Caffeine & Paraxanthine
Address: for Samples: 
Sandwell & West Birmingham Hospitals NHS Trust,
Pathology Department, Dudley Road,
Birmingham, B18 7QH
Contact Points
Laboratory Tel: 0121 507 5345
Caffeine & Paraxanthine
Page last updated: 03 March 2023
Next review date: 03 March 2024

Caffeine is consumed by more than 90% of adults daily and is found in coffee, tea, chocolate and energy drinks. It is also combined with analgesics and produced in a

tablet form for fatigue relief.

Caffeine and its main metabolite paraxanthine are both central nervous system stimulants which, among othereffects, can increase blood pressure and

accentuate heart beats. Caffeine also has psychoactive properties leading to reduced fatigue and increased alertness.

Excessive consumption of caffeine and subsequent withdrawal can lead to non-specific side-effects such as anxiety, depression, palpitations, migraine and insomnia.

Clinical Use of Caffeine Measurement Due to its stimulant effects, caffeine therapy is used in neonates to treat apnoea of prematurity. Monitoring of caffeine levels during treatment is of use in those infants who show signs of toxicity or who are not responding to a standard dose. Caffeine can play a role in a number of clinical presentations such as headache, insomnia and palpitations, and the measurement of caffeine in older children or adults could help identify those patients whose symptoms are caused by an excessive caffeine intake.