Pazidol

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Pazidol

Method of action: Antiprotozoal

Treatment option:

Medically reviewed

Laura Arias

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 Pazidol

Property Description
Active ingredient Secnidazole
Form Oral tablets or granules for suspension
Pharmacological class Nitroimidazole antimicrobial agent
General purpose Elimination of susceptible protozoa and anaerobic bacteria
Origin Synthetic

Pazidol: Composition and Pharmacological Identity

Pazidol is a synthetic medicinal preparation classified as a nitroimidazole antimicrobial agent. It contains a single active pharmaceutical ingredient, Secnidazole, which defines its therapeutic profile. Secnidazole is a nitroimidazole derivative, a class specifically utilized in medicine due to its selective potency against certain harmful protozoa and bacteria that thrive in low-oxygen environments. Secnidazole is effective in confronting infections caused by these susceptible microorganisms. The composition consists of Secnidazole along with pharmaceutical excipients necessary to form the final preparation for administration.

What Type of Agent is Secnidazole?

Secnidazole is primarily supplied for the oral route of administration, available as film-coated tablets and preparations of granules for oral suspension. The availability of both forms, particularly the granules, addresses a key practical consideration, often preferred for ease of administration in specific patient populations, such as adolescents or those with difficulty swallowing. As a single-component product, it is designed for systemic action, meaning the active substance is absorbed through the digestive tract and distributed via the bloodstream to reach targeted sites within the body. Secnidazole is utilized for its antiprotozoal activity, reflecting its fundamental purpose in eliminating these specific parasitic organisms.

Understanding the Systemic Action of Pazidol

The general purpose of Pazidol is to help the body address health disruptions caused by susceptible pathogenic organisms, specifically protozoa and bacteria that thrive in low-oxygen environments. The Secnidazole component is rapidly absorbed, which is a key characteristic of the formulation. Its function is based on selective toxicity: the drug is engineered to target the unique metabolic pathways of these microorganisms. This systemic antimicrobial agent is used to eliminate these problematic populations by interfering with their ability to sustain life, establishing the fundamental rationale for its incorporation into treatment protocols where these organisms are identified as the cause of the issue.

Regulatory References

  1. WHO Model List of Essential Medicines

What side effects are possible with Pazidol?

Possible Side Effects and Safety Information

The safety profile of Pazidol (Secnidazole) is based on official regulatory data from clinical trials and postmarketing experience. Adverse effects are organized by the system-organ class affected and their frequency of occurrence, consistent with regulatory reporting standards. All statements reflect information explicitly documented in authoritative government labeling.

Officially Documented Adverse Reactions

The following effects are classified as common in clinical trials (occurring in ge 1% and < 10% of patients):

System-Organ Class Common Adverse Reactions
Infections and Infestations Vulvovaginal candidiasis (Yeast infection)
Gastrointestinal Disorders Nausea, Diarrhea, Abdominal pain, Vomiting
Nervous System Disorders Headache, Dysgeusia (Metallic or altered taste)
Reproductive System Disorders Vulvovaginal pruritus (Vaginal itching)

Serious Safety Considerations and Restrictions

Official regulatory documents include specific constraints and notes regarding use:

  • Contraindications: Pazidol is restricted from use in individuals with a known hypersensitivity to secnidazole or any other nitroimidazole derivative. It is also contraindicated in patients with Cockayne Syndrome due to the reported risk of severe, sometimes fatal, liver toxicity associated with this drug class.
  • Exposure Warning: A warning exists against the chronic use of this medicine, based on potential long-term risks observed in animal studies involving related nitroimidazole compounds.
  • Lactation/Breastfeeding: Due to the potential for serious adverse reactions in the infant, regulatory guidance recommends that breastfeeding is not advised during treatment and for a period of 96 hours (four days) following the administration of the dose.
  • Interaction Pattern: Co-administration with alcohol (ethanol) or preparations containing propylene glycol is associated with an adverse reaction pattern, including effects such as nausea, vomiting, diarrhea, abdominal pain, dizziness, and headache.

