Iowa Neonatology Handbook: Infection

Use of Drug Monitoring Levels in the Special Care Nurseries

Jonathan M. Klein, MD and Thomas N. George, MD
Peer Review Status: Internally Peer Reviewed

General guidelines

• Antibiotic dosing and intervals for gentamicin and theophylline should be administered as described in the Iowa Neonatology Handbook (pp 133,134). Vancomycin should be dosed at 15mg/kg, at the same intervals as described in the Handbook.
• Antibiotics should be withheld until the level is known, and an order to that effect should be written. If the trough level is greater than acceptable, the drug should not be given and another level checked 6 hours later, and this should be repeated as needed until a safe level is obtained.
• Peak levels are not necessary for patients being treated with a course of antibiotics without an identified organism.
• If a blood culture is positive, and an organism and sensitivities are identified, both peak and trough levels should be obtained to ensure adequate dosing.
• If 10 days of antibiotics are planned, and the first trough level obtained is acceptable, consider repeating the trough levels at 4 to 6 days into therapy to ensure non-toxic levels, especially if there is evidence or concern of impaired renal function.

Gentamicin

• A gentamicin trough level should be obtained within 1 hour of the dose:
  Gestational age ≥ 30 weeks, obtain level prior to the administration of the 3rd dose.
  Gestational age < 30 weeks, obtain level prior to the administration of the 2nd dose.
  If impaired renal function is a concern, a level should be obtained before the 2nd dose.
  An acceptable trough is < 2 mg/mL.
• Peak levels are not necessary for patients being treated with a course of antibiotics without an identified organism. If obtained, an acceptable peak is 5 – 8 mg/mL and should be obtained 30 minutes after the infusion.

Vancomycin

• A vancomycin trough level should be obtained within 1 hour of the dose:
  Gestational age ≥ 30 weeks, obtain level prior to the administration of the 3rd dose.
  Gestational age < 30 weeks, obtain level prior to the administration of the 2nd dose.
  If impaired renal function is a concern, a level should be obtained before the 2nd dose.
  An acceptable trough is < 10 mg/mL.
• Peak levels are not necessary for patients being treated with a course of antibiotics without an identified organism. If obtained, an acceptable peak is 20 – 40 mg/mL and should be obtained 30 minutes after the infusion.

Theophylline

• Either a trough or peak level will provide adequate information regarding dosing. A theophylline trough level should be obtained 0 - 2 hours before the scheduled dose, and the dose administered without awaiting the result. Consider writing the theophylline order to reflect times of administration to be at 8 am, 4 pm and 12 am. This would allow the level to be drawn with morning labs if the patient is on a q 8 h schedule. An acceptable theophylline trough level is 8 – 12 mg/ml. If obtained, an acceptable peak level is 15 - 20 mg/ml, and should be obtained between 2 and 4 hours after drug administration.

Section Top | Title Page