Methylxanthines

Question 1

Mechanism of action

Answer 1

Bronchodilation through inhibition of PDE III and PDE IV

Question 2

Theophylline brand name

Answer 2

Theochron

Question 3

Theophylline dosage forms

Answer 3

ER 12 hour tablets
ER 24 hour tablets
ER 24 hour capsules
Liquid

Question 4

Theophylline age range

Answer 4

12 and up

Question 5

Theophylline AE and Clinical Pearls

Answer 5

AE: Insomnia, gastrointestinal upset, hyperactivity, hypotension, tremor
Dose related toxicity: tachycardia, nausea, vomiting, headache, seizures, arrhythmias
CI: peptic ulcer disease, arrthymias, seizure disorders
DI: Major substrate CYP 3A4, 1A2, 2E1
Increased concentration: cimetidine, erythromycin, clarithromycin, ciprofloxacin, ticlopidine
Decreased concentration: phenobarbital, phenytoin, carbamzepine, rifampin, smoking
PDE III inhibition likely cause for hypotension, tachycardia and nausea