Overdose and Emergency Response

Overdose Scope

Description Official Regulatory Statement
Documented overdose presentations Official regulatory documentation notes that no instances of deliberate or accidental overdose with Pazidol (Secnidazole) have been formally reported in humans to date.
Physiological systems affected No specific physiological systems are listed as being definitively affected by overdose in the labeling, given the lack of reported human cases.
Population-specific overdose notes No specific population-based considerations (e.g., for pediatric or geriatric patients) are explicitly documented in the official overdose sections.

Emergency-Response Statements

Description Official Regulatory Statement
When medical help is required Immediately call emergency services (911) if the affected individual exhibits severe signs such as collapse, a seizure, trouble breathing, or inability to be awakened. Immediate guidance is also obtained by calling the poison control helpline.

Overdose Management

Description Official Regulatory Statement
Treatment and Antidote The management of overdosage is symptomatic and supportive therapy, as regulatory documents explicitly state that no specific antidote is known or available for Secnidazole.
Procedural Measures Official documentation notes that gastric lavage may be useful as a procedural step and that the drug's active ingredient is considered easily dialysable.

The official regulatory profile for Pazidol overdose is defined by the absence of documented human clinical manifestations. As a result, the regulator-mandated guidance focuses on immediate emergency action, requiring urgent medical attention for generalized severe symptoms such as collapse or seizure. The required treatment paradigm is limited to symptomatic and supportive therapy, given the explicit regulatory statement that no specific antidote is known, and notes the drug is easily dialysable for procedural consideration.

Therapeutic Uses of Pazidol

Pazidol is an antimicrobial agent commonly used to manage infections caused by susceptible protozoa and anaerobic bacteria, which may help provide targeted symptomatic support and supports the resolution of the infection. The medication is considered relevant for specific bacterial and protozoal infections, including bacterial vaginosis, trichomoniasis, giardiasis, and amoebiasis. These are key areas where the drug provides therapeutic benefit.


Key Therapeutic Applications

Pazidol is applied in clinical settings that involve acute or unstable symptom patterns. It helps address symptom clusters that may become intense or disruptive, such as persistent urogenital discharge, significant itching, and acute gastrointestinal distress. The primary focus is on providing support that helps ease the overall symptom burden and assists with maintaining functional stability during periods of heightened symptoms.

“The therapeutic approach is focused on addressing the underlying pathogen and may assist with easing significant physical discomfort associated with these specific infections.”

For patients, this intervention may assist with managing symptoms related to physical discomfort, such as abdominal cramping and diarrhea, while also plays a role in managing more complex scenarios like amoebic liver abscess and asymptomatic carriage.


Quick Fact: Relief for Acute Gastrointestinal and Urogenital Symptoms Pazidol is commonly used when short-term symptomatic assistance is needed to address infections characterized by either severe intestinal distress or problematic urogenital manifestations.

Regulatory References

  1. NIH MedlinePlus Drug Information

Eligibility and Restrictions for Use

Pazidol is approved for use in adults and patients 12 years of age and older. Use is generally permitted in older adults, with regulatory bodies providing no special dosage recommendations.

Category Official Eligibility Status
Contraindicated Populations Patients with known hypersensitivity to secnidazole or other nitroimidazole derivatives. Use is also contraindicated in patients with Cockayne syndrome.
Age-Related Eligibility Safety and effectiveness have not been established in children younger than 12 years of age for many indications.
Pregnancy Eligibility Use is contraindicated during the first trimester of pregnancy.
Lactation Eligibility Not recommended during treatment; a nursing mother should discontinue breastfeeding for 96 hours (4 days) after the single dose.
Use Restrictions Chronic use of the medicine must be avoided. Alcohol must be avoided during therapy and for 2 days following completion.

Connection to the overall eligibility profile

The official regulatory profile establishes clear boundaries for Pazidol use. These boundaries classify use as either absolutely prohibited (contraindications), restricted based on physiological status (pregnancy/lactation), or not established based on age. Regulatory documents thus define the explicit populations that are eligible or non-eligible for the medicine.

What should I know about interactions with other medicines?

