Paediatric Prescribing Paediatric Prescribing and Common and Common MedicationsMedications

Paediatric Prescribing Paediatric Prescribing and Common and Common MedicationsMedications

Diana MowbrayDiana MowbrayPaediatric Clinical PharmacistPaediatric Clinical Pharmacist

Rotherham NHS Foundation TrustRotherham NHS Foundation Trust

Things to Consider When Prescribing

• Child’s age and weight (Kg) / surface area

• Allergy status• Obesity / underweight• Immune status• How to get the drug into the body

Common Drugs• Antipyretics• Pain killers• Antibiotics• Inhalers• Anti-epileptics• Anti-reflux medications• Fluids

Antipyretics• Paracetamol

– 15mg/Kg 4hrly

• Ibuprofen– 1-3/12 5mg/Kg TDS/QDS– 3/12 – 1yr 50mg TDS/QDS– 1-4yrs 100mg TDS– 4-7yrs 150mg TDS– 7-10yrs 200mg TDS– 10-12yrs 300mg TDS– >12yrs up to 400mg TDS/QDS

Oral Pain Killers• Paracetamol

– Can go up to 20mg/Kg in > 1/12– Max 90mg/Kg/day– Can use a loading dose

• Ibuprofen– As for antipyretics (max 30mg/Kg/day)

• Diclofenac– Up to 1mg/Kg (max 50mg) TDS

Oral Pain Killers contd• Codeine

– 0-12yrs 0.5-1mg/Kg every 4-6hrs– > 12yrs 30-60mg every 4-6hrs– Max 240mg daily

• Morphine – 1-12/12 80-200micrograms/Kg 4hrly– 1-2yrs 200-400micrograms Kg 4hrly– 2-12yrs 200-500micrograms/Kg 4hrly

max 20mg

– >12yrs 5-20mg 4hrly

Antibiotics. Penicillins eg amoxicillin• Cephalosporins eg cefotaxime• Macrolides eg erythromycin• Aminoglycosides eg gentamicin• Trimethoprim • Metronidazole

Inhalers • Ipratropium bromide

– Can be useful in young babies for wheeze

• Salbutamol– Useful in all ages for wheeze – variable

response in young babies

• Beclometasone– Useful at step 2 upwards of the asthma

management guidelines

Anti-epileptics• Carbamazepine• Sodium valproate• Phenytoin • Phenobarbitone • Midazolam • Clobazam • Diazepam

Anti-reflux medications• Gaviscon infant sachets• Ranitidine• Domperidone • Omeprazole / Lansoprazole

Fluids • Sodium chloride 0.45% with

Dextrose 5% - basic children’s fluid• Dextrose 10% - basic neonatal fluid

• May be with or without potassium chloride dependent on clinical situation

Calculations • Always best calculated against

weight / surface area where possible

• NSF for children recommends all calculations should be documented in patient’s notes

Anti-reflux medications• A 5 week old term baby (4.13Kg)

presents with GORD. They have been treated with Gaviscon infant sachets at home. The child is still vomiting and not gaining weight.

• You are asked to prescribe oral Ranitidine and Domperidone

• What doses would you prescribe?

Anti-reflux medications• Ranitidine – 1mg/Kg TDS

– Prescribe as 4.1mg or 4mg TDS

• Domperidone – 200-400microgram/Kg 3-4 times a day– Prescribe as 830-1650micrograms 3-

4 times a day (0.83-1.65mg)

Anti-reflux medications• Ranitidine comes as 75mg/5ml solution

– Calculate the volume required– 0.27ml

• Domperidone comes as 1mg/ml suspension– Calculate the volume required– 0.83-1.65ml

Anti-epileptics• A 7 yr old (21.7Kg) is admitted with

generalised seizures and needs to be started on sodium valproate 200mg/5ml

• What dose would you prescribe initially and what dose would you anticipate the patient being maintained on?

• What volumes of medication will this mean needs drawing up?

