Paxidorm

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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 Paxidorm

Property Description
Active ingredient Diphenhydramine Hydrochloride
Form Solid Oral Drug Form (e.g., Tablets, Capsules)
Pharmacological class First-generation H1-antihistamine, Sedative-hypnotic
General purpose Allergy relief and temporary sleeplessness
Origin Synthetic

What Type of Medicine is Paxidorm?

Paxidorm is a pharmaceutical preparation containing the synthetic active ingredient, Diphenhydramine Hydrochloride, and is classified as a first-generation H1-antihistamine and a potent sedative-hypnotic agent. The drug's classification as a first-generation H1-antihistamine means it belongs to a class of medications that primarily work by blocking the effects of histamine throughout the body. The specific commercial presentation of Paxidorm distinguishes itself by often focusing its market positioning on its sedative effects for nighttime use, a common feature among products containing Diphenhydramine.

Unlike newer generations of antihistamines, this class is known for its ability to readily cross the blood-brain barrier and bind to central receptors, an attribute associated with its pronounced calming effect. This unique pharmacological characteristic is a result of its central nervous system activity. The common presentation of Paxidorm for systemic absorption is a solid oral drug form, such as tablets or capsules.

Paxidorm's Dual Pharmacological Role and General Purpose

The general purpose of Paxidorm is two-fold: to relieve symptoms associated with allergic conditions and to provide temporary relief for sleeplessness. Its antihistamine action works by reversing the effects of histamine release, which helps manage uncomfortable symptoms associated with allergic conditions like hay fever or seasonal rhinitis. Injectable formulations of the active ingredient are utilized as an adjunct for allergic reactions when oral therapy is not feasible.

Its significant effect on the central nervous system results in pronounced sedation. This characteristic makes it suitable for providing temporary relief for an individual experiencing difficulty falling asleep due to temporary sleeplessness. The active ingredient, Diphenhydramine, is used for the management of insomnia in adults. This dual role makes Paxidorm utilized both for allergy management and for inducing sleep when sedation is the desired effect.

What side effects are possible with Paxidorm?

Possible Side Effects and Safety Information

Paxidorm (Diphenhydramine Hydrochloride) is classified by regulatory authorities as a first-generation antihistamine with notable sedative and anticholinergic activity. The officially documented safety profile is structured around these actions, defining the most common and serious potential adverse reactions.

Adverse Reaction Scope

The majority of documented side effects fall into two key System-Organ Classes:

  • Nervous System Disorders: The most frequent side effects, classified as Common, include drowsiness (somnolence), sedation, dizziness, and fatigue. These effects are often most noticeable at the start of treatment.
  • Anticholinergic Effects: These peripheral effects are commonly documented as dry mouth (xerostomia), constipation, blurred vision, and difficulty passing urine (urinary retention).

Serious Adverse Reactions: Regulatory documents note the potential for rare, but clinically significant, adverse events. These include neurological events such as convulsions (seizures), which are associated with high doses, and rare blood dyscrasias.

Population-Specific Safety Considerations

Specific warnings are provided in official labeling for certain patient groups:

  • Older Adults: This population is noted to have an increased susceptibility to pronounced adverse effects, particularly sedation, dizziness, and confusion, which elevate the risk of falls.
  • Pediatric Patients: The regulatory label documents the potential for paradoxical reactions in children, such as excitement, nervousness, or agitation, rather than the expected sedative effect.
  • Patients with Pre-existing Conditions: Caution is specified for individuals with conditions that may be worsened by anticholinergic activity, such as narrow-angle glaucoma and symptomatic prostatic hypertrophy.

Safety-Related Restrictions

Official labeling imposes clear restrictions regarding concurrent use with other substances and the performance of certain activities:

  • Use with alcohol and other central nervous system depressants is restricted due to the high risk of severely enhanced sedation and cognitive impairment.
  • Due to the high incidence of drowsiness and dizziness, regulatory documents advise against activities that require mental alertness, such as driving or operating machinery, during treatment.

These classifications reflect how government regulatory documents organize and communicate the medicine’s safety profile.

Overdose and Emergency Response

Overdose reactions involving Paxidorm (Diphenhydramine) are officially documented to vary widely, ranging from central nervous system (CNS) depression, such as drowsiness and eventual coma, to CNS stimulation, including agitation, confusion, and convulsions. Other recognized clinical signs are anticholinergic-like symptoms, which may include dry mouth, fixed and dilated pupils, flushing, and rapid heartbeat (tachycardia). Overdose can lead to life-threatening outcomes, including seizures, coma, serious heart rhythm disturbances, or death.

Specific regulatory warnings note that CNS stimulation, convulsions, or death are particularly likely in pediatric patients. Conversely, elderly patients are more susceptible to symptoms such as significant dizziness, sedation, and hypotension following excessive ingestion.

Immediate medical attention is required for any suspected overdose. Contact a Poison Control Center right away, as prompt medical attention is critical for all individuals. Urgent help must be sought immediately if an individual is hallucinating, cannot be awakened, has a seizure, is experiencing trouble breathing, or has collapsed.

The official management approach is defined as symptomatic and supportive treatment, including necessary measures such as activated charcoal and cardiac monitoring. Regulatory documents state that no specific antidote is known, and warn that stimulants should not be used.

Therapeutic Uses of Paxidorm

What Paxidorm Treats: Main Uses and Benefits

Paxidorm is commonly used in areas where short-term symptom management is appropriate, applied in contexts involving specific symptomatic manifestations.

Support for Acute Allergic Discomfort

The therapeutic domains applied include managing symptoms related to allergic conditions (like hay fever and urticaria), helping with symptoms of temporary sleeplessness, and assisting with supportive relief for motion sickness. It is applied when short-term symptomatic assistance is needed to address the functional stress of episodic symptoms.

This application generally contributes to easing the overall symptom load during difficult episodes of heightened discomfort.

The active ingredient may also be relevant in contexts involving heightened systemic burden, such as situations requiring temporary symptom stabilization. This supports general well-being during symptomatic phases, particularly when symptoms interfere with routine activities, such as persistent itching or difficulty initiating sleep.

Quick Fact: Support for Episodic Discomfort
Paxidorm is commonly used across conditions characterized by periods of heightened symptoms, including the symptomatic manifestations of seasonal allergies and transient, occasional sleep difficulties.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

The eligibility for using Paxidorm (Diphenhydramine HCl) is strictly defined by regulatory guidelines based on age, physiological status, and pre-existing medical conditions.

Contraindicated and Restricted Populations

Classification Population or Condition
Must Not Use (Contraindicated) Neonates or premature infants Nursing mothers (breastfeeding women) Individuals with known hypersensitivity to the drug or related antihistamines Patients using other diphenhydramine-containing preparations
Conditional Use (Caution Required) Elderly patients (60-65+ years), due to increased risk of dizziness and confusion Patients with narrow-angle glaucoma or bladder-neck obstruction (e.g., prostatic hypertrophy) Individuals with moderate to severe hepatic or renal impairment Patients with severe respiratory conditions (e.g., chronic bronchitis, emphysema)

Age-Related Eligibility Status

Use is generally permitted for adults and children aged 12 and older. Nonprescription oral use is typically restricted to children aged 6 years and above for self-medication of allergy symptoms. For children under 6 years of age, use is only allowed under the direction of a doctor.

Physiological Status

Use during pregnancy is advised only if clearly needed, as determined by the physician. Use while breastfeeding is strictly prohibited.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Prohibited Combinations and Restrictions

Paxidorm is officially classified as contraindicated for co-administration with Monoamine Oxidase Inhibitors (MAOIs). This restriction requires a mandatory separation period of 14 days after the MAOI has been discontinued. Additionally, co-use is strictly prohibited with any other products containing the active ingredient Diphenhydramine, including both oral and topical formulations, to prevent excessive exposure.


Pharmacodynamic Reinforcement

The medicine carries a documented risk of pharmacodynamic reinforcement due to its central activity. This results in additive CNS depressant effects when co-administered with alcohol and other Central Nervous System (CNS) depressants. Such depressants include various sedatives, hypnotics, opioids, tranquilizers, and certain psychiatric medicines. Furthermore, co-use with agents possessing anticholinergic effects (e.g., some tricyclic antidepressants) is noted to prolong and intensify the adverse anticholinergic outcomes.


Population-Specific Note

Regulatory documents specifically highlight that the elderly population (age 60 and older) is at an increased risk of interaction-related side effects. These additive pharmacodynamic effects are more likely to result in adverse events such as significant dizziness, sedation, and hypotension in this specific age group.

Mechanism of Action

How Paxidorm Works

Paxidorm's action is fundamentally driven by its ability to modulate two distinct but related neurotransmitter systems. The compound, which readily crosses the blood-brain barrier, engages mechanisms that regulate biological activity primarily within the Central Nervous System (CNS), promoting the establishment of a reduced state of alertness within the central nervous system.


Targeting Histamine Receptors for Central Inhibition

Its primary mechanism is acting as a Histamine H1-receptor inverse agonist. By antagonizing the effects of histamine, a neurotransmitter that modulates CNS arousal, the drug initiates a signaling sequence that reduces overactive signaling within the arousal systems, modulating the activity of the arousal system, which corresponds to the observed CNS depressant activity of the compound.


Modulation via Acetylcholine Antagonism

This secondary mechanism involves its function as an antagonist at Muscarinic Acetylcholine Receptors ( mAChR). This action targets signaling patterns characteristic of the cholinergic system, reinforcing the central inhibitory effects and influencing multiple systems through ACh signaling inhibition, which defines a part of the compound's overall pharmacological characteristics.

Dosage and Administration Information

Paxidorm, which contains Diphenhydramine Hydrochloride, is administered via several routes depending on the clinical context. The primary route is oral, utilizing solid forms like tablets or capsules, typically available in strengths of 25 mg and 50 mg. When oral administration is impractical, the medicine can be administered through intramuscular (IM) or intravenous (IV) injection in controlled settings.

Dosing regimens differentiate by the intended high-level use patterns. For symptomatic relief, the standard adult oral dose is 25 mg to 50 mg taken every four to six hours, with the total daily intake restricted to a maximum of 300 mg. When utilized for temporary sleeplessness, the regimen is a single 50 mg dose administered once daily, approximately 20 to 30 minutes before going to bed. This specific administration pattern is designated for short-term periods, and usage is typically limited to no more than 14 consecutive days without further professional evaluation.

The administration guidelines indicate that oral doses may be taken with or without food and are commonly consumed with water. For specific populations, dose adjustments may be utilized; for instance, a lower initial dose is generally utilized for older adults due to enhanced sensitivity. The pediatric dose for children aged 6 to under 12 years for allergy purposes is 12.5 mg to 25 mg every four to six hours.

Recent Clinical Evidence

Paxidorm: Recent Clinical Evidence

Evidence for Use in Temporary Sleeplessness

Research examining the use of Paxidorm for conditions characterized by fluctuating or episodic manifestations related to sleep primarily involves Randomized Controlled Trials (RCTs) with limited follow-up durations. These studies was evaluated in adults experiencing transient or short-term insomnia. The trials were used in research exploring how symptoms change over time, focusing on patient-reported outcomes describing perceived discomfort, such as sleep latency measures. The evidence, as assessed in systematic reviews, was observed in some studies to be heterogeneous, meaning findings were mixed.

Evidence for Use in Symptomatic Allergy Relief

The research base was evaluated for use in conditions involving periods of heightened symptom activity, such as allergies. Its role as a first-generation antihistamine was evaluated in numerous RCTs, systematic reviews, and meta-analyses. These studies research examined measures related to patient-reported outcomes describing perceived discomfort and inflammatory or irritative states, specifically measuring changes in symptom burden, including nasal symptoms and skin symptoms. Comparative research with other antihistamine generations noted that Central Nervous System (CNS) effects (sedation) was observed in the Paxidorm class.

Long-Term Studies and Follow-Up Duration

Most research involves study scenarios focusing on episodes requiring immediate short-term support. Trials primarily feature observing responses over defined time intervals, generally lasting for the duration of the acute symptom episode (e.g., up to two weeks). There is limited information available concerning maintenance use, durability of observed changes, or the effects over extended periods.

Evidence in Specific Age Groups and Populations

Studies exploring allergy relief research examined populations including both adults and adolescents. For the sleep indication, the primary studies focused on a general adult population. Data for older adults (those over 65) with sleep disturbances remain insufficient in the form of large, dedicated RCTs. Study results reflect the specific conditions and demographic groups under which they were conducted.

What Remains Uncertain About Paxidorm's Research

Key research limitations include the fact that follow-up durations were limited across the entire evidence base, meaning that long-term effects are not fully established. For the sleep indication, evidence quality varies across studies, with findings being mixed and some research relying heavily on patient-reported experiences rather than objective physiological outcomes. These limitations contribute to the assessment of certainty, highlighting the extent of what research still monitors for future insight.

Key Studies & References

  1. NIGHTTIME SLEEP-AID - DailyMed (FDA-Published OTC Monograph for Diphenhydramine)
  2. Diphenhydramine: MedlinePlus Drug Information

Frequently Asked Questions (FAQ)

Common questions about Paxidorm (FAQ)

Q: How quickly does Paxidorm usually start to work?

A: According to official product information, a single oral dose of the active ingredient is quickly absorbed. The level of activity is generally described as reaching its maximum concentration in approximately one hour.

Q: How long do the effects of Paxidorm last?

A: The duration of activity following an average dose is described in official sources as lasting for a period between four to six hours. This timeframe reflects the length of time the medicine is generally active in the body.

Q: Is Paxidorm a drug that causes dependency or addiction?

A: Regulatory agencies, such as the US Drug Enforcement Administration, have not classified the active ingredient in Paxidorm as a controlled substance. This classification reflects its regulatory status and is distinct from medications that are subject to stricter federal controls due to high risk of dependence.

Q: What are the long-term effects of taking Paxidorm?

A: Official regulatory documents indicate that long-term studies in animals to determine potential for cancer or genetic changes have not been performed. The available research has limitations in follow-up duration, meaning information on effects over extended periods is not fully established.

Q: Is it possible to develop a tolerance to Paxidorm?

A: Some official drug information sources note that when this class of medicine is used regularly for sleep, the body may develop a tolerance to the sedative effects. If tolerance develops, the drug's intended effect may gradually lessen.

Q: Why do some people say Paxidorm stopped working for them?

A: The medicine’s use for temporary sleeplessness is generally restricted to short periods by regulatory guidance. If tolerance develops, the sedative effect may diminish, which can contribute to a perceived lack of effectiveness over time.

Q: Is Paxidorm a treatment for short-term or long-term problems?

A: For use as a sleep aid, official guidelines designate it for short-term periods only. Its use for allergy relief is generally associated with temporary symptomatic activity, rather than continuous long-term treatment.

Q: Is there a maximum length of time Paxidorm should be used according to official sources?

A: When used for temporary sleeplessness, official guidelines advise against use past 14 consecutive days. If the condition persists beyond this two-week limit, it should be re-evaluated.

Q: Is Paxidorm the same type of medicine as other common sleep aids?

A: Paxidorm contains a first-generation H1-antihistamine. This classification is pharmacologically distinct from other common sleep medications, such as z-drugs or benzodiazepines, which work through different mechanisms in the brain.

Q: What is the difference between Paxidorm and similar treatments for sleep?

A: The action of Paxidorm is primarily driven by blocking histamine and acetylcholine receptors in the brain. This mechanism is different from many newer sleep aids that act by enhancing GABA activity or targeting melatonin pathways.

Q: Can Paxidorm be taken during the day for anxiety or other conditions?

A: Official regulatory documents only list its approved uses as relief from allergy symptoms, treatment for motion sickness, and temporary relief of sleeplessness. Its use for other conditions is not described in the official labeling.

Q: Are there any foods or drinks to avoid when taking Paxidorm?

A: Official warnings specifically advise patients to avoid alcoholic drinks due to the risk of enhanced sedative effects. Apart from alcohol, the administration guidelines state that the medicine may be taken with or without food.

Q: Is it okay to have coffee while using Paxidorm?

A: Official labeling focuses on avoiding substances that cause additive central nervous system (CNS) depression, such as alcohol. Individuals should be aware of the sedative effects of Paxidorm, as stimulants may affect the perceived action.

Q: Do the side effects of Paxidorm go away over time?

A: While official documents note that the Nervous System effects are often most noticeable at the start of treatment, there is no statement confirming that they will fully resolve over time.

Q: Does Paxidorm cause weight gain or weight loss?

A: Weight changes are not listed among the officially documented, frequent, or serious adverse reactions in the regulatory adverse reaction summaries.

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

A: Official guidance often indicates that specific safety information is limited regarding co-administration with complementary medicines or herbal supplements. This caution applies particularly to supplements that may also cause sleepiness.

Q: Is Paxidorm known to interact with blood pressure medications?

A: Official precautions advise caution for patients with a history of hypertension or cardiovascular disease. The drug’s pharmacological characteristics mean that it may affect the heart and circulation.

Q: Is it true that Paxidorm affects dreams?

A: Effects on sleep architecture or dreams, such as vivid dreams or nightmares, are not listed among the officially documented, frequent, or serious adverse reactions in regulatory labeling.

Q: Does Paxidorm cause memory problems?

A: Official labeling notes a risk of confusion and diminished mental alertness, particularly in the elderly population. Specific memory problems are not listed among the commonly reported adverse effects.

Q: Can Paxidorm affect the results of a drug test?

A: Technical literature suggests that the active ingredient in Paxidorm has been reported to cause false-positive results for certain substances, such as opioids, in some initial immunoassay drug screening tests.

Q: What evidence exists for Paxidorm's use in chronic sleep issues?

A: The majority of clinical research focuses on transient or short-term insomnia, consistent with its approval as a temporary sleep aid. Limited information is available concerning its efficacy or safety for chronic, long-term sleep issues.

Q: Are there any known interactions with over-the-counter pain relievers?

A: Official guidance indicates it is generally acceptable to take this medicine with non-opioid pain relievers, such as paracetamol or ibuprofen. The warning to avoid co-use with other products containing the same active ingredient still applies to all formulations.

Q: Does Paxidorm affect blood sugar levels?

A: Changes in blood sugar levels are not listed among the officially documented, frequent, or serious side effects. While not a direct interaction, general guidance often recommends considering sugar-free formulations for diabetic patients.

Q: How is Paxidorm eliminated from the body?

A: The medicine is extensively processed by the liver into various inactive forms (metabolites). These are then primarily eliminated from the body via the kidneys and passed out in the urine.

Q: Is Paxidorm a controlled substance?

A: The active ingredient in Paxidorm is not classified as a controlled substance by the US Drug Enforcement Administration or similar international bodies that regulate medicines with a potential for abuse.

Q: Can Paxidorm be taken on an empty stomach?

A: The official administration guidelines simplify the use of the oral form by explicitly stating that doses may be taken with or without food.

How should Paxidorm be stored and disposed of?

How to Store and Dispose of Paxidorm

The storage and disposal of Paxidorm (Diphenhydramine HCl) are strictly defined by regulatory labeling to ensure product stability and safety.

Official Storage Requirements

Paxidorm must be stored at controlled room temperature, maintaining a range between 20 C and 25 C (68 F and 77 F). Storage areas must avoid excessive heat and the product must be protected from light and moisture. The medicine must be kept in its original, tightly closed container and must remain out of the sight and reach of children.

Storage Restriction Requirement
Temperature Controlled Room Temp. (20 C to 25 C)
Environment Protect from Light and Moisture
Container Keep Tightly Closed
Integrity Do not use if tamper-evident seal is broken

Disposal Instructions

Unused or expired Paxidorm should be disposed of in the household trash after being mixed with an undesirable substance, such as coffee grounds or dirt, and placed in a sealed bag. Alternatively, unused medicine may be returned to authorized drug take-back programs or collection sites.

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

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