Selozok

Quick links to important sections

Medically reviewed

Marina Burgos

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 Selozok

Property Description
Active ingredient Metoprolol
Form Extended-Release Tablet
Pharmacological class Selective β1-Adrenergic Receptor Blocking Agent (Cardioselective β-blocker)
Route of administration Oral
Origin Synthetic compound

What is Selozok and its Core Pharmacological Class?

Selozok is a prescription-only medicine whose fundamental identity is defined by its active ingredient, Metoprolol, which functions as a selective β1-adrenergic receptor blocking agent, widely recognized in medicine as a cardioselective β-blocker. This classification signifies that the synthetic compound preferentially targets β1-receptors predominantly located in the heart muscle, in contrast to non-selective β-blockers that affect receptors throughout the body. The mechanism works to counteract the stimulating effects of adrenaline and related stress hormones on the heart.

Composition and the Extended-Release Formulation

The active component in this medication is Metoprolol succinate, which is delivered in the unique form of an Extended-Release Tablet intended for oral administration. The choice of the succinate salt and the complex tablet structure differentiate Selozok from immediate-release formulations, as the sustained-release system is engineered to provide a controlled and predictable release of Metoprolol over a 24-hour period. The release mechanism is designed to maintain continuous therapeutic levels, indicating that the medication is specifically intended to provide stable, all-day support after a single daily intake. The complex multiple unit system within the tablet structure ensures this gradual release, promoting consistent concentrations of the active ingredient.

General Purpose: How it Supports the Cardiovascular System

The overall general purpose of Selozok is to offer circulatory support by stabilizing the heart's function, a therapeutic role utilized across medical practice. This is achieved through a controlled reduction of heart rate and a decrease in the force of heart contractions, thereby reducing the overall mechanical workload placed upon the cardiac muscle. This process helps ease the strain on the heart. The foundational benefit is the long-term maintenance of stable heart operation and efficient circulation, making it a tool in managing conditions that benefit from consistent heart rate and blood pressure modulation.

What side effects are possible with Selozok?

Possible Side Effects and Safety Information

The official safety information for Selozok (metoprolol succinate extended-release) details possible adverse reactions categorized by frequency and the affected body system, as documented in regulatory sources like the FDA and EMA.

Documented Adverse Reactions

Adverse effects are grouped by their official frequency classification:

  • Very Common (≥ 1/10): Fatigue.
  • Common (≥ 1/100 to < 1/10): Bradycardia (slow heart rate), dizziness, headache, postural hypotension, cold extremities, palpitations, nausea, abdominal pain, diarrhea, and constipation. These effects are classified across System-Organ Classes including Cardiac, Nervous System, and Gastrointestinal disorders.
  • Uncommon to Rare: Less frequent effects include insomnia, depression, weight gain, edema, rash, and bronchospasm (uncommon), as well as visual disturbances, dry mouth, reversible hair loss, and sexual dysfunction (rare).

Serious Safety Considerations and Constraints

Official labeling highlights critical safety concerns. Serious adverse reactions include the worsening of heart failure and the potential for complete heart block. A specific time-related safety pattern is documented: the abrupt cessation of therapy carries a significant risk of exacerbating angina pectoris or myocardial infarction.

Safety is also defined by contraindications, which are conditions where the medication should not be used, such as second- or third-degree heart block, decompensated cardiac failure, and cardiogenic shock. Furthermore, caution is advised for older adults and patients with hepatic impairment due to the potential for altered drug effects.

Overdose and Emergency Response

Overdose and when to seek help

Domain Official Regulatory Statements
Documented overdose presentations Overdose is documented to present with profound cardiovascular and central nervous system effects, including severe bradycardia, hypotension, atrioventricular block, convulsions, and respiratory distress.
Physiological systems affected Cardiovascular System (shock, cardiac arrest), Central Nervous System (impaired consciousness), Respiratory System (bronchospasm), and Metabolic System (hyperkalemia).
Dose-related or exposure-related factors Toxicity from the extended-release formulation may result in delayed or prolonged effects, requiring extended observation.
Population-specific overdose notes Hypoglycemia (low blood sugar) is noted as a specific concern and common finding in children following overdose.
Emergency-response statements Patients must seek immediate emergency medical attention and/or contact a Poison Control Center. Admission to a hospital is required.
When immediate medical help is required Immediately call emergency services if the individual has collapsed, is having a seizure, has trouble breathing, or cannot be awakened.

