Substance
Xanthine derivatives

[Other Names]
Aminophylline
Caffeine
Theophylline

Pathology
Antagonism of adenosine activity and release of catecholamines; in high doses, phosphodiesterase inhibition. Toxic effects are secondary to smooth muscle relaxation, peripheral vasodilation, myocardial stimulation, and CNS excitation.

Symptoms
Nausea, protracted vomiting, hypotension, respiratory alkalosis, metabolic acidosis, hypokalemia, tachycardia, hypercalcemia, ventricular dysrhythmias, seizures, death due to cardiovascular collapse.

Emergency Measures
Activated charcoal. For deteriorating conditions, charcoal hemoperfusion. Treat seizures with benzodiazepines or barbiturates, and cardiac rhythm disturbances with standard ACLS protocols. Monitor theophylline levels several times a day.

Comments
Eliminate drugs that increase theophylline levels, such as erythromycins or related antibiotics, cimetidine, estrogens, or allopurinol. Consider use of safer drugs for obstructive lung diseases, such as albuterol or other inhaled medications.