Prescribing in Children Flashcards
In which groups do you need to consider specific issues when prescribing?
- Neonates, infants, young people, “children”
- Patients with renal or hepatic impairment
- Pregnant women
- Breastfeeding women
- Elderly
- Terminally ill/end of life
- Ethnic minorities or those whose first language is not English
- Culturally diverse groups e.g. Travellers, immigrants, refugees
- Incapacitated patients
- Patients unable to consent to treatment
- A typical patient group in your own specialist area e.g. respiratory patients or patients with mental health problems
- Those with other co-morbidities
What are the issues with prescribing for children?
- Altered pharmacokinetics and pharmacodynamics
- Issues around compliance & route of administration
- Medication errors can be made if doses miscalculated
- Less likely to have polypharmacy
What are the 4 main differences when prescribing for children?
ABCD
- Absorption: how a drug is taken into the body
- Biology:how the drug works in the body
- Clearance: how quickly a drug clears from the body
- Distribution: how its distributed amongst the water, fats & proteins in the body- this differs depending on the nature of the drug-eg fat or water soluble drugs
What are methods of drug absorption?
Orally, rectally, intra-muscularly, subcutaneously, inhalation, topically - except IV which bypasses absorption
What are issues for absorption in children?
- Intake of fluids in infants not guaranteed
- Affected by gastric emptying, gut motility and milk in stomach
- Avoid IM as less muscle, variable absorption and painful
- Rectal maybe possible but not popular in GB
- Skin absorption can cause toxicity in preterm eg alcohol & iodine
What are issues with biology (metabolism) in children?
- Mechanisms can vary between adults & children and within child age groups
eg Paracetamol is metabolised by slower process in neonate - Avoid some medicines in children which cause ADRs - eg aspirin & Reyes
- Effects of certain drugs on growth and development eg steroids
What are issues with drug clearance in children?
Enzyme systems that break drugs down may not have matured thus half life is prologed eg theophylline
GFR increases to adult level over year 1 eg penicillin cleared more slowly
Monitoring of some drugs needed eg phenytoin
What are issues with drug distribution in children?
Differing chemical nature of drugs mean they distribute more in certain components of the body. Eg water is 80% of neonate & 60% of an adult, necessitates higher doses/kg of water soluble drugs in neonates
Drugs with large therapeutic window can be prescribed on body weight or age
Drugs with narrow therapeutic window are often prescribed by body surface area eg cytotoxics
Plasma protein concentration is low in neonates eg bilirubin competes with sulphonamides to bind to albumin
What differences are there between adults and children to consider when prescribing?
Body weight
Body composition
Body surface area
Nutritional status
Organ and enzyme maturation
What are the definitions of these age groups:
- Preterm neonate
- Term neonate
- Post-term neonate
- Neonate
- Infant
- Child
- Adolescent
- Born at < 37 weeks gestation
- Born at 37 to 42 weeks gestation
- Born at >42 weeks gestation
- From 0 to 28 days of age
- From 28 days to 24 months
- From 2 years to 12 years
- From 12 years to 18 years
What considerations could you make for children?
- Like liquids, tablets hard to swallow
- Use nice tasting ones, improves compliance
- Less frequent doses improves adherence
What is an unlicensed medicine?
A medicine lacking UK marketing authorisation
What factors are there in off-label use?
- Dose: may need to be lower or higher than recommended depending on age and weight of child
- Age: Drugs not licensed in children is commonly due to lack of clinical trials
- Indication: Drugs may be used to treat childhood illnesses not covered by license (eg. Diclofenac used for pain post-op, but is only licensed for juvenile idiopathic arthritis)
- Contraindications: May need to be disregarded. (eg. aspirin used in Kawasaki syndrome despite contra-indications)
- Route
