Note that total body water makes up 75% to 80% of body weight in the full-term newborn, decreasing to 60% at 5 months of age.¹

By 5 months of age, total body fat doubles at the expense of total body water.¹

By 2 years of age, protein mass begins to rise at the expense of body fat and is physically noticeable, as infants become toddlers and begin to ambulate.¹

Fat-soluble and water-soluble drugs will therefore distribute differently in a child depending on body composition.¹

These changes in composition are important to recognize in the pediatric patient and may contribute to inadequate drug concentration or toxicity.

The GI tract is a common route of absorption in pediatrics.

Gastric acid is lowest in the newborn and does not reach adult levels until 2 years of age.¹

Motility in the GI tract in the infant is also erratic and characterized by peristalsis, corresponding to longer transit times.¹

Premature infants may have transit times of anywhere from 8 to 96 hours, as opposed to 4 to 12 hours observed in adults.¹

This delayed gastric emptying, also complicated by regurgitation in the infant, may result in delayed absorption in the duodenum.¹

Once a child hits school age, however, there are few differences in the absorption of drugs in the GI tract from adults.¹

Hepatic and renal functions are decreased in the neonate and develop as the child ages.

The ability of the liver and kidney to metabolize drugs develops as these organs mature, usually after 1 year of age.

Rectal administration of drugs is a common route of choice, especially if an infant is vomiting or unable to swallow medicine.¹

Note that medicine administered rectally is absorbed through the hemorrhoidal veins and into the systemic circulation, bypassing first-pass metabolism in the liver.¹

Prophylactic antibiotic usage accounts for about 75% of prescriptions of antibiotics on a surgical service.²

Antibiotics may also be required either as necessary in the management of the primary disease process or as a result of postoperative infection.

Antibiotic prophylaxis is indicated during clean-contaminated, contaminated, and dirty cases.²

If used, the first dose of antibiotics should be given 30 minutes to 1 hour before the first incision.³

Additional doses may be indicated if a procedure lasts longer than 2 half-lives of the drug given to maintain appropriate serum levels or if excessive blood loss is encountered during the procedure.⁴

If prophylaxis is continued postoperatively, antibiotics should not be given for longer than 24 hours.⁴

Note that data for dosing have been extrapolated from adult dosing and based on expert opinion.⁵

In general, fluoroquinolones should not be used for surgical prophylaxis in pediatric patients owing to their potential for toxicity.⁵

Pediatric dosages should not exceed adult dosages.

If a calculated mg per kg dose exceeds adult dosage, as may be found in adolescent patients, adult dosing should be used instead.⁵

The overall risk of venous thromboembolism (VTE) is low in the pediatric patient, estimated to be from 0.02% to 0.33% of injured, hospitalized children.⁶

Adequate prophylaxis is complicated by the fact that there are very few studies investigating VTE and anticoagulation in children. Most of the recommendations used today are extrapolated from adult data.⁶

Despite the lack of trial data, low-molecular-weight heparin (LMWH) agents are the most popular anticoagulant of choice in children.⁷

Benefits of LMWH include reduced need for monitoring and decreased risk of interaction with other medications.⁷

For both neonates and children, target anti-Xa activity should be 0.5 to 1.0 units/mL in a sample taken 4 to 6 hours after injection.⁷

Recent consensus indicates that children younger than 12 years who can ambulate may not require chemical VTE prophylaxis.⁶