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تسجيل

oxicological screening , Theophylline and caffeine

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  p234-235

2026-10-18

75

oxicological screening

Theophylline and caffeine

Theophylline is prescribed to asthmatic children and adults, but serious toxicity can be caused both by therapeutic excess and by overdose. Clinical features include severe hypotension, cardiac arrhythmias and convulsions. Biochemical disturbances include hyperinsulinaemia, hyperkalaemia, glycosuria and metabolic acidosis. Many theophylline preparations are of the slow-release type, so that the onset of toxic symptoms may be delayed for up to 12 h after overdose. Treatment consists of gastric lavage for patients who reach hospital within 1 h of the overdose and multiple oral doses of activated charcoal, which is thought to be as efficient as charcoal haemoperfusion as an elimination procedure. The plasma theophylline concentration is an important diagnostic test and should   be measured urgently. In asymptotic patients levels should be measured 4 h or more after ingestion. Caffeine is prescribed for neonatal apnoea. It is also an ingredient of many proprietary stimulant preparations and is an important adulterant in drugs of abuse. Some patients have an idiosyncrasy for theophylline or caffeine, developing tachycardia at low serum concentrations. Although the lethal dose is large (about 10 g), severe caffeine intoxication with tachyarrhythmias followed by cardiovascular collapse has caused deaths in children. Caffeine also potentiates the effects of sympathomimetic drugs, which contribute to adverse cardiac disorders.

Commercial immunoassay kits are available to determine theophylline and caffeine in serum or plasma. These drugs can be determined by the STIP chromatography system.