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Procainamide| IV Dose | Loading dose: 10-15 mg/kg (yes, milligrams)maximum 1.0 gram maximum rate 50 mg/min or 0.5 mg/kg/min Drip: 30-80 ug/kg/min (yes, micrograms) | | Oral dose | 50-100 mg/kg/day divided q 3-4 hours (q 6 hours for slow release forms) | | Levels | PC 4-8, may go up to 12 ug/ml NAPA <40 ug/ml is well tolerated. ?usefulness | | Kinetics | Peak levels at 1 hour after oral dose. Increased volume of distribution in heart failure. Elimination half-life of PC: 2.5-4.7 hours in adults.13.5 hours in neonates.7 hours in 7-12 year olds.1st order to at least to 26 ug/ml. For slow release forms, t 1/2 = 6-7 hours. Elimination half-life of NAPA: 6-8 hours. | | Cautions | QRS >25% prolongation: no further dosage increases QTc >= 0.500 : stop drug | | Interactions | Amiodarone increases PC and NAPA levels by 57% and 32% respectively. Cimetidine increases PC half-life. Propranolol decreases t 1/2, increases Vd. Digoxin: no known interaction. | | Preparations | Pronestyl non-scored tabs: 250, 375, 500 mg. Capsules 250, 375, 500 mg. Pronestyl SR non-scored matrix tabs: 500 mg. Procan SR wax matrix tabs: 250, 500, 750, 1000 mg.(>500 tabs scored) Pronestyl injection 1000 mg vials:100 mg/cc or 500 mg/cc. | | FDA approval in children | no |
Quindine| IV Dose | Don't! Frequent occurrence of hypotension and cardiovascular collapse! | | Oral dose | Quinidine sulfate: 30-60 mg/kg/day (450-900 mg/m2/day) in children, 10 mg/kg/day in adults, divided q 6 hours.
20% higher for gluconate, given q 8-12 hours
| | Levels | 2-6 ug/ml >7 ug/ml highly correlated with toxicity. | | Kinetics | Peak levels 1-3 hours for sulfate, 4 hours for gluconate after oral dose. Elimination half-life 6.3 hours in adults. 4.7 hours in 4-6 year olds, 6 hours in neonates. | | Cautions | Similar to those for procainamide | | Interactions | Potentiation of warfarin effect. Mean 100-150% increase in digoxin levels. (Probably doesn't occur under 2 months of age.) Levels increased in congestive heart failure. Elimination impaired by cimetidine, amiodarone. Elimination accelerated by phenytoin, propranolol, rifampin. Contraindicated with verapamil: cardiovascular collapse and hypotension frequent. | | Preparations | Quinidine sulfate tablets: 200, 300 mg.
Quinidex Extentabs (Q. sulfate): 1/3 released immediately, 2/3 slow release in GI tract. 300 mg tablets.
Quiniglute Duratabs: non-scored tablets: 324 mg | | FDA approval in children | no |
Disopyramide| IV Dose | No IV form | | Oral dose | < 2 yr.: 23-33 mg/kg/day (mean 30)
2-10 yr.: 9-24 mg/kg/day (mean 20)
>10 yr.: 5-13 mg/kg/day (mean 8)
divided q 6 hours, or q 12 hours for CR forms.
Maximum 1200 mg/day. | | Levels | 2-5 ug/ml, poorly correlated with efficacy | | Kinetics | Peak levels at 0.5-3 hours after oral dose. (3.4-4.0 hours after controlled release form). Nonlinear kinetics due to protein binding. Elimination half-life 5-6 hours at therapeutic levels. Large Vd in children. | | Cautions | Causes significant decreases in contractility! In renal failure, active metabolite (NMD) accumulates, which is even more anticholinergic than parent compound. | | Interactions | None with digoxin.
Atenolol decreases clearance and is synergistic in decreasing cardiac output. (Probably true for allbeta blockers).
Phenytoin increases clearance and decreases levels. | | Preparations | Norpace capsules: 100, 150 mg
Norpace CR: controlled release capsules: 100, 150 mg | | FDA approval in children | yes |
Procainamide| IV Dose | Loading dose: 10-15 mg/kg (yes, milligrams)maximum 1.0 gram maximum rate 50 mg/min or 0.5 mg/kg/min Drip: 30-80 ug/kg/min (yes, micrograms) | | Oral dose | 50-100 mg/kg/day divided q 3-4 hours (q 6 hours for slow release forms) | | Levels | PC 4-8, may go up to 12 ug/ml NAPA <40 ug/ml is well tolerated. ?usefulness | | Kinetics | Peak levels at 1 hour after oral dose. Increased volume of distribution in heart failure. Elimination half-life of PC: 2.5-4.7 hours in adults.13.5 hours in neonates.7 hours in 7-12 year olds.1st order to at least to 26 ug/ml. For slow release forms, t 1/2 = 6-7 hours. Elimination half-life of NAPA: 6-8 hours. | | Cautions | QRS >25% prolongation: no further dosage increases QTc >= 0.500 : stop drug | | Interactions | Amiodarone increases PC and NAPA levels by 57% and 32% respectively. Cimetidine increases PC half-life. Propranolol decreases t 1/2, increases Vd. Digoxin: no known interaction. | | Preparations | Pronestyl non-scored tabs: 250, 375, 500 mg. Capsules 250, 375, 500 mg. Pronestyl SR non-scored matrix tabs: 500 mg. Procan SR wax matrix tabs: 250, 500, 750, 1000 mg.(>500 tabs scored) Pronestyl injection 1000 mg vials:100 mg/cc or 500 mg/cc. | | FDA approval in children | no |
Quindine| IV Dose | Don't! Frequent occurrence of hypotension and cardiovascular collapse! | | Oral dose | Quinidine sulfate: 30-60 mg/kg/day (450-900 mg/m2/day) in children, 10 mg/kg/day in adults, divided q 6 hours.
20% higher for gluconate, given q 8-12 hours
| | Levels | 2-6 ug/ml >7 ug/ml highly correlated with toxicity. | | Kinetics | Peak levels 1-3 hours for sulfate, 4 hours for gluconate after oral dose. Elimination half-life 6.3 hours in adults. 4.7 hours in 4-6 year olds, 6 hours in neonates. | | Cautions | Similar to those for procainamide | | Interactions | Potentiation of warfarin effect. Mean 100-150% increase in digoxin levels. (Probably doesn't occur under 2 months of age.) Levels increased in congestive heart failure. Elimination impaired by cimetidine, amiodarone. Elimination accelerated by phenytoin, propranolol, rifampin. Contraindicated with verapamil: cardiovascular collapse and hypotension frequent. | | Preparations | Quinidine sulfate tablets: 200, 300 mg.
Quinidex Extentabs (Q. sulfate): 1/3 released immediately, 2/3 slow release in GI tract. 300 mg tablets.
Quiniglute Duratabs: non-scored tablets: 324 mg | | FDA approval in children | no |
Disopyramide| IV Dose | No IV form | | Oral dose | < 2 yr.: 23-33 mg/kg/day (mean 30)
2-10 yr.: 9-24 mg/kg/day (mean 20)
>10 yr.: 5-13 mg/kg/day (mean 8)
divided q 6 hours, or q 12 hours for CR forms.
Maximum 1200 mg/day. | | Levels | 2-5 ug/ml, poorly correlated with efficacy | | Kinetics | Peak levels at 0.5-3 hours after oral dose. (3.4-4.0 hours after controlled release form). Nonlinear kinetics due to protein binding. Elimination half-life 5-6 hours at therapeutic levels. Large Vd in children. | | Cautions | Causes significant decreases in contractility! In renal failure, active metabolite (NMD) accumulates, which is even more anticholinergic than parent compound. | | Interactions | None with digoxin.
Atenolol decreases clearance and is synergistic in decreasing cardiac output. (Probably true for allbeta blockers).
