Dosing in paediatrics: principles and adjustments MCQs With Answer

Dosing in paediatrics: principles and adjustments MCQs With Answer

This quiz collection is designed for M.Pharm students to deepen understanding of paediatric dosing principles and practical adjustments. It emphasizes developmental pharmacokinetics—how absorption, distribution, metabolism, and excretion change from preterm neonates to adolescents—and links these changes to dose selection, intervals, and monitoring. Questions cover scaling methods (mg/kg, BSA, allometric), maturation of clearance, calculation of loading and maintenance doses, therapeutic drug monitoring for narrow‑therapeutic‑index drugs, renal function estimation in children, and safety concerns with excipients. Use these MCQs to test applied knowledge required for safe, effective paediatric pharmacotherapy and for interpreting dosing recommendations in clinical practice.

Q1. Which principle best explains why neonates often require lower maintenance doses (per kg) for hepatically metabolized drugs compared with older children?

• Neonates have increased hepatic microsomal enzyme activity leading to faster clearance
• Neonates have reduced maturation of hepatic metabolic enzymes resulting in decreased clearance
• Neonates have higher glomerular filtration rate leading to faster elimination
• Neonates have increased protein binding increasing free drug clearance

Correct Answer: Neonates have reduced maturation of hepatic metabolic enzymes resulting in decreased clearance

Q2. For a loading dose calculation in a child, which pharmacokinetic parameter is primarily used to determine the dose?

• Clearance (CL)
• Volume of distribution (Vd)
• Half‑life (t1/2)
• Bioavailability (F)

Correct Answer: Volume of distribution (Vd)

Q3. Which statement about volume of distribution (Vd) in neonates is most accurate?

• Vd for lipophilic drugs is larger in neonates due to increased body fat
• Vd for hydrophilic drugs is larger in neonates due to higher total body water
• Vd is generally smaller for both hydrophilic and lipophilic drugs in neonates
• Vd does not change with age and is constant across paediatric ages

Correct Answer: Vd for hydrophilic drugs is larger in neonates due to higher total body water

Q4. Which method best accounts for maturational changes in clearance when scaling adult clearance to children across a wide age range?

• Simple mg/kg scaling
• Body surface area (BSA) normalization only
• Allometric scaling combined with a maturation function
• Using adult dose divided by two for children under 12 years

Correct Answer: Allometric scaling combined with a maturation function

Q5. Which CYP enzyme is known to have low activity in neonates but reaches adult levels within the first year of life and significantly affects drug clearance?

• CYP1A2
• CYP2D6
• CYP3A4
• CYP2C19

Correct Answer: CYP3A4

Q6. A 6‑month‑old infant (weight 7 kg) needs a drug with recommended maintenance dose 5 mg/kg/day in two divided doses. What is the dose per administration?

• 17.5 mg every 12 hours
• 35 mg every 12 hours
• 12.5 mg every 12 hours
• 7.5 mg every 12 hours

Correct Answer: 17.5 mg every 12 hours

Q7. Which renal function estimator is commonly used to adjust drug dosing in paediatric patients and incorporates height as a variable?

• Cockcroft‑Gault equation
• Modification of Diet in Renal Disease (MDRD)
• Schwartz formula
• CKD‑EPI equation

Correct Answer: Schwartz formula

Q8. In therapeutic drug monitoring (TDM) of aminoglycosides in neonates, which sampling strategy is most appropriate to assess for toxicity risk?

• Single random concentration at any time
• Peak sample only 30 minutes after infusion
• Trough concentration just before the next dose
• Two samples 2 hours apart during infusion

Correct Answer: Trough concentration just before the next dose

Q9. Which of the following excipients is particularly risky in neonates and has been associated with “gasping syndrome” when used in formulations?

• Sorbitol
• Benzyl alcohol
• Propylene glycol

Correct Answer: Benzyl alcohol

Q10. When converting an adult dose to a paediatric dose for a small child, why is simple mg/kg scaling potentially misleading for many drugs?