Official overdose statements:

  • Life-threatening effects include cardiogenic shock and cardiac arrest (asystole).
  • Management procedures include the administration of activated charcoal, gastric lavage, and specific agents like Glucagon to counteract profound cardiovascular depression.
  • Due to the extended-release nature, continuous cardiac monitoring and observation for at least eight hours is required.

Connection to the overall overdose profile: Regulatory documents define the overdose profile through the documented risk of profound cardiovascular suppression and respiratory compromise, which mandates that the public seek immediate medical attention for any known or suspected overexposure. The event is treated as a severe medical emergency requiring specialized supportive care, as no specific antidote is known.

Therapeutic Uses of Selozok

Selozok (Metoprolol succinate extended-release) is used to provide support in managing symptoms related to systemic imbalance and heightened physiological activity. The medication generally plays a role in managing conditions associated with chronic functional stress and may be part of symptomatic management for cardiovascular health. It is commonly used to help with conditions presenting with systemic or localized discomfort.

The medication is relevant for managing symptoms that interfere with daily comfort associated with several key conditions, including Hypertension, Chronic Heart Failure, Angina Pectoris (chest discomfort), and plays a role in managing recurring symptoms associated with Migraine headaches. It is applied across domains where additional symptomatic support is needed.

Controlling Chronic Symptom Burdens

Selozok is commonly used across conditions presenting with episodic or fluctuating manifestations. It helps address symptom clusters that create noticeable physiological strain, and may be part of symptomatic management following an Acute Myocardial Infarction. The medication helps maintain a sense of stability when symptoms are more noticeable, contributing to improved comfort during symptomatic periods.


Quick Fact: Therapeutic Support

Selozok is commonly used to help with symptoms that become more disruptive during flare-ups, such as recurrent chest discomfort (Angina) and recurring, intense headaches (Migraine), offering symptomatic relief that helps patients cope more steadily with symptom fluctuations.

Regulatory References

  1. official FDA drug label for Metoprolol Succinate Extended-Release

Eligibility and Restrictions for Use

Official Eligibility Rules

Selozok's population eligibility is strictly defined by regulatory documents, identifying who is permitted to use the medicine and who is formally prohibited. Use is contraindicated (prohibited) for patients with a known hypersensitivity to metoprolol or other beta-blockers, as well as those in cardiogenic shock or decompensated cardiac failure. The medicine must also be avoided by individuals with severe bradycardia, sick sinus syndrome (without a pacemaker), or second- or third-degree heart block.

Use is established for adult patients for all approved conditions, and for pediatric patients 6 years and older for the treatment of hypertension. Use in children under 6 years of age is not established and is not recommended.

Condition-Based and Physiological Restrictions

Conditional use is specified for several populations. Patients with hepatic impairment (reduced liver function) require caution and closer monitoring due to the drug's metabolism. While generally avoided in patients with bronchospastic disease, use is permitted if other treatments are unsuccessful, but only at the lowest effective dose. During pregnancy and lactation, use is restricted: it is permitted only if clearly needed, as metoprolol is excreted into breast milk.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documents define the interaction profile of Selozok (Metoprolol succinate extended-release) through pharmacokinetic interference, pharmacodynamic augmentation, and specific administrative prohibitions.

Pharmacokinetic and Pharmacodynamic Interactions

Interaction Type Interacting Medicines/Substances Official Outcome/Restriction
CYP2D6 Inhibition Strong CYP2D6 Inhibitors (e.g., Quinidine, Fluoxetine, Paroxetine) Causes a significant increase in metoprolol plasma concentration, potentially diminishing its cardioselectivity.
Cardiovascular Augmentation Digitalis Glycosides; Oral Verapamil or Diltiazem Increases the risk of bradycardia and heart block due to additive depressant effects on heart rate and AV conduction.
Hypotensive Risk Catecholamine-Depleting Drugs (e.g., MAO Inhibitors, Reserpine) Creates an additive pharmacodynamic effect that increases the risk of marked bradycardia and hypotension.
Antihypertensive Reduction Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) May cause a decrease in the blood pressure-lowering effect of metoprolol.

Formal Prohibitions and Timing Rules

Contraindicated Combination: The intravenous administration of Verapamil or Diltiazem is explicitly restricted due to the serious risk of severe cardiac events, including cardiac arrest.

