Xanthines Basics
What are the three main xanthine agents used in respiratory therapy?
Theophylline, Caffeine, Dyphylline
What condition in neonates is treated with xanthines?
Apnea of Prematurity
Name two CNS effects of xanthines.
CNS stimulation, headache relief
What is the therapeutic serum range for theophylline in asthma?
5 to 15 µg/mL
What xanthine is preferred for treating apnea of prematurity?
Caffeine citrate
From which plant sources is theophylline derived?
Tea leaves
Why is sustained-release theophylline considered a second-line therapy for asthma?
Due to side effects and narrow therapeutic index
What cardiovascular effect makes xanthines useful in headache remedies?
Cerebral vasoconstriction
What serum level of theophylline is associated with seizures?
40 to 45 µg/mL
What is the loading dose of caffeine citrate?
20 mg/kg
What is the general classification of theophylline in terms of its effect on the airways?
Bronchodilator
What does GOLD recommend regarding the use of theophylline in COPD?
As an alternative to β2-agonists and anticholinergics
What is one proposed mechanism of action for xanthines?
Phosphodiesterase inhibition
What is the oral loading dose for rapid theophyllinization?
5 mg/kg of lean body weight
Why is caffeine more effective than theophylline in some infants?
More potent CNS stimulant
Why might caffeine citrate be preferred over theophylline in treating apnea of prematurity?
Safer, higher therapeutic index
Why might caffeine citrate be preferred over theophylline in treating apnea of prematurity?
Safer, higher therapeutic index
How does theophylline affect smooth muscle?
Relaxes bronchial, uterine, and vascular smooth muscle
Name two common side effects of theophylline.
Gastric upset, headache
What makes caffeine dosing more predictable than theophylline?
Simpler dosing regimens
What are the limitations of using xanthines in acute exacerbations of COPD?
Not recommended for acute exacerbations
What are the limitations of using xanthines in acute exacerbations of COPD?
Not recommended for acute exacerbations
What is the role of adenosine antagonism in xanthine activity?
Contributes to CNS and cardiac stimulation
What condition can decrease theophylline levels in the body?
Smoking
How does caffeine’s CNS stimulation compare to theophylline?
More potent stimulant