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Moricizine Hydrochloride

Pronunciation: MAHR-IH-sizz-een HIGH-droe-KLOR-ide
Class: Antiarrhythmic agent

Trade Names

- Tablets 200 mg
- Tablets 250 mg
- Tablets 300 mg


Moricizine is a class 1 antiarrhythmic agent with potent local anesthetic activity and myocardial membrane stabilizing effects. Moricizine reduces the fast inward current carried by sodium ions.



Bioavailability approximately 38% caused by first-pass metabolism. C max usually reached in 0.5 to 2 h.


Vd is 300 L or more. Protein binding approximately 95%.


Moricizine induces its own metabolism. Undergoes extensive first-pass metabolism. Extensive biotransformation to at least 26 metabolites. In an animal model, 2 metabolites are active, moricizine sulfate and phenothiazine-2carbamic acid ethyl ester sulfoxide.


Less than 1% excreted unchanged in urine. Plasma t ½ is 1.5 to 3.5 h. Approximately 56% excreted in feces and 39% in urine. Some enterohepatic recirculation occurs.

Indications and Usage

Treatment of documented life-threatening ventricular arrhythmias (eg, sustained ventricular tachycardia).


Preexisting second- or third-degree AV block; right bundle branch block associated with left hemiblock (bifascicular) unless a pacemaker is present; cardiogenic shock; hypersensitivity to any component of product.

Dosage and Administration


PO Between 600 and 900 mg/day, given every 8 h in 3 equally divided doses. Within this range, adjust dose in increments of 150 mg/day at 3-day intervals, until desired effect obtained. Patients exhibiting beneficial response as judged objectively (eg, Holter monitoring) can be maintained on chronic moricizine therapy. Because the antiarrhythmic effect persists for longer than 12 h, some patients, whose arrhythmias are well controlled on an every 8 h regimen, may be given the same total daily dose on a 12 h regimen to increase convenience and compliance.

Hepatic/Renal Function Impairment

PO Start with 600 mg/day or less and monitor closely, including ECG interval measurements, before dosage adjustment.


Store tablets at controlled room temperature (59° to 86°F). Protect from light.

Drug Interactions

Cimetidine, diltiazem

Plasma levels of moricizine may be elevated, increasing the pharmacologic and adverse effects.

Digoxin, propranolol

Additive prolongation of PR interval.

Diltiazem, theophylline

Levels may be reduced by moricizine, decreasing the pharmacologic effects.


Anticoagulant effect may be increased.

Laboratory Test Interactions

None well documented.

Adverse Reactions


Palpitations (6%); cardiac chest pain, cardiac death, CHF, sustained ventricular tachycardia (2% to less than 5%); bradycardia, cardiac arrest, cerebrovascular events, hypertension, hypotension, MI, pulmonary embolism, superventricular arrhythmias, syncope, thrombophlebitis, vasodilation (less than 2%).


Headache (8%); fatigue (6%); asthenia, hypesthesia, nervousness, paresthesia, sleep disorder (2% to less than 5%); abnormal coordination and gait, agitation, akathisia, anxiety, ataxia, coma, confusion, decreased libido, depression, diplopia, dyskinesia, euphoria, hallucination, memory loss, nystagmus, seizure, somnolence, speech disorder, tremor, vertigo (less than 2%).


Sweating (2% to less than 5%); dry skin, rash, pruritus, urticaria (less than 2%).


Blurred vision, eye pain, pharyngitis, tinnitus (less than 2%).


Nausea (10%); abdominal pain, diarrhea, dry mouth, dyspepsia, vomiting (2% to less than 5%); anorexia, bitter taste, dysphagia, flatulence, ileus (less than 2%).


Dysuria, impotence, kidney pain, urinary incontinence, urinary retention or frequency (less than 2%).




Elevated LFTs, jaundice (rare).


Musculoskeletal pain (2% to less than 5%).


Dyspnea (6%); apnea, asthma, cough, hyperventilation, sinusitis (less than 2%).


Drug fever, hypothermia, periorbital edema, swelling of lips and tongue, temperature intolerance (less than 2%).



Because of the known proarrhythmic properties of moricizine and the lack of evidence of improved survival for any antiarrhythmic agent in patients without life-threatening arrhythmias, it is prudent to reserve the use of moricizine for patients with life-threatening ventricular arrhythmias.


Category B .


Excreted in breast milk.


Safety and efficacy not established.

Electrolyte disturbances

Because may alter the effects of class 1 antiarrhythmic agents, correct electrolyte imbalance before administration.

Hepatic/Renal impairment

Use with caution and start with lower doses.

Proarrhythmic effect

Can provoke new rhythm disturbances or make existing arrhythmias worse.

Sick sinus syndrome

Because moricizine may cause sinus bradycardia, sinus pause, or sinus arrest, use with caution.


Has not been proven to favorably affect survival or incidence of sudden death.



Emesis, lethargy, coma, syncope, hypotension, conduction disturbances, exacerbation of CHF, MI, sinus arrest, arrhythmias, respiratory failure, death.

Patient Information

  • Advise patient that dose of medication may be changed periodically to obtain maximum benefit.
  • Caution patient to take prescribed dose every 8 or 12 h exactly as ordered. Advise patient that serious heart disturbances can result from missing doses or taking more often than prescribed.
  • Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
  • Caution patient not to change the dose or stop taking unless advised by health care provider. Advise patient that serious side effects can result from increasing or decreasing the dose without medical supervision
  • Inform patient that drug controls, but does not cure, abnormal heart rhythm and to continue taking as prescribed once the heart rhythm has been controlled.
  • Instruct patient to continue taking other heart medications as prescribed by health care provider.
  • Instruct patient in BP and pulse measurement skills.
  • Advise patient to monitor and record BP and pulse at home and to inform health care provider if abnormal measurements are noted. Also advise patient to take record of BP and pulse to each follow-up visit.
  • Instruct patient to lie or sit down if experiencing dizziness or lightheadedness when standing.
  • Advise patient to notify health care provider if any of the following occur: frequent episodes of dizziness or lightheadedness, persistent nausea, any other unusual or unexplained symptom.
  • Instruct patient to immediately report fainting, pounding in chest, change in pulse or heart rhythm, or unexplained fever to health care provider.
  • Caution patient that drug may cause dizziness or lightheadedness and to use caution while driving or performing other tasks requiring mental alertness or coordination until tolerance is determined.
  • Advise patient to carry medical identification (eg, card, bracelet) describing cardiac condition and medication regimen.
  • Offer family instruction in basic life support.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.