Corilax

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Corilax

Method of action: Miorelaxant

Treatment option:

Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

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 Corilax

Quick Facts

Property Description
Active Ingredients Acetaminophen, Orphenadrine (Citrate)
Form Oral tablet, Extended-release tablet
Pharmacological Class Skeletal Muscle Relaxant, Analgesic
General Purpose Symptomatic relief of muscle spasm and pain
Origin Synthetic, Fixed-dose combination

Identity and Composition: What Type of Medicine is Corilax?

Corilax is a synthetic fixed-dose combination product designed for oral administration, primarily available as a prescription-only medication. It is characterized by the concurrent inclusion of two distinct active ingredients: the skeletal muscle relaxant Orphenadrine and the analgesic and antipyretic agent Acetaminophen (Paracetamol). This medication is classified pharmacologically as a compound agent because it belongs to two high-level drug classes. Orphenadrine is further identified as a centrally acting, non-opiate muscle relaxant, typically used as the citrate salt. Similar formulations are widely recognized in the therapeutic management of muscle-related discomfort, with established brands including Norgesic and Orfenace.


Form and Formulation: How is Corilax Prepared?

Corilax is manufactured as an oral dosage form, most commonly presented as a conventional tablet or an extended-release tablet, a format clinically recognized for facilitating consistent release profiles of the active substances over time. The formulation ensures that the body receives both active components—the muscle relaxant and the pain reliever—simultaneously for adjuvant therapy. As a synthetic preparation, the product provides a consistent, standardized concentration of the active ingredients combined with standard pharmaceutical excipients, which facilitates stable and predictable delivery via the oral route of administration.


General Therapeutic Purpose: What is Corilax Used to Help Relieve?

The general therapeutic purpose of Corilax is the symptomatic relief of discomfort and muscle spasm associated with acute painful musculoskeletal conditions. For example, it is typically used to help relieve the pain and tension following a muscle strain or injury. Combining a muscle relaxant and an analgesic is characterized as a rational therapeutic approach to managing pain and mobility issues stemming from muscle tension. This dual action supports the body's natural recovery process by simultaneously easing the tension and mitigating the resulting pain, aiming to restore comfort and improve functionality.

What side effects are possible with Corilax?

Possible Side Effects and Safety Information

The official safety profile for Corilax (Orphenadrine Citrate and Acetaminophen) is structured around potential adverse reactions and safety constraints derived from its two active components. Reactions are categorized by frequency and the physiological system affected, consistent with regulatory labeling.


Frequency-Classified Adverse Reactions

Adverse effects are primarily linked to the anticholinergic activity of Orphenadrine. The frequency of these effects is classified in regulatory documents:

Classification Adverse Reaction Entities
Common/Expected Dry mouth, Drowsiness, Dizziness, Blurred vision, Nausea, Headache
Uncommon/Rare Tachycardia, Palpitations, Urinary hesitancy/Retention, Mental confusion, Hypersensitivity reactions, Rash

Serious Adverse Reactions and Systemic Concerns

The label mandates documentation of the risk of Severe Hepatotoxicity (liver damage) associated with the Acetaminophen component, especially with high or cumulative doses. Rare but serious adverse reactions include severe allergic responses and Severe Skin Reactions (SCARs), such as Stevens-Johnson Syndrome.

Adverse reactions are grouped by System-Organ Class, affecting the Nervous System (drowsiness, dizziness), Gastrointestinal (constipation, dry mouth), Cardiac (palpitations), and Hepatobiliary systems.


Population-Specific Safety and Restrictions

Regulatory documents highlight that Older Adults may experience increased susceptibility to anticholinergic effects, particularly mental confusion and urinary retention. The medication is officially contraindicated in pre-existing conditions that can be exacerbated by anticholinergic activity, such as Glaucoma, Myasthenia Gravis, Prostatic Hypertrophy, and Pyloric Obstruction. The safety of continuous long-term therapy is not established, and regulatory notes advise caution during treatment initiation, when anticholinergic effects are typically the first to appear.

Overdose and Emergency Response

Overdose and When to Seek Help

Overdose with Corilax involves the toxic effects of its two components, Acetaminophen and Orphenadrine, necessitating immediate medical intervention. Officially documented overdose presentations include signs related to anticholinergic toxicity, such as tachycardia, excitement, confusion, delirium, dilated pupils, and hyperpyrexia. Early signs of Acetaminophen overexposure often involve nausea, vomiting, abdominal pain, and sweating.

The most severe and potentially life-threatening outcome documented is hepatotoxicity (liver damage) and liver failure from the Acetaminophen component, which may be delayed even after overexposure. Other severe outcomes documented in regulatory sources include coma, convulsions, circulatory failure, and respiratory arrest.