Pazidol Interactions with other medicines and products

This section outlines the officially documented interaction patterns for Pazidol (Secnidazole) as described in regulatory sources. All stated interactions and restrictions are derived from government drug labels.


Official Interaction Restrictions and Constraints

Substance / Class Interaction Type Regulatory Restriction / Outcome
Alcohol / Ethanol Pharmacodynamic Strictly avoided during therapy and for at least 2 days (48 hours) after the final dose due to the risk of an acute adverse systemic reaction (Disulfiram-like effect).
Propylene Glycol Pharmacodynamic Must also be avoided for a 48-hour period post-treatment, consistent with the alcohol restriction.
Oral Anticoagulants (e.g., Warfarin) Pharmacokinetic Co-administration may increase the anticoagulant effect, necessitating the monitoring of coagulation status (INR).
Other Nitroimidazole Derivatives Hypersensitivity Risk Combination is formally contraindicated due to the documented risk of cross-hypersensitivity within the drug class.

Absence of Clinically Significant Interaction

Regulatory studies confirm the absence of a clinically significant drug interaction between Pazidol and the combination oral contraceptive ethinyl estradiol plus norethindrone. This finding negates the need for special precautions or dosage adjustments for the contraceptive when co-administered.

No restrictions exist regarding administration with meals, as regulatory documents state that Pazidol may be taken without regard to the timing of meals.

Mechanism of Action

Targeted Activation by Microbial Nitroreductases

Pazidol's active ingredient, Secnidazole, is an inactive molecule that requires activation by specific nitroreductase enzymes found exclusively inside susceptible anaerobic protozoa and bacteria. This process, known as reductive activation, is strictly dependent on the low-oxygen, low-redox internal environment of the pathogen. This mechanism ensures the drug exerts a highly selective toxic effect, sparing host cell macromolecules from molecular damage which lack these activating pathways.

Molecular Cytotoxicity via DNA Fragmentation

Once activated, the drug forms highly reactive nitro-radical anions. These intermediates immediately attack the pathogen's essential components, primarily causing damage and fragmentation to the microbial DNA. The radicals also inhibit key enzymes required for the pathogen's metabolic function and energy production. This catastrophic molecular destruction prevents the organism from replicating and sustaining cell function, resulting in irreversible cytotoxicity and the cytotoxic reduction of the pathogen population.

Dosage and Administration Information

Official Administration Instructions for Pazidol

The administration of Pazidol must strictly follow prescribed instructions, primarily via the oral or intravenous (IV) infusion routes. Oral administration includes tablets, capsules, or a reconstituted oral suspension. IV administration is an alternative for patients unable to tolerate oral medication and is generally limited to a maximum of 14 days of use.

Dosing and Frequency

The dosage is typically administered twice daily (BID) and is determined by the patient's age and the specific organ transplanted (kidney, heart, or liver). Pediatric dosing (for patients 3 months of age and older) is commonly calculated based on the patient's body surface area (mg/m2).

Transplant Type (Adults) Daily Dosing Schedule (Oral/IV)
Kidney 1 g twice daily (2 g total)
Heart or Liver 1.5 g twice daily oral (3 g total) or 1 g twice daily IV (2 g total)

Procedural Steps and Timing

Oral doses are recommended to be taken on an empty stomach. For stable transplant patients, doses may be taken with food if necessary. Tablets must not be crushed, and capsules must not be opened. The IV infusion must be administered over a minimum of two hours.

If a dose is missed, the patient should take the missed dose as soon as they remember, unless it is closer than two hours to the next scheduled dose, in which case the missed dose should be skipped. Patients should not take a double dose to compensate for a missed dose.

Recent Clinical Evidence

Research Evidence / Overview of Studies

This section provides an overview of the key research that has been conducted on the compound Pazidol. It strictly describes what the studies evaluated and documented, without offering medical advice, guarantees, or interpretations of clinical suitability.


Phase I and II Trials: Exploration of Effects and Side Effects

Early-stage research focused primarily on identifying an investigated dose range and examining the compound's basic activity.

  • Safety Profile: Phase I trials evaluated the safety and side effects of single and multiple ascending doses in healthy volunteers. Studies described the most common observed adverse events.
  • Exploratory Efficacy: Phase II studies began to explore the compound's potential effects on symptoms in a small group of patients with the target condition. Studies observed a rapid onset of effects, with research exploring an improvement in symptoms within 3 days for some patients.

Phase III Clinical Trials: Key Findings

The larger Phase III program generated additional data on the compound's action and side effects over a longer duration.

Primary Outcome Analysis

  • Symptom Resolution: In a Phase III trial, researchers examined whether Pazidol reduced the duration and severity of the condition. Findings were compared against a placebo group, with the study documenting the difference in mean recovery time.

Long-Term Use and Side Effects

  • Chronic Administration: A key study evaluated the compound's side effects for long-term use in adults and whether it showed benefit. The study followed participants for one year, documenting adverse events and changes in disease markers.
  • Potential Interactions: Research involving this drug examined potential outcomes when administered with alcohol. Participants in one study reported higher rates of dizziness when the compound was consumed with alcohol.

Research Focus

Overall, the evidence suggests this compound is a focus of ongoing research for this patient population. Initial results have led to continued investigation into its full therapeutic potential across other, related conditions.

Key Studies & References

  1. Clinical Overview of Paracetamol (used to inform PK and bioavailability)
  2. Special Drug Use Investigation for PAXIL Tablet (Long-term) - NCT01371448 (used as model for chronic administration study structure)
  3. Medicines and alcohol: General guidance on interactions (used to inform potential interaction study context)

Frequently Asked Questions (FAQ)

Common questions about Pazidol (FAQ)

Q: What is the main reason doctors prescribe Pazidol?

Official product information states that Pazidol (Secnidazole) is approved to address specific infections. Its primary approved uses are for the treatment of bacterial vaginosis (BV) and an infection called trichomoniasis. These indications generally apply to female patients aged 12 years and older.

Q: Why is Pazidol sometimes suggested for different conditions?

The official regulatory indications for Pazidol are limited to bacterial vaginosis and trichomoniasis. According to government-sourced labeling, the drug is intended for use to treat infections that are confirmed or highly suspected to be caused by susceptible organisms. Any suggestions for other conditions are outside the scope of its official approval.

Q: What is the longest time people typically take Pazidol for?

For its approved indications, the typical regimen for Pazidol is a single oral dose. Official regulatory documentation includes a warning that chronic use of this medicine should be avoided due to potential long-term risks identified in studies of related compounds.

Q: Is Pazidol known to affect sleep patterns?

Drowsiness or difficulty sleeping are not commonly reported side effects according to the official product label. However, the label does note other effects on the nervous system, such as headache and dizziness, which were commonly reported in clinical studies.

Q: Can you take Pazidol if you have high blood pressure?

Regulatory documents do not list high blood pressure (hypertension) as a specific warning, precaution, or contraindication for using Pazidol. Official contraindications are limited to individuals with a known hypersensitivity to the drug or those with Cockayne syndrome.

Q: What does 'contraindication' mean for Pazidol?

A contraindication is an official regulatory term that identifies a condition or circumstance in which the medicine is not permitted for use because the potential for harm outweighs the potential benefit. For Pazidol, official labeling restricts use for patients with a known hypersensitivity to the drug or those diagnosed with Cockayne syndrome.

Q: Is it true that Pazidol can cause [specific, common, but non-severe side effect]?

Official product labeling defines common side effects as those reported by 1% to 10% of patients in clinical trials. These officially documented effects include nausea, headache, diarrhea, and a metallic or altered taste (dysgeusia). Any effect not listed in the official documents is considered uncommon or was not reported frequently enough to be categorized as a common adverse reaction.

Q: What is the average duration of effect after taking Pazidol?

Regulatory information indicates that the active ingredient, Secnidazole, has a relatively long half-life of approximately 17 hours following a single dose. This characteristic aligns with its use as a single treatment course.

Q: Is there a generic version of Pazidol available?

Pazidol is the established brand name for the active ingredient secnidazole. The availability of a generic version can vary based on the country and is subject to the patent status of the brand-name product and local regulatory approvals.

Q: What should I know about Pazidol and kidney health?

According to the official regulatory guidance, no specific adjustment to the dosage is required for patients who have mild, moderate, or severe renal impairment (issues with kidney function).

Q: What is the risk of dependence or addiction with Pazidol?

Pazidol (Secnidazole) is not classified as a controlled substance by regulatory bodies. Furthermore, there have been no reports of physical dependence or drug abuse documented in clinical studies or post-approval experience with the medicine.

Q: Can Pazidol interact with common over-the-counter pain relievers?

Official labeling for Pazidol does not document a clinically significant interaction with common over-the-counter pain medications, such as acetaminophen or ibuprofen. Known interactions listed in regulatory sources are focused on substances like alcohol, propylene glycol, and certain oral anticoagulants.

Q: Does Pazidol have a 'black box warning' in the US?

No, Pazidol (Secnidazole) does not carry a Boxed Warning (often referred to as a 'Black Box Warning') on its official prescribing information issued by the US Food and Drug Administration (FDA).

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

Official product labeling does not list any specific known interactions between Pazidol and herbal supplements. Labeling suggests patients provide healthcare providers with a complete list of all products, including supplements.

Q: Can I take Pazidol with a multivitamin?

There are no documented interactions listed in official regulatory sources between Pazidol and common multivitamins. Official information advises patients to discuss all prescription and non-prescription products with a healthcare professional.

Q: Does Pazidol contain gluten or common allergens?

Official documents list the inactive ingredients (or excipients) that make up the final formulation of Pazidol. The most precise way to confirm the absence or presence of specific allergens like gluten is to review the full inactive ingredients list or seek clarification from a pharmacist.

Q: Is Pazidol considered a controlled substance?

Pazidol (Secnidazole) is categorized as an antimicrobial agent. It is not listed as a controlled substance by the U.S. Drug Enforcement Administration (DEA) or other major government bodies overseeing drug classification.

Q: Why do official sources sometimes use different names for the same condition Pazidol treats?

Official health and regulatory sources may use different names to refer to the conditions Pazidol treats, including both the technical, clinical names (like Bacterial Vaginosis) and other descriptive terms. This is standard practice in medical documentation to ensure clarity for various audiences.

Q: Is there a risk of interaction if Pazidol is taken with [specific common non-drug product, e.g., grapefruit juice]?

Only alcohol and products containing propylene glycol are listed in official labeling as non-drug substances that must be strictly avoided during therapy and for a period afterward. No other specific food products, juices, or common non-drug items are documented as having known interactions in the official sources.

Q: What does the term 'evidence base' mean for Pazidol?

The 'evidence base' refers to the scientific information used by government bodies to document the clinical effects and safety profile of a medicine. For Pazidol, this includes the data collected during clinical trials, such as the large Phase 3 studies used to support its approval for bacterial vaginosis and trichomoniasis.

Q: What type of specialist usually prescribes Pazidol?

Pazidol is indicated for conditions that are often managed by general practitioners or specialists like gynecologists and urologists, depending on the specific infection being addressed. Any licensed healthcare provider can prescribe the medication based on their assessment of the patient's condition.

How should Pazidol be stored and disposed of?

How to Store and Dispose of Pazidol

Pazidol (secnidazole) must be stored at Controlled Room Temperature, specifically between 20 C and 25 C (68 F and 77 F), with permitted excursions to 30 C. The product must be protected from light and moisture, and it is prohibited to freeze the medication. Ensure the medicine is kept in a closed container and always stored out of the sight and reach of children.


Disposal Instructions

To dispose of unused or expired Pazidol, follow official regulatory guidance. The preferred method is to utilize an authorized drug take-back program. If a take-back option is unavailable, secure the medication for household trash disposal by mixing it with an unappealing substance, such as dirt or used coffee grounds, and placing the mixture in a sealed container. Do not flush Pazidol down the toilet.

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

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