lectures

• Pharmacokinetics


  The study of the movement of drugs within the body, including the processes of absorption, distribution, metabolism, and excretion
• Differences in pharmacokinetics between adults and children

  • Absorption is generally higher in children due to immature epidermal barrier, higher skin hydration, and higher surface area to body ratio
  • Absorption is lower for intramuscular route of administration due to lack of muscle mass and poor perfusion
  • Extracellular fluid is higher in preterm infants and decreases with age
  • Body water content is higher in preterm infants and decreases with age
  • Fat content is lower in younger children except for 1-year-olds who have a high fat content
  • Protein binding is lower in children due to lower serum albumin and total protein concentrations, leading to higher free fraction and volume of distribution of unbound drug
  • Liver metabolism is immature in infancy, leading to longer half-lives and drug accumulation
  • Glomerular filtration rate is lower at birth and increases rapidly in postnatal life, reaching adult values by 3 months of age, and tubular secretory and resorptive capacity is reached by 7 months of age
• Unlicensed medicines


  Medicines that have never received a marketing authorization to be used in adults or children, including specials, extemporaneous preparations, and chemicals for medicinal purposes
• Off-label use


  The use of a drug outside the conditions of the product license or marketing authorization, such as different dose, age, indication, route of administration, or contraindication
• The challenge with off-label use is that there is no reference to double-check against as there is no research on it
• Potential causes of harm when prescribing and using medicines in children

  • Excipients (e.g. propylene glycol, ethanol, benzoic acid, propyl parabens, sorbitol, glucose, sucrose, colorants)
  • Overdose, underdose, adverse effects, toxicity (e.g. poor quality product, incorrect weight-based dosing, failing to update doses for chronic conditions, complex calculations)
  • Off-license prescribing (high risk of medication error, unclear or competing reference sources)
  • Communication issues with children, parents, or between healthcare providers
  • Different medication formulations (e.g. dose predicted by volume instead of body surface area, misinterpreting dosing schedule)
  • Inexperience working with children (adult practices implied, medication errors)
• Properties of each hydrocortisone formulation

  • Tablets(10/20mg) may require splitting, rendering them off-label and inaccurate , also forms non-uniform dispersion.
  • Soluble tablets (10mg) produces a true solution, more accurate dosing
  • Oral solution is unlicensed, due to formulation limitation
  • Granules in capsules(alkindi (0.5mg,1mg,2mg) have different bioavailability in comparison to other formulation , risk of adrenal crisis
• Advantages and disadvantages to consider for each hydrocortisone formulation

  • Cost
  • Licensed status and hierarchy of risk
  • Formulary status and accessibility
  • Route of administration
• Hydrocortisone is a high-risk drug used to treat a rare condition (congenital adrenal hyperplasia), requiring high doses to replace deficient glucocorticoids and suppress overproduction of sex steroids
• How pharmacists can support safer prescribing and medicines use in children

  • Checking prescriptions in clinical areas or during dispensing
  • Collecting and reviewing audit data
  • Contributing to risk management processes and educational interventions
  • Implementing electronic prescribing systems to flag drugs and complex calculations
  • Taking part in quality improvement initiatives