|Clinical Use:||Clinicians use caffeine testing to monitor therapy and assess toxicity in neonates.|
|Background:||Caffeine is used to treat apnoea that occurs in newborn infants, the most frequent complication seen in the neonatal nursery.
Caffeine is administered orally (nasogastric tube) as a loading dose of 3 mg/kg followed by a maintenance dose of 1 mg/kg administered once every 24 to 48 hours, depending on the patient’s response and the serum level.
In neonates, caffeine has a half-life that ranges from 20 to 100 hours, which is much longer than in adults (typically 4-6 hours) due to the immaturity of the neonatal liver. This requires that small doses be administered at much longer intervals than would be predicted based on adult pharmacokinetics.
The volume of distribution of caffeine is 0.6 L/kg and the drug is approximately 35% protein bound.
Toxicity observed in neonates is characterized by central nervous system and skeletal muscle stimulation and bradycardia. These symptoms are seen in adults at lower levels than in neonates, suggesting that neonates have much greater tolerance to the drug.
|Reference Ranges:||10 – 30 mg/L|
|Patient Preparation:||None required|
|Specimen Requirements:||Serum or plasma. Blood specimen in a plain (red top) tube or lithium heparin tube. NOT SST.|
|Turnaround Time:||1 week|
|Referred Test:||Referred test|
|Location:||Medical Toxicology Unit|