DTO

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DTO

Method of action: Antiprotozoal

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 DTO

Quick Facts: DTO (Ofloxacin and Ornidazole)

Property Description
Active Ingredients Ofloxacin and Ornidazole
Form Oral Tablet (Fixed-Dose Combination)
Pharmacological Class Broad-Spectrum Combination Antimicrobial
General Purpose Targeting susceptible bacteria and protozoa
Origin Entirely Synthetic

What Type of Medicine is DTO (Ofloxacin and Ornidazole)?

DTO is defined as a Fixed-Dose Combination (FDC) Antimicrobial Agent that requires a prescription for use. It is a chemically synthetic preparation delivered primarily as an Oral Dosage Form, typically a tablet. Pharmacologically, this medicine belongs to the Broad-Spectrum Combination Antimicrobial class. This FDC structure is designed to deliver both active compounds simultaneously, which helps support patient compliance and ensures a specific ratio of agents is consistently maintained, a unique characteristic compared to co-administering two separate drugs.


Composition of DTO: The Dual-Action Formulation

The medicine’s composition includes two key Active ingredients: Ofloxacin and Ornidazole. Ofloxacin is classified as a Fluoroquinolone Antibacterial, working to eliminate susceptible bacteria by interfering with their DNA replication machinery. The second component, Ornidazole, is a 5-nitroimidazole Antiprotozoal agent, which damages the cellular structures of susceptible protozoa and specific anaerobic bacteria. This formulation is used for its ability to treat infections where both bacterial and protozoal pathogens are implicated, such as complex gastrointestinal or gynecological infections. This dual mechanism provides a synergistic approach, which is crucial when facing the challenges of polymicrobial infections.


General Purpose of the Combination Antimicrobial

The general purpose of this Fixed-Dose Combination is to neutralize or eliminate infections caused by a combination of susceptible bacteria and protozoa. Since many complex diseases can be polymicrobial (involving both types of organisms), the strategic co-formulation ensures that both bacterial and protozoal elements are actively targeted at the same time. This comprehensive approach provides the general benefit of addressing the entire spectrum of suspected microorganisms implicated in a composite infection, thereby simplifying the therapeutic strategy for the prescriber. Popular brands utilizing this specific Ofloxacin and Ornidazole formulation often include Oflomac-Oz and Oflostar-Oz, underscoring the common therapeutic use of this combination across multiple geographies.

What side effects are possible with DTO?

Possible Side Effects and Safety Information for DTO

DTO is a prescription medication that combines two active components, Ofloxacin and Ornidazole, and has a defined safety profile derived from clinical data and post-marketing surveillance. This information is based on governmental regulatory documents.

Adverse Reaction Scope

Classification Common Examples of Adverse Reactions (Very Common / Common)
Gastrointestinal Nausea, vomiting, diarrhea, abdominal pain, loss of appetite, metallic taste in mouth.
Nervous System Headache, dizziness, insomnia, nervousness.
Skin / General Mild skin rash, itching, fatigue, fever.

Serious and Clinically Significant Adverse Reactions:

Regulatory documents emphasize the risk of Tendonitis and Tendon Rupture, a class-effect risk associated with fluoroquinolones (Ofloxacin component). This risk is elevated in patients over 60 years of age, those taking corticosteroids, and those with kidney, heart, or lung transplants.

Other serious risks include the potential for Seizures (particularly in those with pre-existing CNS disorders) and the worsening of Myasthenia Gravis due to neuromuscular blocking activity. Allergic reactions, including anaphylaxis, are also reported.

Safety-Related Restrictions and Monitoring

Contraindications: Use is restricted in patients with a history of hypersensitivity or severe allergic reactions to quinolones, nitroimidazoles, or any component of the formulation. The drug is generally contraindicated during pregnancy and breastfeeding.

Population-Specific Considerations: Caution is advised for use in pediatric patients (under 18) and older patients (over 60) due to increased susceptibility to serious side effects. Use requires caution in patients with liver impairment, kidney impairment, or G6PD deficiency.

Exposure- or Dose-Related Patterns: The combination may cause a disulfiram-like reaction (severe nausea, vomiting, etc.) when taken with alcohol, an interaction which persists for at least 48 hours after the final dose.

Overdose and Emergency Response

Overdose and when to seek help

Official regulatory information for DTO (Ofloxacin and Ornidazole) outlines specific manifestations and mandatory actions in cases of overdose, which require immediate medical attention.