Withdrawal Timing: When co-administered with Clonidine, Metoprolol must be gradually withdrawn several days before Clonidine withdrawal to mitigate the documented risk of rebound hypertension.

Hepatic Impairment: For patients with hepatic impairment, caution is advised due to potential exposure-related issues, which may necessitate careful consideration regarding co-administered interacting drugs.

Mechanism of Action

Selozok, containing metoprolol succinate, functions as a cardioselective competitive beta1-adrenergic receptor antagonist. Its primary biological targets are the beta1-adrenergic receptors, which are predominantly localized in the myocardial tissue. The molecule binds to these receptors, thereby occupying the binding sites and preventing the activation by endogenous catecholamines, specifically norepinephrine and epinephrine.

This antagonistic interaction blocks the stimulatory G-protein-coupled receptor pathway. The consequence of beta1 antagonism in the myocardium is a negative chronotropic effect (decreased heart rate) and a negative inotropic effect (decreased force of myocardial contraction). The drug also reduces the rate of impulse conduction through the atrioventricular (AV) node.

Downstream, the reduced cardiac output, resulting from the combined effects on rate and contractility, leads to a system-level modulation of hemodynamics. Furthermore, the blockade of beta1-receptors on the juxtaglomerular cells in the kidney decreases the release of renin, which initiates the renin-angiotensin-aldosterone system (RAAS) cascade. This systemic reduction in sympathetic drive and RAAS activity contributes to the overall physiological modulation.

Dosage and Administration Information

How to Use Selozok: Administration Guidelines

This section details the formal administration and dosing requirements for Selozok (Metoprolol succinate extended-release), focusing strictly on procedural usage and schedules.


Core Administration Protocol

Feature Instruction
Route of Administration The standard method is oral administration.
Dosing Frequency The extended-release formulation is designed for once-daily intake (qDay) to ensure consistent drug levels over 24 hours.
Timing Relative to Meals The tablet is typically taken with food or immediately after a meal.
Tablet Handling The tablet, or its scored halves, must be swallowed whole and must not be crushed or chewed to avoid premature release of the active ingredient.

Dosing and Procedural Structure

The standard protocol for initiating treatment involves a gradual dosage increase (titration). The initial adult dose for hypertension, for example, is typically 25 mg to 100 mg once daily. Doses are subsequently adjusted at weekly or longer intervals until the appropriate level is achieved, up to a maximum of 400 mg per day for certain uses.

Special Population Note: For pediatric patients (age geq 6 years) with hypertension, dosing is weight-based, starting at 1 mg/kg once daily. If treatment with Selozok is to be discontinued, guidelines indicate the dosage should be gradually reduced over a period of one to two weeks.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Selozok

Evidence for Use in Chronic Heart Failure Management

The use of Selozok was studied for chronic heart failure management in several large research initiatives, which were set up as controlled trials. These studies involved large populations of patients to gather outcomes related to systemic or functional imbalance. Specifically, research examined whether using this medication was associated with changes in major health outcomes, such as all-cause mortality and hospitalizations due to heart failure.

Studies reported measurements of all-cause mortality and hospitalization rates in the observed group receiving the medication compared to the placebo group. Reported outcomes also included measurements of hospitalization rates attributed to heart failure. This evidence contributes to the broader evidence landscape describing the use of the medicine for conditions marked by functional limitations.


Evidence for Use in High Blood Pressure (Hypertension)

Selozok was evaluated in research contexts involving high blood pressure, where studies explored outcomes related to systemic or functional imbalance. These trials focused on the extended-release characteristic of the formulation.

Research highlights changes measured during the study period, indicating data show patterns related to measured blood pressure metrics. The full change in the measured metric (e.g., heart rate or blood pressure) was observed to occur within the first few weeks of observation. The research contributes to understanding observed blood pressure patterns.


Evidence for Use in Angina Pectoris and Migraine Prophylaxis

Selozok was studied for conditions characterized by fluctuating or episodic manifestations, such as angina pectoris (chest discomfort) and migraine. Research examined the use of the drug in trials assessing short-term or episodic symptom patterns. For angina, studies explored outcomes describing episodic or acute changes. For migraine prophylaxis (prevention), the drug was evaluated in conditions involving periods of heightened symptoms. Research provides context for patient-reported outcomes when the drug was studied for this use.


