Nabesac

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Nabesac

Method of action: Miorelaxant

Treatment option:

Medically reviewed

Marina Burgos

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 Nabesac

What is Nabesac? (Overview)

Nabesac is a prescription medication that functions as a fixed-dose combination product, delivering a skeletal muscle relaxant and an analgesic within a single oral tablet. This specific composition includes two distinct active ingredients: Orphenadrine (often utilized as the citrate salt) and Acetaminophen, the latter commonly recognized as Paracetamol. Both compounds are synthetic in origin.

Property Description
Active ingredients Acetaminophen, Orphenadrine
Form Oral Tablet (Immediate- or Extended-Release)
Pharmacological class Skeletal Muscle Relaxant and Analgesic/Antipyretic
Common use (General) Relief of pain associated with muscle spasm
Origin Synthetic

What Type of Medicine is Nabesac and What is its Composition?

The medication is dual-classified, reflecting the complementary properties of its constituents. The presence of Orphenadrine provides muscle-relaxing action by influencing the Central Nervous System, while Acetaminophen contributes the functions of generalized pain relief and fever reduction. Orphenadrine is characterized as an anticholinergic agent with muscle relaxant properties. This precise fixed-dose combination distinguishes it from similar compounds, such as Norgesic, which shares the same active ingredients but may vary in release profile or dosage strengths. The drug is manufactured for oral administration and is supplied in a tablet form.


How Do the Components of Nabesac Work Together?

The components of Nabesac are formulated to provide symptomatic relief by addressing the discomfort that stems from muscular conditions, such as acute pain following a muscle strain. The Orphenadrine component acts centrally to relieve abnormal tension, stiffness, or involuntary contraction (spasm) of the skeletal muscles. Concurrently, the Acetaminophen component serves as an analgesic by interrupting pain signals. This multimodal approach is utilized for the management of localized musculoskeletal discomfort. The general therapeutic purpose of this combination therapy is to offer a comprehensive approach to managing acute muscular discomfort by addressing both the muscle spasm and the associated pain.

Regulatory References

  1. Label: ORPHENADRINE CITRATE tablet - DailyMed (NIH)

What side effects are possible with Nabesac?

Possible Side Effects and Safety Information

The safety profile of Nabesac (Orphenadrine/Acetaminophen) reflects the combined characteristics of its two active components, structured by official regulatory documentation to define the risk framework.

Frequency and System-Organ Classifications

Adverse reactions are organized by System Organ Class (SOC) and assigned a frequency rating. The most commonly reported effects are generally linked to the anticholinergic properties of the Orphenadrine component, primarily affecting the Nervous System and Gastrointestinal System. These often include dry mouth, drowsiness (somnolence), dizziness, and blurred vision.

System Organ Class (SOC) Examples of Officially Documented Effects
Nervous System Drowsiness, dizziness, headache, confusion
Gastrointestinal Dry mouth, constipation, nausea, vomiting
Cardiac Palpitations, tachycardia

Serious Adverse Reactions and Safety Constraints

The product is associated with risks that are infrequent but clinically significant. The most serious concern is the potential for Severe Hepatic Injury or failure, a risk specifically linked to the Acetaminophen component, particularly when maximum recommended amounts are exceeded. Regulatory documents also list the rare risk of Serious Skin Reactions (e.g., Stevens-Johnson syndrome) and Blood Dyscrasias (e.g., Agranulocytosis).

Due to the anticholinergic component, the medicine is contraindicated in patients with specific pre-existing conditions, including glaucoma, myasthenia gravis, and conditions causing obstruction in the gastrointestinal or urinary tracts (e.g., prostatic hypertrophy).

Population-Specific Safety Notes

Safety statements advise that older adults may be more susceptible to central nervous system effects (such as confusion) and anticholinergic side effects. Additionally, patients with severe hepatic impairment are typically restricted from using this product due to the inherent hepatotoxicity risk. For long-term use, regulatory documents advise that periodic monitoring of certain laboratory values (blood, urine, liver function) may be recommended.

