What is theophylline, and how does it work (mechanism of action)?
Theophylline belongs to a class of medications
called bronchodilators, used in treating
asthma
and other airway diseases.
Asthma
is a breathing problem caused by narrowing of the airways, the breathing
passages that allow air to move in and out of the lungs. Airways can be narrowed
due to accumulation of mucus, spasm of the muscles that surround these airways,
or swelling of the lining of the airways. Airway narrowing leads to symptoms of
shortness of breath, wheezing, cough, and congestion. The narrowed airways can
open either spontaneously or with medications. Medications that open airways are
called bronchodilators. Theophylline opens airways by relaxing the smooth
muscles in the walls of the airways. Theophylline also can be helpful in
patients with
emphysema and
chronic bronchitis when their symptoms are partially related to reversible
airway narrowing. Theophylline also strengthens right heart function and diaphragm movement. Theophylline was approved by the FDA in April 1979.
What brand names are available for theophylline?
Elixophyllin, Theo-24
Is theophylline available as a generic drug?
Yes
Do I need a prescription for theophylline?
Yes
What are the uses for theophylline?
Theophylline is used for the relief and prevention of airway
narrowing (bronchospasm) in patients with asthma. Theophylline also can be used
in treating patients with emphysema and chronic bronchitis when their symptoms
are related to reversible airway narrowing. Theophylline can be administered
together with other bronchodilators, such as albuterol (Ventolin, Proventil) for
added bronchodilator effect.
What are the side effects of theophylline?
Common side effects are:
- nausea,
- vomiting,
- diarrhea,
- headaches,
- irritability,
- flushing and
- palpitations.
Other important and more serious side effects include seizures and heart
arrhythmias. Theophylline should be used cautiously in patients with
high
blood pressure,
peptic
ulcer disease,
seizure
disorders, and serious
heart
disease, especially heart rhythm problems.
What is the dosage for theophylline?
Theophylline may be taken with or without food but should not be
crushed or chewed. High blood theophylline levels can lead to symptoms of
toxicity (see below). Therefore, theophylline blood levels are monitored
periodically during treatment to assure achievement of optimal and safe levels.
The initial dose is 300-600 mg once daily or as a divided dose for 3 days. The
maintenance dose is 400-600 mg daily.
Which drugs or supplements interact with theophylline?
Certain groups of patients breakdown theophylline slowly, and can develop elevated blood levels and potential toxicity even on normal doses. These patients include those with liver disease, older men with chronic lung diseases, infants, patients with high fever or heart failure, and patients taking other medications that increase blood theophylline levels.
Examples of medications that can elevate theophylline blood levels include ephedrine, allopurinol (Zyloprim), cimetidine (Tagamet), ciprofloxacin (Cipro), clarithromycin (Biaxin), itraconazole (Sporanox), ketoconazole, erythromycin, oral contraceptives, fluvoxamine (Luvox), and propranolol (Inderal).
Theophylline toxicity can cause nausea, vomiting, insomnia, seizures, agitation and life- threatening heart rhythm abnormalities. St. John's Wort, rifampin, and carbamazepine decrease levels of theophylline and potentially its effect by increasing its elimination. Theophylline may decrease levels and the effect of carbamazepine by increasing its elimination. Theophylline is metabolized mainly by the liver and dosages should be reduced in patients with liver dysfunction. On the other hand, theophylline is generally metabolized more rapidly in smokers (both tobacco and marijuana) and higher dosages may be required.
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Is theophylline safe to take if I’m pregnant or breastfeeding?
There are no adequate studies in pregnant women.
Theophylline is excreted in breast milk and may cause mild side effects such as irritability in the infant.
What else should I know about theophylline?
What preparations of theophylline are available?
Capsule (extended release): 100, 200, 300, and 400 mg
How should I keep theophylline stored?
Theophylline should be stored at room temperature, below 77 C F (25
C) in a tightly closed container.