Life-threatening ventricular arrhythmias
Adult: As hydrochloride: 1.2 g daily in 2 or 3 divided doses, adjust dose according to response and tolerance. Max: 2.4 g/day.
Indications and Dosage
Oral
Life-threatening ventricular arrhythmias Adult: As hydrochloride: 1.2 g daily in 2 or 3 divided doses, adjust dose according to response and tolerance. Max: 2.4 g/day.
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Renal Impairment
Severe: Reduce dose by 50%.
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Hepatic Impairment
Dose reduction may be needed.
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Contraindications
Hypersensitivity to amide-type drugs, 2nd or 3rd degree AV block without pacemaker, lactation.
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Special Precautions
Pregnancy, preexisting bone marrow failure, uncompensated heart failure. Impaired renal or hepatic function. Initiate treatment in hospital under ECG monitoring. Monitor blood counts wkly for the first 12 wk of therapy and mthly thereafter. Correct hypokalaemia before initiating therapy.
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Adverse Reactions
Tremor, dizziness, paraesthesia, lightheadedness, nausea, vomiting, anorexia, constipation, diarrhoea, rash, blurred vision, tinnitus, lupus erythematosus, sweating, taste disturbances, liver disorders.
Potentially Fatal: Haematological toxicity leading to neutropenia, agranulocytosis, thrombocytopenia, aplastic anaemia. Pulmonary toxicity (interstitial pneumonitis; pulmonary fibrosis, other respiratory disorders). Stevens-Johnson syndrome, exfoliative dermatitis. |
Overdosage
Convulsions, complete heart block and asystole. Treatment is symptomatic and supportive. Haemodialysis and charcoal hemoperfusion may be useful. Treatment may be prolonged due to long half-life of tocainide.
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Drug Interactions
Increases serum levels of theophylline. Cimetidine, rifampicin and other hepatic enzyme inducers decrease tocainide plasma levels. Additive CNS side effects with lignocaine.
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Action
Description: Tocainide is a class Ib antiarrhythmic with properties similar to lignocaine. It suppresses the automaticity of conduction tissue by increasing electrical stimulation threshold, spontaneous depolarisation of the ventricles and blocking of both the initiation and conduction of nerve impulses resulting in inhibition of depolarisation with resultant blockade of conduction.
Pharmacokinetics: Absorption: Readily and completetly absorbed from GI tract. Distribution: Widely distributed. Protein-binding: 10%. Metabolism: Undergoes metabolism to inactive metabolites. Excretion: Excreted in urine as (unchanged drug 30-50%). Elimination half-life: 10-20 hr. |
MIMS Class
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