Rythmonorm

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Rythmonorm

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 Rythmonorm

Quick Facts

Property Description
Active ingredient Propafenone hydrochloride (Propafenonum)
Form Oral tablets and extended-release capsules
Pharmacological class Antiarrhythmic agent (Class Ic)
General purpose Heart rhythm stabilization
Origin Synthetic compound

What Type of Medicine is Rythmonorm?

Rythmonorm is a prescription-only medicine that contains the active ingredient Propafenone hydrochloride (Propafenonum), a synthetic compound that functions as an antiarrhythmic agent. This medicine is consistently classified as a Class Ic antiarrhythmic. This classification provides a clear identity: the drug acts primarily as a potent sodium channel blocker. Its action in stabilizing the cardiac electrical system is clinically recognized and supported by pharmacological studies, focusing on its ability to depress conduction velocity in the heart. This mechanism is key because it gives the medicine the ability to correct and maintain organized heart activity.

Propafenone: Composition, Forms, and General Purpose

The medication is supplied as a single-ingredient product for oral administration, available as both conventional film-coated tablets and modified-release extended-release capsules. The active component, Propafenone, exists as a racemic mixture of two mirror-image forms, both of which contribute to the overall pharmacological effect. This formulation feature is common to other Propafenone preparations, such as Rythmol or Norfenon. The general purpose of Rythmonorm is to provide essential heart rhythm stabilization by targeting and correcting the disorganized electrical impulses that lead to an arrhythmia. This targeted action allows the medication to control symptomatic irregular heartbeats, typically prescribed for conditions like supraventricular tachycardias and certain ventricular arrhythmias, thereby helping patients maintain a consistent and steady cardiac rhythm.

What side effects are possible with Rythmonorm?

Possible Side Effects and Safety Information

The safety profile of Rythmonorm (Propafenone hydrochloride) details the officially documented adverse reactions and safety constraints as established by regulatory authorities.

Classification Examples of Documented Adverse Reactions
Very Common (mathbfgeq 1/10) Dizziness (vertigo) and taste disturbance (dysgeusia).
Common (mathbfgeq 1/100 to mathbf< 1/10) Headache, palpitations, bradycardia, nausea, vomiting, constipation, dry mouth, fatigue, fever, and abnormal liver enzyme values.
Uncommon Thrombocytopenia, syncope, visual impairment, and hypotension.

The official label organizes reactions by body system, including Cardiac disorders (e.g., heart block), Nervous system disorders (e.g., convulsion), and Gastrointestinal disorders.

Serious Adverse Reactions

Regulatory documents highlight significant potential risks, including Proarrhythmia—the capacity of the medicine to worsen existing arrhythmias or induce new ones, such as ventricular fibrillation. Other documented serious events include Agranulocytosis (a severe drop in white blood cells) and the potential for exacerbation of congestive heart failure symptoms.

Safety Constraints and Special Populations

Safety notes specify that effects like proarrhythmia may be more likely at the start of treatment or during dose escalation. A critical constraint is the formal restriction, found in official prescribing information, against use in patients with severe uncontrolled heart failure or severe hepatic impairment. Furthermore, the safety profile underscores the increased risk of mortality documented in patients with structural heart disease.

Overdose and Emergency Response

Overdose of Propafenone hydrochloride (Rythmonorm) is formally documented to present with severe cardiotoxicity and central nervous system (CNS) manifestations. The officially listed cardiovascular signs include profound hypotension and bradycardia, alongside specific electrocardiogram changes such as QRS widening and PR interval prolongation, which indicate impaired cardiac conduction. CNS toxicity is defined by formally documented symptoms including somnolence, dizziness, and convulsions (seizures).

The profile of a severe overdose indicates a high risk of life-threatening outcomes. Regulatory labeling identifies potential complications such as the development of ventricular tachycardia, ventricular fibrillation, cardiovascular collapse, cardiac arrest, and death.

Due to the extreme documented severity of these risks, regulatory guidance explicitly mandates the requirement to seek immediate medical attention. When severe symptoms like collapse, seizure, or profound respiratory difficulty are evident, official documentation specifies contacting emergency services immediately.

Treatment, as described in official documents, is centered on symptomatic and supportive care, as no specific antidote is known for Propafenone. Procedural measures may include gastric lavage, and specific agents like atropine or isoprenaline are described for managing severe cardiac disturbance. Continuous hospital monitoring is required, and elimination procedures like hemodialysis are noted as unlikely to succeed.

