Drug treatment in children differs from that in adults, most obviously because it is usually based on weight or surface area. Doses (and dosing intervals) differ because of age-related variations in drug absorption, distribution, metabolism, and elimination. A child cannot safely receive an adult drug dose, nor can it be assumed that a child's dose is proportional to an adult's dose (ie, that a 7-kg child requires 1/10 the dose of a 70-kg adult). Most drugs have not been adequately studied in children, although federal legislation (the Best Pharmaceuticals for Children Act of 2001 and the Pediatric Research Equity Act of 2003 [both renewed in 2007]) provides the statutory and regulatory authority to begin those studies.

Adverse effects and toxicity: Children are generally subject to the same adverse effects as adults (see Adverse Drug Reactions), but they have increased risk with certain drugs because of differences in pharmacokinetics or because of drug effects on growth and development. Common drugs with unique or higher risk of adverse effects in children are listed in Table 1: Principles of Drug Treatment in Children: Drugs Manifesting Unusual Toxicity in Children.

Table 1
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Drugs Manifesting Unusual Toxicity in Children Drug Clinical Syndrome Mechanism Comments Anesthetics, topical (eg, benzocaineSome Trade Names AMERICAINE ANBESOL HURRICAINE ORAJEL BABY TEETHING Click for Drug Monograph , mixture of lidocaineSome Trade Names XYLOCAINE Click for Drug Monograph and prilocaineSome Trade Names CITANEST PLAIN DENTAL Click for Drug Monograph ) Cyanosis Formation of methemoglobin (ferrous iron oxidized to ferric iron) Incidence rare CeftriaxoneSome Trade Names ROCEPHIN Click for Drug Monograph Jaundice Kernicterus Bilirubin displaced from albumin Affects only neonates Diphenoxylate Respiratory depression Death CNS depression (in immature CNS) Overdose syndrome, usually in children < 2 yr Fluoroquinolones Cartilage toxicity Unknown Suspected based on animal studies, but adverse effects in humans unproved HexachloropheneSome Trade Names PHISOHEX Click for Drug Monograph In neonates, cystic brain lesions and death Unknown Topical disinfectant formerly used to wash preterm infants LindaneSome Trade Names KWELL Click for Drug Monograph (topical) Seizures CNS toxicity Probably enhanced absorption in children Should not be used in children < 50 kg (alternative should be used) ProchlorperazineSome Trade Names COMPAZINE Click for Drug Monograph Altered CNS function Extrapyramidal effects Opisthotonus Bulging fontanelles Actions via multiple CNS receptors Febrile and dehydrated infants especially at risk SSRIs Suicidal ideation Unknown Increased incidence of suicidal ideation in children and adolescents TetracyclineSome Trade Names ACHROMYCIN V TETRACYN TETREX Click for Drug Monograph Discoloration and pitting of tooth enamel Chelation with Ca in growing teeth Not given to children < 8 yr

Younger children are at especially high risk of accidental poisoning when they discover and take caregivers' vitamins or drugs. Infants are at risk of toxicity from drugs used by adults; toxicity can occur prenatally when they are exposed via placental transfer or postnatally when exposed through breast milk (numerous agents—see Approach to the Care of Normal Infants and Children: Drugs and see Table 4: Approach to the Care of Normal Infants and Children: Some Drugs Contraindicated for Breastfeeding Mothers) or skin contact with caregivers who have recently applied certain topical drugs (eg, scopolamineSome Trade Names
TRANSDERM SCOP
Click for Drug Monograph
for motion sickness, malathion for lice, diphenhydramineSome Trade Names
BENADRYL
NYTOL
Click for Drug Monograph
for poison ivy).

Adverse effects, including death, have occurred in children receiving OTC cough and cold preparations containing some combination of an antihistamine, sympathomimetic decongestant, and the antitussive dextromethorphanSome Trade Names
BENYLIN DM
DELSYM
DEXALONE
Click for Drug Monograph
. Current recommendations are that such products should not be given to children < 4 yr.

Last full review/revision June 2009 by Cheston M. Berlin, Jr., MD

Content last modified February 2012