2.3 Anti-arrhythmic drugs
To be initiated on the advice of a paediatric cardiologist advice
|Class 1 anti–arrhythmics (membrane stabilising drugs)|
|Class 2 anti–arrhythmics (beta–blockers)|
Anti–arrhythmics are complex agents; with the exception of adenosine, intravenous injections or infusions should not be given without consultation with paediatric cardiologist.
- flecainide tablets 50mg, 100mg; liquid 25mg/5mL (named patient)
Oral maintenance doses
- Birth-12 years, 2mg/kg two to three times a day.
- 12-18 years, 50-100mg twice daily (max. 300mg daily).
- propranolol tablets 10mg, 40mg, 80mg, 160mg; solution 5mg/5mL
- Birth-12 years, 250-500microgram/kg three to four times a day.
- 12-18 years, 10-40mg three to four times a day. Doses adjusted according to response.
- adenosine injection 3mg/mL
- Birth-12 years, initial dose *50-100microgram/kg increased in 50microgram/kg increments at 2 minute intervals until tachycardia terminated or to a maximum dose of 300microgram/kg <1month or 500microgram/kg >1month. Max. 3mg daily.
- 12-18 years, initial dose 3mg increased after 2 minutes if necessary to 6mg, increase after a further 2 minutes if necessary to 12mg. Increments should not be given if high level AV block develops at any particular dose.
- digoxin tablets 62.5micrograms, 125micrograms and 250micrograms; elixir 50micrograms/mL. Maintenance doses (for initial doses refer to BNFC)
- Neonate < 2.5kg, 4-6micrograms/kg daily in 1-2 divided doses.
- Neonate >2.5kg–5years, 10micrograms/kg daily in 1-2 divided doses.
- 5-10 years, 6micrograms/kg daily in 1-2 divided doses.
- 10-18 years, 62.5-750micrograms daily in 1-2 divided doses. In practice, it is rare to exceed 375micrograms daily.
*The starting dose of 50micrograms of adenosine is rarely effective. Efficacy of treatment is defined as a single block in conduction and if tachycardia recurs immediately, there is no indication to use adenosine again. Treatment rather than termination drugs should be used instead. Vagal manoeuvres should be tried before administering adenosine.
Adenosine is the only intravenous agent that can be given without specialist advice. Cardiology should be informed if it has been administered.
Propranolol may be used in larger doses for hypertrophic cardiomyopathy on advice from a cardiologist.
Nadolol or propranolol may be initiated by a cardiologist for prolonged QT syndrome.
Flecainide liquid has a local anaesthetic effect and should be given at least 30minutes before or after food. Milk, infant formula and dairy products may reduce absorption , separate doses from feeds.
- For oral digoxin therapy dose should be rounded to the nearest 5micrograms to assist administering the dose.
- Although beta-blockers are not recommended in patients with asthma, they are often given on advice from a cardiologist without ill effect in such situations. They are not usually prescribed where there are good alternatives.