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Nasohist

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Nasohist

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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 Nasohist

What is Nasohist?

Nasohist is a combination medication designed to manage symptoms associated with the common cold, upper respiratory allergies, and hay fever. It typically contains two active components: an antihistamine and a nasal decongestant.

Components and Mechanism

The medication works through the combined action of its primary ingredients:

  • Antihistamine: This component targets histamine, a naturally occurring substance in the body that triggers allergic responses. By blocking histamine receptors, it helps reduce symptoms such as sneezing, itching, and watery eyes.
  • Decongestant: This component acts on the blood vessels in the nasal passages. It works by narrowing these vessels, which helps to decrease swelling and congestion, making it easier to breathe through the nose.

Therapeutic Use

Nasohist is used for the temporary relief of symptoms involving the nasal passages and sinus cavities. It is primarily utilized to address:

  • Nasal congestion and sinus pressure.
  • Runny nose and persistent sneezing.
  • Itching of the nose or throat.
  • Itchy, watery eyes due to environmental allergens.

As a combination therapy, it is intended to provide multisymptom relief when both congestion and allergic reactions are present simultaneously.

Regulatory References

  1. Chlorpheniramine: MedlinePlus Drug Information

What side effects are possible with Nasohist?

Possible Side Effects and Safety Information

The safety profile of Nasohist, an antihistamine-decongestant combination, is characterized by effects primarily related to its two active components. The adverse reactions are officially classified based on their frequency of occurrence according to regulatory standards.

Adverse Reaction Scope

The most commonly expected adverse reaction is drowsiness or sedation, which is often noted in regulatory documents as a very common effect. Other common effects affecting the Nervous System Disorders class include dizziness, headache, insomnia, and nervousness. Adverse reactions impacting Gastrointestinal Disorders typically involve dry mouth, nausea, and constipation.

Classification Example Adverse Reaction (SOC Category)
Very Common Drowsiness (Nervous System Disorders)
Common Dizziness, Dry Mouth (Nervous System, Gastrointestinal Disorders)
Rare Palpitations, Urinary retention (Cardiac, Renal Disorders)

Safety Considerations and Restrictions

The medicine is associated with specific safety constraints. Serious adverse reactions are rare but include severe cardiovascular events such as hypertensive crisis and severe allergic reactions (anaphylaxis).

Regulatory safety information notes an increased susceptibility to adverse effects in the older adult population, particularly regarding CNS effects and the risk of urinary retention. Furthermore, the official labeling includes a mandatory restriction: Nasohist is contraindicated for use concurrently with, or within 14 days of discontinuing, a Monoamine Oxidase Inhibitor (MAOI), due to the potential for critical safety consequences.

Overdose and Emergency Response

The official regulatory profile for a Nasohist overdose is defined by the combined actions of its components, which may lead to severe and life-threatening events. Overdose manifestations are categorized into two primary systems: Central Nervous System (CNS) effects and Cardiovascular instability.

CNS manifestations range from profound sedation, drowsiness, and deep coma to paradoxical excitation, toxic psychosis, and generalized seizures. Anticholinergic signs, such as mydriasis, fever, and dry mouth, are also documented. Cardiovascular signs include severe hypertension, palpitations, and potentially fatal arrhythmias, culminating in cardiovascular or circulatory collapse and cerebral hemorrhage.

Regulators classify these as severe outcomes requiring immediate medical advice or attention, even if the patient appears well. Urgent help must be sought for serious symptoms like trouble breathing or passing out.

Official guidance states that no specific antidote is known, and management is strictly symptomatic and supportive. Procedures include reducing drug absorption via gastric lavage or activated charcoal, and treating complications, such as using intravenous diazepam for convulsions. Population-specific warnings exist, stating that children are more susceptible to CNS excitation, while elderly patients are more vulnerable to CNS depression and hypotension. Monitoring of cardiac, respiratory, and fluid balance is required.

