Specific antiarrhythmic drugs used in poisoning; drugs to avoid are also shown
| Toxin | First line antiarrhythmic agents | Other antiarrhythmic agents | Antiarrhythmic agents to avoid |
|---|---|---|---|
| Ensure adequate resuscitation and supportive treatment. Arrhythmias may be relatively benign in healthy children and drug therapy should be avoided wherever possible. | |||
| Antihistamines | Sodium bicarbonate | Magnesium sulphate | Class Ia and III27 |
| Antihistamines terfenadine or astemizole | Sodium bicarbonate | Propanolol, isoprenaline, flecainide27, magnesium sulphate | Class Ia and III |
| Class I antiarrhythmics, e.g. Ia quinidine and procainamide, Ib lignocaine, Ic flecainide | Sodium bicarbonate, run mildly alkalotic and keep potassium low normal33 | Atropine, phenytoin33 | Class I (although lignocaine can be used for arrhythmias due to Ia and Ic)33 |
| Class II antiarrhythmics, i.e. β blockers | Atropine, glucagon, cardiac pacing27 | Adrenaline, isoprenaline, dopamine, dobutamine34 | |
| Class III antiarrhythmics, i.e. sotalol and amiodarone | Amiodarone—toxicity is generally low Sotalol—initial treatment as for other β blockers | Lignocaine—for sotalol,27 magnesium sulphate34 | Isoprenaline can result in tachyarrhythmias27 |
| Class IV antiarrhythmics, i.e. calcium channel antagonists | Calcium gluconate,33,34 cardiac pacing | Atropine, glucagon, dopamine | |
| Cocaine | Sodium bicarbonate35 | Diazepam, GTN, calcium antagonists36–38 | |
| Dextropropoxyphene | Naloxone,39 sodium bicarbonate40 | Magnesium sulphate, phenytoin, atenolol27,41 | Class I, atropine27 |
| Digoxin | Correct hyperkalaemia (avoid calcium), digoxin antibodies , cardiac pacing | Atropine, lignocaine, amiodarone, phenytoin27 | Class Ia, Ic,29 DC shock,29 calcium, inotropes |
| Quinine | Keep potassium low normal | Phenytoin, β blockers, glucagon27 | Class Ia27 Lignocaine may precipitate convulsions27 |
| Theophylline | Avoid treatment if at all possible—2nd line agents may cause bronchoconstriction | Propanolol,42 esmolol, adenosine27—all may produce bronchoconstriction in asthmatics | Verapamil, lignocaine42 |
| Tricyclic antidepressants | Sodium bicarbonate, try to avoid other agents as much as possible | Phenytoin, atenolol,27 glucagon,43 lignocaine for ventricular arrhythmias, magnesium sulphate | Class Ia27 |