TONOCARD
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TONOCARD (TONOCARD).
Class Ib antiarrhythmic agent; blocks sodium channels, decreasing the rate of phase 0 depolarization, and shortens action potential duration. Increases the fibrillation threshold of the ventricles.
| Metabolism | Primarily hepatic, via cytochrome P450 isoenzymes (CYP2D6 and CYP1A2). Produces active metabolites: N-acetylprocainamide (NAPA) is not a major metabolite for lidocaine (tonocard). |
| Excretion | Renal: ~90% (10% unchanged, remainder as metabolites); biliary/fecal: minimal (<5%) |
| Half-life | Terminal elimination half-life: 2–3 hours; prolonged to 8–12 hours in severe hepatic impairment; clinical context: requires q8h dosing for arrhythmia suppression |
| Protein binding | 55–65% bound; primarily to alpha-1-acid glycoprotein (AAG) and albumin |
| Volume of Distribution | 1.5–2.0 L/kg; extensive tissue distribution, with high affinity to myocardium |
| Bioavailability | Oral: 85–95% (first-pass metabolism minimal) |
| Onset of Action | IV: 2–3 minutes; oral: 30–60 minutes |
| Duration of Action | IV: 15–30 minutes; oral: 6–8 hours; clinical notes: short duration mandates frequent dosing; therapeutic effect correlates with plasma levels of 3–6 mcg/mL |
Intravenous loading: 1.0-1.5 mg/kg over 10-15 minutes, followed by continuous infusion of 1-4 mg/min; maximum dose: 4 mg/min; oral: not applicable.
| Dosage form | TABLET |
| Renal impairment | GFR >50 mL/min: no adjustment; GFR 10-50 mL/min: reduce maintenance infusion by 25-50%; GFR <10 mL/min: reduce maintenance infusion by 50-75%. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce maintenance infusion by 50%; Child-Pugh Class C: use contraindicated or reduce by 75% with close monitoring. |
| Pediatric use | Loading dose: 1 mg/kg IV over 10-15 minutes; maintenance infusion: 20-50 mcg/kg/min; maximum single dose: 100 mg; use with extreme caution. |
| Geriatric use | Elderly patients: reduce initial loading dose to 0.75-1 mg/kg; maintenance infusion lower end of range (1-2 mg/min); monitor for hypotension and bradycardia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TONOCARD (TONOCARD).
| Breastfeeding | Excreted into breast milk in low concentrations. M/P ratio not established. American Academy of Pediatrics considers compatible with breastfeeding. Monitor infant for bradycardia and arrhythmias. |
| Teratogenic Risk | FDA Pregnancy Category B. First trimester: No evidence of teratogenicity in animal studies; human data limited but no increased risk of major malformations reported. Second and third trimesters: Potential for fetal bradycardia, QT prolongation, and electrolyte disturbances if maternal toxicity occurs. Use only if clearly needed. |
■ FDA Black Box Warning
None explicitly in FDA labeling; however, use in patients with underlying structural heart disease may be associated with increased mortality.
| Serious Effects |
["Hypersensitivity to lidocaine or amide-type local anesthetics","History of severe adverse reactions to lidocaine","Hypotension","Severe bradycardia","Heart block (second- or third-degree) without pacemaker","Wolff-Parkinson-White syndrome","Sick sinus syndrome","Severe left ventricular dysfunction","Uncontrolled heart failure"]
| Precautions | ["May cause CNS effects (dizziness, drowsiness, confusion, respiratory depression)","Cardiac toxicity including asystole, bradycardia, hypotension, and arrhythmias","Metallic taste reported","Use caution in patients with hepatic impairment, heart failure, or renal failure","Hypersensitivity reactions (rash, urticaria, anaphylactoid reactions)","Potential for increased risk of arrhythmias with pre-existing heart block or sick sinus syndrome"] |
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| Fetal Monitoring |
| Maternal: Continuous ECG monitoring during IV administration; periodic serum electrolytes, renal function. Fetal: Heart rate monitoring during labor if used for maternal arrhythmia. |
| Fertility Effects | No known impact on human fertility based on limited data. Animal studies show no adverse effects on fertility. |