Editing Theophylline (section)

==Adverse effects==
The use of theophylline is complicated by its interaction with various drugs and by the fact that it has a narrow [[therapeutic window]] (<20 mcg/mL).<ref name=barnes/> Its use must be monitored by direct measurement of serum theophylline levels to avoid [[toxicity]]. It can also cause nausea, diarrhea, increase in heart rate, [[Heart arrhythmia|abnormal heart rhythms]], and CNS excitation (headaches, [[insomnia]], irritability, [[dizziness]] and [[lightheadedness]]).<ref name=barnes/><ref>{{Cite web|url=https://medlineplus.gov/druginfo/meds/a681006.html|archive-url=https://web.archive.org/web/20160705111407/https://www.nlm.nih.gov/medlineplus/druginfo/meds/a681006.html |title=Theophylline | work = MedlinePlus Drug Information|archive-date=July 5, 2016| publisher = U.S. National Library of Medicine }}</ref> [[Seizure]]s can also occur in severe cases of toxicity, and are considered to be a neurological emergency.<ref name=barnes/> 

Its toxicity is increased by [[erythromycin]], cimetidine, and [[fluoroquinolones]], such as [[ciprofloxacin]]. Some lipid-based formulations of theophylline can result in toxic theophylline levels when taken with fatty meals, an effect called [[dose dumping]], but this does not occur with most formulations of theophylline.<ref>{{cite journal | vauthors = Hendeles L, Weinberger M, Milavetz G, Hill M, Vaughan L | title = Food-induced "dose-dumping" from a once-a-day theophylline product as a cause of theophylline toxicity | journal = Chest | volume = 87 | issue = 6 | pages = 758–765 | date = June 1985 | pmid = 3996063 | doi = 10.1378/chest.87.6.758 | s2cid = 1133968 }}</ref> Theophylline toxicity can be treated with [[beta blocker]]s. In addition to seizures, tachyarrhythmias are a major concern.<ref>{{cite journal | vauthors = Seneff M, Scott J, Friedman B, Smith M | title = Acute theophylline toxicity and the use of esmolol to reverse cardiovascular instability | journal = Annals of Emergency Medicine | volume = 19 | issue = 6 | pages = 671–673 | date = June 1990 | pmid = 1971502 | doi = 10.1016/s0196-0644(05)82474-6 }}</ref> Theophylline should not be used in combination with the [[Selective serotonin reuptake inhibitor|SSRI]] [[fluvoxamine]].<ref>{{cite journal | vauthors = DeVane CL, Markowitz JS, Hardesty SJ, Mundy S, Gill HS | title = Fluvoxamine-induced theophylline toxicity | journal = The American Journal of Psychiatry | volume = 154 | issue = 9 | pages = 1317–1318 | date = September 1997 | pmid = 9286199 | doi = 10.1176/ajp.154.9.1317b | doi-access =  }}</ref><ref>{{cite journal | vauthors = Sperber AD | title = Toxic interaction between fluvoxamine and sustained release theophylline in an 11-year-old boy | journal = Drug Safety | volume = 6 | issue = 6 | pages = 460–462 | date = November 1991 | pmid = 1793525 | doi = 10.2165/00002018-199106060-00006 | s2cid = 21875026 }}</ref>