Therapeutic Uses of Nasohist

What Nasohist Treats: Main Uses and Benefits

Nasohist is an intranasal medication that is applied in addressing symptom clusters that may become intense or disruptive in the nasal passages. This medication is relevant for managing symptoms related to inflammatory or irritative states linked to conditions characterized by periods of heightened symptoms, such as allergic rhinitis. This approach may provide supportive relief when symptoms interfere with routine activities and is relevant when supportive symptom management is appropriate.

The active ingredients often found in such nasal preparations are commonly used to help with the management of symptoms of seasonal and perennial allergic rhinitis. This means it supports relief for related symptoms including sneezing, runny nose, and nasal itching. The medication is often used during phases when symptoms become more noticeable, particularly when supportive symptom management is appropriate.

“The core function of this medication contributes to improved comfort during periods of heightened symptoms.”

Nasohist supports patients during episodes of heightened discomfort and contributes to easing the overall symptom load, which may help patients cope more steadily with symptom fluctuations. The medication is applicable across domains where additional symptomatic support is needed.

Quick Fact: Relief for Symptoms that Interfere with Daily Functioning

Eligibility and Restrictions for Use

Who Can and Cannot Use Nasohist?

The eligibility for using Nasohist (levocabastine nasal spray) is strictly defined by regulatory labeling and is based on a patient's medical history, age, and physiological status.

Contraindications and Restrictions

Nasohist must not be used by:

  • Individuals with known hypersensitivity or allergy to levocabastine hydrochloride or any other ingredient in the product.

Use is Restricted or Not Recommended for:

Population Group Regulatory Status
Children under 12 years Not recommended; safety not established.
Elderly patients (over 65 years) Safety and efficacy have not been established.
Pregnant women Should not be used unless benefits clearly outweigh potential risks.
Nursing women Caution advised due to potential excretion into breast milk.
Patients with Renal Impairment Caution is required due to limited clinical data.

These limitations reflect the official statements in drug regulatory documents, emphasizing that use is not established, not recommended, or strictly contraindicated in these specific groups.

What should I know about interactions with other medicines?

Nasohist Interactions with Other Medicines and Products

This section outlines the clinically relevant drug and substance interactions for Nasohist (Chlorphenamine and Phenylephrine) as documented in official government regulatory information.

Contraindicated Combinations

The co-administration of Nasohist with Monoamine Oxidase Inhibitors (MAOIs) is strictly contraindicated. This prohibition remains in effect for two weeks after stopping MAOI therapy, due to the official risk of intensifying the pressor effects of Phenylephrine and prolonging anticholinergic effects of Chlorphenamine.

️ Officially Documented Interaction Categories

Regulatory documents highlight several categories of interactions that require specific constraints:

  • Central Nervous System (CNS) Depressants: Concurrent use with medicines classified as sedatives, tranquilizers, or alcoholic beverages may lead to increased drowsiness or sedation due to additive effects.
  • Potentiation Risks: Interactions where one component's effect is reinforced include: the pressor effect of Phenylephrine being potentiated by Oxytocic Drugs; and anticholinergic effects being potentiated by other agents with anticholinergic activity.
  • Metabolic Interactions: The Chlorphenamine component is officially documented to inhibit the metabolism of Phenytoin, which can result in increased Phenytoin exposure and risk of toxicity.
  • Substance Avoidance: Patients are advised to avoid alcoholic beverages and excessive caffeine intake.

Population-Specific Interaction Notes

Official labeling states that children and the elderly may be more susceptible to interaction-related adverse neurological effects, including enhanced anticholinergic effects and paradoxical excitation.

Mechanism of Action

Nasohist acts through two primary, distinct mechanistic domains: receptor antagonism and sympathomimetic agonism. The drug's first active component is a histamine H1 receptor antagonist. This molecule executes its mechanism by competing with the endogenous mediator histamine for binding sites on the H1 receptor, effectively preventing receptor activation. This competitive antagonism modifies the intracellular signaling cascades typically initiated by histamine release. The second component is a sympathomimetic agent that selectively engages alpha-adrenergic receptors (alpha-ARs). Its agonist activity stimulates alpha-ARs located on the vascular smooth muscle, triggering a signaling sequence that culminates in localized vasoconstriction within the microvasculature. This physiological consequence results in a regulated, altered baseline tone within the targeted microcirculatory pathways.

Dosage and Administration Information

Nasohist is an Oral combination medicine, meaning it is intended to be swallowed for systemic effect. Its use is defined by established dosing and administration rules.

Official Administration Guidelines

Category Official Instruction
Route of administration Oral (Taken by mouth).
Dosing schedule (Adults greater than or equal to 12 years) Standard Dose: One unit (e.g., 4 mg Chlorphenamine Maleate/10 mg Phenylephrine HCl).
Maximum Daily Intake: Do not exceed 6 tablets (or equivalent volume of syrup/solution) in 24 hours.
Frequency and Timing Dose may be repeated every 4 to 6 hours as needed. A minimum interval of 4 hours between successive doses must be maintained.
Timing in relation to meals Can be taken with or without food.
Preparation requirements Syrup/Oral Solution: Requires measurement using a calibrated dosing device (e.g., dosing cup or syringe).
Age-group administration rules Children 6 to under 12 years: A specific, reduced dose is used, typically one-half the adult dose every 4 to 6 hours. Children under 6 years: Consult a doctor; use is generally not recommended.
Course Duration Intended for short-term use; discontinue if symptoms do not improve within 7 days.

Resulting Procedural Structure

The official use protocol for Nasohist requires patients to administer the medicine orally in the approved dosage forms (tablet or syrup). The dose must be taken every 4 to 6 hours, and the total intake must not exceed the specified maximum amount in a 24-hour period. Tablets must be swallowed whole (not crushed or chewed), and liquid forms must be measured accurately. These procedural steps and dose limits are established to standardize the medicine's use.

Recent Clinical Evidence

Research Evidence for Common Cold Symptom Relief

Research has evaluated the Nasohist combination (Chlorphenamine and Phenylephrine) in studies exploring measurements of physical discomfort associated with the common cold. The evidence base includes Randomized, Placebo-Controlled Trials (RCTs) and Systematic Reviews. These studies monitored core measurements of discomfort, typically using a Total Symptom Score (TSS) over short-term periods.

A key research limitation is that many pivotal trials documented these measurements using a triple-combination product that included an analgesic, which limits the ability to assign the measured results specifically to the dual Nasohist combination alone.

Research Evidence for Allergic Rhinitis Symptom Relief

For allergic rhinitis, Nasohist was evaluated in settings that address conditions characterized by fluctuating or episodic manifestations, primarily relying on Phase IV/Post-Marketing Surveillance Studies. Rhinitis research also examined measurements of the Total Symptom Score (TSS), tracking changes in outcomes linked to inflammatory or irritative states in both adult and pediatric groups.

There is a limited volume of large-scale Randomized Controlled Trials (RCTs) focusing exclusively on the specific dual combination for this condition, meaning the evidence quality varies across studies.

Evidence Gaps and Special Populations

The research base for Older Children and Adults is characterized by a higher volume of controlled trials. However, when considering Young Children and Infants (under six years), data remain insufficient, and findings were mixed, leading to regulatory caution.

Additionally, follow-up durations are generally limited to 3 to 5 days, meaning long-term effects are not fully established in the available research record. Comparative evidence is lacking in large-scale studies directly comparing Nasohist against newer alternatives.

Key Studies & References

  1. Safety and efficacy of over-the-counter cough and cold medicines for use in children: scientific and ethical considerations

How should Nasohist be stored and disposed of?

How to Store and Dispose of Nasohist

Nasohist must be stored at Controlled Room Temperature, officially maintained between 20 C and 25 C (68 F and 77 F). The product must be kept in its original, tightly closed container and placed out of the sight and reach of children for safety.

Storage Protection and Prohibitions

The medication requires protection from light and moisture, and users must avoid excessive heat. Liquid forms of Nasohist must not be frozen. The product should be kept in a safe location away from humidity.

Disposal Requirements

Do not flush unused or expired Nasohist down the toilet or pour it into a drain. It must be properly discarded according to local regulations. The preferred disposal method is using an official drug take-back program.

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

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