What Remains Uncertain in the Research Landscape

Comparative evidence is limited for some common uses, meaning that head-to-head evaluation against other treatments is not fully established. Furthermore, subgroup findings are uncertain for certain categories of patients with comorbid conditions, and evidence quality varies across studies, reflecting that data for certain groups remain insufficient. The research provides context but not individual predictions, and findings describe group patterns, not personal outcomes. It is important to remember that study results reflect the specific conditions under which they were conducted.

Key Studies & References

  1. FDA Drug Label for Metoprolol Succinate Extended-Release (DailyMed)
  2. MERIT-HF Trial Summary: Metoprolol for Heart Failure (NCBI Bookshelf)
  3. Clinical Trial Registry: Study on Metoprolol Extended-Release in Angina Pectoris

Frequently Asked Questions (FAQ)

Common questions about Selozok (FAQ)

Q: Can Selozok cause weight gain?

A: Regulatory documents state that weight gain has been reported as an adverse reaction. Official prescribing information classifies this effect as uncommon to rare.

Q: Can Selozok affect my sleep or cause insomnia?

A: Official product information notes that insomnia (difficulty sleeping) has been reported as an uncommon to rare side effect. Reports of nightmares are also included among the adverse reactions in the official labeling.

Q: Is it true that Selozok can cause hair loss in some people?

A: The official product information mentions that reversible hair loss (alopecia) has been reported rarely in patients. This information comes from documented post-marketing experience and clinical studies.

Q: Can taking Selozok make me feel tired or fatigued?

A: Yes, fatigue is one of the most frequently reported side effects. Official prescribing information lists fatigue as a very common adverse reaction, meaning it is noted in a high percentage of patients.

Q: What are the signs that my body is not tolerating Selozok well?

A: Possible signs of intolerance may relate to the documented side effects. These can include severe dizziness, marked bradycardia (a very slow heart rate), or signs of worsening heart failure. If symptoms of intolerance are experienced, official guidelines provide information regarding when to seek further evaluation.

Q: Is it common to experience stomach upset or nausea when starting Selozok?

A: Adverse reactions such as gastrointestinal issues are classified as common in official documents. These include nausea, diarrhea, abdominal pain, and constipation.

Q: What are the long-term safety concerns (beyond 5 years) of using Selozok?

A: Official labeling highlights certain serious potential safety concerns that apply to long-term use. These include the risk of worsening heart failure and the potential for severe reactions if the medication is abruptly discontinued instead of being discontinued without a gradual reduction plan.

Q: What is the list of foods or drinks I should strictly avoid while on Selozok?

A: The official prescribing information does not list any specific foods that must be strictly avoided during treatment. The instruction for administration is to take the tablet with food or immediately after a meal.

Q: Do I have to take Selozok at the exact same time every single day?

A: The extended-release formulation is designed for once-daily intake to maintain consistent drug levels over a 24-hour period. Consistency in intake supports the medication's extended-release design.

Q: What should I do if I accidentally miss a dose of Selozok?

A: Regulatory patient information outlines protocols for missed doses, which typically advise against taking double doses. Specific guidance addresses when to take the dose if it is remembered late versus when to wait for the next scheduled dose.

Q: Is Selozok okay to take if I have asthma or breathing problems?

A: The official warning and precautions section advises caution regarding the use of the drug in patients with bronchospastic diseases, such as asthma. This is due to the potential for it to block beta2-receptors.

Q: Can Selozok be taken if I also have diabetes?

A: Official warnings advise caution for patients with diabetes. This medication may mask certain warning signs of low blood sugar (hypoglycemia), specifically a rapid pulse rate.

Q: Can Selozok cause problems with sexual function?

A: Sexual dysfunction is listed in the official documents as an adverse reaction. This effect is documented as being rare among patients using the medication.

Q: Is it safe to take painkillers like ibuprofen or naproxen with Selozok?

A: Official interaction documents note that Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), such as ibuprofen, may decrease the blood pressure-lowering effect of the medication. This documented interaction is a factor in co-administration.

Q: Does Selozok interact with common cold and flu medicines?

A: Interactions have been documented with medicines that contain certain ingredients. Cold and flu medicines that use Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) or specific catecholamine-depleting drugs may have noted interactions.

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

A: Official labeling includes information and specific instructions for use in patients with renal impairment (kidney problems). Consideration for this population is detailed in regulatory documents.

Q: What is the purpose of Selozok if I don't feel any symptoms of high blood pressure?