• Because children always require proportionally higher doses than adults
• Because pharmacokinetic parameters scale linearly with weight across all ages
• Because maturation of clearance and non‑linear relationships between body size and drug handling make mg/kg inaccurate
• Because body surface area is always the correct method instead

Correct Answer: Because maturation of clearance and non‑linear relationships between body size and drug handling make mg/kg inaccurate

Q11. A drug has Vd = 0.6 L/kg in adults and is hydrophilic. In neonates with higher total body water, which dosing implication is most likely?

• Neonates will require a smaller loading dose per kg
• Neonates will require a larger loading dose per kg
• No change in loading dose is needed based on Vd
• Only maintenance dose needs to be increased

Correct Answer: Neonates will require a larger loading dose per kg

Q12. For a drug eliminated primarily by renal filtration, which paediatric population is most at risk for accumulation if dosing is not adjusted?

• Adolescents with mature renal function
• Infants aged 6–12 months
• Preterm neonates with immature glomerular filtration
• Children aged 6–12 years

Correct Answer: Preterm neonates with immature glomerular filtration

Q13. Which dosing strategy is used when rapid therapeutic concentrations are needed and maintenance clearance is lower in neonates than older children?

• Give only a maintenance dose and wait several half‑lives
• Use a loading dose followed by an appropriately reduced maintenance dose
• Double the maintenance dose without a loading dose
• Avoid loading dose to prevent toxicity

Correct Answer: Use a loading dose followed by an appropriately reduced maintenance dose

Q14. Which factor most reduces plasma protein binding in neonates compared to adults, increasing free fraction of acidic drugs?

• Higher alpha‑1‑acid glycoprotein levels
• Lower albumin concentration and altered binding affinity
• Increased competitive binding by benzyl alcohol
• Higher hematocrit levels

Correct Answer: Lower albumin concentration and altered binding affinity

Q15. Phenytoin exhibits nonlinear (Michaelis‑Menten) kinetics. In a 4‑year‑old child, which dosing consideration is most important?

• Phenytoin dosing can be increased linearly without monitoring
• Small increases in dose may lead to disproportionate increases in plasma concentration, requiring close TDM
• Phenytoin is renally cleared so no TDM is needed in hepatic immaturity
• Use mg/kg dosing up to adult doses without concern for nonlinearity

Correct Answer: Small increases in dose may lead to disproportionate increases in plasma concentration, requiring close TDM

Q16. Which clinical parameter should be prioritized when adjusting antibiotic dosing in a critically ill child with augmented renal clearance?

• Serum albumin only
• Measured creatinine clearance or estimated renal function trends
• Patient weight alone
• Age in years only

Correct Answer: Measured creatinine clearance or estimated renal function trends

Q17. A 2‑year‑old weighs 12 kg. The recommended gentamicin pediatric regimen is 7 mg/kg as a single daily dose. What is the single daily dose?

• 84 mg
• 42 mg
• 24 mg
• 96 mg

Correct Answer: 84 mg

Q18. Which statement about using allometric scaling with exponent 0.75 for clearance is correct in paediatrics?

• It fully accounts for enzyme maturation in neonates and infants
• It provides a size‑based estimate but must be combined with a maturation function for young infants
• It is only valid for oral bioavailability adjustments
• It should be replaced by simple mg/kg dosing for accuracy

Correct Answer: It provides a size‑based estimate but must be combined with a maturation function for young infants

Q19. Which monitoring practice is most appropriate for vancomycin dosing in a 10‑year‑old with normal renal function?

• No monitoring is needed for children
• Measure trough concentrations before the fourth dose to guide dosing
• Measure peak immediately after infusion completion only
• Adjust dose solely by patient weight without concentration measurement

Correct Answer: Measure trough concentrations before the fourth dose to guide dosing

Q20. When assessing dose adjustments for a child with hepatic impairment, which principle is most relevant?

• Maintain adult maintenance dose because hepatic impairment does not affect paediatric dosing
• Estimate reduced clearance due to impaired metabolism and consider lower maintenance dose or longer dosing intervals
• Only loading doses need to be reduced; maintenance doses are unchanged
• Switch all drugs to renal elimination pathways automatically

Correct Answer: Estimate reduced clearance due to impaired metabolism and consider lower maintenance dose or longer dosing intervals

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