Ottoprim

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Ottoprim

What is Ottoprim? A Concise Overview

Property Description
Active ingredients Sulfamethoxazole and Trimethoprim
Form Tablet, Oral Suspension, and Intravenous Solution
Pharmacological class Antibiotic / Antifolate Antibacterial Agent
Common purpose Systemic resolution of bacterial infections
Origin Fully Synthetic

What Type of Medicine is Ottoprim (Co-trimoxazole)?

Ottoprim is a brand name for the fixed-dose combination generic medicine Co-trimoxazole (INN), a fully synthetic antimicrobial agent used for the systemic treatment of bacterial infections. This combination is officially classified as an Antifolate Antibacterial Agent, a designation reflecting its activity against a broad spectrum of susceptible organisms. The two active components, Sulfamethoxazole and Trimethoprim, are combined to ensure a potent therapeutic outcome. Ottoprim, along with other common brands such as Bactrim and Septra, is a prescription-only (Rx) medication.

Composition: What is Ottoprim Made of?

The medicine is composed of two primary active ingredients that work in concert: Sulfamethoxazole, which belongs to the sulfonamide class, and Trimethoprim, a diaminopyrimidine. Combining these two structurally different substances achieves a unique synergistic effect that enhances antimicrobial activity. The final preparation is available in multiple dosage forms, including the tablet and oral suspension for oral use, and a dedicated aqueous solution designed for intravenous administration in settings requiring rapid delivery of the anti-infective agents.

General Purpose and Mechanism: Why is this Combination Used?

The fundamental purpose of this fixed combination is to ensure a reliable bactericidal effect, which actively eliminates bacteria, rather than relying on the growth-inhibiting effect of either agent used alone. This action is achieved through a controlled sequential blockade of the bacteria's essential metabolic pathway. This dual-target strategy maximizes the drug's effectiveness, making it an agent for the general purpose of resolving infections throughout the body, such as complicated urinary tract infections.

What side effects are possible with Ottoprim?

Possible Side Effects and Safety Information

This section summarizes the officially documented adverse reactions and safety information for Ottoprim, strictly as classified in authoritative government regulatory documents.

Serious and Clinically Significant Adverse Reactions

The safety profile highlights the potential for Serious Cutaneous and Systemic Hypersensitivity Reactions, including life-threatening conditions such as Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Additionally, Hematologic (Blood) Disorders are a key concern, encompassing serious conditions like agranulocytosis, aplastic anemia, hemolytic anemia, and thrombocytopenia.

Acute Hepatic Necrosis/Failure and Acute Renal Failure are also documented as rare but serious adverse reactions.

Frequency-Classified Adverse Reactions

Adverse reactions are classified by frequency based on regulatory standards:

  • Very Common: Includes hyperkalemia (high potassium levels in the blood).
  • Common: Includes gastrointestinal issues (nausea, vomiting), headache, and skin rash.
  • Uncommon: Includes diarrhea and fungal infections.
  • Rare: Includes severe skin reactions, severe blood disorders, liver toxicity, depression, and megaloblastic anemia.

Population-Specific Safety Considerations

The medicine's regulatory safety profile identifies certain patient groups as being at increased risk of severe effects:

  • Elderly Patients are at a higher risk of serious adverse reactions, particularly blood dyscrasias and electrolyte imbalances.
  • Individuals with severe renal or hepatic impairment are subject to regulatory contraindications or requirements for extreme caution.
  • Patients with pre-existing folate deficiency have an increased risk of developing megaloblastic anemia, which may be reversible with folinic acid.

Safety-Related Restrictions

Official documents mandate caution regarding photosensitivity, warning of increased skin sensitivity to sunlight. Monitoring of blood cell counts, renal function, and serum potassium levels is required during treatment, especially for high-risk patients, to manage documented internal risks.

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory information describes both acute and chronic manifestations of Ottoprim (Co-trimoxazole) overdose. Acute overexposure may present with gastrointestinal symptoms, including nausea, vomiting, and diarrhea, along with neurological signs like dizziness, headache, and confusion. Chronic, high-dose overdosage is officially associated with severe hematological toxicity, notably bone marrow depression leading to leukopenia and thrombocytopenia, and megaloblastic anemia.

Documented Severe Outcomes and Required Actions

The regulatory profile highlights the potential for life-threatening outcomes affecting key systems. These include hyperkalemia (high potassium levels) due to the Trimethoprim component and severe renal complications from Sulfamethoxazole, such as crystalluria and potential acute renal failure.

Upon any suspicion of overdose, the official mandate requires individuals to seek immediate medical attention and contact emergency services. The regulatory documentation states that no specific antidote is known for acute overdose; therefore, management is symptomatic and supportive.

Supportive measures officially documented include procedures like gastric lavage or administration of activated charcoal if ingestion was recent. Patients are required to undergo close monitoring of vital parameters, including serum potassium levels and renal function. For chronic toxicity, the administration of leucovorin (folinic acid) is described as necessary to counteract specific adverse effects.

Therapeutic Uses of Ottoprim

What Ottoprim Treats: Main Uses and Benefits

Easing the Burden of Uro-Genital Pain and Discomfort

The active ingredients in Ottoprim are commonly used in the symptomatic management of acute bacterial infections across various body systems. This combination is relevant for easing symptoms associated with conditions such as urinary tract infections (UTIs), acute exacerbations of chronic bronchitis, and specific gastrointestinal illnesses like traveler's diarrhea and Shigellosis.

It is frequently applied in clinical settings that involve acute or unstable symptom patterns, including those where painful urination or pronounced respiratory distress create noticeable physiological strain. The medication supports the management of these episodes, particularly where the infection is caused by susceptible bacteria.

This supportive therapy contributes to easing the overall symptom load and may help patients cope more steadily during periods of heightened symptoms. The drug is considered relevant for managing severe opportunistic conditions, such as Pneumocystis jirovecii pneumonia (PJP) prophylaxis in immunocompromised individuals.


Quick Fact: Relief for Painful Symptoms Ottoprim assists with managing symptoms related to inflammatory or irritative states, such as the dysuria (painful urination) linked to lower UTIs and the severe watery stools experienced in acute bacterial diarrhea, supporting general well-being during symptomatic phases.

Eligibility and Restrictions for Use

Ottoprim (Co-trimoxazole) eligibility is strictly defined by regulatory documents, distinguishing between approved use, conditional use, and absolute contraindications. Approved use generally extends to adults and pediatric patients two months of age and older.


Eligibility Scope

Eligibility Status Population or Condition
Allowed Adults and children ge 2 months
Not Recommended Severe renal impairment ( CrCl < 15 mL/min)
Contraindicated Hypersensitivity to trimethoprim or sulfonamides

Official Eligibility Statements

  • Infants under two months of age are contraindicated due to the risk of kernicterus.
  • Use is contraindicated in patients with marked hepatic damage or severe, unmonitored renal insufficiency.
  • The medicine is contraindicated in patients with megaloblastic anemia due to folate deficiency and those with acute porphyria.
  • Use is contraindicated for pregnant patients and nursing mothers.
  • Older adults are advised to use this medicine with particular care due to increased susceptibility to adverse reactions, and dose adjustment is required for moderate renal impairment ( CrCl 15–30 mL/min).

What should I know about interactions with other medicines?

Ottoprim (Co-trimoxazole) has formally documented interaction patterns defined by specific pharmacokinetic and pharmacodynamic effects, as detailed in regulatory prescribing information.


Contraindicated Combinations

The co-administration of Ottoprim is contraindicated with certain medicines due to the high risk of severe adverse outcomes. This includes Dofetilide, as the combination significantly increases Dofetilide concentration, which poses a risk of serious ventricular arrhythmias. The use of Clozapine is also prohibited because of the increased danger of severe haematological reactions, such as neutropenia.


Interactions Affecting Drug Exposure

Co-trimoxazole is documented to alter the plasma levels of several substances. The combination increases the exposure of Warfarin through the inhibition of its metabolism, leading to a potentiation of its effect. Exposure to Phenytoin is also increased due to a prolonged half-life. Furthermore, Trimethoprim competes for the OCT2 renal transporter, causing a documented increase in the plasma concentrations of drugs like Metformin and Lamivudine. The combination may also increase Digoxin plasma levels, a finding noted particularly in elderly patients.


Pharmacodynamic Interactions

Ottoprim has additive effects with other substance classes. Co-administration with Methotrexate or high-dose Pyrimethamine carries a documented risk of megaloblastic anaemia due to combined anti-folate action. Combining the medicine with other drugs that cause hyperkalaemia, such as ACE inhibitors or Potassium-sparing diuretics, may result in clinically relevant hyperkalaemia.

Mechanism of Action

Sequential Blockade of Bacterial Folate Synthesis

Ottoprim, a fixed-dose combination of Sulfamethoxazole and Trimethoprim, utilizes a dual mechanism known as sequential blockade. This action specifically targets the bacterial folate synthesis pathway by inhibiting two essential enzymes in sequence. Sulfamethoxazole acts first, inhibiting dihydropteroate synthase ( DHPS). Trimethoprim acts subsequently, inhibiting dihydrofolate reductase ( DHFR). This coordinated molecular interference prevents the bacteria from producing tetrahydrofolic acid ( THF), an essential co-factor.


Selective Disruption of Nucleic Acid Precursors

The combined enzyme inhibition results in the failure to synthesize purines and ultimately DNA and RNA precursors. The mechanism is selective, favoring microbial targets because human cells utilize pre-formed folate and have structurally different enzymes. The resulting physiological effect is bactericidal—inducing microbial cell death by shutting down the ability to replicate and sustain cellular integrity. This function is biologically constrained in scenarios where bacteria can bypass the synthesis pathway by absorbing environmental folate or through genetic mutations in the target enzymes.

Dosage and Administration Information

How to Use Ottoprim

Ottoprim, a brand name for Co-trimoxazole (Sulfamethoxazole/Trimethoprim), is administered according to specific, standardized regimens. The medicine is available for oral intake (as tablets or suspension) and for administration via intravenous (IV) infusion. Intramuscular injection or rapid intravenous injection is not an approved route of administration.


Administration and Dosing Principles

Usage Aspect Standard Parameters
Standard Adult Frequency Twice daily (every 12 hours) is the usual schedule for acute infections.
Dosing Regimen The dose is typically based on the Double Strength (DS) tablet (800 mg SMX / 160 mg TMP) or calculated in mg per kg of body weight for children and for high-dose regimens.
Treatment Duration The course ranges from a short-term 5-day regimen for certain acute infections to an extended 14- to 21-day course for conditions like Pneumocystis jirovecii pneumonia (PJP) treatment.
Contextual Intake Should be taken with a full glass of water to maintain adequate fluid intake. The medicine may be taken with food to minimize gastrointestinal upset.
Dose Adjustments A 50% dose reduction or frequency adjustment is required for adult patients whose renal function is moderately impaired (CrCl 15 to 30 mL/min).

Preparation and Handling

The oral tablets should preferably be swallowed whole; they must not be chewed or crushed. The intravenous solution is a concentrate that must be diluted in a compatible fluid prior to infusion and administered slowly over a period of 60 to 90 minutes.

Recent Clinical Evidence

Ottoprim: Overview of Studies

This section describes the types of research and clinical trials conducted for Ottoprim (Co-trimoxazole), focusing on what studies explored and what remains uncertain according to the evidence.


Evidence by Key Indication

Ottoprim was studied for Urinary Tract Infections (UTI) primarily through Randomized Controlled Trials (RCTs). Research explored outcomes such as bacteriological eradication and symptom measurements over short periods. For Pneumocystis Jirovecii Pneumonia (PJP) prevention and treatment, the evidence is supported by Systematic Reviews and long-term cohort studies. These trials monitored critical endpoints, including changes in PJP incidence and measurements of mortality rates, mainly in the HIV-infected population.


Respiratory and Gastrointestinal Evidence

Comparative trials research examined Ottoprim for Acute Exacerbations of Chronic Bronchitis (AECB), where studies monitored symptom changes and bacteriological clearance. For specific gastrointestinal infections, research explored endpoints like measurements of acute diarrhea duration. A key limitation across all infectious disease studies is the widespread emergence and increase in antimicrobial resistance, which affects the current applicability of historical findings.


Research Gaps and Special Populations

Evidence for use in specific patient groups was evaluated in studies focusing on pediatric patients (over two months) and individuals with renal impairment. However, follow-up durations were limited in many key trials, and long-term effects are not fully established. The majority of high-quality, long-term evidence is concentrated in specific patient groups, and data for certain subgroups remain insufficient, illustrating where additional research is needed.

Key Studies & References

  1. Sulfamethoxazole and Trimethoprim (Composition and Mechanism, NCBI Bookshelf)
  2. Sulfamethoxazole and Trimethoprim (Pharmacological Class, MedlinePlus)

Frequently Asked Questions (FAQ)

Common questions about Ottoprim (FAQ)

Q: How quickly does Ottoprim start working after the first use?

According to official product information, the active ingredients in Ottoprim are rapidly absorbed into the bloodstream after taking the medicine by mouth. Peak concentrations of the drug in the blood are typically reached within 1 to 4 hours of administration, indicating when it begins to exert its therapeutic action.

Q: How long do the effects of Ottoprim typically last?

The duration of the medicine's effect is related to how long the active components stay in the body, a measure known as the half-life. Official regulatory documents indicate that the mean half-life for both Sulfamethoxazole and Trimethoprim is generally 8 to 10 hours. This pharmacokinetic information helps determine the standardized dosing frequency used by healthcare providers.

Q: Does Ottoprim interact with common over-the-counter pain relievers?

