copyright ©2008 by pearson education, inc. upper saddle river, new jersey 07458 all rights...

Copyright ©2008 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Focus on Pharmacology, First EditionBy Jahangir Moini

Focus on PharmacologyEssentials for Health

Professionals

Chapter 30Pediatrics

Jahangir Moini, MD, MPH




Terms

• Neonate: birth to 28 days • Infant: 29 days to walking age (typically

1 year)• Toddler: 1 to 3 years of age




Factors that Affect Pharmacokinetics in Children

• Drugs inactivated by low pH gastric contents should not be given orally.

• Peristalsis is irregular and slower.• Rate of gastric emptying is variable.




Physiologic Impacts on Pharmacokinetics

The physiologic processes that influence pharmacokinetics in children include: – GI function– Tissue blood flow– Body fluid levels– Plasma protein concentrations– Liver function– Renal function.




Drug Distribution in Children

• Neonates have higher total body water than adults.

• Body fat is about 15%.• Protein binding of drugs is lower in

neonates.




Drug Absorption in Children

• Physiologic conditions can reduce rate of blood flow to site of administration: heart failure, cardiovascular shock, vasoconstriction

• If peripheral blood circulation improves, sudden increase of circulating drugs may cause toxic drug concentrations.




Drug Metabolism in Children

• Neonates exhibit substantially lower drug-metabolizing activities of oxidases and conjugating enzymes

• Dose-response relationships of some drugs may change markedly during first few weeks after birth




Drug Elimination in Children

• Glomerular filtration rate is lower in neonates.

• Drugs that require renal function for elimination are removed from the body very slowly during first weeks of life.




Limited Clinical Studies

• Very few clinical drug studies are done in children.

• Little data on effects of drugs in this population.

• Efficacy and dosage difficult to establish.




Pediatric Dosage Forms

• Elixirs: alcoholic solutions that offer consistent dissolution and distribution of drugs

• Suspensions: contain undissolved drug particles; must be shaken to evenly distribute drug particles




Drug Safety During Lactation

If data are not available about a certain drug and its effects on breastfeeding, the mother should not take it.




Pediatric Pharmacokinetic Differences

The differences in pharmacokinetics can lead to stronger or weaker drug effects in children compared with those of young adults.




Pediatric Drug Doses

• Based on proportionally reduced adult doses

• Based on body surface area, age, or body weight

copyright ©2008 by pearson education, inc. upper saddle river, new jersey 07458 all rights...

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