Overdose and Emergency Response

Nabesac overdose presents a dual risk profile due to the combined toxicities of its two components, Orphenadrine and Acetaminophen. Officially documented overdose manifestations include early symptoms such as paleness, nausea, vomiting, and abdominal pain related to Acetaminophen exposure. Additionally, anticholinergic signs from Orphenadrine may appear, including tachycardia, hyperpyrexia, confusion, delirium, and urinary retention.

Severe or life-threatening outcomes are documented in regulatory information. These include acute liver failure, which is a critical, delayed risk that may not manifest until 12 to 48 hours post-ingestion. Other serious outcomes involve the central nervous system (CNS), resulting in coma and convulsions, alongside risks of circulatory and respiratory failure. Regulatory sources note that the toxicity risk is increased for individuals with pre-existing hepatic impairment or a history of alcoholism.

Regulatory guidance mandates that immediate medical treatment must be sought in all suspected cases of overdose, even if the patient appears asymptomatic. Emergency actions detailed in official sources include the administration of the Acetaminophen antidote, N-acetylcysteine, and intensive monitoring. Although no specific antidote exists for Orphenadrine toxicity, management involves supportive care for emergent anticholinergic effects. Contacting emergency services is required if life-threatening symptoms such as collapse or seizure occur.

Therapeutic Uses of Nabesac

What Nabesac Treats: Main Uses and Benefits

Nabesac (Orphenadrine/Acetaminophen) is commonly used to provide targeted symptomatic relief for conditions presenting with systemic or localized discomfort, particularly those marked by a dual burden of painful muscle spasm and general musculoskeletal pain. This combination is applied as an adjunct to rest and physical therapy for conditions such as acute painful muscular conditions, whiplash injury, acute torticollis, and tension headache associated with muscle tension. It is often used during phases when symptoms become more noticeable, where short-term symptomatic assistance is needed to support recovery.

Key Symptom Relief Areas

This medicine helps address symptom clusters that may appear or fluctuate, relevant across domains where symptoms related to physical discomfort are heightened. Nabesac is relevant for easing tension and pain in conditions including strains, sprains, and symptomatic low back pain. It is also applied in managing generalized myalgia and related discomfort, including fever, when symptoms cluster together.

“Nabesac is generally applied in contexts where distressing symptoms are characteristic of muscle contraction and pain.”

This supportive relief contributes to easing the overall symptom load and helps maintain a sense of stability when symptoms are more noticeable.

Quick Fact: Symptom Management for Muscle Spasm


Easing Tension and Trauma-Related Discomfort

Nabesac is applied in clinical settings that involve symptoms of increased neurological or muscular activity, such as involuntary, sustained muscle contraction. Used as adjunct therapy, it provides supportive relief when symptoms interfere with routine activities and assists with maintaining functional stability.

Regulatory References

  1. FDA Verification Portal Summary

Eligibility and Restrictions for Use

The eligibility for using Nabesac is strictly defined by regulatory authorities based on the properties of its active ingredients, Orphenadrine and Acetaminophen. Use is permitted for Adults and Teenagers (aged 12 and older) as an adjunct to rest and physical therapy.


Contraindicated Populations (Must Not Use)

This medicine is contraindicated due to the anticholinergic effects of Orphenadrine in patients with:

  • Glaucoma or high intraocular pressure.
  • Myasthenia gravis.
  • Prostatic hypertrophy or obstruction of the bladder neck.
  • Gastrointestinal obstructive diseases (e.g., pyloric or duodenal obstruction, achalasia, or stenosing peptic ulcers).
  • Severe active liver disease (due to Acetaminophen toxicity risk).

Age and Physiological Restrictions

Population Regulatory Status Restriction Basis
Children (Under 12) Not Recommended Safety and effectiveness have not been established [1.3].
Older Adults (Geriatric) Use with Caution Increased susceptibility to anticholinergic effects [1.1].
Pregnancy Not Recommended Use only if benefits clearly outweigh risks (FDA Category C) [1.3].
Lactation Not Recommended Components are excreted into breast milk [2.1].