Phenytoin increases clearance and decreases levels. | | Preparations | Norpace capsules: 100, 150 mg
Norpace CR: controlled release capsules: 100, 150 mg | | FDA approval in children | yes |
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Lidocaine| IV Dose | Loading does: 1 mg/kg, given no faster than 50 mg/min.
May repeat twice q 5-10 mins.
Drip 20-50 ug/kg/min.
Decrease rate by 50% at 24 hours! | | Oral dose | No PO form | | Levels | 1.5-5 ug/ml.
Toxicity (esp. confusion) frequent >6 ug/ml. | | Kinetics | Elimination half-life 1.8 hours in adults and children aged 6 m- 3 years, 3.2 hours in neonates.
Decreased clearance in congestive heart failure. | | Cautions | Vertigo, paraesthesias, slurred speech and confusion are the first signs of toxicity. | | Interactions | Propranolol decreases liver blood flow and lidocaine clearance.
Isoproterenol, phenobarbital, phenytoin increase clearance. | | Preparations | Xylocaine injection, 100 mg/5 cc (amps or syringes) | | FDA approval in children | yes |
Mexiletine | IV Dose | No IV form | | Oral dose | Children: 1.4-5.1 mg/kg/dose, given q 8 hours.
May increase to 8.0 mg/kg/dose in infants.
Adults: 450-1200 mg/day divided TID | | Levels | 0.8-2.0 ug/ml
Poor correlation with therapeutic efficacy | | Kinetics | Elimination half-life 6.3-11.8 hours in adults
Increased to 15.4 hours in heart failure.
Peak levels 1-3 hours after oral dose | | Cautions | | | Interactions | Phenytoin, rifampin increase clearance | | Preparations | Mexitil capsules: 150, 200, 250 mg | | FDA approval in children | no |
Phenytoin| IV Dose | Loading: 10-15 mg/kg to maximum of 1.0 gram.
1/13 given IV bolus every 5 mins, flushed with NS.
(D5W will precipitate drug in line) | | Oral dose | Loading: 15 mg/kg divided QID x 24 hours, then 7.5 mg/kg divided QID x 24 hours.
Additional day of 7.5 optional, depending on response and levels.
Maintenance: By age:
0-2 wk.: 4-8 mg/kg/d divided q 12 hours
Infants > 2 wk.: 8-12 mg/kg/d divided q 8 hours
Children: 5-6 mg/kg/d divided q 12 hours
Adults: 300-400 mg/day divided q 12 hours. | | Levels | 10-25 ug/ml
Toxicity common at > 20 ug/ml. | | Kinetics | Zero-order (t 1/2 depends on concentration) e.g. At high levels, additional dose increases may raise levels drastically.
Average t 1/2 = 22 hours at therapeutic levels (range 7-40 hours) in adults, 8 hours at 1 month, 21 hours in full term newborns, 75 hours in prematures.
Peak levels at 1.5-3 hours after oral dose of Infatabs, 4-12 hours for Kapseals. | | Cautions | In pregnancy, 11% incidence of fetal hydantoin syndrome, 31% incidence of lesser impairments. | | Interactions | Amiodarone increases levels
Phenobarbital decreases levels
Phenytoin potentiates warfarin anticoagulation
Phenytoin decreases digoxin half-life | | Preparations | Dilantin suspension SHOULD NEVER BE GIVEN
Dilantin Infatabs- best absorbed 50 mg
Dilantin Kapseals: 30, 100 mg. | | FDA approval in children | yes |
Moricizine| IV Dose | No IV form | | Oral dose | 200 mg/m2/day (5 mg/kg/day) divided q 8 hours. Increase slowly to 600 mg/m2/day | | Levels | Not useful | | Kinetics | Elimination of half-life 2-5 hours | | Cautions | 3.7% risk of proarrhythmia | | Interactions | None known | | Preparations | Ethmozine non-scored tablets 200, 250, 300 mg | | FDA approval in children | no |
Lidocaine| IV Dose | Loading does: 1 mg/kg, given no faster than 50 mg/min.