Documented Overdose Manifestations

Overdose exposure is documented to cause significant effects on the Central Nervous System (CNS), including convulsions (seizures), loss of consciousness, tremor, confusion, and somnolence. Gastrointestinal symptoms such as nausea and vomiting may also be severe. Serious systemic outcomes cited in regulatory warnings include the risk of QT interval prolongation (a serious heart rhythm abnormality), liver failure, and severe hypoglycemia (low blood sugar), which can lead to coma, particularly in the elderly or those with diabetes. The potential for tendon rupture or aortic rupture is also a documented concern for the Ofloxacin component.

Official Emergency Actions

Regulatory authorities mandate that if an overdose is suspected, individuals must seek immediate medical attention and go to the closest hospital emergency department. Because no specific antidote is known, the required management approach involves providing symptomatic and supportive treatment. Due to cardiac risk, ECG monitoring should be undertaken. Patients are instructed to bring the medicine label with them to aid medical professionals. Immediate help is required for severe symptoms such as unmanageable confusion, seizures, or sudden severe chest, stomach, or back pain.

Therapeutic Uses of DTO

What Dextromethorphan (DTO) Treats: Main Uses and Benefits

Dextromethorphan (DTO) is generally an ingredient commonly used to help with symptoms related to physical discomfort, specifically as an antitussive (cough suppressant). DTO is applied across domains where additional symptomatic support is needed to temporarily ease coughs. Its use is relevant in conditions characterized by periods of heightened symptoms, such as those accompanying the common cold or flu.


DTO primarily helps address symptom clusters that may become intense or disruptive. It is applied in scenarios where additional management of discomfort is required for short-term symptomatic assistance, and is relevant when supportive symptom management is appropriate. This supports the patient during difficult episodes by easing distress from a persistent cough. DTO is commonly used to help with short-term, acute coughs and may assist with maintaining functional stability.

The goal of its use contributes to improved comfort during symptomatic periods and may help patients cope more steadily with symptom fluctuations.

Quick Fact: Relief for Acute Cough

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Eligibility Profile: Who Can and Cannot Use DTO

This section defines the official population eligibility and non-eligibility for DTO, based strictly on authoritative governmental regulatory documents (e.g., FDA Prescribing Information, EMA Summary of Product Characteristics).

Non-Eligible Populations (Contraindications)

Individuals must not use DTO if they have an absolute contraindication, which includes:

  • A known hypersensitivity or allergic reaction to the active substance or any of the product’s inactive ingredients (excipients).
  • Any specific, high-risk medical condition that is explicitly listed as a contraindication in the regulatory labeling (e.g., severe, uncontrolled organ failure).

Restricted and Conditional Use

Use of DTO is restricted or requires specific precautions and monitoring in several populations:

  • Age: The medicine is not authorized for use in pediatric patients (typically under 18 years of age) because safety and effectiveness have not been established in this group.
  • Organ Function: Patients with moderate to severe hepatic or renal impairment may require close clinical monitoring or, in severe cases, the medicine is not recommended due to altered drug clearance.
  • Pregnancy and Lactation: Use during pregnancy and breastfeeding is generally not recommended unless a regulatory-defined risk-benefit assessment dictates otherwise. A decision must be made to discontinue the medicine or discontinue breastfeeding.

Eligible Population

DTO is authorized for use in adults (age 18 and older) who do not have any documented contraindications or conditions requiring restriction.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The official interaction profile for Ofloxacin/Ornidazole is governed by potential pharmacokinetic and pharmacodynamic effects from both active components. This information is derived exclusively from regulatory documents.

Pharmacokinetic (PK) Interactions and Timing Rules

Co-administration with multivalent cations (e.g., iron salts, magnesium/aluminum-containing antacids) significantly reduces the oral absorption of Ofloxacin. To strictly manage this absorption interference, these cation-containing products must not be taken within 2 hours before or after Ofloxacin administration. The Ornidazole component’s clearance may be reduced by agents like Cimetidine, which can lead to increased Ornidazole plasma levels. Conversely, co-use with drugs such as Phenobarbital or Phenytoin may be documented to reduce Ornidazole's half-life. The excretion of Acamprosate can also be decreased by Ofloxacin.

Pharmacodynamic (PD) and Regulatory Restrictions

The combination carries documented risks of additive effects. Ofloxacin co-administration with NSAIDs or drugs that prolong the QT interval (e.g., Class IA and III antiarrhythmics) may potentiate the risk of CNS toxicity or cardiac rhythm changes. Ornidazole potentiates the effect of coumarin-type oral anticoagulants (e.g., Warfarin), an effect requiring clinical awareness. A mandatory restriction exists: Alcohol (Ethanol) is prohibited during treatment and for a minimum of three days after discontinuation due to the risk of an Ornidazole-related disulfiram-like reaction. Caution is officially noted for administering the combination in patients with hepatic or renal insufficiency, as altered clearance may heighten interaction severity.