Therapeutic Uses of Rythmonorm

What Rythmonorm Treats: Main Uses and Benefits


Managing Irregular Heart Rhythm Symptoms

Propafenone is applied in addressing conditions characterized by periods of heightened symptoms related to abnormal heart rhythms (arrhythmias). This includes addressing conditions involving episodic or fluctuating manifestations, such as Atrial Fibrillation, Atrial Flutter, and certain ventricular arrhythmias. It is applied to help manage recurrent or episodic manifestations and is relevant when supportive symptom management is appropriate, particularly during phases when symptoms become more noticeable.

Symptom Relief and Stabilization

This medication generally helps address symptom clusters by moderating the disruptive manifestations of an irregular heart rhythm. This includes managing symptoms related to physical discomfort like heart palpitations (a fluttering or pounding sensation) and associated feelings of dizziness or lightheadedness, which are symptoms that interfere with daily functioning. The key therapeutic benefit supports general well-being during symptomatic phases by providing supportive relief when symptoms interfere with routine activities.

Quick Fact: Management for Palpitations
This medication is commonly used to help with symptoms related to heightened physiological activity, providing supportive relief when these manifestations intensify.

Eligibility and Restrictions for Use

Eligibility: Who Can and Cannot Use Rythmonorm?

The use of Rythmonorm (Propafenone) is governed by strict population eligibility rules outlined in official regulatory documents. The medicine is contraindicated and must not be used by certain patient groups.

Absolute Contraindications

Use is forbidden for individuals with heart failure, cardiogenic shock, or Known Brugada Syndrome. The medicine is also contraindicated in patients with severe obstructive pulmonary disease or marked electrolyte imbalance. Furthermore, patients with cardiac conduction disorders (like Sick Sinus Syndrome or second-degree AV block) cannot use the medicine unless they have a functional artificial pacemaker.

Restricted and Conditional Use

  • Pediatric Population (< 18 years): Safety and efficacy are not established; therefore, use is not recommended.
  • Organ Impairment: Patients with impaired hepatic function or impaired renal function must be administered the medicine cautiously.
  • Pregnancy/Lactation: Use during pregnancy is permitted only if the potential benefit justifies the potential risk. Use with caution is advised during lactation.

What should I know about interactions with other medicines?

Rythmonorm's official interaction profile primarily documents its ability to alter the exposure of co-administered medicines and the risk of combined effects on cardiac conduction.

Formal Restrictions and Exposure Modification Co-administration with Ritonavir is formally documented as contraindicated by regulatory sources. There is an advisory to avoid the simultaneous use of both a strong CYP2D6 inhibitor and a strong CYP3A4 inhibitor, as this combination may significantly increase Propafenone plasma concentrations. Propafenone also acts as an enzyme inhibitor, which has been shown to result in clinically relevant pharmacokinetic interactions. For instance, Propafenone is documented to increase serum Digoxin levels by 35% to 85% and substantially increases Warfarin plasma concentrations, which is associated with increased prothrombin times. Conversely, CYP inducers like Rifampicin may decrease Propafenone levels, while inhibitors such as Fluoxetine and Quinidine increase them.

Pharmacodynamic and Specific Cautions Due to the potential for additive effects on cardiac conduction and repolarization, combining Propafenone with other Class IA and Class III antiarrhythmic agents is avoided; a minimum withholding period of five half-lives is formally required before beginning Propafenone. Caution is documented for patients who are CYP2D6 poor metabolizers and those with hepatic impairment, as increased Propafenone exposure in these populations can heighten interaction risks. The consumption of Grapefruit Juice has also been noted to increase Propafenone concentrations.

Mechanism of Action

Rythmonorm is a Class IC antiarrhythmic agent that acts primarily by blocking the fast inward sodium channel current (INa) in myocardial tissue. This channel blockade decreases the rate of phase 0 depolarization in myocardial action potentials. The resultant effect on cellular electrophysiology includes a reduction in conduction velocity and an increase in the effective refractory period within the His-Purkinje system and accessory pathways. The drug also exhibits a weak beta-adrenergic receptor-blocking activity, contributing to its dual mechanistic profile. The resulting electrophysiological changes are consistent with a Vaughan Williams Class IC action and a Class II action, which modifies the excitability and impulse propagation characteristics of cardiac cells.

Dosage and Administration Information

How Rythmonorm is Used: Official Administration Guidelines

Propafenone (Rythmonorm) is an antiarrhythmic agent administered via the oral route (tablets and capsules) or intravenously (IV solution). The initial dosing and determination of the appropriate maintenance level for oral therapy must be performed under specialist supervision in a hospital setting to ensure proper cardiac monitoring.