May repeat twice q 5-10 mins.
Drip 20-50 ug/kg/min.
Decrease rate by 50% at 24 hours! | | Oral dose | No PO form | | Levels | 1.5-5 ug/ml.
Toxicity (esp. confusion) frequent >6 ug/ml. | | Kinetics | Elimination half-life 1.8 hours in adults and children aged 6 m- 3 years, 3.2 hours in neonates.
Decreased clearance in congestive heart failure. | | Cautions | Vertigo, paraesthesias, slurred speech and confusion are the first signs of toxicity. | | Interactions | Propranolol decreases liver blood flow and lidocaine clearance.
Isoproterenol, phenobarbital, phenytoin increase clearance. | | Preparations | Xylocaine injection, 100 mg/5 cc (amps or syringes) | | FDA approval in children | yes |
Mexiletine | IV Dose | No IV form | | Oral dose | Children: 1.4-5.1 mg/kg/dose, given q 8 hours.
May increase to 8.0 mg/kg/dose in infants.
Adults: 450-1200 mg/day divided TID | | Levels | 0.8-2.0 ug/ml
Poor correlation with therapeutic efficacy | | Kinetics | Elimination half-life 6.3-11.8 hours in adults
Increased to 15.4 hours in heart failure.
Peak levels 1-3 hours after oral dose | | Cautions | | | Interactions | Phenytoin, rifampin increase clearance | | Preparations | Mexitil capsules: 150, 200, 250 mg | | FDA approval in children | no |
Phenytoin| IV Dose | Loading: 10-15 mg/kg to maximum of 1.0 gram.
1/13 given IV bolus every 5 mins, flushed with NS.
(D5W will precipitate drug in line) | | Oral dose | Loading: 15 mg/kg divided QID x 24 hours, then 7.5 mg/kg divided QID x 24 hours.
Additional day of 7.5 optional, depending on response and levels.
Maintenance: By age:
0-2 wk.: 4-8 mg/kg/d divided q 12 hours
Infants > 2 wk.: 8-12 mg/kg/d divided q 8 hours
Children: 5-6 mg/kg/d divided q 12 hours
Adults: 300-400 mg/day divided q 12 hours. | | Levels | 10-25 ug/ml
Toxicity common at > 20 ug/ml. | | Kinetics | Zero-order (t 1/2 depends on concentration) e.g. At high levels, additional dose increases may raise levels drastically.
Average t 1/2 = 22 hours at therapeutic levels (range 7-40 hours) in adults, 8 hours at 1 month, 21 hours in full term newborns, 75 hours in prematures.
Peak levels at 1.5-3 hours after oral dose of Infatabs, 4-12 hours for Kapseals. | | Cautions | In pregnancy, 11% incidence of fetal hydantoin syndrome, 31% incidence of lesser impairments. | | Interactions | Amiodarone increases levels
Phenobarbital decreases levels
Phenytoin potentiates warfarin anticoagulation
Phenytoin decreases digoxin half-life | | Preparations | Dilantin suspension SHOULD NEVER BE GIVEN
Dilantin Infatabs- best absorbed 50 mg
Dilantin Kapseals: 30, 100 mg. | | FDA approval in children | yes |
Moricizine| IV Dose | No IV form | | Oral dose | 200 mg/m2/day (5 mg/kg/day) divided q 8 hours. Increase slowly to 600 mg/m2/day | | Levels | Not useful | | Kinetics | Elimination of half-life 2-5 hours | | Cautions | 3.7% risk of proarrhythmia | | Interactions | None known | | Preparations | Ethmozine non-scored tablets 200, 250, 300 mg | | FDA approval in children | no |
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Flecainide| IV Dose | No IV form | | Oral dose | 50-200 mg/m2/day divided q 12 hours Maximum 400 mg/day.