Mechanism of Action

The fixed-dose combination (DTO) targets susceptible microbes through two distinct and complementary molecular pathways, defining the pharmacodynamic scope against a broad range of pathogens.


DNA Gyrase Inhibition in Susceptible Bacteria

The Ofloxacin component acts as an inhibitor of DNA Gyrase and Topoisomerase IV, two essential bacterial enzymes responsible for managing DNA structure during replication and repair. Ofloxacin stabilizes the enzyme-DNA complex, causing irreversible double-strand breaks in the bacterial chromosome. This mechanism arrests all core genomic functions, resulting in the cessation of bacterial cell viability.


Free Radical DNA Damage in Anaerobes and Protozoa

The Ornidazole component requires bioactivation by specific microbial nitroreductase enzymes found in susceptible anaerobic bacteria and protozoa. This reduction process generates highly cytotoxic free radicals which chemically attack and fragment the pathogen's nucleic acids. This direct chemical damage causes irreparable structural failure and loss of cell viability in the anaerobic and protozoal organisms.


Orthogonal Mechanistic Complementarity

The combination utilizes these two orthogonal mechanisms: one relying on enzymatic inhibition against aerobic/facultative bacteria, and the other relying on chemical free radical damage against anaerobic bacteria and protozoa. This dual, non-overlapping action results in a comprehensive mechanistic coverage against polymicrobial pathogens, thereby establishing the pharmacodynamic scope of the combination.

Dosage and Administration Information

How to Use Ofloxacin and Ornidazole FDC: Administration Guidelines

This section describes the standardized administration of the Ofloxacin and Ornidazole Fixed-Dose Combination (FDC) antimicrobial.


Core Administration Protocol

The approved route for this medicine is strictly oral use, typically administered as a film-coated tablet. The usual adult regimen involves taking one fixed-dose unit twice daily (e.g., every 12 hours), ensuring consistent scheduling for the duration of the prescribed course. Standard instructions indicate that the tablet must be swallowed whole with liquid and should not be crushed or chewed, a requirement tied to maintaining the intended delivery of both active ingredients. Dosing is generally permitted with or without food.


Dosage Duration and Adjustments

The Ofloxacin and Ornidazole FDC is used for a fixed, short-course treatment, often ranging from 5 to 10 days, with the entire course required for completion as specified in the prescription.

Population-specific adjustments are required for certain patients. Dose modifications or extended intervals are typically necessary for individuals with severe renal or hepatic impairment to manage how the body processes the respective components. For instance, the Ofloxacin component, being largely renally excreted, requires caution and adjustment in severe renal dysfunction. In the event of a missed dose, the dose should be taken immediately unless it is close to the next scheduled time, in which case the user should skip the missed dose and resume the regular schedule; double doses must not be taken to compensate. These instructions define the standardized, time-dependent approach to using the FDC.

Recent Clinical Evidence

Research evidence / Overview of studies for DTO (Dextromethorphan)

This section summarizes the type of research that has been conducted on DTO, which was studied in the context of cough outcomes related to physical discomfort often associated with the common cold. The text focuses only on the research structure and reported patterns, without giving clinical advice or making statements of certainty about the medicine's performance.


Evidence for use in Acute Cough

Research into DTO for cough associated with the common cold has primarily relied on short-term, placebo-controlled Randomized Controlled Trials (RCTs) and Systematic Reviews. These studies monitored measurements of cough frequency and patient-reported outcomes describing perceived discomfort. Studies focused on outcomes over a few hours post-dose or up to seven days. Some adult trials reported measurements that sometimes differed from placebo in some analyses. However, the findings were mixed across systematic reviews. Many researchers noted difficulty separating the measured difference from the significant placebo effect. Overall, the available evidence contributes to understanding symptom patterns but is characterized as having low certainty.


Comparisons with Placebo and Measured Outcomes

Research examined DTO by comparing it directly against an inactive placebo. Studies monitored specific outcomes such as measurements of cough frequency and subjective ratings of cough effort or intensity. Systematic reviews reported that DTO research has historically been heterogeneous, meaning the studies used different methods, and evidence quality varies across studies. Some research explored whether DTO differed from other antitussive agents, but findings related to comparative effects were mixed.


Long-term Studies and Durability of Effect

Since DTO was studied in the context of acute cough, most research studies explored only short-term symptom changes. Follow-up durations were limited, typically lasting only a few days or hours. There is limited information for long-term outcomes or the durability of any observed effects. Research does not provide insight into whether any observed short-term changes would be sustained over weeks or months.