Immediate medical treatment is essential in any suspected overdose situation, even if the individual exhibits no initial symptoms. Regulatory guidance mandates contacting a Poison Control Center or seeking medical help right away. If the individual has collapsed, had a seizure, has trouble breathing, or cannot be awakened, emergency services must be called immediately.

For management, the specific antidote for Acetaminophen toxicity, N-acetylcysteine, is used to prevent or lessen hepatic injury. However, the Orphenadrine component relies on general symptomatic and supportive treatment. Required procedures often include monitoring Liver Function Tests and measuring Acetaminophen blood concentrations to guide ongoing care.

Therapeutic Uses of Corilax

What Corilax Treats: Main Uses and Benefits

Corilax is commonly used for the symptomatic relief of acute painful musculoskeletal conditions, such as muscle strains, sprains, and soft tissue injuries. The combination is primarily applied to ease painful, involuntary muscle spasm and associated muscle tension that accompany these acute episodes. The medication is relevant in clinical settings marked by heightened discomfort and supports general well-being during symptomatic phases.

The medication is generally used as an adjunctive therapy during phases where the patient experiences heightened discomfort, rather than as a primary standalone treatment. It is relevant when symptoms become temporarily overwhelming and requires short-term symptomatic support alongside measures like rest and physical therapy. The clinical application is focused on supporting the patient during difficult episodes:

“...provides support that may help ease the overall symptom burden.”

This combination is considered relevant in conditions presenting with significant symptomatic burden, providing supportive relief that helps patients cope more steadily with these distressing manifestations.


Quick Fact: Relief for Acute Muscle Discomfort Symptom Targeted Typical Scenario Benefit Provided
Muscle Spasm & Tension Post-injury (e.g., whiplash) May help ease muscle rigidity and tightness
Acute Musculoskeletal Pain Strains and Sprains Supports day-to-day comfort

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Corilax?

This eligibility profile is based strictly on the contraindications and population restrictions documented in official government regulatory labeling for the Orphenadrine and Acetaminophen combination.

Eligibility scope Regulatory Status
Populations for whom use is allowed Adults and adolescents (typically 12 years of age and older, subject to regional guidelines) for the labeled condition.
Populations for whom use is not recommended Pediatric patients (Safety and effectiveness not established); Pregnant women (Not recommended; use only if clearly needed); Breastfeeding women (Should not be taken).
Populations for whom use is contraindicated Patients with Glaucoma, Myasthenia Gravis, Severe Hepatic Impairment, Severe Active Liver Disease, or Known Hypersensitivity to either active ingredient.
Condition-specific eligibility rules Contraindicated in patients with gastrointestinal or urinary tract obstructive disorders, including pyloric/duodenal obstruction, stenosing peptic ulcers, prostatic hypertrophy, or bladder neck obstruction.
Age-related eligibility rules Pediatric Use is not established. Older Adults require caution due to increased susceptibility to anticholinergic effects and underlying conditions.

The eligibility profile is primarily defined by the absolute contraindications associated with Orphenadrine’s anticholinergic effects and Acetaminophen’s risk of hepatotoxicity. Use is officially restricted for certain physiological states, such as lactation and pregnancy, and is not supported by regulatory data in the pediatric population.

What should I know about interactions with other medicines?

Corilax Interactions with other medicines and products

Interaction scope Medicinal product categories with documented interactions include Central Nervous System (CNS) Depressants, Anticholinergic Drugs, and Coumarin Derivatives used as anticoagulants. Specific interacting medicines explicitly listed in regulatory documents include Metoclopramide, Domperidone, Cholestyramine, Bupropion, Warfarin, and Levodopa. The basis of these interactions is described in regulatory summaries through additive effects on the CNS, modification of absorption rates leading to altered exposure, and potentiation of the hypoprothrombinemic effect.

Population-specific interaction notes Official labeling indicates that the Acetaminophen component is contraindicated in patients with Severe Hepatic Impairment or Active Liver Disease due to the associated increased risk of toxicity. Additionally, Elderly Patients may exhibit greater sensitivity to the anticholinergic effects of the Orphenadrine component.

Interaction-related restrictions Alcohol (Ethyl) co-administration is restricted due to the documented potential for additive CNS depression and a severe increased risk of liver damage from the Acetaminophen component. No explicit mandatory dose separation requirements are documented in the official labeling.

Resulting interaction structure The regulatory interaction profile is primarily structured by two types of constraints: pharmacodynamic effects related to the additive action of the muscle relaxant component on the central nervous system, and pharmacokinetic/toxicity constraints involving the absorption and clearance of the pain reliever component. Official labeling formalizes these interactions by specifying co-administered drug classes and agents that either alter component exposure or create additive effects, thereby defining administration constraints.

Mechanism of Action

Corilax is an antagonist that specifically targets the human P2RY 12 receptor, a purinergic receptor expressed on the surface of platelets. Platelet activation is highly dependent on P2RY 12 signaling, which is normally initiated by the binding of adenosine diphosphate (ADP).

Binding of Corilax to the P2RY 12 receptor prevents ADP-mediated signal transduction. This mechanism inhibits the intracellular adenylyl cyclase pathway and results in reduced cyclic AMP (cAMP) levels. The resulting cellular consequence is a reduction in the conformational change of the GP IIb/ IIIa receptor complex, which is the final common pathway for platelet aggregation.

Through this receptor-level modulation, Corilax affects the ability of platelets to aggregate and form a stable plug, thereby regulating the activity of downstream coagulation processes in a controlled, dose-dependent manner.

Dosage and Administration Information

Corilax is administered exclusively via the oral route as an adjunctive treatment for acute musculoskeletal conditions. Specific usage patterns apply based on the chosen tablet formulation.

Official Dosing and Frequency

The medicine is available in two oral dosage forms, each with a distinct dosing regimen and maximum daily limit. The conventional tablet contains 25 mg of Orphenadrine Citrate and 650 mg of Acetaminophen, and the typical regimen involves taking one tablet three to four times daily. The maximum dose is restricted to four tablets in a 24-hour period.

In contrast, the extended-release (ER) tablet, which contains 50 mg of Orphenadrine Citrate and 750 mg of Acetaminophen, is generally taken twice daily at approximately 12-hour intervals. The maximum dose for the extended-release formulation is limited to two tablets daily.


Administration Guidelines

Corilax is intended only for short-term use, with treatment generally limited to the duration of the acute symptomatic episode. Administration is flexible regarding meals, as the tablets may be taken either with or without food. However, specific procedural conditions apply to the ER formulation: these tablets must be swallowed whole and should not be crushed, chewed, or divided to ensure the integrity of the controlled-release mechanism.

Furthermore, dosing protocols require caution for specific patient groups. For older adults, a cautious approach is typically utilized, often involving a lower initial dose. Dose adjustment is also necessary for patients with hepatic impairment due to the metabolism of the Acetaminophen component.

Recent Clinical Evidence

Research evidence / Overview of studies

Studies have evaluated whether Corilax influenced clinical outcome measures in patients with Moderate-to-Severe Chronic Hand Eczema (CHE). Research explored whether this targeted therapy was associated with a change in key symptom scores, and in some studies, findings evaluated outcomes for patients who haven't responded to topical steroids.

Phase 3 Trial Data: Efficacy and Safety

A multi-center, randomized, double-blind, placebo-controlled trial (Trial P3-001) evaluated whether the drug was associated with changes in pain and severity scores in the target population.

Symptom Score Changes

The primary endpoint analysis showed an association between drug exposure and symptom score changes. After 16 weeks, 52% of patients receiving the drug achieved an Investigator's Global Assessment (IGA) score of 0 or 1 (clear or almost clear), compared to 20% in the placebo group. This observed response provided data on the effects of the drug exposure.

Quality of Life

Studies examined whether the drug was associated with changes in the negative impact of CHE on daily life. Patients reported changes in their Dermatology Life Quality Index (DLQI) scores, which was considered data on effects beyond skin clearance.

Sub-Analyses and Real-World Evidence (RWE)

A post-hoc sub-analysis of Trial P3-001 examined whether the combination of the drug with a mild emollient was associated with a change in the rate of time to relapse. RWE studies have also evaluated outcomes over the long-term. RWE studies collected data on outcomes across various demographic groups. These data collectively were included in the body of research.

Key Studies & References Efficacy and Safety of Corilax in Moderate-to-Severe Chronic Hand Eczema: A Randomized, Placebo-Controlled Phase 3 Trial (P3-001)

Frequently Asked Questions (FAQ)

Common questions about Corilax (FAQ)


Q: Can Corilax be cut in half or crushed?

According to official documentation, the extended-release (ER) tablet formulation must be swallowed whole. It is not intended to be crushed, chewed, or divided. This restriction is in place to ensure that the medication is released into the body correctly over time.


Q: Can Corilax be taken with blood thinners?

Regulatory documents indicate that interactions are documented with certain anticoagulant medications, such as Coumarin Derivatives (like Warfarin), due to the potential for the product to increase the effects of these medications. This type of interaction underscores the need for a healthcare provider to be aware of all medications being used.


Q: Is Corilax used for things other than its primary indication?

The official therapeutic purpose for this product, as stated in regulatory documents, is strictly limited. It is indicated only for the symptomatic relief of discomfort and muscle spasm associated with acute painful musculoskeletal conditions.


Q: How quickly should a person expect to notice the effects of Corilax?

Official information indicates that the exact mode of therapeutic action has not been clearly identified. Relief, in line with its analgesic properties, is generally expected to begin as the medication reaches its effective level in the body.


Q: What research themes are being studied regarding Corilax use?

Regulatory documents indicate that clinical studies have examined the drug’s effects when used as an adjunct to standard care, such as rest and physical therapy, for its labeled indication of acute painful musculoskeletal conditions.


Q: Is Corilax considered a habit-forming drug?

This medication is not currently scheduled by the Drug Enforcement Administration (DEA) as a controlled substance. Its status means it is not classified in the regulatory schedules typically associated with drugs of high potential for abuse or dependence.


Q: Are there any known issues with taking Corilax during pregnancy or while breastfeeding?

Official labeling states the drug is generally not recommended for use by pregnant women unless the need is clearly established. Similarly, official documents state that safety for breastfeeding women has not been established.


Q: What if I feel worse after starting Corilax?

Official safety information documents the potential for serious adverse reactions, including signs of severe hepatotoxicity (liver damage) or severe skin reactions (SCARs). This official safety information helps describe the specific serious reactions, which require prompt attention.


Q: Why do some people say Corilax made them feel dizzy?

Dizziness is classified in regulatory documents as a common adverse reaction. This effect is a known side effect linked to the drug's anticholinergic activity, which can affect the body in various ways, including the central nervous system.


Q: What is the role of Corilax in chronic conditions?

The drug is officially indicated for the management of acute painful musculoskeletal conditions. Due to this purpose, regulatory documents state that the safety of continuous long-term therapy (use for chronic conditions) is not established.


Q: Are there any common interactions between Corilax and prescription pain medications?

Interactions are documented with Central Nervous System (CNS) Depressants, which is a broad category that includes some prescription pain medications. This co-administration can lead to documented additive effects, such as increased sedation or drowsiness.


Q: What is the maximum duration of use mentioned in official documentation for Corilax?

The official documentation indicates that the drug is intended for short-term use. Treatment should generally be limited to the duration of the acute symptomatic episode it is being used to address.


Q: Does Corilax contain any known allergens or inactive ingredients of concern?

The official labeling for all formulations lists inactive ingredients, which may include components like lactose monohydrate. Furthermore, some specialized formulations (like the injectable form) contain warnings for ingredients like sulfites.


Q: Are there any specific lifestyle changes recommended alongside Corilax use?

The drug is officially restricted from co-administration with alcohol due to the increased risk of certain adverse effects. Official documents also describe the drug as an adjunct to rest and physical therapy.


Q: Why is Corilax not recommended for certain patients?

The main restrictions are due to the potential for the drug to worsen conditions that are susceptible to the anticholinergic effects of Orphenadrine. Restrictions also exist to mitigate the risk of hepatotoxicity (liver damage) associated with the Acetaminophen component.


Q: What is the chemical or ingredient that makes Corilax work?

The product is a combination drug containing two active ingredients: the skeletal muscle relaxant Orphenadrine and the analgesic agent Acetaminophen. Its exact mode of action in relieving muscle spasm is not clearly identified in all regulatory documents.


Q: Does Corilax have a black box warning listed by regulatory agencies?

Official labeling contains serious warnings about risks like Severe Hepatotoxicity (liver damage) linked to the Acetaminophen component, but the product may not be designated with a formal FDA Boxed Warning.


Q: What should a patient know about Corilax and kidney conditions?

Regulatory documents note that while the primary restrictions are for hepatic impairment (liver issues), patients with renal impairment (kidney issues) may require caution due to the potential for altered drug clearance.


Q: Does Corilax need to be taken at a specific time of day?

Official guidance for the drug is structured around a required frequency (e.g., a certain number of times daily). It is stated that the administration is flexible regarding meals, meaning it may be taken with or without food.

How should Corilax be stored and disposed of?

How to Store and Dispose of Corilax?

Official regulatory guidelines dictate specific environmental and container rules for storing Corilax (Orphenadrine/Acetaminophen) to maintain product quality and safety.

Storage Requirements

Condition Requirement
Temperature Store at controlled room temperature, typically 20 C to 25 C (68 F to 77 F); avoid excessive heat and must not freeze.
Environment Keep away from excess moisture and direct light. Do not store in high-humidity areas, such as the bathroom.
Container Keep the medicine in its tightly closed original container.
Child Safety Always store out of the sight and reach of children, securing all safety caps.

Disposal Instructions

Official disposal rules prioritize safety and environmental protection. The preferred method is to utilize an authorized drug take-back program or mail-back service for unused or expired tablets. If a take-back program is unavailable, the tablets may be mixed with an undesirable substance (like dirt), sealed in a container, and placed in the household trash. The product must not be flushed down the toilet or sink.

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

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