Dosing and Administration Schedules

The dosage is highly structured and depends on the specific form used, with dose increases permitted only after specified time intervals:

Administration Form Initial Dose Dosing Frequency Titration Interval
Immediate-Release (IR) Tablet 150 mg Three times daily (q8h) Minimum of 3 to 4 days
Extended-Release (ER) Capsule 225 mg Twice daily (q12h) Minimum of 5 days

Standard adult maintenance ranges from 450 mg to 900 mg per day for IR tablets and up to 850 mg per day for ER capsules.


Procedural and Population-Specific Instructions

Oral forms must be swallowed whole with liquid and should never be crushed, chewed, or divided due to the specific formulation and anesthetic properties of the compound. While ER capsules may be taken with or without food, IR tablets are typically taken with or after food. During treatment, grapefruit juice must be avoided as a general administration constraint.

For older adults, the initial phase of treatment requires a more gradual dosage increase than standard titration, with dose adjustments considered only after five to eight days. Additionally, a dose reduction is necessary for patients with known hepatic impairment. If a scheduled dose is missed, it should be skipped if it is almost time for the next dose, and the patient should resume the regular dosing schedule; doses should not be doubled.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Rythmonorm

This overview summarizes the type of clinical research that has been conducted on Propafenone (Rythmonorm), focusing on the structure of the studies, the outcomes that were measured, and the areas where research is still limited, as documented in authoritative scientific sources.


Evidence for Use in Paroxysmal Supraventricular Tachycardia (PSVT)

Studies have primarily used Randomized Controlled Trials (RCTs) to evaluate Propafenone was studied for PSVT, a condition characterized by fluctuating or episodic manifestations. Research explored outcomes related to the recurrence of these episodes over time, alongside measurements of the time elapsed before a new episode of a fast rhythm occurred. Findings describe patterns observed in the studies related to rhythm status following administration. Evidence is limited regarding the consistency of rhythm status over many years.


Evidence for Use in Paroxysmal Atrial Fibrillation and Atrial Flutter

Propafenone was evaluated in research exploring short-term symptom changes associated with Atrial Fibrillation (AF) and Atrial Flutter. The evidence base includes a mix of RCTs, meta-analyses, and real-world observational studies. Studies monitored rhythm status (cardioversion) and examined the time to recurrence. Outcomes tracked included metrics capturing phases of heightened symptom activity. A key limitation noted by regulatory agencies is that the evidence describes significant limitations for its use in individuals with underlying structural heart disease.


Evidence in Special Populations and Long-Term Durability

Propafenone was observed in studies over defined time intervals. Typical follow-up durations were intermediate (e.g., six months) to intermediate-to-long (e.g., up to one year). Evidence is limited for outcomes extending beyond the typical one-year study period. Data for pediatric populations are not as extensive, and use in this group may be subject to stricter evaluation. Furthermore, the research does not determine whether an individual will respond similarly to the group patterns observed in the trials.

Key Studies & References

  1. Preliminary report: effect of encainide and flecainide on mortality in a randomized trial of arrhythmia suppression after myocardial infarction (The CAST Trial)

Frequently Asked Questions (FAQ)

Common questions about Rythmonorm (FAQ)


Q: How quickly is Rythmonorm expected to start working?

Official information indicates that consistent levels of the medicine in the blood, known as steady-state conditions, are typically reached after 3 to 5 days of administration. Achieving this steady-state level is generally associated with the full intended therapeutic effect.


Q: Do food or dairy products affect how Rythmonorm is absorbed?

Regulatory information notes that the absorption of the medicine, known as bioavailability, may be enhanced when the drug is administered with food. Specific regulatory guidance regarding dairy products themselves is not generally detailed in the product information.


Q: How long does Rythmonorm stay in the body after the last dose?

The time the medicine stays in the body can vary significantly between patients due to different metabolic rates. For most people (fast metabolizers), the elimination half-life is approximately 5.5 hours, which means it takes that amount of time for half the medicine to leave the body. For a smaller group of people (slow metabolizers), this time is longer, around 17 hours.


Q: What kind of monitoring might a doctor recommend while someone is on Rythmonorm?

Official documentation recommends ECG evaluation (monitoring the heart’s electrical activity) both before and periodically during treatment. Additionally, monitoring for changes in blood pressure is noted, and official documentation also notes the importance of monitoring the function of any implanted devices, such as pacemakers or defibrillators.