Conditional Use and Caution

Nabesac should be used with caution in patients with impaired liver or kidney function, and in those with pre-existing cardiac conditions such as cardiac decompensation, coronary insufficiency, or tachycardia [1.1, 1.3].

What should I know about interactions with other medicines?

Interactions with other medicines and products

This section details the officially documented interaction patterns for Nabesac, a fixed-dose combination containing Orphenadrine and Acetaminophen.

Contraindicated Combinations and Restrictions

Co-administration with other medicinal products containing Acetaminophen is strictly prohibited in regulatory documents due to the risk of exceeding the maximum daily dose, which can lead to severe liver damage. Furthermore, the consumption of alcohol must be avoided due to the significant and potentially fatal increase in hepatotoxic risk associated with the Acetaminophen component.

Documented Pharmacokinetic and Pharmacodynamic Interactions

Interacting Substance/Class Official Interaction Description
CNS Depressants (e.g., Sedatives, Opioids) Documented additive CNS effects, including increased sedation and drowsiness, due to the Orphenadrine component.
Anticholinergic Drugs Additive anti-muscarinic effects are noted, which may increase the severity of related side effects.
Oral Anticoagulants (e.g., Warfarin) Acetaminophen may potentiate the hypoprothrombinemic effect, potentially increasing the risk of bleeding, especially with prolonged use.
Metoclopramide or Domperidone Officially documented to increase the absorption rate of the Acetaminophen component.
Cholestyramine Officially documented to decrease the absorption rate of the Acetaminophen component.

Population-Specific Interaction Notes

Acetaminophen is formally contraindicated in patients with severe active liver disease or severe hepatic impairment due to the documented heightened risk of toxicity. Elderly patients may also be more susceptible to the additive anticholinergic effects of Orphenadrine.

Mechanism of Action

Dual-Action Modulation of Cellular Signaling

Nabesac functions as a multi-target inhibitor that modulates fundamental intracellular processes by acting on several interconnected signaling pathways. Its primary mechanism involves the inhibition of the PI3K-p110gamma enzyme, a crucial component of the Phosphoinositide 3-kinase (PI3K)/AKT/mTOR cascade. This inhibition disrupts the cascade responsible for promoting cell growth and survival.

Simultaneously, Nabesac modulates the cell's intrinsic controls: it suppresses the pro-survival NF-kappaB pathway and activates the p53 transcription factor. This dual-action mechanism initiates a cascade leading to a profound shift in cellular fate toward cell cycle arrest and programmed cell death (apoptosis). The resulting physiological consequence is the elimination of compromised cells and a reduction in dysregulated cellular growth signaling.

Dosage and Administration Information

How Nabesac is used: Official Administration Guidelines

Nabesac (Orphenadrine/Acetaminophen) is a medication for oral administration and is supplied in a tablet form. The standard usage profile includes specific parameters for dosage, frequency, and conditions for administration.

Feature Guideline
Route of administration Oral
Dosing schedule (Adults) The standard adult dose for the immediate-release tablet is typically two tablets per dose.
Frequency and Schedule Dosing is usually administered three times daily (TID), with the requirement that doses are appropriately spaced.
Maximum Dose Constraint Daily intake must adhere to the defined maximum dosage, often constrained to six tablets of the common strength within a 24-hour period.
Timing in relation to meals The medication may be taken with or without food.

Procedural and Population Constraints

The use of this combination product is defined as an adjunct to rest and physical therapy for acute conditions. All tablets must be swallowed whole; extended-release forms, when applicable, must not be crushed, chewed, or broken, to maintain the drug's release profile. Regarding specific populations, a dose reduction should be considered for older adults due to increased sensitivity to the Orphenadrine component. Furthermore, the safety and administration profile for patients younger than 18 years have not been fully established. The treatment course is maintained until a prescribing clinician instructs discontinuation.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Nabesac

The research base for Nabesac, the combination of Orphenadrine and Acetaminophen, consists primarily of comparative clinical trials and reviews that examined the drug for use alongside rest and physical therapy for conditions associated with acute or disruptive episodes where muscle spasm and pain are present. The evidence focuses on research exploring short-term symptom changes in adult populations, and the findings describe group patterns observed in the studies over defined time intervals.