A: The official purpose of the drug is to lower blood pressure, regardless of symptoms. Lowering blood pressure is intended to reduce the risk of serious cardiovascular events in the future, such as stroke and heart attack (myocardial infarction).

Q: Is it normal to feel a little bit dizzy when first starting Selozok?

A: Dizziness is listed as a common adverse reaction in the official product information. This effect is commonly noted by patients, particularly during the initial period when treatment is being started.

Q: Can women take Selozok while they are breastfeeding?

A: Official labeling states that the active ingredient, metoprolol, is present in human milk. It advises monitoring the breastfed infant for signs of bradycardia (slow heart rate) or other symptoms related to beta-blockade.

Q: Are there any non-prescription medicines that interact negatively with Selozok?

A: Interactions have been documented with non-prescription products that contain certain ingredients. For example, products that include Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are noted in the official interaction profile.

Q: Is there an increased risk of depression while taking Selozok?

A: Depression has been reported as an adverse reaction in clinical studies. Official data indicates this occurred in approximately 5 out of 100 patients studied.

Q: Can Selozok be used to prevent migraines?

A: Official labeling for the active ingredient, metoprolol, describes it as indicated for the prophylaxis (prevention) of migraine headaches. This information is available in the list of approved uses.

Q: How long does it usually take for Selozok to reach its full effect on blood pressure?

A: According to official dosage and administration information, the maximum effect of any given dose on blood pressure reduction is generally observed after one week of therapy.

Q: What evidence supports the use of Selozok for people who have had a heart attack?

A: The active ingredient is indicated for use to reduce the risk of further heart problems, including myocardial infarction (heart attack). This use is based on clinical evidence and included in the official indications.

Q: Are there any genetic factors that influence how well Selozok works for someone?

A: Regulatory documents note that the drug is metabolized predominantly by the enzyme CYP2D6. Because this enzyme has genetic variations among the population, the concentration of the drug in an individual’s body can be affected.

Q: Does Selozok affect blood sugar levels?

A: Official warnings state that this medication may cause changes in blood sugar levels and can also mask certain signs of low blood sugar, specifically a rapid pulse rate, which is an important consideration for patients with diabetes.

Q: Does Selozok affect driving or operating machinery?

A: Due to the potential for side effects like dizziness and tiredness, official labeling describes the potential impact on performing tasks that require full attention, such as driving or operating machinery.

Q: Is Selozok considered a long-term medication?

A: Yes, the medication is formally indicated for the long-term treatment of certain cardiovascular conditions. This includes the management of stable angina pectoris (chest discomfort).

Q: Do studies show a benefit of Selozok in people with heart failure?

A: Clinical studies reviewed by regulatory agencies support the use of this drug in patients with stable heart failure. The demonstrated benefit is described as a reduction in cardiovascular mortality and hospitalizations.

Q: Does taking Selozok impact my ability to exercise?

A: The mechanism of action for this medication is to reduce heart rate and cardiac output. Because of this, the official pharmacological description indicates the drug can affect how the body responds to physical exertion and exercise.

Q: Can I take Selozok if I am taking a medicine for depression or anxiety?

A: Caution is advised because some medicines used for depression or anxiety are known as strong CYP2D6 inhibitors. These specific medicines can significantly increase the concentration of metoprolol in the body, which is a factor to consider when using these medications together.

Q: Does Selozok interact with alcohol?

A: Alcohol may have additive effects with this medication in lowering blood pressure. This combination can increase the risk of side effects like dizziness and fainting, according to official patient information.

Q: Does Selozok make you gain or lose water weight?

A: Official documents list edema (swelling or fluid retention) as an uncommon side effect. Furthermore, peripheral edema is noted as a potential sign of worsening heart failure, which is a serious safety consideration.

How should Selozok be stored and disposed of?

Storage and Disposal Requirements for Selozok

Selozok (metoprolol succinate extended-release) must be stored strictly according to regulatory guidelines to maintain its stability. The medication requires storage at Controlled Room Temperature, which is between 20 C and 25 C (68 F and 77 F). The tablets must be protected from light and moisture and kept in the original, tightly closed container.

For child safety, the product must be stored out of the reach of children.

Disposal of unused or expired Selozok must comply with national and local regulations for pharmaceutical waste. Do not flush the tablets into surface water or the sanitary sewer system. Regulatory agencies recommend utilizing an official drug take-back program as the preferred method for discarding unused medicine.

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

Available in countries:

Equivalent of Selozok found in:

A-Z Index: