Paediatric Prescribing and Common Medications

advertisement

Paediatric Prescribing and Common

Medications

Diana Mowbray

Paediatric Clinical Pharmacist

Rotherham 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

– 3/12 – 1yr

– 1-4yrs

– 4-7yrs

– 7-10yrs

– 10-12yrs

– >12yrs

5mg/Kg TDS/QDS

50mg TDS/QDS

100mg TDS

150mg TDS

200mg TDS

300mg TDS 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

– > 12yrs

– Max 240mg daily

0.5-1mg/Kg every 4-6hrs

30-60mg every 4-6hrs

• Morphine

– 1-12/12

– 1-2yrs

– 2-12yrs

– >12yrs

80-200micrograms/Kg 4hrly

200-400micrograms Kg 4hrly

200-500micrograms/Kg 4hrly max 20mg

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

?

Download