Evidence for Use in Acute Painful Musculoskeletal Conditions

Clinical research, often using short-term Randomized Controlled Trials (RCTs), explored how symptoms change over time related to physical discomfort in conditions like strains and sprains. These studies typically included adult populations experiencing acute episodes.

Measured outcomes were related to physical discomfort and functional imbalance, including patient-reported outcomes describing perceived discomfort (like pain intensity scales) and objective measurements of muscle spasm severity. Findings describe patterns observed in the studies where measured outcomes varied across the comparison groups, which often included Acetaminophen monotherapy or an inactive placebo.


Long-Term Studies and Follow-Up Duration

Due to the focus on research exploring short-term symptom changes, the clinical trials that examined this combination product generally involve follow-up durations that were limited, often lasting only 5 to 10 days. Therefore, the long-term effects are not fully established, and there is limited information for long-term outcomes or the durability of symptomatic changes.

Scientific reviews describe that the evidence base for skeletal muscle relaxants, including Orphenadrine, generally reflects these short-term follow-up durations.


What Research Gaps and Uncertainties Remain

Key limitations in the existing research are often noted. The evidence describes that comparative evidence is lacking for trials that directly evaluate the combination against Orphenadrine monotherapy or against other skeletal muscle relaxant medications. Furthermore, the number of well-controlled trials is considered small by some reviews. Data for certain groups remain insufficient, particularly for pediatric or older adult populations, meaning the results apply only to the populations studied in the major clinical trials.

Key Studies & References

  1. FDA Verification Portal Summary: Drug Registration DRP-11746-01_PI_01 (Regulatory Monograph)

Frequently Asked Questions (FAQ)

Common questions about Nabesac (FAQ)


Q: How does Nabesac differ from other medicines used for the same purpose?

Nabesac is defined by regulatory documents as a fixed-dose combination product containing two active ingredients: a skeletal muscle relaxant (Orphenadrine) and an analgesic (Acetaminophen). This dual composition distinguishes it from products that contain only one of these components, reflecting its combined therapeutic intent to manage muscle spasm and pain.


Q: Is Nabesac available as a generic version, and is it considered medically equivalent?

Yes, the medication is available as a generic version. According to the U.S. Food and Drug Administration (FDA) standards, generic drugs are classified as therapeutically equivalent to the brand-name product. This regulatory status means the generic version contains identical active ingredients, strength, and dosage form.


Q: Does Nabesac affect liver function or require regular blood monitoring?

Official documents note the risk of severe hepatic (liver) injury associated with the Acetaminophen component. For long-term use, regulatory documents advise that periodic monitoring of certain laboratory values, including liver function, may be recommended. This monitoring aligns with regulatory caution regarding the potential for hepatic adverse effects during extended use.


Q: Can Nabesac affect mood, anxiety, or mental health?

Officially documented Nervous System effects of the drug include confusion and dizziness. Some literature also mentions other rare or uncertain-incidence effects, such as agitation or anxiety. These effects are usually linked to the anticholinergic properties of the drug.


Q: What common over-the-counter pain relievers or cold medicines interact with Nabesac?

Official documents strictly prohibit co-administration with any other medicinal product containing Acetaminophen due to the risk of exceeding the maximum safe daily dose. Nabesac may also have additive Central Nervous System (CNS) effects, such as increased drowsiness, when taken with certain over-the-counter products classified as CNS depressants (e.g., some antihistamines).


Q: Do herbal supplements or vitamins interact with Nabesac?

Regulatory caution is generally advised regarding the co-administration of Nabesac with other products, including supplements. Literature describes that certain herbal products may interact with the Acetaminophen component.