Regulatory documents list interactions with various medications, including those that are used for pain and anti-inflammatory purposes, such as Methotrexate. Furthermore, caution is described when combining Ottoprim with any product that might affect potassium levels or blood cell counts. Official guidance recommends that a patient's healthcare provider is made aware of all medicines and supplements being taken.

Q: What happens if I miss a scheduled time for Ottoprim?

Regulatory guidance typically advises patients that missed doses should not be doubled. Instead, the general recommendation is to follow the instruction of the prescribing healthcare provider regarding how to proceed with the regimen. Always seek specific guidance from a medical professional if a dose is missed.

Q: Does Ottoprim cause drowsiness or affect concentration?

Drowsiness is not classified as a common side effect in the official safety profile. However, rare adverse reactions involving the nervous system, such as headache or depression, are documented and could potentially impair function. For this reason, official patient information advises caution when driving or operating heavy machinery.

Q: Does Ottoprim affect the way birth control pills work?

The official product information notes that Ottoprim has the potential to interact with certain hormonal medications, including some oral contraceptives. This potential interaction can lead to an increase in the blood levels of the hormonal components. The official documentation emphasizes the importance of a patient consulting a healthcare professional regarding hormonal contraceptives prior to starting Ottoprim.

Q: Is it true that Ottoprim can cause changes in sleep patterns?

Changes in sleep patterns are not listed as a common or very common adverse reaction. Official safety profiles do, however, list rare effects related to mood and the nervous system, such as depression, which may indirectly influence sleep. Any significant or persistent changes experienced by the user are generally advised to be discussed with a healthcare provider.

Q: Does Ottoprim change the results of any common lab tests?

Yes, regulatory documents indicate that Ottoprim can interfere with certain lab procedures used to measure substances in the blood. Specifically, it may cause false elevations in the measured levels of serum creatinine and serum potassium. Clinicians are aware of this potential interference when interpreting results.

Q: What should be done if an interaction with another medicine is suspected?

If an interaction is suspected or unusual effects are noted, official patient guidance consistently advises that this information should be immediately communicated to a doctor, nurse, or pharmacist. They are best equipped to evaluate the situation and determine the appropriate steps.

Q: Does Ottoprim affect blood pressure?

Official safety information notes a rare risk of circulatory shock, a condition that is often associated with hypotension (low blood pressure). Additionally, Ottoprim is documented to cause hyperkalemia (high blood potassium), an electrolyte change that can affect the circulatory system, particularly when combined with certain blood pressure medications.

Q: Are there any known interactions between Ottoprim and herbal supplements?

While specific herbal supplements may not be individually named, official regulatory information emphasizes the importance of a healthcare provider being aware of all substances being taken. This ensures that the healthcare provider can check for potential drug-herb interactions or additive side effects.

Q: Is it safe to drive or operate machinery while taking Ottoprim?

Official patient information often advises caution regarding driving or operating machinery. This warning is based on the potential for some users to experience side effects like headache or rare neurological effects that could temporarily affect their ability to perform these tasks safely.

Q: What happens when Ottoprim is stopped abruptly?

Regulatory guidance emphasizes the importance of completing the full prescribed course of treatment. Studies in specific patient groups (e.g., HIV prophylaxis) have noted that abrupt cessation can lead to an increased incidence of certain infections. Therefore, the drug's cessation is typically managed by a healthcare professional.

Q: How is Ottoprim eliminated from the body?

According to official prescribing information, Ottoprim is eliminated from the body primarily by the kidneys. The active components are excreted through a combination of filtration and secretion processes in the renal system. This elimination pathway is a consideration for healthcare providers, particularly for individuals with kidney impairment.

Q: If I experience a mild side effect, is it necessary to stop taking Ottoprim?

Patient guidance generally states that mild side effects, such as common stomach issues, are often not serious and may resolve with time. However, any side effect that is severe, persistent, or rapidly worsening should be promptly communicated to a doctor for evaluation and to determine if the medicine needs to be stopped.

How should Ottoprim be stored and disposed of?

How to Store and Dispose of Ottoprim

The storage and disposal of Ottoprim (sulfamethoxazole and trimethoprim) must strictly adhere to the conditions documented in official regulatory labeling.


Storage Conditions

Requirement Specifics
Temperature Range Store at Controlled Room Temperature (20 C to 25 C / 68 F to 77 F) [1].
Protection Tablets and suspension must be kept in a dry place [2]. The intravenous solution concentrate must be protected from light and not frozen [3].
Stability Limits After initial entry, the IV vial contents must be used within 48 hours. Diluted IV solutions have specific stability limits and must be discarded if crystallization occurs [3].

Disposal and Safety

All forms of the medicine must be stored out of the reach of children [2]. Unused or expired Ottoprim must be disposed of according to local requirements or national regulations [4].

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

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