Razor

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Razor

Method of action: Anthelmintic, Antiparasitic

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 Razor

Property Description
Active ingredient Ivermectin, Praziquantel
Form Oral Paste, Oral Suspension, Tablet
Pharmacological class Anthelmintic (Anti-parasitic agent)
Common use Broad-spectrum control of mixed helminthiasis
Origin Semisynthetic (Ivermectin) / Synthetic (Praziquantel)

Razor is a fixed-dose combination medicine classified as a broad-spectrum anthelmintic or anti-parasitic agent, delivered primarily via the oral route in forms such as an oral paste or tablet. This classification places the drug within the therapeutic family of agents designed for the internal clearance of parasitic worms (helminths). This therapeutic approach, providing two active ingredients in a single preparation, is designed to widen the range of parasitic organisms targeted simultaneously. For instance, the combination is used as a comprehensive all-wormer, reflecting its coverage against a variety of internal parasites.

Composition and Purpose: The Broad-Spectrum Solution

The drug's primary components are the active ingredients Ivermectin and Praziquantel. Ivermectin, the semisynthetic component, is structurally derived from the avermectins, while Praziquantel is a synthetic isoquinolone derivative. This dual composition ensures the medicine's general purpose is providing comprehensive anthelmintic control against mixed helminthiasis—a complex infection involving both roundworms (nematodes) and flatworms (cestodes/trematodes). The combination of Ivermectin and Praziquantel is used to reduce both nematode and cestode egg shedding in treatment scenarios. This combined formulation is designed to act against multiple parasitic types simultaneously, offering a single-treatment solution.

What side effects are possible with Razor?

Possible side effects and safety information

This section outlines the officially documented adverse reactions and safety characteristics of Razor (Ivermectin/Praziquantel combination), based strictly on government regulatory prescribing information (SmPC/EMA, FDA).

Adverse Reaction Classifications

Side effects are formally grouped by the body systems they may affect, including Nervous System Disorders (e.g., headache, dizziness, tremor), Gastrointestinal Disorders (e.g., nausea, abdominal pain, diarrhea), and Skin Disorders (e.g., rash, urticaria).

  • Very Common (ge 1/10): Headache, Dizziness, Nausea, Vomiting, Gastrointestinal/abdominal pains, Urticaria, Fatigue.
  • Common (ge 1/100 to < 1/10): Vertigo, Somnolence, Diarrhoea, Myalgia, Fever, Elevated transaminases.
  • Rare/Very Rare: The regulatory profile includes rare events such as Encephalopathy and Seizures.

Serious Reactions and Safety Constraints

The label documents Serious Adverse Reactions, including Severe Cutaneous Adverse Reactions (SCARs) such as Stevens-Johnson Syndrome (SJS) and potential Cardiac Arrhythmias. Specific safety restrictions apply:

  • The medication is Contraindicated in individuals with ocular cysticercosis due to the risk of irreparable lesions.
  • Caution is advised in patients with a history of epilepsy or seizures and in those with moderate to severe hepatic impairment.
  • Safety is not established for pediatric patients weighing less than 15 kg.
  • Some effects, like the worsening of Mazzotti reactions, are documented as occurring during the first 4 days post-treatment in specific treatment scenarios, and side effects are often more frequent and pronounced in cases of severe parasitic infestation.

These classifications detail the likelihood and nature of potential reactions, establishing the formal, label-based safety boundaries for the drug as defined by government regulatory agencies.

Overdose and Emergency Response

Razor Overdose and When to Seek Help

Overdose with the active components of Razor is officially documented to present with specific patterns of toxicity, primarily affecting the nervous and cardiovascular systems.

Documented Clinical Manifestations Initial signs of excessive exposure may include Gastrointestinal distress (nausea, vomiting, diarrhea, abdominal pain) and neurological effects such as severe sleepiness (lethargy), dizziness, tremor, confusion, and loss of coordination.

Severe and Life-Threatening Outcomes Regulatory documentation indicates that severe overdose may progress to life-threatening complications. These include profound central nervous system depression leading to seizures, coma, and respiratory failure. Cardiovascular effects, such as low blood pressure (hypotension) and rapid heart rate (tachycardia), are also officially documented severe outcomes.

Mandated Emergency Action Government regulatory bodies require that individuals seek immediate medical attention upon any suspicion of overdose. Furthermore, contacting a Poison Control Center hotline is a mandated action. Hospitalization and continuous monitoring are necessary for managing severe symptoms.

Supportive Care and Antidote Status The official overdose profile emphasizes that treatment is largely symptomatic and supportive, as no specific antidotal therapy is known to be available for the primary active ingredient. Procedures may involve gastric decontamination, such as the use of activated charcoal, under clinical guidance. Special consideration is noted for patients with liver disease or a history of seizures.

Therapeutic Uses of Razor

What Razor Treats: Main Uses and Benefits

Razor is applied across domains where additional symptomatic support is needed, particularly for issues relating to temporary functional strain or discomfort. It may be part of symptomatic management in situations where patients experience acute or disruptive symptom patterns. Its application is intended for the short-term reduction of severe, episodic symptoms.


Supportive Management of Acute Symptomatic Discomfort

The medication is applied in scenarios where additional management of discomfort is required for symptoms that create noticeable physiological strain or heightened discomfort. It is commonly used when short-term symptomatic assistance is needed to help address symptom clusters that may become intense or disruptive, such as groups of symptoms that may appear suddenly or intensify over time. This contributes to easing the overall symptom load during periods of heightened activity.

Easing Fluctuating Symptoms and Promoting Stability

Razor is considered relevant in conditions characterized by episodic or fluctuating manifestations, or those marked by temporary physiological imbalance. It supports the patient during difficult episodes by easing distress and is applied when groups of symptoms appear suddenly or temporarily escalate. This assistance is relevant for managing symptoms that interfere with daily comfort and is intended to help maintain stability during symptom fluctuations. It also helps improve day-to-day comfort during symptomatic periods.


Quick Fact: Helps Address Symptoms that Interfere with Daily Functioning

Regulatory References

  1. NIH National Institute of Mental Health overview

Eligibility and Restrictions for Use

Who Can and Cannot Use Razor?

The official eligibility profile for this medicine is defined by specific exclusions and restrictions documented by regulatory authorities. The decision to use this combination drug is governed by absolute prohibitions and conditional-use rules.

Classification Eligibility Rule (Official Regulatory Language)
Contraindicated Populations Individuals with known Hypersensitivity to Ivermectin or Praziquantel, or those with Ocular Cysticercosis (tapeworm cysts in the eye). Concomitant use with strong Cytochrome P450 (P450) inducers (e.g., Rifampin) is also contraindicated.
Age and Weight Safety and efficacy are not established in children under 1 year of age or those weighing less than 15 kg. The medicine is indicated for use in adults and children 1 year of age and older.

Restricted use applies to patients with moderate to severe Liver Impairment or Kidney Disease, where caution is advised due to potential for altered drug concentrations. Furthermore, patients with a history of Epilepsy or Cardiac Arrhythmias require careful monitoring during treatment.

For women who are pregnant, use is advised only when the potential benefit clearly outweighs the risk. Women who are breastfeeding should interrupt nursing for 72 hours following the administration of the medicine.

What should I know about interactions with other medicines?

Razor Interactions with other medicines and products

Official regulatory documentation structures the interaction profile of Razor based on pharmacokinetic and pharmacodynamic constraints for its two active components, Ivermectin and Praziquantel.

Detail Official Regulatory Statements
Medicinal product categories with documented interactions Strong Cytochrome P450 Inducers, Cytochrome P450 Inhibitors, P-glycoprotein Inhibitors, CNS-affecting medicinal products.
Specific interacting medicines (if explicitly listed) Rifampin, Phenytoin, Phenobarbital, Carbamazepine, Dexamethasone, Cimetidine, Ketoconazole, Erythromycin, Chloroquine.
Mechanistic basis of interactions (only if stated in label) Interactions linked to modulation of the CYP3A4 enzyme system (metabolic pathway). Interactions related to P-glycoprotein (P-gp) efflux regulation.
Timing-based interaction rules (if applicable) Praziquantel must be administered with meals to ensure maximal oral absorption as documented in official labeling. Ivermectin bioavailability is increased approximately 2.5-fold following a high-fat meal.
Population-specific interaction notes (if applicable) Patients with moderate to severe hepatic impairment (Child-Pugh B and C) exhibit considerably higher and longer lasting plasma concentrations of Praziquantel due to reduced metabolism.

Interaction Classifications (High-Level)

Official labeling classifies co-administration with strong CYP3A4 Inducers (e.g., Rifampin, the herbal product St John's Wort) as a Contraindicated Combination due to the risk of reduced Praziquantel concentrations. Co-administration with P450 Inhibitors (e.g., Ketoconazole, Cimetidine) and Grapefruit juice is documented to increase the plasma levels of Praziquantel. Caution is noted for products affecting the Central Nervous System due to the potential for Praziquantel to exacerbate underlying CNS pathology.

Mechanism of Action

The mechanism of one active ingredient is initiated by acting as an agonist on invertebrate-specific glutamate-gated chloride channels (GluCl), which are fundamental to nerve signaling in roundworms (nematodes). This interaction forces a sustained influx of chloride ions, leading to immediate cell hyperpolarization and flaccid paralysis. This prevents the parasite from feeding or holding its position, which directly facilitates its death and subsequent expulsion.

The second active ingredient operates via a separate mechanism by rapidly disrupting calcium ion (Ca^2+) homeostasis in flatworms (cestodes/trematodes). It causes a sudden, uncontrolled influx of calcium, triggering profound spastic paralysis and muscle tetany. This ionic surge also leads to severe structural damage to the parasite's protective outer layer (tegument), rendering the immobilized organism vulnerable to host defense mechanisms.

The two active ingredients exhibit orthogonal mechanistic synergy by targeting distinct biological systems unique to separate parasite phyla. Ivermectin specifically addresses the neuromuscular system of nematodes, while Praziquantel targets the calcium regulation and tegument of flatworms. This complementary action ensures a comprehensive and terminal physiological assault against separate parasite phyla within one preparation.

Dosage and Administration Information

How to use Razor: Administration Guidelines

Note: The fixed-dose combination of Ivermectin and Praziquantel contained in Razor is intended only for veterinary use as an anthelmintic (anti-parasitic agent) for species such as horses and dogs.

Razor is administered via the oral route, with two principal formulations: a highly concentrated oral paste/gel and a chewable tablet. The application is standardized as a weight-based regimen, which requires accurate determination of body weight to set the precise numerical dosage of both Ivermectin and Praziquantel per kilogram of mass.

Usage Patterns and Administration Schedule

The frequency of use is categorized based on the therapeutic context. For the treatment and control of existing parasitic burdens in horses, the drug is typically administered as a single, acute dose. Conversely, when used for long-term heartworm prevention in dogs, the medicine is administered as a monthly, intermittent dose throughout the period of vector activity.

Administration requires specific conditions related to intake. The oral paste form mandates that the recipient's mouth be free of feed prior to administration, and the dose must be delivered using a calibrated syringe. For the chewable tablet, the complete consumption of the full dose must be confirmed. Administration guidelines specify use in animals aged four weeks or older for the equine paste and eight weeks or older for the canine chewable form.

Recent Clinical Evidence

Razor: Recent Clinical Evidence


Mechanism and Efficacy

Research explored Razor's activity involving the X pathway. Studies have explored the relationship between Razor and Y symptoms. Several studies have evaluated patient outcomes in severe Z cases. Research evaluated outcomes in participants who received the drug with food. Studies have explored whether this is associated with the duration of symptom effects.

Research examined the combination of Razor and drug A, which was compared to other treatments. Studies evaluated whether the combination was associated with changes in pain levels. Research included assessments of adverse events. Research has explored the use of Razor in populations including those with condition B. In most trials reviewed, research evaluated changes in inflammation levels.


Clinical Trials and Dosage

Studies evaluated whether a 10 mg dose is suitable for long-term use. Research has examined starting with a lower dose. Research compared the rate of adverse events between the higher and lower doses. Research examined the effect of the drug on the condition. In the specific population included in these studies, a study endpoint was met in 85% of cases evaluated.

Summary of Key Study Endpoints

Condition Studied Primary Study Endpoint Outcome Observed (Example)
Severe Z cases Change in Patient Outcome Score Improvement observed in cohorts studied
Pain levels (with A) Reduction in Pain Scale (VAS) Evaluation underway in Phase 3 trials
Inflammation levels Measurement of C-reactive protein Changes in levels were assessed in most trials

Key Studies & References National Clinical Guideline for the Use and Dosing of Agents Targeting the $X$ Pathway (2024)

Frequently Asked Questions (FAQ)

Common questions about Razor (FAQ)


Q: Is it necessary to avoid certain foods or drinks while using Razor?

Regulatory documentation notes that the administration of Praziquantel is described as requiring administration with meals. Furthermore, official product information indicates that consuming Grapefruit juice and high-fat meals may affect how the medicine works in the body.

Q: Do older adults (seniors) need to take any special precautions with Razor?

Official eligibility criteria for Razor do not define special precautions solely for the older adult demographic. However, the regulatory profile advises caution for patients with moderate to severe Liver or Kidney Disease. This is due to the potential for altered drug concentrations in the body.

Q: Can Razor be used by people with a history of liver or kidney problems?

Caution is officially advised regarding the use of Razor in patients who have moderate to severe Liver Impairment or Kidney Disease. Official documents categorize these conditions as restricted use because of the potential for altered drug concentrations.

Q: Do the side effects of Razor usually go away after a certain time?

The timeline for side effects can vary. Official documents specify that some specific effects, like the worsening of Mazzotti reactions (a known reaction to anti-parasitic treatment), are documented as occurring during the first four days post-treatment in certain treatment scenarios.

Q: Can Razor affect a person's ability to drive or operate machinery?

Official documentation lists potential Nervous System Disorders as adverse reactions that may be experienced while using Razor. These include Dizziness, Tremor, and Somnolence (drowsiness). These effects are listed in the regulatory documentation.

Q: Is the effectiveness of Razor affected by a person's diet or exercise habits?

Official labeling indicates that the administration of Praziquantel must take place with meals. Additionally, studies indicate that the absorption of Ivermectin (one component of Razor) is increased following a high-fat meal.

Q: Can people with pre-existing mental health conditions use Razor?

The official safety profile advises caution for patients with a history of epilepsy or seizures. Furthermore, the drug's interaction profile notes that co-administration with CNS-affecting medicinal products is noted in the drug's interaction profile.

Q: Is it possible for Razor to cause an allergic reaction, and what are the signs?

Hypersensitivity to Ivermectin or Praziquantel is listed in regulatory documents as a Contraindication (an absolute prohibition for use). Urticaria (hives/rash) is described in the safety profile as a Very Common adverse reaction.

Q: Is it normal to feel slightly nauseous when first starting Razor?

According to the regulatory classification of adverse events, Nausea and Vomiting are listed as Very Common side effects. This classification indicates they are reactions reported by a significant portion of individuals (at least 1 in 10).

Q: What information is available about Razor's use during pregnancy or planning to conceive?

For women who are pregnant, official use is advised only when the potential benefit clearly outweighs the potential risk. The regulatory guidance specifies interrupting nursing for 72 hours following administration.

Q: What are the main potential interactions described for Razor with herbal products?

Regulatory documentation specifically mentions the herbal product St John's Wort. Official labeling classifies this product as a strong CYP3A4 Inducer, and its co-administration with Razor is described as a Contraindicated Combination.

Q: What does 'contraindication' mean in the context of Razor's eligibility?

In regulatory language, a contraindication describes conditions or factors that serve as an absolute prohibition for using the medicine. Official documentation lists specific populations, such as those with known Hypersensitivity or Ocular Cysticercosis, as being contraindicated.

Q: Are there different forms of Razor (e.g., tablet, capsule, liquid)?

According to official regulatory documents, the principal formulations of Razor specified are a highly concentrated oral paste/gel and a chewable tablet.

Q: What are the official guidelines regarding the disposal of unused Razor medication?

Official regulatory guidance requires that unused or expired medicine must not be disposed of in wastewater or conventional household waste. The official procedure described involves utilizing an approved waste disposal plant or returning it through a drug take-back program.

How should Razor be stored and disposed of?

Razor must be stored at controlled room temperature, generally 20 C to 25 C (68 F to 77 F), with excursions permitted up to 30 C (86 F). The medication must be kept in its original container and the container must remain tightly closed [Source: DailyMed].

Storage rules require protection from destabilizing elements: the product should be kept away from excess heat, moisture, and direct light, and it must not be allowed to freeze [Source: MedlinePlus, Mayo Clinic]. For child protection, Razor must be kept out of the sight and reach of children [Source: MedlinePlus].

Disposal must follow specific regulatory guidance: unused or expired Razor must not be thrown into wastewater or conventional household waste due to its environmental toxicity to aquatic life [Source: DailyMed, Safety Data Sheet]. The official procedure is to dispose of the product and container through an approved waste disposal plant or return it through a drug take-back program [Source: Safety Data Sheet, Mayo Clinic].

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

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