Engflag

Tosen

Quick links to important sections

Tosen

Tosen_EN

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 Tosen

Property Description
Active ingredient Hexachlorophene, Tolnaftate
Form Topical preparation (Solution, Cream, Ointment)
Pharmacological class Antifungal-Antiseptic Combination
General purpose Broad-spectrum topical microbial control
Origin Synthetic

What Type of Medicine Is Tosen? (Identity and Classification)

Tosen is a fixed-dose combination product classified as an Antifungal-Antiseptic Combination, intended exclusively for external use as a topical preparation. This polycomponent drug is derived from synthetic chemical compounds and delivers a dual therapeutic scope directly to the skin surface. The formulation is clinically recognized for combining two distinct antimicrobial strategies in a single application. Tolnaftate, one of the active agents, belongs to the class of thiocarbamate antifungals, indicating its primary function is to inhibit the growth of fungi.

Composition and Physical Form of Tosen

The two active pharmaceutical ingredients are Hexachlorophene and Tolnaftate. Hexachlorophene is a chlorinated bisphenol compound, which is known for its antiseptic and bacteriostatic properties, effective against various surface bacteria. This combined approach is often utilized in scenarios where superficial fungal infections may be complicated by secondary bacterial contamination. Tosen is available in various dosage forms, such as a rapidly absorbing solution, a cream suitable for drier skin, or a barrier-forming ointment, with the specific base serving as the vehicle for efficient topical application.

General Function and Dual Action

The general purpose of Tosen is to provide comprehensive broad-spectrum topical defense by utilizing its dual mechanism of action. The Tolnaftate component provides a fungistatic effect, interfering with critical structural components of fungal organisms, thereby preventing their proliferation. Concurrently, the Hexachlorophene component restricts the survival and growth of surface bacteria. This combination ensures that the medicine addresses a wider range of potential microbial contaminants, supporting the maintenance of a controlled skin environment where both fungal and bacterial populations are inhibited.

What side effects are possible with Tosen?

Possible Side Effects and Safety Information

The official safety profile for Tosen (Hexachlorophene and Tolnaftate topical combination) is categorized by local cutaneous reactions and critical safety constraints related to the potential systemic absorption of the antiseptic component. The most commonly documented adverse reactions are generally confined to the Skin and Subcutaneous Tissue Disorders category.

Documented Safety Characteristics

Safety Domain Regulatory Classification and Detail
Local Adverse Reactions Generally described as mild, local skin reactions such as reddening, burning, itching, or swelling at the application site. Frequency classifications for these effects are typically not specified in regulatory summaries.
Systemic Neurotoxicity Risk Classified as a serious adverse reaction associated with systemic absorption of Hexachlorophene. Signs of this toxicity include convulsions and clonic muscular contractions. This risk is explicitly linked to improper use or use on compromised skin.
Population-Specific Constraints Use is not recommended in infants and premature babies due to a heightened risk of absorption and associated neurotoxicity. Use on children under 2 years is generally not recommended unless medically directed.
Application Restrictions Strictly for external use. The product must not be applied to mucous membranes (e.g., eyes, mouth) or broken or burned skin due to the significantly increased risk of systemic absorption. Regular use on large areas of the body is also restricted.

Regulatory Safety Summary

Official safety documentation structures the risk profile by prioritizing the prevention of systemic exposure in vulnerable individuals and through defined usage limitations. While minor, localized skin irritation is the common experience, the key constraint is avoiding conditions that could lead to the absorption of Hexachlorophene, which carries the documented risk of severe neurotoxicity.

Overdose and Emergency Response

Overdose and When to Seek Help

The primary danger following an overdose is severe, delayed liver damage (hepatotoxicity), which can progress to fatal acute liver failure. Acute renal failure may also develop.

Immediate Actions

Urgent medical advice must be sought immediately following a suspected overdose, even if the person feels well. Initial symptoms are often non-specific and do not reflect the severity of internal organ damage. The maximum protective effect of the antidote, N-acetylcysteine, is achieved only if administered within eight hours of ingestion.

Documented Manifestations

Symptoms in the first 24 hours may include pallor, nausea, vomiting, abdominal pain, and general malaise. Clinical and laboratory evidence of liver injury may not appear until 12 to 48 hours after ingestion, presenting as upper quadrant pain, metabolic acidosis, and abnormalities in glucose metabolism.

Risk Factors

Individuals with specific risk factors, such as chronic alcohol use, pre-existing hepatic impairment, or those who are severely malnourished (glutathione deplete), have an increased risk of severe liver damage following an overdose of 5 grams or more.