Or
6.7-9.5 mg/kg/d divided tid in Japanese study
Acta Paediatr Jpn 1994 Feb;36(1):44-8 Improved efficacy with TID dosage in young children and patients with toxicity. Increase in 50 mg/m2 increments every 4 days
Decrease by 50% when used with amiodarone. | | Levels | Therapeutic effects at 0.200-1.000 ug/ml.
Increased proarrhythmia and toxicity at > 1.0 ug/ml. | | Kinetics | Elimination half-life 7-19 hours (mean 13). in adults, and 7-12 hours (mean 8.7) in children aged 1 month to 13 years.
Reduced clearance in congestive heart failure.
Peak levels at 2-3 hours after oral dose. | | Cautions | Proarrhythmic effect worst in poor LV function. Significant negative inotropic effect. | | Interactions | Amiodarone increases levels by 100%.
Additive negative inotropic effect when used with propranolol, verapamil, or disopyramide.
Increases digoxin levels 24% average. | | Preparations | Tambocor scored tablets: 50, 100 mg. | | FDA approval in children | no |
Propafenone| IV Dose | 0.2 mg/kg q 10 min to 2.0 mg/kg maximum. Give with volume.
Drip 0.004-0.007 mg/kg/min
(IV preparation not available in USA)
| | Oral dose | 300-400 mg/m2/day divided q 6 hours | | Levels | Not yet proven to be useful. | | Kinetics | Nonlinear, saturable kinetics
Variable elimination half-life: 2.4-11.8 hours (Up to 26 hours in slow metabolizers).
Peak levels 2-3 hours after oral dose. | | Cautions | 1/40 propranolol beta-blocking effect, 50 times the normally achievable propranolol concentrations. | | Interactions | Increases digoxin levels by 40-100%.
Aggravates ventricular arrhythmias, especially torsades de pointes, when used with amiodarone. | | Preparations | Rythmol scored tablets, 150 mg, 300 mg | | FDA approval in children | no |
Flecainide| IV Dose | No IV form | | Oral dose | 50-200 mg/m2/day divided q 12 hours Maximum 400 mg/day.
Or
6.7-9.5 mg/kg/d divided tid in Japanese study
Acta Paediatr Jpn 1994 Feb;36(1):44-8 Improved efficacy with TID dosage in young children and patients with toxicity. Increase in 50 mg/m2 increments every 4 days
Decrease by 50% when used with amiodarone. | | Levels | Therapeutic effects at 0.200-1.000 ug/ml.
Increased proarrhythmia and toxicity at > 1.0 ug/ml. | | Kinetics | Elimination half-life 7-19 hours (mean 13). in adults, and 7-12 hours (mean 8.7) in children aged 1 month to 13 years.
Reduced clearance in congestive heart failure.
Peak levels at 2-3 hours after oral dose. | | Cautions | Proarrhythmic effect worst in poor LV function. Significant negative inotropic effect. | | Interactions | Amiodarone increases levels by 100%.
Additive negative inotropic effect when used with propranolol, verapamil, or disopyramide.
Increases digoxin levels 24% average. | | Preparations | Tambocor scored tablets: 50, 100 mg. | | FDA approval in children | no |
Propafenone| IV Dose | 0.2 mg/kg q 10 min to 2.0 mg/kg maximum. Give with volume.
Drip 0.004-0.007 mg/kg/min
(IV preparation not available in USA)
| | Oral dose | 300-400 mg/m2/day divided q 6 hours | | Levels | Not yet proven to be useful. | | Kinetics | Nonlinear, saturable kinetics
Variable elimination half-life: 2.4-11.8 hours (Up to 26 hours in slow metabolizers).
Peak levels 2-3 hours after oral dose. | | Cautions | 1/40 propranolol beta-blocking effect, 50 times the normally achievable propranolol concentrations. | | Interactions | Increases digoxin levels by 40-100%.
Aggravates ventricular arrhythmias, especially torsades de pointes, when used with amiodarone. | | Preparations | Rythmol scored tablets, 150 mg, 300 mg | | FDA approval in children | no |
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