Evidence in Special Populations

DTO was evaluated in specific age groups, primarily adults and a defined group of pediatric patients (children aged 6 to 11 years). Research highlights that the data for certain groups remain insufficient. For instance, the data for DTO in very young children (typically those under 6 years of age) are not fully established by systemic clinical trials.


Summary of Evidence Consistency and Research Gaps

The research evidence for DTO contributes to the broader evidence landscape, but it clearly highlights areas where certainty remains low. Key gaps include: evidence quality varies across studies; subgroup findings are uncertain regarding how people with different levels of cough severity may respond; and comparative evidence is lacking for many potential alternatives. Overall, the available evidence highlights what is known—and what is still uncertain—about the research base for DTO in acute cough.

Key Studies & References

  1. Systemic review of randomized controlled trials of over the counter cough medicines for acute cough in adults (BMJ)
  2. Objective and self-reported evidence of dextromethorphan antitussive efficacy in children, aged 6-11 years, with acute cough due to the common cold (Pediatric Pulmonology)
  3. Summary of the evidence: Cough (acute): antimicrobial prescribing (NICE Guidance NG120)
  4. Dextromethorphan: MedlinePlus Drug Information

Frequently Asked Questions (FAQ)

Common questions about DTO (FAQ)


Q: How quickly does DTO typically start working?

A: Official information indicates that the Ofloxacin component reaches its highest concentration in the bloodstream approximately one to two hours after a dose is taken orally. This time frame gives an idea of the drug's absorption profile. The time it takes to see an overall resolution of the infection can vary based on the specific condition being treated.


Q: What are the most common reasons a doctor prescribes DTO?

A: Regulatory documents state that this fixed-dose combination is officially indicated for the treatment of infections caused by susceptible bacteria and protozoa. This often includes cases of mixed infections, such as those found in the gastrointestinal tract or female reproductive system, where both types of organisms may be involved.


Q: Can DTO affect sleep patterns?

A: According to the official product information, adverse reactions involving the nervous system have been reported. These include insomnia (difficulty sleeping) and nervousness. If a person experiences a change in sleep patterns, official guidance is available through a healthcare professional.


Q: Is DTO considered a long-term treatment option?

A: The official administration protocol describes this medicine as a fixed, short-course treatment, typically used for a period ranging from 5 to 10 days. Treatment should generally not exceed two months. It is not intended for continuous or chronic long-term use.


Q: Are there any known food or drink interactions with DTO?

A: Official instructions indicate that the medicine is generally permitted to be taken with or without food. However, regulatory documents state that products containing multivalent cations (like iron supplements or some antacids) must be managed to avoid administration within two hours of DTO, as this can reduce the absorption of the Ofloxacin component.


Q: Can older adults typically use DTO?

A: DTO is authorized for use in adults, including older adults. However, official warnings advise that patients over 60 years of age should use caution due to an increased susceptibility to serious side effects; for instance, the risk of tendon-related issues is noted to be elevated in this population.


Q: Is DTO available as a generic version?

A: Yes, official governmental drug listings in various jurisdictions confirm that fixed-dose combinations containing both Ofloxacin and Ornidazole are available under multiple generic brand names, in addition to any existing brand names.


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

A: The time it takes for half of the drug to be eliminated from the body is known as the half-life. The Ofloxacin component's half-life is described in official documents as approximately 4 to 5 hours following multiple oral doses. This pharmacokinetic data helps guide the standard dosing frequency.


Q: Is DTO a controlled substance?

A: No, according to the official classification systems used by major regulatory bodies, the Ofloxacin and Ornidazole Fixed-Dose Combination is not listed as a scheduled controlled substance.


Q: Are there restrictions on driving while taking DTO?

A: Official product information notes that the medicine may cause adverse reactions such as dizziness or confusion in some users. Because these effects could potentially impair alertness, users should be aware of this risk when taking DTO.


Q: Does taking DTO require any special precautions or preparations?

A: Yes, regulatory documents list several special precautions. For example, official precautions include the need to manage sun exposure due to the potential for photosensitivity (increased sensitivity to sunlight), and caution is necessary if a patient has a history of certain central nervous system disorders.


Q: Can DTO interact with birth control pills?

A: Official regulatory guidelines have not documented a significant interaction between fluoroquinolone antibiotics, such as the Ofloxacin component, and combined hormonal contraceptives (birth control pills) that reduces their effectiveness.


Q: What is the purpose of the initial testing described before starting DTO?

A: While specific testing is not universally required, official labeling advises caution in or contraindicates use for patients with severe organ impairment (liver or kidney) or certain genetic conditions, such as G6PD deficiency. These warnings suggest that baseline laboratory testing may be required in some cases to assess the patient's eligibility and monitor organ function.


Q: What is the safety profile of DTO compared to a placebo in studies?

A: Clinical trial data reported that adverse reactions were generally non-serious and reversible when compared to the study control group. The most frequent occurrences included nausea, headache, dizziness, and insomnia.


Q: How is DTO generally classified by regulatory bodies?

A: Official systems classify DTO as a fixed-dose combination antimicrobial agent. This means it strategically combines two different types of agents: a fluoroquinolone antibacterial (Ofloxacin) and a nitroimidazole antiprotozoal (Ornidazole).


Q: Are there different forms (tablet, liquid) of DTO available?

A: The medicine is officially manufactured and regulated primarily as a fixed-dose combination oral tablet.


Q: How do official sources describe the expected outcomes when using DTO?

A: Official sources describe the expected outcome as the successful elimination or neutralization of the susceptible pathogenic bacteria and protozoa. This action is intended to resolve the polymicrobial infection for which the medicine is prescribed.


Q: What are the described circumstances where DTO might be discontinued?

A: Official documentation outlines the need to stop immediately in case of serious adverse reactions, such as tendon pain, severe or persistent diarrhea (indicating C. difficile infection), or signs of an allergic reaction.


Q: How is DTO eliminated from the body?

A: The Ofloxacin component is primarily eliminated from the body by the kidneys. This renal (kidney) elimination pattern is why dose adjustments and monitoring may be required for patients who have severe kidney impairment.


Q: What age groups are typically included in the research for DTO?

A: Clinical trials for the components of DTO have primarily included adult populations (18 years and older). However, research for its indicated uses has also involved defined groups of pediatric patients (typically those over 6 years old).


Q: Can I stop taking DTO suddenly?

A: Regulatory instructions define that the full course must be completed as prescribed to ensure effectiveness. Abrupt cessation is typically described only when serious adverse reactions occur.


Q: What is the official brand name of the drug DTO?

A: This specific combination of Ofloxacin and Ornidazole is marketed under various official brands depending on the regulatory region. Examples of common official brands include Oflomac-Oz and Floxyl-O.


Q: What kind of side effects are possible with DTO?

A: Official documents list adverse effects ranging from common to serious. Common effects include temporary issues like nausea, vomiting, diarrhea, headache, and insomnia. Serious risks that require immediate medical attention are listed, such as the potential for tendon rupture or seizures.


Q: Is it necessary to have blood tests while taking DTO?

A: The official labeling advises close clinical monitoring for patients with severe kidney or liver impairment. While not all patients require them, this monitoring often necessitates baseline and follow-up blood tests to track organ function and ensure the drug is cleared correctly.


Q: What research studies are available on DTO?

A: Official research is based on studies such as short-term, placebo-controlled Randomized Controlled Trials (RCTs) and Systematic Reviews. These studies examine outcomes like pathogen elimination and patient-reported symptoms related to the infection.


Q: Is DTO intended to cure a condition or manage symptoms?

A: DTO is an antimicrobial agent, meaning its primary intent is to eliminate the susceptible pathogenic organisms (bacteria and protozoa) that cause the infection, rather than simply managing symptoms.


Q: What are the non-drug-related conditions that might prevent someone from using DTO?

A: Official documentation identifies pre-existing medical conditions that may restrict use. These include specific neurological disorders (like a history of seizures), severe renal or hepatic impairment, and G6PD deficiency.

How should DTO be stored and disposed of?

Storage and Disposal Map: DTO (Dextromethorphan) Official Regulatory Information

Item Requirement (Strictly Regulatory)
Labeled storage temperature requirements Store at room temperature (e.g., 15 C to 30 C / 59 F to 86 F).
Light/moisture protection requirements Keep away from excess heat and moisture. Do not store in high-humidity areas, such as the bathroom.
Handling requirements Liquid formulations must not be frozen.
Packaging-related storage rules Keep in the original container, which must remain tightly closed.
Disposal instructions Do not flush the medication down the toilet unless the label specifically instructs this action. If a take-back program is unavailable, mix the unused product with an undesirable substance (e.g., dirt) and place in a sealed container before discarding in household trash.
Child-protection storage requirements Must be stored out of the sight and reach of children and pets, utilizing a child-resistant cap.

Official regulatory documents define the storage profile for DTO by mandating room temperature and protecting the product from excess heat and moisture to maintain stability. The handling profile is structured around child safety, requiring the medicine be stored in its tightly closed, original container, out of children's reach. The required disposal method stipulates that the product should not be flushed and must be made unappealing before being placed in household waste, consistent with government guidance for unused medicine disposal.

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

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