Therapeutic Uses of Tosen

Quick Facts: Tosen (Qalsody™)

  • Targeted Population: Adults who have Amyotrophic Lateral Sclerosis (ALS) associated with a superoxide dismutase 1 (SOD1) gene mutation.
  • Therapeutic Focus: Management of the condition in this specific patient group.

What Tosen treats: Main Uses and Benefits

Tosen, also known by the brand name Qalsody™, is a prescription medication utilized in the management of Amyotrophic Lateral Sclerosis (ALS), commonly referred to as Lou Gehrig's disease. Specifically, it is indicated for adults who have a confirmed mutation in the superoxide dismutase 1 (SOD1) gene.

Its clinical role is to address this specific genetic form of ALS, which is a progressive neurological condition. The use of Tosen may contribute to the reduction of certain biomarkers associated with the condition, such as plasma neurofilament light chain (NfL), which is a marker of neuronal damage. The therapeutic goal is to offer a mechanism for managing the progression of this ultra-rare, serious disease in individuals with the SOD1 mutation. Continued evidence may be required to confirm clinical benefit.

Eligibility and Restrictions for Use

Who Can and Cannot Use Tosen? (Qalsody / Tofersen)

The eligibility for Tosen is officially defined by regulatory authorities based on specific patient populations, age, and physiological status. The medicine is indicated for the treatment of Adults with Amyotrophic Lateral Sclerosis (ALS) who have a confirmed mutation in the superoxide dismutase 1 (SOD1) gene.

Eligibility Scope Official Regulatory Status
Populations for whom use is allowed Adults (geq 18 years) with confirmed SOD1 gene mutation.
Populations for whom use is contraindicated Patients with known hypersensitivity to the active substance or any excipients (EMA labeling). The US FDA label lists no contraindications.
Age-related restrictions Safety and efficacy have not been established in pediatric patients (below 18 years).
Use in Pregnancy/Lactation Use is not recommended during pregnancy or for women of childbearing potential not using effective contraception. Conditional decision required for use during lactation.
Eligibility-related restrictions Use has not been studied in patients with severe renal or hepatic impairment.

Connection to the overall eligibility profile:

Official regulatory documents establish a profoundly restrictive eligibility profile centered on the genetic requirement of the SOD1 gene mutation. This genetic criterion forms the primary constraint for use, alongside formal rules that exclude individuals based on hypersensitivity. Use is further limited in populations, such as pediatric patients and those with organ function issues, where efficacy and safety data are officially listed as not established or not studied.

What should I know about interactions with other medicines?

Interaction Map: Interactions with other medicines and products — official regulatory information for Tosen (Tofersen/Qalsody™)

Interaction scope

Medicinal product categories with documented interactions:

  • Other Intrathecal Medicinal Products (Co-administration safety unestablished)

Specific interacting medicines (if explicitly listed):

  • None explicitly listed as having a formal pharmacokinetic or pharmacodynamic drug-drug interaction.

Mechanistic basis of interactions (only if stated in label):

  • Tosen is officially stated as not being an inhibitor or inducer of Cytochrome P450 (CYP) enzymes, the primary pathway for oxidative metabolism of many drugs.
  • The medicine is also not a substrate or inhibitor of major drug transporters (e.g., P-gp).

Timing-based interaction rules (if applicable):

  • Must not be mixed: Tosen must not be physically co-mingled with any other medicinal products in the solution or administration equipment.

Population-specific interaction notes (if applicable):

  • None explicitly stated regarding altered interaction severity in specific populations such as hepatic or renal impairment.

Interaction-related restrictions:

  • The safety of co-administration with other intrathecal medicinal products has not been evaluated and is not established.
  • No known interaction with food or drinks is documented in the regulatory label.

Interaction classifications (high-level)

Interaction severity classification (as defined in official documents):

  • None of the evaluated co-administered drugs are formally labeled with a severity classification (e.g., contraindicated, major).

Regulatory basis (EMA / FDA / etc.):

  • Information is derived from FDA Prescribing Information and EMA Summary of Product Characteristics.

Interaction-context constraints (as defined in official documents):

  • Interaction testing focused on pharmacokinetic interference and physical solution compatibility.

Resulting interaction structure

Official interaction statements:

  • Tosen is not predicted to cause significant changes in the plasma concentrations of co-administered systemic medicines because it does not interfere with the major CYP enzyme pathway.
  • Co-administration with other intrathecal products is not evaluated and the safety of this practice is not known.
  • The medicine must not be physically mixed with any other product due to compatibility restrictions.