Q: Is it common for Rythmonorm to be used in conjunction with blood thinners?

Regulatory information establishes that the medicine can significantly increase the blood level of Warfarin, a common blood thinner. Official guidance emphasizes that if the two medicines are used together, close monitoring and potential dosage adjustments of the blood thinner are necessary.


Q: What are the main research conclusions about the effectiveness of Rythmonorm?

The medicine’s indication is supported by clinical data documented in official sources. It is indicated by regulatory bodies to prolong the time to recurrence of certain symptomatic atrial arrhythmias, such as atrial fibrillation, in eligible patients.


Q: If I miss taking Rythmonorm, what generally happens?

The recommended procedure for a missed dose is to skip the missed dose if it is almost time for the next scheduled dose. Official guidance states that patients should continue their regular schedule, and doses should not be doubled to compensate for the missed dose.


Q: Does Rythmonorm interact with common cold or flu medications?

Official sources note potential interactions with certain components frequently found in over-the-counter cold and flu remedies. Specifically, interactions are documented with sympathomimetic agents and dextromethorphan, which can increase the risk of cardiovascular side effects.


Q: Are there any specific vitamins or supplements that are known to interact with Rythmonorm?

Official patient guidance emphasizes that patients should inform their healthcare providers about all supplements and herbal/natural preparations they use. This is because these products may potentially affect how the medicine works or is processed in the body.


Q: Is it common to feel dizzy or lightheaded when first starting Rythmonorm?

Dizziness (vertigo) is described as a very common side effect in official documents. This frequency is documented in regulatory sources. Safety notes also indicate that adverse effects may be more likely at the start of treatment or during dose escalation.


Q: How does the liver process Rythmonorm?

Official pharmacological data confirms that the medicine is highly metabolized by the liver. This process, known as extensive first-pass hepatic metabolism, means the drug is processed significantly by the liver shortly after ingestion.


Q: Can Rythmonorm affect blood pressure readings?

Yes, the medicine is known to cause hypotension (low blood pressure) as a potential side effect. Regulatory guidelines recommend that blood pressure be monitored during treatment.


Q: Is Rythmonorm commonly prescribed for people with Wolff-Parkinson-White (WPW) syndrome?

Pharmacological studies documented in official documents show the medicine’s action in patients with Wolff-Parkinson-White (WPW) syndrome. It is shown to reduce conduction and increase the effective refractory period in the accessory pathway relevant to this condition.


Q: Is Rythmonorm safe for people who have kidney problems?

Official guidance recommends that the medicine should be administered cautiously to patients with impaired renal function (kidney problems). Regulatory documents recommend that these patients be carefully monitored for signs of overdosage.


Q: Are there any common reasons why a patient might be switched from Rythmonorm to another medicine?

Official warnings about serious adverse reactions, such as proarrhythmia (worsened or new arrhythmias) or worsened heart failure, represent clinical risks that may lead to discontinuation or switching. Agranulocytosis (a severe decrease in white blood cells) is another serious event noted in official safety information.


Q: Is a metallic taste in the mouth a common side effect of Rythmonorm?

The official documentation describes taste disturbance (dysgeusia) as a very common side effect, affecting many patients. This taste disturbance can manifest as a bitter or metallic taste.


Q: Can Rythmonorm interact with common antacids or stomach medicines?

Interactions are documented with certain stomach medicines, including acid reducers. For example, cimetidine may increase propafenone levels, and others like famotidine or magnesium hydroxide carry a risk of interaction related to cardiac rhythm or electrolyte imbalance.

How should Rythmonorm be stored and disposed of?

Official Storage and Disposal Requirements

Rythmonorm (propafenone hydrochloride) must be stored according to regulatory labeling to ensure product quality and safety.

Storage Conditions

  • Temperature: Store at Controlled Room Temperature between 20 C to 25 C (68 F to 77 F).
  • Protection: Keep the medicine away from excess heat and moisture; do not store in areas like the bathroom.
  • Container Integrity: Keep the medicine in the original container and ensure the bottle is tightly closed at all times.

Handling and Child Safety

The extended-release capsules must not be crushed, chewed, or divided. The product must be stored out of the sight and reach of children, and the safety cap must be locked immediately after use.

Disposal Instructions

Unused or expired Rythmonorm should be disposed of via a drug take-back program. If this option is unavailable, the medicine can be mixed with an undesirable substance, such as dirt or used coffee grounds, sealed in a bag, and discarded in the household trash. Do not flush the medication down the toilet unless specifically instructed by the official product labeling.

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

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