Editing Theophylline (section)

====Excretion====
Theophylline is excreted unchanged in the urine (up to 10%). Clearance of the drug is increased in children (age 1 to 12), teenagers (12 to 16), adult smokers, elderly smokers, as well as in [[cystic fibrosis]], and [[hyperthyroidism]]. Clearance of the drug is decreased in these conditions: elderly, acute congestive heart failure, cirrhosis, hypothyroidism and febrile viral illnesses.<ref name=barnes/>

The elimination [[half-life]] varies: 30 hours for premature neonates, 24 hours for neonates, 3.5 hours for children ages 1 to 9, 8 hours for adult non-smokers, 5 hours for adult smokers, 24 hours for those with [[hepatic impairment]], 12 hours for those with congestive heart failure [[NYHA]] class I-II, 24 hours for those with congestive heart failure NYHA class III-IV, 12 hours for the elderly.{{medical citation needed|date=February 2022}}