Ritalmex (Capsules) Instructions for Use

Marketing Authorization Holder

ICN Hungary, Co. Ltd. (Hungary)

ATC Code

C01BB02 (Mexiletine)

Active Substance

Mexiletine (Rec.INN registered by WHO)

Dosage Form

Ritalmex

Capsules 200 mg: 30 pcs.

Dosage Form, Packaging, and Composition

10 pcs. – blister packs (3) – cardboard packs.

Clinical-Pharmacological Group

Antiarrhythmic drug. Class I B

Pharmacotherapeutic Group

Antiarrhythmic agent

Pharmacological Action

Antiarrhythmic agent of class I B. The mechanism of action is due to the blockade of sodium channels in cardiomyocyte membranes.

It reduces the duration of the action potential and the effective refractory period in Purkinje fibers, suppressing their automaticity.

When used in average therapeutic doses, it practically does not affect myocardial contractility and does not cause slowing of AV conduction.

Pharmacokinetics

After oral administration, it is rapidly and almost completely (90%) absorbed from the gastrointestinal tract.

C_max is reached within 2-4 hours.

The therapeutic concentration is 0.75-2 mcg/ml, toxic – more than 2 mcg/ml.

Plasma protein binding is 55%.

It penetrates the placental barrier and is excreted in breast milk.

After intravenous administration, the plasma concentration decreases rapidly, and a steady-state equilibrium develops within 1 to 3 days.

It is metabolized in the liver to form inactive metabolites.

T_1/2 is 10-14 hours. It is excreted by the kidneys (70-80%), mainly in the form of metabolites. Excretion decreases with reduced creatinine clearance and alkalinization of urine.

Indications

Ventricular extrasystole, paroxysmal ventricular tachycardia, prevention of ventricular fibrillation (including in the acute period of myocardial infarction).

ICD codes

Dosage Regimen

Determine the dose, route of administration, and treatment duration individually based on the clinical situation.

For oral administration, initiate therapy with a loading dose of 400 mg, followed by a maintenance dose of 200 mg every 8 hours.

Adjust the maintenance dose based on therapeutic response and tolerability. The usual maintenance dosage range is 150-300 mg administered every 8 hours.

For some patients, a dosing interval of 12 hours may be sufficient. Do not exceed a maximum daily dose of 1200 mg.

In severe cases, such as life-threatening ventricular arrhythmias, a higher initial dose may be required under strict medical supervision.

For patients with hepatic impairment, reduce the initial daily dose by 50%.

For patients with renal impairment, exercise caution and monitor plasma concentrations; dosage reduction may be necessary.

For intravenous administration, administer as a slow infusion or bolus. Dilute the solution appropriately before infusion.

Monitor the patient’s ECG and plasma concentrations regularly during therapy. The therapeutic plasma concentration range is 0.75-2 mcg/ml.

Discontinue therapy gradually to avoid a rebound effect. Transfer patients from other antiarrhythmic agents under careful monitoring.

Adverse Reactions

From the digestive system taste disturbance, nausea, vomiting, hiccups, diarrhea, liver function disorders, unpleasant taste in the mouth.

From the CNS and peripheral nervous system drowsiness, articulation disorder, nystagmus, diplopia, accommodation disorder, ataxia, tremor, paresthesia, confusion, dysarthria, dizziness, headaches, sleep disorders.

From the cardiovascular system chest pain, peripheral edema; rarely – bradycardia, arterial hypotension, arrhythmogenic effect (atrial fibrillation, ventricular extrasystole).

Allergic reactions skin rash.

From the hematopoietic system leukopenia, thrombocytopenia.

Contraindications

Hypersensitivity to mexiletine; pronounced bradycardia, pronounced arterial hypotension, cardiogenic shock, chronic heart failure, parkinsonism.

Use in Pregnancy and Lactation

Use during pregnancy and lactation (breastfeeding) is possible only for vital indications.

Use in Hepatic Impairment

Use with caution in patients with impaired liver function. In case of impaired liver function, the initial daily dose should be reduced by 2 times. If AST activity increases, Mexiletine should be discontinued.

Use in Renal Impairment

Use with caution in patients with impaired renal function.

Special Precautions

Use with caution in patients with myasthenia gravis, epilepsy, mental illness, impaired liver and kidney function, AV block of II and III degree, WPW syndrome, sick sinus syndrome.

During use, an increase in the symptoms of parkinsonism is possible.

Influence on the ability to drive vehicles and mechanisms

During the treatment period, one should refrain from potentially hazardous activities that require increased attention and rapid psychomotor reactions.

Drug Interactions

With simultaneous use with almasilate, atropine, a slowdown in the absorption of mexiletine is possible; with metoclopramide – acceleration of mexiletine absorption; with morphine – a decrease in the absorption of mexiletine.

With simultaneous use with propafenone, quinidine, an increase in the plasma concentration of mexiletine is possible in patients with high activity of the CYP2D6 isoenzyme.

With simultaneous use with theophylline, an increase in the plasma concentration of theophylline and an increase in its side effects are possible.

With simultaneous use with phenytoin, rifampicin, the rate of metabolism and clearance of mexiletine increases, which leads to a decrease in its effectiveness.

With simultaneous use with fluoxetine, a theoretical enhancement of the effects of mexiletine is possible.

With simultaneous use, cimetidine may reduce the gastrointestinal side effects of mexiletine.

Storage Conditions

Store at 2°C (36°F) to 25°C (77°F). Keep in original packaging, protected from light. Keep out of reach of children.

Dispensing Status

Rx Only

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.