Connection to the overall interaction profile (2–4 sentences): The official regulatory profile primarily defines the product’s structure by the absence of expected systemic pharmacokinetic interactions with common enzyme and transporter systems. The main constraints documented are procedural, mandating that the medicine cannot be physically combined with other solutions and noting the unestablished safety of concurrent use with other products administered via the intrathecal route.

Mechanism of Action

How Tosen Works: Mechanism of Action

Tosen acts as an Antisense Oligonucleotide ( ASO), a molecule designed to target and bind specifically to the messenger RNA ( mRNA) that carries the template for the Superoxide Dismutase 1 ( SOD1) protein. This molecular action takes place within the cells of the central nervous system ( CNS).

The binding of Tosen to the mRNA recruits the cell’s native enzyme, Ribonuclease H ( RNase H). RNase H recognizes the resulting DNA/ RNA hybrid structure and initiates the rapid degradation of the SOD1 mRNA. This sequence of events prevents the mRNA from being translated into the SOD1 protein, resulting in a reduction in the production of the protein.

This decrease in the SOD1 protein level modulates the underlying biological process within the neurons. This molecular change is associated with a corresponding decrease in the levels of neurofilament light chain ( NfL), a measurable molecular component reflecting neuronal structure.

Dosage and Administration Information

How to Use Tosen (Tofersen) — Official Administration Guidelines

Tosen is administered exclusively by intrathecal injection, meaning the medicine is injected directly into the fluid surrounding the spinal cord (cerebrospinal fluid or CSF) through a lumbar puncture. This procedure must be performed by a healthcare professional experienced in lumbar punctures.

Dosing Schedule

Phase Dose Amount Frequency
Loading 100 mg (15 mL) Three doses, 14 days apart
Maintenance 100 mg (15 mL) Once every 28 days thereafter

Administration Procedure

  1. Preparation: The refrigerated single-dose vial must be allowed to warm to room temperature (25 C or 77 F) before use. The solution should be inspected and must not be shaken or diluted. Any unused portion must be discarded.
  2. CSF Removal: Prior to injecting the 15 mL dose, it is recommended that approximately 10 mL of CSF be removed through the lumbar puncture needle.
  3. Injection: The 15 mL dose is administered slowly as an intrathecal bolus injection over a period of 1 to 3 minutes.

Missed Doses

  • If the second loading dose is missed, it should be administered as soon as possible, and the third loading dose should then be given 14 days later.
  • If the third loading dose or any maintenance dose is missed, it should be administered as soon as possible, and the next scheduled dose should be given 28 days later.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Tosen

Evidence for Use in SOD1-ALS

Tosen (Tofersen) was studied for adults who have Amyotrophic Lateral Sclerosis (ALS) associated with a specific genetic change known as a Superoxide Dismutase 1 (SOD1) gene mutation. The research included short-term randomized, placebo-controlled trials (RCTs), followed by longer, uncontrolled open-label extension (OLE) studies, which collected outcomes. These studies examined outcomes reflecting daily functioning and changes in biological markers in patients with this rare genetic form of the condition.

Studies Focused on Functional Measures and Clinical Outcomes

The main research measured the change in a functional rating scale (ALSFRS-R) which is used in research exploring how symptoms change over time. The main controlled study did not meet the primary goal of showing a statistically significant change on the functional rating scale. The core research also monitored outcomes related to breathing, specifically the Slow Vital Capacity (SVC).

Studies Focused on Biomarkers and Genetic Targets

Research examined specific biological markers, including the SOD1 protein and plasma Neurofilament Light Chain (NfL). The findings describe patterns observed in the studies where there was a reduction in the concentration of both CSF SOD1 protein and the plasma NfL biomarker levels. This change in the biomarker was associated with the medicine’s accelerated approval pathway, with the reduction serving as a basis for the indication.

Long-Term Studies and Follow-up Data

The initial controlled research periods were limited to a short duration. Data show patterns where participants who received Tosen earlier in the OLE studies were observed to have a different rate of change in functional outcomes compared to those who started later. Certainty remains low when interpreting data from these long-term, uncontrolled settings, as other factors may influence the patterns observed.

Frequently Asked Questions (FAQ)

Common questions about Tosen (FAQ)

Q: Is the initial tiredness feeling after taking Tosen normal?

A: Fatigue is described in official product information for Qalsody (tofersen) as a very common adverse reaction observed in clinical studies. This means that tiredness is one of the more frequently reported effects associated with the medicine.

Q: What is considered a rare side effect of Tosen?

A: Official regulatory documents classify side effects by how often they occur, using designations such as very common, common, uncommon, or rare. For Tosen (Qalsody), a number of reactions are classified under the very common and common categories. The full list of these frequencies is provided in the complete regulatory information.

Q: Can Tosen be used by women who are breastfeeding?

A: Official prescribing information indicates that a conditional decision is required when considering the use of Qalsody (tofersen) while breastfeeding. This decision balances the potential benefit of the drug to the mother against the potential benefit of breastfeeding for the child.

Q: Can Tosen tablets be split or crushed?

A: Tosen is not available in a pill or tablet form. The administration guidelines for the injection and the instructions for the topical product forms (solution, cream, ointment) do not include any guidance for splitting or crushing the medicine.

Q: Does Tosen cause weight changes?

A: Official data from clinical trials for Qalsody (tofersen) does not include weight changes (gain or loss) among the adverse reactions classified as common or very common.

Q: Can Tosen cause sleep disturbances?

A: Sleep disturbances like insomnia are not listed among the common or very common adverse effects reported in the clinical trials for Qalsody (tofersen).

Q: What are the requirements for being eligible for Tosen treatment?

A: The primary eligibility requirement for Qalsody (tofersen) is that the patient must be an adult with a confirmed genetic mutation in the Superoxide Dismutase 1 (SOD1) gene. This genetic criterion is the primary constraint defined by regulatory authorities for the use of this medicine.

Q: What is the evidence for Tosen use in pediatric patients?

A: The safety and effectiveness of Qalsody (tofersen) have officially not been established for pediatric patients (individuals under 18 years old). Separately, the topical form of Tosen is generally not recommended for children under 2 years due to specific safety constraints.

Q: Is Tosen used for pain relief?

A: Tosen is indicated for treating adults with a specific type of Amyotrophic Lateral Sclerosis (SOD1-ALS) in its injectable form. The topical formulation is used as an antifungal and antiseptic combination. Neither of the official regulatory indications is for primary pain relief.

Q: Are there any known issues with taking Tosen long-term?

A: The approval for Qalsody (tofersen) is conditional, pending the results from ongoing confirmatory trials that are required to verify the clinical benefit over time. These long-term studies continue to collect safety and effectiveness data.

Q: How long does it usually take to see an effect from Tosen?

A: In research studies of Qalsody (tofersen), a reduction in the plasma NfL biomarker was observed in participants as early as 12 to 16 weeks after initiating therapy. This biomarker is used in research to reflect changes in neuronal structure.

Q: Is Tosen a drug you take for a long period of time?

A: The official product information for Qalsody (tofersen) describes an ongoing maintenance schedule following an initial series of loading doses. The maintenance phase involves administration once every 28 days.

Q: Is Tosen the same as [Drug X] or a generic version?

A: Tosen (Qalsody) is an approved brand-name medication known scientifically as tofersen. It is classified as an Antisense Oligonucleotide (ASO) and is not currently available as a generic version.

Q: Does Tosen interact with common over-the-counter cold medicines?

A: Official interaction testing indicates that Qalsody (tofersen) is not expected to interfere with the body's major enzyme system, the CYP enzymes. This means it is generally not predicted to significantly alter the systemic concentration of other co-administered medicines, including most over-the-counter cold remedies.

Q: What are the key signs of a serious Tosen interaction?

A: Official documents list specific serious reactions associated with Qalsody (tofersen) administration. These include conditions like myelitis (spinal cord inflammation), aseptic meningitis, radiculitis, and elevated intracranial pressure, which may present as papilledema.

Q: Can Tosen be taken with daily blood pressure medication?

A: Regulatory information states that Qalsody (tofersen) does not interfere with the major enzyme system that metabolizes most drugs (CYP enzymes). Therefore, it is not generally expected to cause significant changes in the blood concentrations of co-administered systemic medicines, such as blood pressure drugs.

Q: Does Tosen affect your ability to drive or operate machinery?

A: The official product information for Tofersen (Qalsody) states that the medicine has only a minor influence on a person’s ability to drive or use machinery.

Q: Does Tosen have a black box warning?

A: The FDA approved the drug's labeling for Qalsody (tofersen) without including a Boxed Warning (also known as a Black Box Warning).

Q: Is Tosen a recently approved drug?

A: Qalsody (tofersen) is a relatively recent drug, having received approval through the FDA's accelerated approval pathway in April 2023.

Q: What kind of research is currently being done on Tosen?

