Caffeine

Apnea is most frequently seen in premature infants and is a significant contributor to the morbidity of low birth weight infants. Caffeine is administered to reduce the number of episodes of neonatal apnea. 

Caffeine has a half-life of 3 to 4 days in neonates and is given in small doses at longer intervals. Monitoring of caffeine levels is usually performed only on those neonates who are unresponsive to high doses of caffeine or who have signs of toxicity. 

Toxicity is a concern because neonates do not have a well-developed cytochrome P450 system to metabolize caffeine. Signs of toxicity include tachycardia, gastrointestinal intolerance, and jitteriness.  

The therapeutic range is 8-20 mcg/mL. This range is effective in reducing the number of episodes of apnea. Severe life threatening toxicity can occur at caffeine levels of 30 mcg/mL or higher. 

Caffeine can be measured by a homogeneous enzyme immunoassay Specimen requirement is one red top Microtainer blood collection tube.

Reference 

Goodman & Gilman: The Pharmacological Basis of Therapeutics. 14th ed. McGraw-Hill Education; 2023