Sodium Valproate• Initiate on 5-7.5mg/Kg BD

– 108.5-162.75mg BD– Ideally prescribe 110-165mg BD– 2.7-4.1ml BD

• Maintenance is 12.5-15mg/Kg BD– 272-324mg BD– 6.6-8.1ml BD

Lamotrigine• A 3yr old (14.5Kg) known epileptic

on sodium valproate 3.8ml BD for 8 months is admitted with uncontrolled seizures.

• You are asked to prescribe Lamotrigine in addition

• What dose will you prescribe?

Lamotrigine• Lamotrigine interacts with sodium

valproate (inhibits hepatic catabolism) and so a lower dose is required than would be if it was used with any other anti-epileptic

• Initial dose: 150microgram/Kg OD for 14 days, increasing gradually to a usual maintenance of 1-5mg/Kg in 1-2 divided doses (max 100mg)

• Calculate the doses required

Lamotrigine• Initial dose is 2.2mg (2.175mg)• This can be achieved by dissolving

a 5mg tablet in 5ml water and giving 2.2ml

• Maintenance is 14.5-72.5mg/day

Other problem• This child is also on a low dose of sodium

valproate for it’s weight.• 3.8ml = 152mg = 10.5mg/Kg/dose• Usual maintenance is

12.5-15mg/Kg/dose• This is probably due to weight increase

in the last 8 months and should be adjusted accordingly (perhaps before considering an additional drug!)

Prescribing problems• A patient arrives with the following list of

medication from mum (who has left the drugs at home). Which ones would you be confident to prescribe?

• Baclofen 20ml TDS• Glycopyrollate 4ml QDS• Clonazepam 3.5ml BD• Sodium Valproate 10ml BD• Levetiracetam 3ml BD• Alimemazine 7.5ml ON

Prescribing Problems• Baclofen only comes as 5mg/5ml• Glycopyrollate is only available as a

“special”• Clonazepam is only available as a

“special”• Sodium valproate only comes as

200mg/5ml• Levetiracetam only comes as 100mg/ml• Alimemazine is available in 2 strengths

Neonatal infusions• A 760g neonate requires a

dopamine infusion to run at 7.5microgram/Kg/minute

• The infusion is prepared as 30mg dopamine in 50ml of 10% dextrose

• What rate should the prescription state for the pump to run at?

Neonatal infusions• 0.76Kg x 7.5micrograms/Kg/min =

5.7micrograms/min• 5.7micrograms/min x 60mins =

342micrograms/hour• 30mg dopamine in 50ml contains 30 x

1000 / 50ml = 600micrograms/ml• The infusion needs to run at 342 / 600

= 0.57ml/hour

Common problems• Decimal points may not be clear

– Trailing zeros eg 2.0 may be mistaken for 20– Missing zeros eg .5 may be mistaken for 5

• Use of abbreviations to be avoided• Concentration errors when only a volume

is prescribed• Frequencies / times of administration not

prescribed on kardex = drugs not given

Common problems• Not reading all the information in

BNFC to find an appropriate dose– Mixing up of routes and doses– Mixing up of reason for giving and

doses– Using correct age range (especially in

neonatal period) for doses and frequencies

Quick Quiz• How many mg of adrenaline in 1ml of

– 1 in 1000?– 1 in 10,000?

• How many mmol of sodium in 500ml of 0.45% sodium chloride with 5% glucose?

• A 10Kg child requires 0.2mmol/Kg (50mg/Kg) magnesium sulphate. How much of a 50% solution do you need?

Answers • 1g in 1000ml = 1mg/ml

1g in 10,000ml = 0.1mg (100microgram) /ml

• 0.9% sodium chloride contains 150mmol Na/L = 75mmol in 500ml = 37.5mmol in 500ml of 0.45%

• 10Kg x 50mg/Kg = 500mg. A 50% solution contains 50g/100ml = 50,000mg/100ml = 500mg/ml

Questions

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