Q: What is the official guidance on using Nabesac during pregnancy?

Nabesac is officially Not Recommended during pregnancy and is classified as FDA Category C. This regulatory classification describes that the risk to the fetus cannot be definitively ruled out. Regulatory documents state that use during pregnancy is considered only when the potential benefit is assessed to justify the potential risk to the fetus.


Q: Is Nabesac use mentioned in official documents for people with kidney or liver disease?

Yes, official documents provide specific constraints. Use is contraindicated (prohibited) in patients with severe active liver disease, according to official regulatory information. However, it should be used with caution in patients who have other forms of impaired liver or kidney function.


Q: Does Nabesac treat the underlying cause of the condition or only the symptoms?

The therapeutic purpose of this combination therapy is to provide symptomatic relief for acute muscular discomfort, such as pain and spasm. The medication is officially defined as an adjunct to rest and physical therapy, not as a cure for the underlying cause of the condition.


Q: How do people know if Nabesac is working correctly for their condition?

The medication’s effectiveness in clinical trials is measured by changes in patient-reported outcomes, such as pain intensity scales. This indicates that a noticeable reduction in perceived discomfort or objective muscle spasm severity is the basis upon which its therapeutic effect is evaluated.


Q: Is it necessary to protect Nabesac medication from light or moisture?

Yes, storage guidelines are specific about environmental controls. The tablets must be protected from moisture, excess heat, and direct light. The drug must be kept in its original, tightly closed container at all times to meet storage requirements.


Q: Why is it necessary to take Nabesac at a specific time of day?

The standard dosing schedule is usually administered three times daily (TID). Regulatory guidelines require that these doses are appropriately spaced throughout the day. This regimen is intended to help achieve and maintain consistent therapeutic levels of the drug in the body.


Q: Is it common for the Nabesac pill color or shape to change between refills?

Official regulations permit generic versions of the drug to differ in their color, size, or shape from the brand-name product. This change is allowed as long as the active ingredients, strength, and therapeutic effect remain identical and therapeutically equivalent.


Q: Can Nabesac affect dental or eye health?

Some documented side effects, linked to the anticholinergic properties of the drug, include dry mouth and blurred vision. The official documentation notes that continued dry mouth may increase the chance of dental disease, such as tooth decay. Blurred vision is also a documented anticholinergic side effect.


Q: Are there any specific lifestyle changes that are recommended or discouraged while taking Nabesac?

The consumption of alcohol must be avoided due to the documented potential for severe adverse effects linked to the Acetaminophen component. Additionally, the medication is officially defined as an adjunct to rest and physical therapy for its indicated uses.


Q: What types of side effects are considered common but not serious?

According to the official safety profile, the most commonly reported effects are typically linked to the anticholinergic properties of the drug. These often include dry mouth, drowsiness (somnolence), dizziness, and blurred vision.


Q: Does Nabesac interact with any common anti-anxiety medications?

The medication has documented additive Central Nervous System (CNS) effects when co-administered with other CNS Depressants. The combined use may result in documented additive Central Nervous System (CNS) effects, such as increased sedation and drowsiness.

How should Nabesac be stored and disposed of?

How to Store and Dispose of Nabesac

Nabesac (Orphenadrine/Acetaminophen tablets) must be stored according to specific environmental and container requirements documented by regulatory bodies to maintain product integrity.


Storage Requirements

  • Temperature: Store the medication at room temperature and below 30 C (86 F). It is mandatory to keep the product from freezing.
  • Protection: The tablets must be protected from moisture, excess heat, and direct light. Do not store the medicine in high-moisture areas like a bathroom.
  • Container: Keep the medication in the original container and ensure the container is tightly closed at all times.

Child-Safety and Disposal

To prevent accidental ingestion, the medication must be stored out of the sight and reach of children, and any safety caps must be locked. Unused or expired Nabesac should not be kept. For proper disposal, consult a healthcare professional or return the product to a local pharmacy or authorized collection point for safe pharmaceutical waste handling.

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

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