A: Ongoing research includes the Phase 3 ATLAS trial, which is an open-label, randomized study. This trial is investigating the use of Qalsody (tofersen) in adults who have the SOD1 mutation but have not yet developed symptoms of ALS.

Q: Does Tosen interact with caffeine?

A: Regulatory interaction data suggests that Qalsody (tofersen) is not expected to interfere with the major enzyme pathway (CYP enzymes) that metabolizes many systemic compounds. Therefore, it is not predicted to significantly alter the blood concentrations of caffeine or other co-administered systemic medicines.

Q: What is the typical duration of treatment with Tosen?

A: Following the initial loading dose period, the treatment schedule for Qalsody (tofersen) is defined by a continuous maintenance dose administered once every 28 days.

Q: Are there specific mental health side effects associated with Tosen?

A: Official safety documentation for Qalsody (tofersen) lists neurological events like aseptic meningitis and radiculitis, but specific mental health disorders such as anxiety or depression are not listed among the common adverse reactions.

Q: Is Tosen only available in pill form?

A: Tosen is not available in a pill or tablet form. The injection (Qalsody) is an administered solution, and the topical product is available as a solution, cream, or ointment.

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

A: The official administration schedule for Qalsody (tofersen) is defined by 14-day and 28-day intervals between doses. There is no requirement specified in the schedule for the medicine to be administered at a specific time of day.

Q: Is Tosen commonly prescribed outside of the US?

A: The medicine (Qalsody/tofersen) has received regulatory approval from authorities outside of the US, including the European Medicines Agency (EMA), indicating its availability and use in the European Union.

Q: Are there any known issues with generic versions of Tosen?

A: Qalsody (tofersen) is an approved brand-name medication. Since there is currently no approved generic version of this medicine, there are no known issues regarding generic-to-brand substitution.

Q: How often should liver function be checked when taking Tosen?

A: Regulatory information does not mandate or recommend routine liver function testing during Qalsody (tofersen) treatment. However, the medicine has not been studied in patients with severe hepatic (liver) impairment.

Q: Is there a maximum recommended age for Tosen use?

A: Qalsody (tofersen) is indicated for use in adults. The official prescribing information defines the eligible population by a minimum age (18 years) but does not list a specific maximum age limit.

Q: Can I use Tosen if I have a history of heart problems?

A: Official prescribing information for Qalsody (tofersen) does not list heart problems or cardiovascular issues as a formal contraindication or specific warning.

Q: Does Tosen interact with common pain relievers like ibuprofen?

A: Interaction studies indicate that Qalsody (tofersen) is not expected to interfere with the major enzyme pathway (CYP enzymes) that metabolizes many systemic drugs. Therefore, it is generally not predicted to significantly alter the blood concentrations of common pain relievers like ibuprofen.

Q: How long does Tosen stay in your system after the last dose?

A: Regulatory documents include detailed information on the medicine's pharmacokinetic properties, such as its concentration levels in the cerebrospinal fluid and plasma over time. However, the label does not provide a single, simple number for the duration the medicine remains in the system.

Q: Is it necessary to gradually stop taking Tosen if discontinuing treatment?

A: The official administration guidelines for Qalsody (tofersen) provide instructions for managing missed doses but do not include specific regulatory requirements or instructions for tapering off the drug if treatment is discontinued.

Q: Does Tosen affect fertility?

A: According to the official regulatory documents for Qalsody (tofersen), there are currently no data available concerning the potential effects of the medicine on human fertility.

Q: Is Tosen a steroid?

A: Official classification documents confirm that Qalsody (tofersen) is an Antisense Oligonucleotide (ASO). It is not classified as a steroid medicine.

Q: Does Tosen affect blood sugar levels?

A: Official safety information for Qalsody (tofersen) does not list common adverse reactions related to blood sugar levels, such as hyperglycemia or hypoglycemia.

How should Tosen be stored and disposed of?

The official storage and disposal guidelines for Tosen (tofersen) injection must be strictly followed.

Storage Requirements

Unopened vials must be stored under refrigeration between 2 C and 8 C (36 F and 46 F); the product must not be frozen and must be protected from light by remaining in its original carton. Once removed from the refrigerator, the unopened vial has a limited stability period before administration. Tosen must be stored out of the sight and reach of children.

Disposal Instructions

Any unused portion of the single-dose vial must be discarded. The medicine must not be disposed of via wastewater or household waste and disposal must adhere to local requirements for medicinal products to ensure environmental safety.

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

Available in countries:

flagTaiwan

Equivalent of Tosen found in:

A-Z Index: