac formulations (the active ingredient in Clafen).

Administration Scope

Administration routes include Oral use (tablets) and Topical use (solutions or patches).

Dosage Form Daily Dosing Range Frequency
Oral Tablet (Delayed-Release) 100 mg to 150 mg Two to three times daily
Topical Solution (e.g., 2% w/w) 40 mg (2 pump actuations) per knee Two times daily
Topical System (Patch) One patch per site Every 12 hours

Procedural and Timing Instructions

  1. Lowest Effective Dose: The medicine is used at the lowest effective dose for the shortest duration necessary to manage symptoms, with the need for continued treatment re-evaluated periodically.
  2. Oral Tablets: Taking the delayed-release tablets with food may delay the onset of absorption.
  3. Topical Solution: Apply to clean, dry skin and spread evenly over the treatment area. Hands must be washed completely immediately after application. The pump must be primed before the first use.
  4. Topical Restriction: Do not apply external heat, occlusive dressings, or excessive direct sunlight to the application sites of topical formulations.
  5. Population Specifics: Dosing may require adjustment for patients weighing less than 60 kg, and geriatric patients should be monitored.

Use Protocol

The administration protocol dictates a structured approach: administer the specified dose via the prescribed route at the defined frequency, while adhering to the administration technique (e.g., topical application rules). This structure ensures standardized use.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Clafen

This summary outlines the types of research that have been conducted on Clafen for its approved uses. The intent is to describe the scope of the available evidence, what was measured in the studies, and what remains unclear, using only neutral and patient-friendly language. This section does not offer medical advice, describe safety information, or make claims about individual outcomes.


Evidence for use in Osteoarthritis (OA)

Studies involving Clafen have explored the symptoms of osteoarthritis (OA), primarily using short-term, randomized controlled trials (RCTs). These are studies where participants with mild to moderate OA are assigned by chance to receive either Clafen, a non-active vehicle (placebo), or sometimes an active comparator medication. These trials were typically conducted over periods of up to 12 weeks.

Researchers monitored patient experiences using tools like the WOMAC Index, which provides patient-reported outcomes describing perceived discomfort (pain), outcomes related to physical discomfort (stiffness), and outcomes reflecting daily functioning. The studies documented patterns observed in the measured scores on these scales between the different groups, and the results contribute to understanding how patients reported their experience during the short-term study period.


Evidence for use in Rheumatoid Arthritis (RA) and Ankylosing Spondylitis (AS)

Clafen was evaluated in research involving conditions characterized by fluctuating or episodic manifestations such as Rheumatoid Arthritis (RA) and Ankylosing Spondylitis (AS). These trials included participants diagnosed with these conditions and primarily monitored outcomes linked to inflammatory or irritative states, such as changes in swollen and tender joints and general assessments of disease activity.

Limited information for long-term outcomes is available from these controlled trials, as the research was designed to assess symptom patterns rather than disease course over many years. Also, the evidence quality varies across studies, meaning the information may not fully align with modern treatment protocols.


What is Still Uncertain About Clafen Research

While Clafen was studied for its use in several conditions, the research highlights areas where certainty remains low and where more information is needed. A primary limitation is that comparative evidence is limited for many direct, head-to-head trials against all other similar medications used today. The existing evidence primarily provides insight into short-term changes, but long-term effects are not well-characterized.

Frequently Asked Questions (FAQ)

Common questions about Clafen (FAQ)

Q: Is Clafen the same as other medicines used for similar issues?

Clafen contains Diclofenac, which belongs to the pharmacological class known as Non-Steroidal Anti-Inflammatory Drugs (NSAIDs).

Official drug information indicates that this classification is shared by many medicines used for similar issues. The distinction between Clafen and other specific drugs in the same class relates to differences in formulation, dosing, and specific safety profiles.

Q: How quickly can someone expect Clafen to start working?

The onset of absorption for Clafen oral tablets can be affected by food intake.

Regulatory documents state that taking the delayed-release tablets alongside food may delay the start of absorption by approximately 1 to 4.5 hours.

Q: How long does the effect of one dose of Clafen typically last?

According to pharmacokinetic data in official prescribing information, the terminal half-life of the unchanged active ingredient is approximately 2 hours.

This measurement of how long the substance remains in the body is part of the data used to establish appropriate dosing intervals.

Q: Can Clafen cause drowsiness or affect energy levels?

Yes, official prescribing information lists side effects related to the Central Nervous System (CNS).

These commonly reported reactions include reports of drowsiness and dizziness.

Q: Is it better to take Clafen in the morning or the evening?

For certain formulations used to manage long-term conditions, official documents address the possibility of evening intake.

Regulatory patient information states that if symptoms are most pronounced during the night or early morning, the medicine may preferably be taken in the evening.

Q: Can people who are generally healthy take Clafen?

The medicine is indicated for use in specific medical conditions, such as forms of arthritis or pain syndromes.

Prescribing information strictly outlines the populations who should not use it (contraindications), focusing on individuals with pre-existing conditions like severe heart, kidney, or gastrointestinal issues.

Q: What is the difference between Clafen and (a similar drug name)?

Clafen contains Diclofenac, which belongs to the pharmacological class known as Non-Steroidal Anti-Inflammatory Drugs (NSAIDs).

Official drug information indicates that this classification is shared by many medicines used for similar issues. The distinction between Clafen and other specific drugs in the same class relates to differences in formulation, dosing, and specific safety profiles.

Q: Are there any common foods or drinks that should be avoided when taking Clafen?

Official labeling advises that the combination of the medicine with alcohol increases the risk of serious gastrointestinal adverse events, including bleeding.

Separately, for oral tablets, taking them alongside food can slow down the absorption process.

Q: If I miss a dose of Clafen, what is the best thing to do?

Patient information guidance generally indicates that the missed dose may be taken as soon as it is remembered.

However, if the time is nearly right for the next scheduled dose, the missed one should be skipped. Two doses should not be taken together.

Q: Can Clafen affect the results of common lab blood tests?

Yes, regulatory authorities recommend monitoring certain measures through laboratory blood tests during prolonged treatment.

This monitoring typically involves checking blood count and hepatic (liver) and renal (kidney) function.

Q: Is Clafen considered safe for people with minor kidney concerns?

The drug is strictly contraindicated for patients with severe renal failure.

For individuals with mild to moderate impaired renal function, regulatory documents state that a specific dose adjustment may not be indicated, but caution and monitoring are warranted.

Q: Are there research findings that Clafen helps with conditions other than its main approved uses?

Clinical research for Clafen typically focuses on its approved uses, such as inflammatory and degenerative rheumatic forms and certain pain syndromes.

It is noted that regulatory documents for some formulations may list conditions like acute migraine among the drug's approved indications.

Q: Why do some users on forums mention they feel 'foggy' after taking Clafen?

Side effects related to the Central Nervous System (CNS) are listed in the official prescribing information.

These include reports of dizziness and drowsiness, which could contribute to a user's subjective feeling of being 'foggy.'

Q: What is the risk of dependence or addiction with Clafen?

Clafen is a Non-Steroidal Anti-Inflammatory Drug (NSAID) and is not classified as a controlled substance by regulatory bodies.

Therefore, the drug is not associated with the risk of dependence or addiction.

Q: Is it common for Clafen users to experience headaches as a side effect?

Yes, headache is a reaction listed among the possible side effects in regulatory patient information leaflets.

Q: What if I take Clafen and feel it isn't working at all?

Regulatory documents advise that the medicine must be used at the lowest effective dose for the shortest duration necessary.

Official guidance emphasizes that the need for symptomatic relief and response to the therapy must be re-evaluated periodically by a healthcare provider.

Q: Are there any official warnings about taking Clafen with herbal supplements?

Official patient guidance generally recommends discussing the use of all medicines, including herbal supplements, with a healthcare provider.

This is because some supplements may carry the potential to affect the drug's safety or efficacy profile.

Q: What is the purpose of the different strengths of Clafen mentioned in official labeling?

Different strengths and formulations of the active ingredient are made available to achieve specific therapeutic goals.

This allows for flexible dosing schedules and helps ensure the use of the lowest effective dose for the shortest duration possible, as mandated by regulatory authorities.

Q: Can Clafen affect sleep patterns?

Official prescribing information lists Central Nervous System (CNS) side effects such as drowsiness.

This type of effect can potentially influence sleep patterns.

Q: What kind of research has been done on Clafen in different age groups?

Regulatory documents specify dosage and caution requirements for older (geriatric) patients, indicating clinical evaluation was performed for this group.

However, safety and efficacy are stated as not generally established for systemic forms in patients under 12 years of age.

Q: What are the common symptoms of taking too much Clafen?

Regulatory information on overdosage indicates that symptoms can include lethargy, drowsiness, nausea, vomiting, and pain in the upper abdomen.

In cases of overdosage, there is a risk that more serious events, such as gastrointestinal bleeding or acute renal failure, may also occur.

Q: What specific conditions is Clafen officially approved to treat?

According to official prescribing information, approved indications generally include inflammatory and degenerative forms of rheumatism, such as rheumatoid arthritis and osteoarthritis.

It is also approved for painful conditions involving the vertebral column and for post-traumatic or post-operative pain.

Q: What percentage of people experience the most common side effects of Clafen?

Official labeling, based on clinical trial data, provides incidence rates for certain serious adverse events.

This includes the percentage occurrence of upper gastrointestinal ulcers, gross bleeding, or perforation in patients over specific timeframes.

Q: Can Clafen make people more sensitive to the sun?

Patient instructions for topical formulations carry a procedural warning regarding light exposure.

Users are generally advised to avoid excessive direct sunlight and artificial ultraviolet light on the application sites.

Q: What do patient information leaflets typically say about stopping Clafen?

Regulatory information emphasizes that the medicine should be used for the shortest duration possible to manage symptoms.

Regulatory guidance states that treatment should generally not be discontinued without prior discussion with a prescriber.

Q: Is it true that Clafen must be taken with a full glass of water?

Yes, patient information accompanying the medicine generally instructs users to swallow the oral tablets whole with a full glass of water.

Q: What is known about Clafen's effect on liver enzymes?

Official warnings indicate that values of one or more liver enzymes may increase with Clafen use.

Due to the risk of liver injury (hepatotoxicity), regulatory documents recommend the regular monitoring of hepatic function during prolonged treatment.

How should Clafen be stored and disposed of?

Storage and Disposal Requirements

Clafen (diclofenac) must be stored according to regulatory requirements to ensure its stability. The product generally requires storage at Controlled Room Temperature, defined as 20°C to 25°C (68°F to 77°F), and must be protected from excessive heat (above 40°C). Some formulations, such as topical gels, also require protection from freezing and light.

Classification Storage Condition Type
Temperature Range Controlled Room Temperature
Protection Constraints Avoid excessive heat, Do not freeze, Protect from light

All forms of the medicine must be stored out of the sight and reach of children and pets. Unused or expired Clafen must be disposed of in accordance with local requirements. For used topical patches, the regulatory instruction specifies they must be folded sticky sides together and placed in a sealed container for safe disposal, ensuring they remain out of the reach of children and pets.

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

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